Patent Publication Number: US-2023149623-A1

Title: Infusion pumps

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of application Ser. No. 16/397,582, filed Apr. 29, 2019, which is a continuation of application Ser. No. 14/578,996, filed Dec. 22, 2014, now U.S. Pat. No. 10,272,196, which is a continuation of application Ser. No. 12/890,135, filed Sep. 24, 2010, now U.S. Pat. No. 8,915,879, which is incorporated herein by reference in their entirety. 
    
    
     BACKGROUND 
     1. FIELD 
     The present devices and methods relate generally to ambulatory infusion pumps. 
     2. Description of the Related Art 
     Ambulatory infusion pumps (also referred to herein simply as “infusion pumps”) are relatively small, at least substantially self-contained devices that are used to introduce drugs and other infusible substances (collectively “medicament”) into patients&#39; bodies. Some infusion pumps are configured to be worn on a belt or carried in a clothing pocket. Other infusion pumps are configured to be adhered to skin in patch-like fashion. Infusion pumps are advantageous in that they may be used to, for example, subcutaneously introduce (or “infuse”) medicament on an ongoing or even continuous basis outside of a clinical environment. Infusion pumps are also advantageous in that they greatly reduce the frequency of subcutaneous access events such as needle-based shots. One example of a medicament that may be introduced by an infusion pump is a liquid formulation of insulin, which is a relatively large protein molecule used to treat diabetes mellitus. Other exemplary medicaments that may be introduced by an infusion pump include, but are not limited to, drugs that treat cancers and drugs that suppress the perception of pain. 
     Many conventional infusion pumps have improved patient health and quality of life. Nevertheless, the present inventors have determined that conventional infusion pumps are susceptible to a wide range of improvements. By way of example, but not limitation, the present inventors have determined that it would be desirable to provide an infusion pump that is smaller, more accurate and/or provides more operational flexibility than conventional infusion pumps. 
     SUMMARY 
     A medicament cartridge in accordance with at least one of the present inventions includes a medicament reservoir, that has a total filled volume, and a plunger movable to controllably dispense out of the reservoir an amount of medicament of 0.1% or less of the total filled volume and with a single-dose precision of better than plus or minus 20%. The reservoir may be defined by a cartridge barrel, and/or the precision may be obtained within a dispensing period of less than eight hours. The present inventions also include apparatus that comprise such a cartridge in combination with a pump assembly configured to drive fluid from the cartridge, such a cartridge in combination with a baseplate that can be attached to a pump assembly, and such a cartridge in combination with a cannula that may be in fluid communication with the reservoir, as such pump assemblies, baseplates and cannulas are described in the context of the examples herein, defined by the claims herein or known to those of skill in the art, as well as systems that comprise such a cartridge in combination with two or more of a pump assembly, a baseplate and a cannula. 
     A method in accordance with at least one of the present inventions includes pushing a plunger so as to controllably dispense out of a medicament reservoir an amount of medicament of 0.1% or less of the total filled volume of the reservoir and with a single-dose precision of better than plus or minus 20%. The precision may be obtained within a dispensing period of less than eight hours. 
     A medicament cartridge in accordance with at least one of the present inventions includes a barrel and a plunger. The barrel defines at least a substantial portion of a medicament reservoir having an inner surface and an outlet port. The plunger may be located within the barrel, include a plunger body having an outer surface with a pair of outer plunger-body rings that have tight tolerances with the inner surface of the barrel, a circumferential recessed area between plunger-body rings, and an o-ring structure, in the circumferential recessed area and compressed by an inner surface of the barrel, having a pair of spaced circumferential compressible rings. The present inventions also include apparatus that comprise such a cartridge in combination with a pump assembly configured to drive fluid from the cartridge, such a cartridge in combination with a baseplate that can be attached to a pump assembly, and such a cartridge in combination with a cannula that may be in fluid communication with the reservoir, as such pump assemblies, baseplates and cannulas are described in the context of the examples herein, defined by the claims herein or known to those of skill in the art, as well as systems that comprise such a cartridge in combination with two or more of a pump assembly, a baseplate and a cannula. 
     A medicament cartridge in accordance with at least one of the present inventions includes a barrel defining an inner diameter and a plunger movable over a stroke length. The stroke length to inner diameter ratio may be about 1.0 or less. The present inventions also include apparatus that comprise such a cartridge in combination with a pump assembly configured to drive fluid from the cartridge, such a cartridge in combination with a baseplate that can be attached to a pump assembly, and such a cartridge in combination with a cannula that may be in fluid communication with the reservoir, as such pump assemblies, baseplates and cannulas are described in the context of the examples herein, defined by the claims herein or known to those of skill in the art, as well as systems that comprise such a cartridge in combination with two or more of a pump assembly, a baseplate and a cannula. 
     A medicament cartridge in accordance with at least one of the present inventions includes a cartridge body defining a medicament reservoir and having an outlet port, a manifold, connected to the cartridge body, having a through-bore in fluid communication with the outlet port. The present inventions also include apparatus that comprise such a cartridge in combination with a pump assembly configured to drive fluid from the cartridge, such a cartridge in combination with a baseplate that can be attached to a pump assembly, and such a cartridge in combination with a cannula that may be in fluid communication with the reservoir, as such pump assemblies, baseplates and cannulas are described in the context of the examples herein, defined by the claims herein or known to those of skill in the art, as well as systems that comprise such a cartridge in combination with two or more of a pump assembly, a baseplate and a cannula. 
       100101  A system in accordance with at least one of the present inventions includes an infusion pump assembly, a medicament cartridge and a baseplate. The infusion pump assembly may include a housing, a cartridge receiving area in th e housing, and a plunger pusher. The medicament cartridge may include a plunger, a through-bore and a medicament reservoir having an outlet port. The baseplate may be configured to be attached to the housing. The infusion pump assembly and the medicament cartridge may be respectively configured such that plunger will be operably aligned with the plunger pusher when the medicament cartridge is positioned in the cartridge receiving area and the baseplate is attached to the housing. The present inventions also include the pump assembly, medicament cartridge and baseplate in the system on an individual basis, as well as any and all pairings thereof. 
     An infusion pump system in accordance with at least one of the present inventions includes a disposable first portion and a reusable second portion. The disposable first portion includes a medicament reservoir, medicament in the reservoir, and the entire medicament fluid path of the infusion pump system. The reusable second portion includes a motor and is free of any portion of the medicament fluid path. The disposable first portion and the reusable second portion may be respectively configured such that the reusable second portion is positionable in an operative position where operation of the motor causes the medicament to be dispensed out of the medicament reservoir. The present inventions also include the disposable and reusable portions of the system on an individual basis. 
     An apparatus in accordance with at least one of the present inventions includes a medicament cartridge with a barrel having a reservoir and a plunger, and an infusion pump assembly including a housing with a cartridge receiving area, a plunger pusher and a drive mechanism to drive the plunger pusher. The pusher may be unconnectable to the plunger and incapable of applying a pulling force to the plunger. The present inventions also include the pump assembly and medicament cartridge in the apparatus on an individual basis. The present inventions also include systems that comprise such an apparatus in combination with a baseplate and/or a cannula, as such baseplates and cannulas are described in the context of the examples herein, defined by the claims herein or known to those of skill in the art. 
     A medicament cartridge in accordance with at least one of the present inventions includes a barrel defining a reservoir and a plunger, located in the barrel, that does not include structure which would allow a pump assembly plunger pusher to pull the plunger. The present inventions also include apparatus that comprise such a cartridge in combination with a pump assembly configured to drive fluid from the cartridge, such a cartridge in combination with a baseplate that can be attached to a pump assembly, and such a cartridge in combination with a cannula that may be in fluid communication with the reservoir, as such pump assemblies, baseplates and cannulas are described in the context of the examples herein, defined by the claims herein or known to those of skill in the art, as well as systems that comprise such a cartridge in combination with two or more of a pump assembly, a baseplate and a cannula. 
     An infusion pump assembly in accordance with at least one of the present inventions includes a housing including a medicament cartridge storage area, a first face having a medicament cartridge insertion opening, a second face opposite the first face and having a cartridge observation opening, a fluid displacement device associated with the cartridge storage area, and a drive mechanism that drives the fluid displacement device. The present inventions also include apparatus that comprise such a pump assembly in combination with a medicament cartridge, such a pump assembly in combination with a baseplate that can be attached thereto, and such a pump assembly in combination with a cannula, as such cartridges, baseplates and cannulas are described in the context of the examples herein, defined by the claims herein or known to those of skill in the art, as well as systems that comprise such a pump assembly in combination with two or more of a medicament cartridge, a baseplate and a cannula. 
     An infusion pump assembly in accordance with at least one of the present inventions includes a pump housing having opposing first and second faces, a plunger pusher and a drive mechanism that moves the plunger pusher bi-directionally along an axis. The first face may have an insertion opening generally normal to the axis through which the medicament cartridge can be inserted into an inserted position. The present inventions also include apparatus that comprise such a pump assembly in combination with a medicament cartridge, such a pump assembly in combination with a baseplate that can be attached thereto, and such a pump assembly in combination with a cannula, as such cartridges, baseplates and cannulas are described in the context of the examples herein, defined by the claims herein or known to those of skill in the art, as well as systems that comprise such a pump assembly in combination with two or more of a medicament cartridge, a baseplate and a cannula. 
     An apparatus in accordance with at least one of the present inventions includes an infusion pump assembly and a baseplate. The infusion pump assembly may include a housing having opposing first and second faces, a plunger pusher, and a drive mechanism that moves the plunger pusher along an axis. The first face may have a medicament cartridge insertion opening through which the medicament cartridge can be inserted to an inserted position in the housing and operatively aligned with the plunger pusher. The baseplate may be attachable to the housing so as to at least partially cover the insertion opening with a cartridge in the inserted position. The present inventions also include the pump assembly and baseplate in the apparatus on an individual basis. The present inventions also include systems that comprise such an apparatus in combination with a medicament cartridge and/or a cannula, as such cartridges and cannulas are described in the context of the examples herein, defined by the claims herein or known to those of skill in the art. 
     A method in accordance with at least one of the present inventions includes the step of inserting a medicament cartridge, which has a medicament reservoir and a plunger, through a pump assembly housing insertion opening in a direction generally perpendicular to the drive axis of the pump assembly plunger pusher to an inserted position where the plunger is operatively aligned with the plunger pusher. 
     An infusion pump assembly in accordance with at least one of the present inventions includes a housing having a medicament cartridge insertion opening, a chassis defining a medicament cartridge compartment communicating with the insertion opening, and a plunger pusher movable in and out of the medicament cartridge compartment. The insertion opening may be generally normal to a longitudinal axis of the plunger pusher. The present inventions also include apparatus that comprise such a pump assembly in combination with a medicament cartridge having a plunger, such a pump assembly in combination with a baseplate that can be attached thereto, and such a pump assembly in combination with a cannula, as such cartridges, baseplates and cannulas are described in the context of the examples herein, defined by the claims herein or known to those of skill in the art, as well as systems that comprise such a pump assembly in combination with two or more of a medicament cartridge, a baseplate and a cannula. 
     An infusion pump apparatus in accordance with at least one of the present inventions includes an infusion pump assembly, with a housing and a plunger pusher, and a medicament cartridge. The medicament cartridge may be positionable in the housing in an inserted position and have a cartridge front wall with an outer surface, a medicament reservoir, and a plunger having a dry side. The infusion pump assembly may also have a clamp that clamps the reservoir between the dry side of the plunger and the outer surface of the cartridge front wall. The present inventions also include the pump assembly and medicament cartridge in the apparatus on an individual basis. The present inventions also include systems that comprise such an apparatus in combination with a baseplate and/or a cannula, as such baseplates and cannulas are described in the context of the examples herein, defined by the claims herein or known to those of skill in the art. 
     An infusion pump apparatus in accordance with at least one of the present inventions includes an infusion pump assembly, with a housing, and a medicament cartridge. The pump assembly housing may have a cartridge receiving area defining a forward corner. The medicament cartridge may have a reservoir and an unpowered part of an occlusion sensor. A powered part of the occlusion sensor may be positioned in the pump assembly housing, outside of the medicament cartridge and proximate to the forward corner of the cartridge receiving area. The infusion pump assembly may also include at least one resilient member positioned to bias the medicament cartridge when in the inserted position into the forward corner of the receiving area. The present inventions also include the pump assembly and medicament cartridge in the apparatus on an individual basis. The present inventions also include systems that comprise such an apparatus in combination with a baseplate and/or a cannula, as such baseplates and cannulas are described in the context of the examples herein, defined by the claims herein or known to those of skill in the art. 
     An infusion pump assembly in accordance with at least one of the present inventions includes a housing having therein a plunger pusher and a chassis. The chassis defines a forward area and a rear end, and may include first and second side frame members, attached together and forming a cartridge receiving compartment at the forward area of the chassis, and a gear cap attached with at least one fastener to at least one of the first and second side frame members at the rear end of the chassis. The present inventions also include apparatus that comprise such a pump assembly in combination with a medicament cartridge, such a pump assembly in combination with a baseplate that can be attached thereto, and such a pump assembly in combination with a cannula, as such cartridges, baseplates and cannulas are described in the context of the examples herein, defined by the claims herein or known to those of skill in the art, as well as systems that comprise such a pump assembly in combination with two or more of a medicament cartridge, a baseplate and a cannula. 
     An infusion pump assembly in accordance with at least one of the present inventions includes a housing with a cartridge insertion opening and a cartridge receiving area communicating with the insertion opening, a rigid wall securely mounted in the cartridge receiving area, a device that engages an aft end of a medicament cartridge and pushes the medicament cartridge against the rigid wall to a held position. A plunger pusher and a plunger pusher drive mechanism may be provided in the housing. The present inventions also include apparatus that comprise such a pump assembly in combination with a medicament cartridge, such a pump assembly in combination with a baseplate that can be attached thereto, and such a pump assembly in combination with a cannula, as such cartridges, baseplates and cannulas are described in the context of the examples herein, defined by the claims herein or known to those of skill in the art, as well as systems that comprise such a pump assembly in combination with two or more of a medicament cartridge, a baseplate and a cannula. 
     An infusion pump assembly in accordance with at least one of the present inventions includes a housing having a cartridge receiving area, a plunger pusher and a pusher drive mechanism, and a contact member biased forward so that an end thereof extends into the cartridge receiving area. The contact member, with a cartridge in the cartridge receiving area and the plunger pusher in a non-retracted position, may be blocked from rearward movement relative to the cartridge receiving area and thereby locking the cartridge in the cartridge receiving area. The contact member, with the plunger pusher in a retracted position, may be able to retract relative to the receiving area thereby allowing the cartridge to be inserted into or removed from the inserted position. The present inventions also include apparatus that comprise such a pump assembly in combination with a medicament cartridge, such a pump assembly in combination with a baseplate that can be attached thereto, and such a pump assembly in combination with a cannula, as such cartridges, baseplates and cannulas are described in the context of the examples herein, defined by the claims herein or known to those of skill in the art, as well as systems that comprise such a pump assembly in combination with two or more of a medicament cartridge, a baseplate and a cannula. 
     An infusion pump assembly in accordance with at least one of the present inventions includes a housing and an interlock. The housing may have a cartridge receiving area, a plunger pusher and a plunger drive mechanism. The interlock prevents removal of a medicament cartridge from the cartridge receiving area when the cartridge is in the inserted position and the plunger pusher is in a non-retracted position, and allows removal of the medicament cartridge from the cartridge receiving area when the cartridge is in the inserted position and the plunger pusher is a retracted position. The present inventions also include apparatus that comprise such a pump assembly in combination with a medicament cartridge, such a pump assembly in combination with a baseplate that can be attached thereto, and such a pump assembly in combination with a cannula, as such cartridges, baseplates and cannulas are described in the context of the examples herein, defined by the claims herein or known to those of skill in the art, as well as systems that comprise such a pump assembly in combination with two or more of a medicament cartridge, a baseplate and a cannula. 
     A method of operating a pump module in accordance with at least one of the present inventions includes the step of causing a cartridge biasing member to change from a blocking condition where the member blocks removal of a medicament cartridge from the pump module, to a release condition where the cartridge biasing member allows the medicament cartridge to be removed from the pump module, in response to a receipt of an instruction from a remote control. 
     An infusion pump assembly in accordance with at least one of the present inventions includes a housing with a medicament cartridge receiving area, a plunger pusher located in the housing and movable in and out of the cartridge receiving area, and a slidable latch movable between a first position that does not prevent a medicament cartridge from being inserted into and removed from the cartridge receiving area and a second position, when at least a portion of the pusher is in the cartridge receiving area, that prevents removal of the medicament cartridge from the cartridge receiving area. The present inventions also include apparatus that comprise such a pump assembly in combination with a medicament cartridge, such a pump assembly in combination with a baseplate that can be attached thereto, and such a pump assembly in combination with a cannula, as such cartridges, baseplates and cannulas are described in the context of the examples herein, defined by the claims herein or known to those of skill in the art, as well as systems that comprise such a pump assembly in combination with two or more of a medicament cartridge, a baseplate and a cannula. 
     An infusion pump assembly in accordance with at least one of the present inventions includes a housing with a medicament cartridge receiving area, a plunger pusher located in the housing and movable between a home position outside the cartridge receiving area and a position within the cartridge receiving area, a drive mechanism, including a motor, operatively connected to the plunger pusher, and a switch. The switch may be located relative to the plunger pusher such that the switch is actuated when the plunger pusher is retracted, from a position where at least a portion of the plunger pusher is within the cartridge receiving area, to a home position. The present inventions also include apparatus that comprise such a pump assembly in combination with a medicament cartridge, such a pump assembly in combination with a baseplate that can be attached thereto, and such a pump assembly in combination with a cannula, as such cartridges, baseplates and cannulas are described in the context of the examples herein, defined by the claims herein or known to those of skill in the art, as well as systems that comprise such a pump assembly in combination with two or more of a medicament cartridge, a baseplate and a cannula. 
     An infusion pump assembly in accordance with at least one of the present inventions includes a housing having a cartridge receiving area, a plunger pusher movable in and out of the cartridge receiving area, a pusher drive mechanism including a motor and a controller. The controller may be configured to automatically cause the motor to withdraw the plunger pusher out of the cartridge receiving area (a) after receiving a signal from the encoder indicating that a predetermined number of rotation counts of the motor, which indicate that the reservoir is empty, have occurred or (b) when there is a lack of encoder signals. The present inventions also include apparatus that comprise such a pump assembly in combination with a medicament cartridge, such a pump assembly in combination with a baseplate that can be attached thereto, and such a pump assembly in combination with a cannula, as such cartridges, baseplates and cannulas are described in the context of the examples herein, defined by the claims herein or known to those of skill in the art, as well as systems that comprise such a pump assembly in combination with two or more of a medicament cartridge, a baseplate and a cannula. 
     An apparatus in accordance with at least one of the present inventions includes a medicament cartridge and an infusion pump assembly. The medicament cartridge may have a reservoir and a plunger. The infusion pump assembly may include a housing having a cartridge receiving compartment and a plunger pusher defining a longitudinal axis. The plunger pusher may be movable from a home position allowing the medicament cartridge to be inserted into and removed from the cartridge receiving compartment in a direction generally perpendicular to the longitudinal axis of the plunger pusher and another position wherein at least a portion of the plunger pusher is in the medicament cartridge. The present inventions also include the pump assembly and medicament cartridge in the apparatus on an individual basis. The present inventions also include systems that comprise such an apparatus in combination with a baseplate and/or a cannula, as such baseplates and cannulas are described in the context of the examples herein, defined by the claims herein or known to those of skill in the art. 
       100301  An apparatus in accordance with at least one of the present inventions includes an infusion pump assembly, a medicament cartridge and a latch assembly. The infusion pump assembly may include a housing and a plunger pusher that moves the plunger pusher along a pusher axis. The medicament cartridge may include a barrel, defining a medicament reservoir, and a plunger in the barrel, and be positioned in the housing such that the plunger pusher is positioned to push the plunger. The latch assembly may be configured to block removal of the medicament cartridge from the housing in a direction orthogonal to the pusher axis when at least a portion of the pusher is within the cartridge. The present inventions also include the pump assembly, medicament cartridge and latch assembly in the apparatus on an individual basis. The present inventions also include systems that comprise such an apparatus in combination with a baseplate and/or a cannula, as such baseplates and cannulas are described in the context of the examples herein, defined by the claims herein or known to those of skill in the art. 
     An apparatus in accordance with at least one of the present inventions includes an infusion pump assembly with a housing having a cartridge receiving area, a baseplate that is attachable to the housing and has an opening and bottom surface adhesive, a movable member, and an alarm. The movable member may be pushed to a first position by the user&#39;s skin when the baseplate is adhered to the user&#39;s skin by the adhesive and may be biased to a second position extended out the opening in the baseplate when the baseplate is separated from the user&#39;s skin after attachment thereto. The alarm may be activated in response to the movable member moving to the second position. The present inventions also include the various components in the apparatus on an individual basis, as well as any and all combinations thereof. The present inventions also include systems that comprise such an apparatus in combination with a medicament cartridge and/or a cannula, as such cartridges and cannulas are described in the context of the examples herein, defined by the claims herein or known to those of skill in the art. 
     An apparatus in accordance with at least one of the present inventions includes an infusion pump assembly with a housing having a cartridge receiving area, a controller, an alarm, a baseplate that is attachable to the housing and has bottom surface adhesive, and an RF circuit. The RF circuit may include a transmitting antenna and a receiving antenna, and be configured to send a signal to the controller, indicating that the baseplate has become separated from the user&#39;s skin. The controller may activate the alarm in response. The present inventions also include the various components in the apparatus on an individual basis, as well as any and all combinations thereof. The present inventions also include systems that comprise such an apparatus in combination with a medicament cartridge and/or a cannula, as such cartridges and cannulas are described in the context of the examples herein, defined by the claims herein or known to those of skill in the art. 
     An apparatus in accordance with at least one of the present inventions includes an infusion pump assembly with a housing having a cartridge receiving area, a controller, an alarm, a baseplate that is attachable to the housing and has bottom surface adhesive, and an electrical circuit. The electrical circuit may include a first terminal and a second terminal spaced from the first terminal, be configured to be completed between the first and second terminals by the user&#39;s skin when the baseplate is adhered to the skin by the adhesive, to be broken when the baseplate becomes separated from the user&#39;s skin, and to send a signal to the controller when the baseplate has become separated from the user&#39;s skin. The controller may activate the alarm in response. The present inventions also include the various components in the apparatus on an individual basis, as well as any and all combinations thereof. The present inventions also include systems that comprise such an apparatus in combination with a medicament cartridge and/or a cannula, as such cartridges and cannulas are described in the context of the examples herein, defined by the claims herein or known to those of skill in the art. 
     An infusion pump assembly in accordance with at least one of the present inventions includes a housing having a cartridge compartment, a fluid displacement device, and a rechargeable battery, adapted to drive the fluid displacement device, mounted in the housing outside of the cartridge compartment. The present inventions also include apparatus that comprise such a pump assembly in combination with a medicament cartridge, such a pump assembly in combination with a baseplate that can be attached thereto, and such a pump assembly in combination with a cannula, as such cartridges, baseplates and cannulas are described in the context of the examples herein, defined by the claims herein or known to those of skill in the art, as well as systems that comprise such a pump assembly in combination with two or more of a medicament cartridge, a baseplate and a cannula. 
     A method in accordance with at least one of the present inventions may include the steps of removing, from an assembled device that includes an infusion pump assembly with a medicament cartridge therein and a baseplate secured to the pump assembly housing, the pump assembly housing from the baseplate, connecting the recharging terminals on the pump assembly to a recharging device, and recharging the rechargeable battery in the housing. 
     A system in accordance with at least one of the present inventions includes a baseplate, a cannula, a pump assembly, a battery recharging unit, and a controller. The pump assembly may include a housing, a medicament reservoir, a fluid displacement device, and a rechargeable battery for the fluid displacement device in the housing. The housing may be separable from the baseplate and cannula with the cannula remaining secured to and extending out from the baseplate such that the housing is in a separate condition. The housing, in the separate condition, may be operatively connected to the battery recharging unit such that the recharging of the battery by the recharging unit is controlled by the controller. The present inventions also include the various components in the system on an individual basis, as well as any and all combinations thereof. 
     An infusion pump assembly in accordance with at least one of the present inventions includes a housing with a cartridge receiving area, a plunger pusher, a stepper motor, having a shaft and coils, operatively connected to the plunger pusher, an encoder, operably connected to the motor shaft, that generates encoder output representative of shaft position, a battery operatively connected to the motor, an analog-to-digital (A/D) converter that generates A/D converter output that is a digital representation of battery voltage, and a controller. The controller may (a) operate through a driver circuit to control the operation of the motor and to pulse-width modulate energy from the battery applied to the motor coils, (b) read the encoder output and (c) read the A/D converter output. The present inventions also include apparatus that comprise such a pump assembly in combination with a medicament cartridge, such a pump assembly in combination with a baseplate that can be attached thereto, and such a pump assembly in combination with a cannula, as such cartridges, baseplates and cannulas are described in the context of the examples herein, defined by the claims herein or known to those of skill in the art, as well as systems that comprise such a pump assembly in combination with two or more of a medicament cartridge, a baseplate and a cannula. 
     An infusion pump assembly in accordance with at least one of the present inventions includes a housing, having a medicament cartridge receiving area, a fluid displacement device, a drive mechanism that drives the fluid displacement device, a receiving area sensor that senses when the cartridge sensor element is in a predetermined location within the cartridge receiving area, and a controller operably connected to the sensor and drive mechanism. The controller may be configured to prevent the drive mechanism from driving the fluid displacement device unless the receiving area sensor senses that the cartridge sensor element is in the predetermined location. The present inventions also include apparatus that comprise such a pump assembly in combination with a medicament cartridge, such a pump assembly in combination with a baseplate that can be attached thereto, and such a pump assembly in combination with a cannula, as such cartridges, baseplates and cannulas are described in the context of the examples herein, defined by the claims herein or known to those of skill in the art, as well as systems that comprise such a pump assembly in combination with two or more of a medicament cartridge, a baseplate and a cannula. 
     An infusion pump assembly in accordance with at least one of the present inventions includes a housing, a plunger pusher, a medicament reservoir, a plunger, a drive mechanism that drives the plunger pusher and has a stepper motor and an encoder, and a controller. The controller may be configured to cause the motor to propel the pusher against the plunger according to a medicament dispensing program having a plurality of dispensing operations and to, for at least one of the dispensing operations, cause the motor to stop from a pusher propelling velocity by slowly decreasing the frequency of the waveform delivered to the motor to maintain constant positive control of the motor and thereby to precisely control how many turns the motor makes and thus the precise distance the pusher advances before stopping. Such precise distance control results in accurate controlled medicament dispensing from the reservoir. The present inventions also include systems that comprise such an apparatus in combination with a baseplate and/or a cannula, as such baseplates and cannulas are described in the context of the examples herein, defined by the claims herein or known to those of skill in the art. 
     A method in accordance with at least one of the present inventions includes the steps of propelling a plunger pusher relative to the plunger of a medicament cartridge with a motor, and controlling motor torque such that the torque is continuously within a range having a lower limit that is sufficient to overcome stiction of the cartridge plunger and move the plunger and an upper limit that is low enough so as to not cause leakage past plunger seals due to excessive pressure in the cartridge reservoir. 
     A system in accordance with at least one of the present inventions includes a medicament cartridge, an infusion pump assembly, a baseplate, and a cannula. The medicament cartridge may have a medicament reservoir and a manifold connected to the medicament reservoir and having a through-bore. The infusion pump assembly may be configured to receive the medicament cartridge. The baseplate may have a baseplate opening and bottom surface adhesive, and be configured to be secured to the infusion pump assembly. The cannula may be dimensioned to be inserted through the through-bore and the baseplate opening, when the medicament cartridge in place in the infusion pump assembly and the baseplate attached to the infusion pump assembly, to an inserted position. The baseplate and the cannula may be respectively configured such that the baseplate and the cannula will be secured to one another when the cannula reaches the inserted position and will remain secured to one another when the infusion pump assembly is subsequently removed from the baseplate. The present inventions also include the pump assembly, medicament cartridge, baseplate and cannula in the system on an individual basis, as well as any and all pairings thereof. 
     A system in accordance with at least one of the present inventions includes a medicament cartridge having a reservoir and a manifold through-bore, a pump assembly including a medicament cartridge receiving area, a bottom surface, and a bottom surface opening, and a baseplate, having a baseplate opening, configured to be secured to the pump assembly. The medicament cartridge, pump assembly and baseplate may be respectively configured such that when the baseplate is secured to the pump assembly with the medicament cartridge in the cartridge receiving area, the baseplate will be over the bottom surface opening and the baseplate opening will be aligned with the manifold through-bore. The cannula may be dimensioned to be inserted into the manifold through-bore and the baseplate opening. The present inventions also include the pump assembly, medicament cartridge, baseplate and cannula in the system on an individual basis, as well as any and all pairings thereof. 
     An infusion pump cannula in accordance with at least one of the present inventions includes a cannula head having a bottom opening, a side opening, a medicament fluid path between the side and bottom openings, an upper sealing device above the side opening and a lower sealing device below the side opening, and a cannula tube connected to the cannula head and in fluid communication with the medicament fluid path. The cannula head and/or the cannula may be configured to secure the infusion pump cannula to the opening in an infusion pump baseplate. The present inventions also include apparatus that comprise such a cannula in combination with a pump assembly configured to drive fluid from a cartridge, such a cannula in combination with a baseplate that can be attached to a pump assembly, and such a cannula in combination with a cartridge, as such pump assemblies, baseplates and cartridges are described in the context of the examples herein, defined by the claims herein or known to those of skill in the art, as well as systems that comprise such a cannula in combination with two or more of a pump assembly, a baseplate and a cartridge. 
     An apparatus in accordance with at least one of the present inventions includes an infusion pump assembly and a baseplate. The infusion pump assembly may include a housing having a cartridge receiving area, a bottom opening, and housing electrical contacts. The infusion pump assembly may also include a fluid displacement device, a drive mechanism that drives the fluid displacement device, and a slidable latch associated with the housing. The slidable latch may be movable between a unlatched position that does not prevent the medicament cartridge from being inserted into and removed from the cartridge receiving area and a latched position that prevents removal of the medicament cartridge from the cartridge receiving area, and have a protruding portion. The baseplate may be configured to at least partially cover the housing bottom opening, and may have an upper surface, a recessed area on the upper surface, and baseplate electrical contacts. The infusion pump assembly and baseplate may be respectively configured such that (1) the baseplate and housing may be attachable to one another with the baseplate electrical contacts in electrical contact with the housing electrical contacts and (2) the baseplate and housing can only be attached to one another when the slidable latch is in the latched position and the protruding portion mates with the recessed area. The present inventions also include the pump assembly and baseplate in the apparatus on an individual basis. The present inventions also include systems that comprise such an apparatus in combination with a medicament cartridge and/or a cannula, as such cartridges and cannulas are described in the context of the examples herein, defined by the claims herein or known to those of skill in the art. 
     An apparatus in accordance with at least one of the present inventions includes an infusion pump assembly and a baseplate. The infusion pump assembly may include a housing having a medicament cartridge receiving area, a fluid displacement device in the housing, and a drive mechanism operably connected to the fluid displacement device. The baseplate may be attachable to the housing, define a bottom surface and a cannula opening, and include a first adhesive on the bottom surface adjacent to an opening for a cannula and a second adhesive on the bottom surface and spaced a distance away from the opening, the first adhesive being an adhesive that adheres more aggressively to human skin than the second adhesive. The present inventions also include the pump assembly and baseplate in the apparatus on an individual basis. The present inventions also include systems that comprise such an apparatus in combination with a medicament cartridge and/or a cannula, as such cartridges and cannulas are described in the context of the examples herein, defined by the claims herein or known to those of skill in the art. 
     An apparatus in accordance with at least one of the present inventions includes an infusion pump assembly and a baseplate. The infusion pump assembly may include a housing, having a cartridge receiving area, a fluid displacement device, and a fluid displacement device drive mechanism. The baseplate may include a plate member having a top opening, an edge opening and a baseplate fluid path between the top opening and the edge opening, a tubing at the edge opening and communicating with an end of the fluid path, and a connector having an opening in the cartridge receiving area that defines at least a portion of a fluid path between the cartridge receiving area and the baseplate fluid path. The present inventions also include the pump assembly and baseplate in the apparatus on an individual basis. The present inventions also include systems that comprise such an apparatus in combination with a medicament cartridge and/or a cannula, as such cartridges and cannulas are described in the context of the examples herein, defined by the claims herein or known to those of skill in the art. 
     A method in accordance with at least one of the present inventions includes making a baseplate type determination with the controller based on the baseplate identification device and controlling the fluid displacement device with the controller based at least in part on the determined baseplate type. 
     A system in accordance with at least one of the present inventions includes a housing, a fluid displacement device and drive mechanism in the housing, a rechargeable battery in the housing and adapted to power the drive mechanism, a pair of contacts operatively connected to the rechargeable battery and supported by the housing, and a controller. The controller may determine from a detected resistor value whether the pair of contacts is operatively connected to terminals of a first baseplate having a first resistor value or to terminals of a second baseplate having a second resistor value. The controller may also operate the drive mechanism in a first mode associated with the first baseplate in response to a first baseplate determination and operate the drive mechanism is a second mode associated with the second baseplate in response to a second baseplate determination. The present inventions also include systems that also include a medicament cartridge and/or a cannula, as such cartridges and cannulas are described in the context of the examples herein, defined by the claims herein or known to those of skill in the art. 
     A kit in accordance with at least one of the present inventions includes a first baseplate, a second baseplate, and an infusion pump assembly. The first baseplate may have a first baseplate pattern of targets, and the second baseplate may have a second baseplate pattern of targets that is different than the first pattern. The infusion pump assembly may include an emitter/detector configured to detect the first and second baseplate patterns and a controller configured to determine, based on a detected baseplate pattern, which of the first and second baseplates is attached to the housing. The controller may also be configured to operate in a first mode when the first baseplate is attached to the housing, and to operate in a second mode, which is different than the first mode, when the second baseplate is attached to the housing. The targets may be, in some implementations, reflective and/or occluded targets. The present inventions also include the pump assembly and baseplate sets of the kit on an individual basis. The present inventions also include a kit that comprises a baseplate set and a medicament cartridge. The present inventions also include systems that comprise such a kit in combination with a medicament cartridge and/or a cannula, as such cartridges and cannulas are described in the context of the examples herein, defined by the claims herein or known to those of skill in the art. 
     A kit in accordance with at least one of the present inventions includes a first baseplate, a second baseplate, and an infusion pump assembly. The first baseplate may have a first baseplate identification device, and the second baseplate may have a second baseplate identification device. The infusion pump assembly may include a connector assembly that operatively connects to an identification device on a baseplate that is secured to the housing. The controller may be configured to determine, based on a detected baseplate identification device, which one of the first and second baseplates is attached to the housing. The present inventions also include the pump assembly and baseplate sets of the kit on an individual basis. The present inventions also include a kit that comprises a baseplate set and a medicament cartridge. The present inventions also include systems that comprise such a kit in combination with a medicament cartridge and/or a cannula, as such cartridges and cannulas are described in the context of the examples herein, defined by the claims herein or known to those of skill in the art. 
     A system in accordance with at least one of the present inventions includes a medicament cartridge, an infusion pump assembly, a baseplate, and a cannula. The medicament cartridge, infusion pump assembly, baseplate and cannula may be respectively configured such that, when the medicament cartridge is in the pump assembly cartridge receiving area and the baseplate is attached to the pump assembly housing, the cannula can be inserted through a cartridge through-bore and a baseplate opening and connected to the baseplate, thereby defining a baseplate-cartridge-cannula unit. The medicament cartridge, infusion pump assembly, baseplate and cannula may also be configured such that, when the pump assembly pusher is in the home position and a latch is in the non-blocking position, the infusion pump assembly is separable from the baseplate-cartridge-cannula unit. The present inventions also include the pump assembly, medicament cartridge and baseplate in the system on an individual basis, as well as any and all pairings thereof. 
     A method in accordance with at least one of the present inventions includes the step of arranging a medicament cartridge, infusion pump assembly, baseplate and cannula into an assembled system where at least the medicament cartridge and the cannula define a medicament dispensing flow path unit, and removing the infusion pump assembly from the medicament dispensing flow path unit. 
     An apparatus in accordance with at least one of the present inventions includes a medicament cartridge and an infusion pump assembly. The medicament cartridge may include a medicament reservoir, a plunger and an outlet port. The infusion pump assembly may include a housing having a cartridge receiving area, a plunger pusher, a drive mechanism, that drives the plunger pusher and has a motor, a lead screw, a gear assembly operatively positioned between the motor and the lead screw, and an encoder, and a controller. The medicament cartridge may be insertable through an opening in the housing and into the cartridge receiving area to an inserted position where the plunger is proximate to but spaced from the plunger pusher. The controller may be configured to execute, with the medicament cartridge in the inserted position, a plunger pusher zeroing procedure including causing the motor to advance the plunger pusher to contact the plunger and then to back the plunger pusher off a predetermined distance from the plunger. The present inventions also include the pump assembly and medicament cartridge in the apparatus on an individual basis. The present inventions also include systems that comprise such an apparatus in combination with a baseplate and/or a cannula, as such baseplates and cannulas are described in the context of the examples herein, defined by the claims herein or known to those of skill in the art. 
     An apparatus in accordance with at least one of the present inventions includes a medicament cartridge and an infusion pump assembly. The medicament cartridge may include a medicament reservoir, a plunger, an outlet port, a removable seal positioned at the outlet port, The infusion pump assembly may include a housing with a cartridge receiving area, a plunger pusher, and a drive mechanism. The medicament cartridge may be inserted through an opening in the housing with the seal in a sealed position and into the cartridge receiving area to an inserted position where the plunger proximate to but spaced a small distance from the plunger pusher. The present inventions also include the pump assembly and medicament cartridge in the apparatus on an individual basis. The present inventions also include systems that comprise such an apparatus in combination with a baseplate and/or a cannula, as such baseplates and cannulas are described in the context of the examples herein, defined by the claims herein or known to those of skill in the art. 
     An infusion pump method in accordance with at least one of the present inventions, which may be associated with an infusion pump assembly including a plunger pusher and a medicament cartridge including a reservoir and a plunger that has a dry side and an outlet port, includes the steps of propelling the plunger pusher such that the plunger pusher contacts the dry side of a plunger while the plunger outlet port is sealed and, in response to sensing that the plunger pusher has contacted the plunger, reversing the drive direction of the motor to withdraw the plunger pusher a predetermined distance from the dry side of the plunger as part of a plunger pusher zeroing procedure. 
     An infusion pump assembly in accordance with at least one of the present inventions includes a housing, having a cartridge receiving area, a plunger pusher, a motor to drive the plunger pusher, an encoder associated with the motor, and a controller. The controller may be configured to control the operation of the motor and to adjust a medicament dispensing program to compensate for the amount of reverse rotation of the motor that occurs when electrical power is not being delivered to the motor and the controller receives a signal from the encoder that the controller interprets as a reverse motor rotation signal. The present inventions also include apparatus that comprise such a pump assembly in combination with a medicament cartridge, such a pump assembly in combination with a baseplate that can be attached thereto, and such a pump assembly in combination with a cannula, as such cartridges, baseplates and cannulas are described in the context of the examples herein, defined by the claims herein or known to those of skill in the art, as well as systems that comprise such a pump assembly in combination with two or more of a medicament cartridge, a baseplate and a cannula. 
     An infusion pump assembly in accordance with at least one of the present inventions includes a housing, a plunger pusher, a drive mechanism, with a motor and an encoder, to drive the plunger pusher, and a controller. The controller may store a medicament dispensing program and be configured to determine from signals from the encoder, when the motor is not being electrically driven, whether the motor is rotating in reverse and to adjust the medicament dispensing program to take into account the amount of reverse rotation. The present inventions also include apparatus that comprise such a pump assembly in combination with a medicament cartridge, such a pump assembly in combination with a baseplate that can be attached thereto, and such a pump assembly in combination with a cannula, as such cartridges, baseplates and cannulas are described in the context of the examples herein, defined by the claims herein or known to those of skill in the art, as well as systems that comprise such a pump assembly in combination with two or more of a medicament cartridge, a baseplate and a cannula. 
     An infusion pump assembly in accordance with at least one of the present inventions includes a housing having a cartridge receiving area, a plunger pusher, a drive mechanism, with a motor and a gear assembly, that drives the plunger pusher, and a controller. The controller may be configured to detect operation errors of the motor and/or gear assembly and/or to detect reverse turning of the motor when not receiving electrical power. The present inventions also include apparatus that comprise such a pump assembly in combination with a medicament cartridge, such a pump assembly in combination with a baseplate that can be attached thereto, and such a pump assembly in combination with a cannula, as such cartridges, baseplates and cannulas are described in the context of the examples herein, defined by the claims herein or known to those of skill in the art, as well as systems that comprise such a pump assembly in combination with two or more of a medicament cartridge, a baseplate and a cannula. 
     A method in accordance with at least one of the present inventions includes the steps of dispensing medicament from an infusion pump assembly reservoir in accordance with a medicament dispensing program and adjusting the medicament dispensing program to compensate for an amount of reverse rotation of the infusion pump assembly motor that occurs when electrical power is not being delivered to the motor. 
     An infusion pump assembly in accordance with at least one of the present inventions includes a housing, having cartridge receiving area, a plunger pusher, a pusher drive mechanism with a motor, a lead screw, a gear assembly operatively between the lead screw and the motor, and an encoder, and a controller operably connected to the motor. The controller may be configured to (1) cause the motor to be powered at a predetermined dispensing torque level and (2) determine that the gear assembly is not operating properly, when the cartridge is not in the receiving area, in response to receipt of at least one signal from the encoder indicating that the motor is turning when the motor is being powered to run at a low torque level that is below the predetermined dispensing torque level. The present inventions also include apparatus that comprise such a pump assembly in combination with a medicament cartridge, such a pump assembly in combination with a baseplate that can be attached thereto, and such a pump assembly in combination with a cannula, as such cartridges, baseplates and cannulas are described in the context of the examples herein, defined by the claims herein or known to those of skill in the art, as well as systems that comprise such a pump assembly in combination with two or more of a medicament cartridge, a baseplate and a cannula. 
     An infusion pump assembly in accordance with at least one of the present inventions includes a housing, having a cartridge receiving area, a plunger pusher, a drive mechanism, including a motor, that drives the plunger pusher, and a controller that controls the operation of the motor. The controller may be configured to automatically withdraw the pusher to a home position in response to a receipt of a signal indicating that the medicament reservoir is empty. The present inventions also include apparatus that comprise such a pump assembly in combination with a medicament cartridge, such a pump assembly in combination with a baseplate that can be attached thereto, and such a pump assembly in combination with a cannula, as such cartridges, baseplates and cannulas are described in the context of the examples herein, defined by the claims herein or known to those of skill in the art, as well as systems that comprise such a pump assembly in combination with two or more of a medicament cartridge, a baseplate and a cannula. 
     A method in accordance with at least one of the present inventions includes the steps of pushing the plunger of a medicament cartridge located in an infusion pump assembly with a plunger pusher such that a portion of the plunger pusher is within the medicament cartridge, and withdrawing the plunger pusher from within the medicament cartridge, without instruction from the user to do so, in response to a determination by the infusion pump assembly that the medicament cartridge is empty. 
       100631  An infusion pump assembly in accordance with at least one of the present inventions includes a housing configured to receive a medicament cartridge, a plunger pusher, a pusher drive mechanism with a motor, a lead screw, a gear assembly, and an encoder, and a controller. The controller may be configured to execute a gear assembly verification procedure including the following procedure parts: (a) delivering motor driving sequence of pulses to the motor instructing torque to be applied in a rewind direction to the motor at less than 70% of a torque applied for normal delivery in a forward direction and thereby rotating the motor, (b) determining that the gear assembly is not operating properly if signals from the encoder indicate that the motor is approximately synchronized with the motor driving sequence of pulses, and (c) determining that the gear assembly is operating properly if signals from the encoder indicate that the motor is not synchronized with the motor driving sequence of pulses. The present inventions also include apparatus that comprise such a pump assembly in combination with a medicament cartridge, such a pump assembly in combination with a baseplate that can be attached thereto, and such a pump assembly in combination with a cannula, as such cartridges, baseplates and cannulas are described in the context of the examples herein, defined by the claims herein or known to those of skill in the art, as well as systems that comprise such a pump assembly in combination with two or more of a medicament cartridge, a baseplate and a cannula. 
     An infusion pump assembly in accordance with at least one of the present inventions includes a housing, a plunger pusher, a drive mechanism and alarm. The pump assembly may be configured such that the alarm will be activated when one, all, or any combination of less than all of the following conditions is met: (1) no baseplate is attached to the housing, (2) a baseplate attached to the housing becomes separated from the skin of a user, (3) the plunger pusher does not contact the dry side of a reservoir plunger after advancing a predetermined distance or a range of predetermined distances corresponding to an expected location of the dry side of the plunger in a pusher zeroing procedure, (4) a temperature in the housing exceeds a predetermined temperature, (5) motor current is too low, and (6) the battery has a charging fault. The present inventions also include apparatus that comprise such a pump assembly in combination with a medicament cartridge, such a pump assembly in combination with a baseplate that can be attached thereto, and such a pump assembly in combination with a cannula, as such cartridges, baseplates and cannulas are described in the context of the examples herein, defined by the claims herein or known to those of skill in the art, as well as systems that comprise such a pump assembly in combination with two or more of a medicament cartridge, a baseplate and a cannula. 
     An apparatus in accordance with at least one of the present inventions includes an infusion pump assembly and a remote control. The infusion pump assembly may include a controller that stores medicament dispensing program information, determines time remaining in the dispensing program based at least in part on the medicament dispensing program information and encoder signals, and generates a time remaining signal. Alternatively, or in addition, the controller may be configured to determine the amount of time remaining until the pump assembly battery will require recharging and generate a time remaining signal. The remote control may include a user interface, be operably connected to the pump assembly controller, and be configured to generate an indicator detectable by a user which indicates the time remaining in the medicament dispensing program and/or the time remaining until the pump assembly battery will require recharging. The present inventions also include the pump assembly and remote control in the apparatus on an individual basis. The present inventions also include systems that comprise such an apparatus in combination with a medicament cartridge and/or a cannula and/or a baseplate, as such cartridges, cannulas and baseplates are described in the context of the examples herein, defined by the claims herein or known to those of skill in the art. 
     A method in accordance with at least one of the present inventions includes the steps of learning from a remote control the amount of time remaining in a subcutaneous dispensing program and/or time remaining until a pump assembly battery will require recharging, determining whether or not removing a medicament cartridge from the associated infusion pump and replacing the removed medicament cartridge with a new medicament cartridge at the end of the time remaining would be convenient or inconvenient and/or determining whether or not recharging the pump assembly battery at the end of the time remaining would be convenient or inconvenient, and replacing the medicament cartridge before the medicament cartridge is empty and/or recharging the pump assembly battery before it requires recharging in response to a determination that replacement at the end of the time remaining would be inconvenient. 
     The features and attendant advantages of the present inventions will become apparent as the inventions become better understood by reference to the following detailed description when considered in conjunction with the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Detailed description of exemplary embodiments will be made with reference to the accompanying drawings. 
         FIG.  1    is an exploded perspective view of an exemplary infusion pump kit including an infusion pump system, with an infusion pump assembly, a medicament cartridge, and a baseplate, a cannula and two additional baseplates. 
         FIG.  1 A  is a schematic view showing use of an exemplary infusion pump system. 
         FIG.  1 B  is a schematic view showing use of an exemplary infusion pump system. 
         FIG.  2    is a precision graph showing dispensing performance. 
         FIG.  3    is an exploded perspective view of an exemplary medicament cartridge. 
         FIG.  3 A  is an end view of the interior of an exemplary medicament cartridge. 
         FIG.  4    is a section view taken along line  4 - 4  in  FIG.  3   . 
         FIG.  5    is an exploded perspective view of the cartridge portion of a pressure sensor. 
         FIG.  6    is a section view of the cartridge portion of another exemplary pressure sensor. 
         FIG.  7    is a schematic block diagram of another exemplary pressure sensor. 
         FIG.  8    is a schematic block diagram of another exemplary pressure sensor. 
         FIG.  9    is a perspective view of a portion of the plunger in the exemplary medicament cartridge illustrated in  FIG.  3   . 
         FIG.  10    is a perspective view of the body portion of the plunger illustrated in  FIG.  9   . 
         FIG.  11    is a perspective view of the seal portion of the plunger illustrated in  FIG.  9   . 
         FIG.  12    is a section view of the plunger illustrated in  FIG.  3   . 
         FIG.  13    is a section view of another exemplary plunger. 
         FIG.  14    is a simplified view of medicament cartridge with a removal tab. 
         FIG.  15    is a perspective view of an exemplary pump assembly. 
         FIG.  16    is a bottom view of the exemplary pump assembly illustrated in  FIG.  15   . 
         FIG.  17    is perspective view of the exemplary pump assembly illustrated in  FIG.  15    with a cartridge inserted. 
         FIG.  18    is a perspective view of an exemplary pump module. 
         FIG.  19    is a perspective view of the pump module illustrated in  FIG.  18    with the end gear cap omitted. 
         FIG.  20    is a plan view of an exemplary chassis. 
         FIG.  21    is a front exploded perspective view of the chassis of  FIG.  20   . 
         FIG.  22    is a rear exploded perspective view of the chassis of  FIG.  20   . 
         FIG.  23    is a section view of the pump module illustrated in  FIG.  19    with a partially filled medicament cartridge positioned therein and a latch mechanism in a lock position. 
         FIG.  24    is a section view taken on line  24 - 24  in  FIG.  23   . 
         FIG.  25    is a section view of the pump module illustrated in  FIG.  19    with an empty medicament cartridge positioned therein and the latch mechanism in an unlock position. 
         FIG.  26    is a section view taken on line  26 - 26  in  FIG.  25   . 
         FIG.  27    is an elevation view of a portion of the latch mechanism illustrated in  FIGS.  23 - 26   . 
         FIG.  28    is a section view of the lead screw, gear, thrust bearing and pusher portions of the pump module illustrated in  FIG.  19   . 
         FIG.  29    is a simplified view showing a switch that detects when a plunger pusher is in a home position. 
         FIG.  30    is a section view of an exemplary pump module with various structures omitted and medicament cartridge reservoir clamping forces displayed. 
         FIG.  31    is a perspective view of an exemplary infusion pump system with the pump assembly removed from the medicament cartridge, cannula and baseplate. 
         FIG.  32    is a perspective view of an alternative exemplary chassis and latch. 
         FIG.  33    is a section view of an exemplary pump assembly including the latch illustrated in  FIG.  32    in an unlatched state. 
         FIG.  34    is another section view of a pump assembly including the latch illustrated in  FIG.  32    in an unlatched state. 
         FIG.  35    is another section view of a pump assembly including the latch illustrated in  FIG.  32    in a latched state. 
         FIG.  35 A  is a section view taken along line  35 A- 35 A in  FIG.  35   . 
         FIG.  36    is a simplified section view of another alternative latch in an unlatched position. 
         FIG.  37    is a simplified section view of the latch illustrated in  FIG.  36    in a latched position. 
         FIG.  38    is a simplified view showing an alternative mechanism that biases a medicament cartridge against the front wall of a chassis. 
         FIG.  39    is a schematic view of a motor and an encoder. 
         FIG.  40 A  is a schematic view of an optical encoder system. 
         FIG.  40 B  is a schematic view of another optical encoder system. 
         FIG.  40 C  is a schematic view of yet another optical encoder system. 
         FIG.  40 D  is a schematic view of still another optical encoder system. 
         FIG.  40 E  is a schematic view of another optical encoder system. 
         FIG.  40 F  is a schematic view of yet another optical encoder system. 
         FIG.  40 G  is a schematic view of a magnetic encoder system. 
         FIG.  40 H  is a schematic view of another magnetic encoder system. 
         FIG.  40 I  is a schematic view of yet another magnetic encoder system. 
         FIG.  41    is a section view of an exemplary pressure sensor arrangement. 
         FIG.  42    is another section view of the pressure sensor arrangement illustrated in  FIG.  43   . 
         FIG.  43    is a section view of an exemplary fall-off detector. 
         FIG.  44    is another section view of the fall-off detector illustrated in  FIG.  43   . 
         FIG.  45    is a section view of another exemplary fall-off detector. 
         FIG.  46    is a schematic representation of yet another exemplary fall-off detector. 
         FIG.  47    is a schematic representation of still another exemplary fall-off detector. 
         FIG.  48    is a perspective view of an exemplary infusion pump system with the pump assembly and medicament cartridge removed from the cannula and baseplate. 
         FIG.  49    is a perspective view of an infusion pump assembly, with a medicament cartridge therein, being attached to a battery recharging device. 
         FIG.  50    is a graph showing recharging temperature during an exemplary battery recharging method. 
         FIG.  51    is a schematic view of an exemplary infusion pump assembly controller. 
         FIG.  51 A  is a block diagram showing certain functional relationships of the battery charging system illustrated in  FIG.  49    and the controller illustrated in  FIG.  51   . 
         FIG.  52    is a flow chart showing an exemplary motor torque control method. 
         FIG.  52 A  is a diagram of an exemplary motor driving bridge circuit. 
         FIG.  53    is a perspective view of an exemplary baseplate. 
         FIG.  54    is a section view of a portion of a system including the baseplate illustrated in  FIG.  53   . 
         FIG.  55    is a bottom perspective view of the system illustrated in  FIG.  54    with the adhesive liner removed. 
         FIG.  56    is a perspective view of an exemplary cannula. 
         FIG.  57    is a section view of the cannula illustrated in  FIG.  56    inserted through a cartridge and secured to a baseplate. 
         FIG.  57 A  is a section view of the baseplate illustrated in  FIG.  57   . 
         FIG.  58    is a perspective view of another exemplary cannula. 
         FIG.  59    is a section view of the cannula illustrated in  FIG.  58   . 
         FIG.  60    is a perspective view of a portion of an exemplary pump assembly housing. 
         FIG.  61    is a perspective view of a portion of an exemplary baseplate. 
         FIG.  62    is a perspective view of an exemplary baseplate and infusion set. 
         FIG.  63    is a section view of a portion of a system including the baseplate illustrated in  FIG.  62   . 
         FIG.  64    is a perspective view of an exemplary baseplate. 
         FIG.  65    is a section view of a portion of a system including the baseplate illustrated in  FIG.  64   . 
         FIG.  66    is a perspective view of a portion of an exemplary baseplate. 
         FIG.  67    is a perspective view of a portion of an exemplary baseplate. 
         FIG.  68    is a perspective view of a portion of an exemplary baseplate. 
         FIG.  69    is a bottom view of a portion of an exemplary pump assembly. 
         FIG.  70    is a perspective view of a portion of an exemplary baseplate. 
         FIG.  71    is a perspective view of a portion of an exemplary baseplate. 
         FIG.  72    is a perspective view of a portion of an exemplary baseplate. 
         FIG.  73    is a diagrammatic representation of exemplary baseplate identification instrumentalities. 
         FIG.  74    is a diagrammatic representation of exemplary baseplate identification instrumentalities. 
         FIG.  75    is a diagrammatic representation of exemplary baseplate identification instrumentalities. 
         FIG.  76    is a diagrammatic representation of exemplary baseplate identification instrumentalities. 
         FIG.  77    is a diagrammatic representation of exemplary baseplate identification instrumentalities. 
         FIG.  78    is a diagrammatic representation of exemplary baseplate identification instrumentalities. 
         FIG.  79    is a flow chart showing an exemplary medicament cartridge removal and replacement method. 
         FIG.  80    is a section view showing a medicament cartridge being inserted into the exemplary pump assembly illustrated in  FIG.  33   . 
         FIGS.  81 - 83    are section views showing the pump assembly and cartridge illustrated in  FIG.  80    during an exemplary pusher zeroing procedure. 
         FIG.  84    is a section view showing the removal of a plug from the cartridge illustrated in  FIG.  83    and the attachment of a body adherable baseplate to the pump assembly. 
         FIG.  85    is a section view showing a cannula inserter, with a cannula, attached to the exemplary system including the pump assembly, baseplate and cartridge illustrated in  FIG.  84   . 
         FIG.  86    is a front view showing a patient&#39;s skin being cleaned. 
         FIG.  87    is a section view showing the system illustrated in  FIG.  85    on the cleaned skin prior to cannula insertion. 
         FIG.  88    is a section view showing the system illustrated in  FIG.  87    after cannula insertion. 
         FIG.  89    is a section view showing the system illustrated in  FIG.  88    on the skin with the cannula inserted and the inserter being removed. 
         FIG.  90    is a section view showing the system illustrated in  FIG.  89    dispensing medicament by way of the cannula. 
         FIG.  91    is a flow chart showing exemplary cartridge position check and pusher zeroing methods. 
         FIG.  92    is a flow chart showing an exemplary dispensing method with occlusion detection. 
         FIG.  93    is a flow chart showing a number of exemplary occlusion detection methods that may form part of the dispensing method illustrated in  FIG.  92   . 
         FIG.  94    is a flow chart showing an exemplary reverse rotation of an unpowered motor correction method. 
         FIG.  95    is a graph showing motor rotational speed during an exemplary motor stopping method. 
         FIG.  96    is a flow chart showing an exemplary automatic plunger pusher retraction method. 
         FIG.  97    is a flow chart showing an exemplary gear assembly verification method. 
         FIG.  98    is a perspective view of an exemplary remote control. 
         FIG.  99    is a block diagram of the exemplary remote control illustrated in  FIG.  98   . 
         FIG.  100    is a flow chart showing exemplary alarm conditions. 
     
    
    
     DETAILED DESCRIPTION 
     The following is a detailed description of the best presently known modes of carrying out the inventions. This description is not to be taken in a limiting sense, but is made merely for the purpose of illustrating the general principles of the inventions. 
     The detailed description of the exemplary embodiments is organized as follows:
         I. Introduction   II. Exemplary System Overview   III. Exemplary Medicament Cartridges   IV. Exemplary Pump Assemblies
           A. Exemplary Housings   B. Exemplary Pump Modules Overview   C. Exemplary Chassis   D. Exemplary Plunger Pushers and Drive Mechanisms   E. Exemplary Reservoir Clamping   F. Exemplary Cartridge Lock and Bias Apparatus   G. Exemplary Encoders   H. Exemplary Pressure/Occlusion Sensors   I. Exemplary Fall-Off Detectors   J. Exemplary Batteries and Battery Rechargers   K. Exemplary Alarms   L. Exemplary System Controllers   M. Exemplary Motor Control   
           V. Exemplary Baseplates and Cannulas   VI. Exemplary Baseplate Identification   VII. Exemplary Basic Operation   VIII. Exemplary Operational Methodologies
           A. Exemplary Cartridge Position Check   B. Exemplary Pusher “Zeroing” Procedure   C. Exemplary Occlusion Detection   D. Exemplary Accounting For Unpowered Motor Reverse   E. Exemplary Motor Stopping   F. Exemplary Automatic Plunger Pusher Retraction Procedures   G. Exemplary Gear Assembly Verification Procedure   
           IX. Exemplary Remote Controls and Associated Methodologies       

     The section titles and overall organization of the present detailed description are for the purpose of convenience only and are not intended to limit the present inventions. 
     It should also be noted here that the specification describes a wide variety of structures and methods, mainly in the context of cartridge-based infusion pumps that are especially well-suited for the subcutaneous delivery of very high concentration insulin (e.g., the U-500 insulin discussed below). Nevertheless, it should be appreciated that the present inventions are applicable to a wide variety of infusion pumps and medicaments. By way of example, but not limitation, many of the present inventions are also applicable to infusion pumps that are not cartridge-based (e.g., pumps with refillable reservoirs and single use pumps). Also, although the illustrated embodiments may employ a cartridge with a plunger, a fluid displacement device in the form of a plunger pusher, and a drive mechanism that includes a motor, other fluid displacement devices may include, regardless of the type of cartridge or reservoir employed, piston pumps (e.g., electromagnet pumps), MEMS pumps, peristaltic pumps and any other suitable pumps as well as corresponding drive mechanisms. The present inventions are also applicable to medicaments such as, for example, drugs to mask pain, chemotherapy and other cancer related drugs, antibiotics, hormones, GLP-1, Glucagon, various other drugs that include large molecules and proteins that may require a high level of delivery accuracy, as well as to relatively high concentration insulin (i.e., U-200 and above) such as U-400 insulin. 
     I. Introduction 
     From the perspective of most patients, two important aspects of ambulatory infusion pumps are size and convenience. As noted above, some ambulatory infusion pumps are frequently intended to be worn on a belt, carried in a pocket, or otherwise supported within a holder of some kind (referred to collectively as “pocket pumps”). Such infusion pumps transfer fluid from a reservoir to an infusion set by way of an elongate tube. Subcutaneous access may be obtained by way of a cannula in the infusion set. Other ambulatory infusion pumps are intended to be adhered to the skin at the delivery site (sometimes referred to as “patch pumps”). Here, the cannula or other subcutaneous access device may extend directly from the infusion device. Given these modes of use, patients typically prefer the pump to be as small as possible so that the pump will be more comfortable, less obtrusive, and less visible. 
     One commercially available ambulatory infusion pump is the OmniPod® insulin pump from Insulet Corporation in Bedford, Mass. The OmniPod® insulin pump has overall dimensions of about 62.5 mm×42.9 mm×17.7 mm, i.e., has an overall volume of about 47.5 cc, and has a reservoir volume of about 2.0 cc. Although this pump is relatively small, many patients would prefer an even smaller pump. Reducing reservoir volume is a simple method of reducing the overall size of an infusion pump. Unfortunately, when the volume of the reservoir is reduced, all other things being equal, there is a corresponding reduction in convenience because the smaller reservoir requires more frequent refilling or replacement. 
     The present inventors have determined that smaller reservoirs can be employed, without a corresponding reduction in convenience, by increasing the concentration of the medicament dispensed therefrom. In the exemplary context of insulin therapy, some conventional infusion pumps have reservoirs which hold 2 milliliters (ml) of U-100 insulin. U-100 insulin is an insulin containing 100 international units (IU) of insulin activity per  1  ml and, accordingly, the 2 ml reservoir stores 200 IUs. One common insulin dose is 0.5 IU, which equates to a dispensed volume of 5 microliters (μl) of U-100 per dose, 400 doses per 2 ml reservoir, and about 4.5 days of therapy at the common dosage. At least some conventional infusion pumps are capable of delivering 5 μl/dose with a delivery accuracy level that is acceptable for relatively low concentration U-100 insulin. 
     Higher concentration insulins are, however, commercially available. Humulin® R U-500 insulin, which is available from Eli Lilly and Company in Indianapolis, Ind., contains 500 IU/ml. Although the use of high concentration insulin would facilitate the use of a much smaller reservoir (e.g., 300 IU in a 0.600 ml reservoir), and could result in much smaller pumps for a given number of dosages, the five-fold increase in insulin concentration (as compared to U-100 insulin) necessitates a five-fold increase in fluid delivery accuracy. U-500 insulin is currently administered by injection and with certain conventional insulin pumps for patients who require more than about 200 IU/day. The accuracy of certain conventional pumps is adequate for patients who require about 200 IU/day or more. For example, conventional insulin pumps generally alert the patient (e.g., with an alarm) when approximately 3 IUs of U-100 insulin are missed on delivery, which corresponds to 30 μl of missed delivery. Using U-500 insulin, the missed volume for a 3 IUs alert is reduced to six μl due to the higher insulin concentration, and conventional infusion pumps are not capable of this level of accuracy. 
     The present inventors have determined that there are a plethora of factors that must be addressed if the goal is to deliver 1 μl/dose at an acceptable level of delivery accuracy. For example, the six μl alert requirement means that the present infusion pump assembly must be very stiff (or “low compliance”) to ensure delivery accuracy over all conditions of operating pressures, frictions, temperatures and so forth. In the context of the exemplary cartridges described below, the displacement may be about 1 IU of U-500 insulin per 0.001 inch of stroke, i.e., 2.0 μl/0.001 inch of stroke. The present inventors have determined that factors which can contribute to accuracy/precision during drug delivery may include: rotational accuracy of gearform (wobble and gearform consistency); encoder resolution; motor backdrive; encoder consistency (rotational spacing); motor phase balance; and motor control circuit excitation consistency (excitation pulse width accuracy and switch accuracy). The present inventors have determined that factors which can contribute to axial (error) movement under load may include: thrust bearing (internal movement); thrust bearing (slip in mount); lead screw (axial deformation); nut-to-lead screw gearform deflection; plunger body compression; plunger body-to-seal axial slip; plunger seal-to-low friction layer axial slip; thrust bearing-to-lead screw axial slip; cartridge body deformation/axial slip; lead screw-to-transverse gear axial slip; lead screw-to-transverse gear axial slip; push rod-to-nut axial deformation; cartridge body hydraulic expansion; sense diaphragm hydraulic deflection; infusion set hydraulic expansion; cannula movement in cartridge extending or shortening fluid path; and fluid path bubble compression. The relevance of many of these factors is discussed below in the appropriate contexts. 
     Another convenience related issue identified by the present inventors relates to the fact that a patient may desire to use a pocket pump in some instances and a patch pump in others. In addition to the added expense, switching between two different infusion pumps may adversely effect the patient&#39;s medicament delivery regimen. Notwithstanding the desire of some patients to switch back and forth, the mere fact that some patients prefer a pocket pump while others prefer a patch pump forces manufacturers to choose between designing, testing and obtaining approval for two different pumps or simply staying out of one of the markets. 
     II. System Overview 
     Exemplary ambulatory infusion systems, which are generally represented by reference numerals  10 ,  11  and  12  in  FIG.  1   , include a medicament cartridge (or “cartridge”)  100 , an ambulatory infusion pump assembly (or “pump assembly”)  200 , and one of the baseplates  500 ,  501  and  502 . Generally speaking, the cartridge  100  may be inserted into the pump assembly  200  and the appropriate baseplate  500 - 502  may be secured to the pump assembly. To that end, and as discussed in greater detail in Section V below, the baseplates  500 - 502  in the illustrated implementations are configured for different modes of system operation. Baseplate  500  is a body adherable baseplate that may be used in conjunction with a cannula (e.g., cannula  600  in  FIGS.  56 - 57   ) that is directly connected to the cartridge  100  so that the system  10  may be deployed as a “patch-pump” ( FIG.  1 A ). Baseplate  501  is configured to connect the cartridge  100  to an infusion set  503  so that the system  11  may be deployed as a “pocket pump,” a “belt-worn pump” or some other wearable pump ( FIG.  1 B ). Baseplate  502  is a medicament non-delivery baseplate that may be used to seal the cartridge  100  during periods of non-use (e.g., by way of plug  504 ), thereby defining a non-use system  12 . 
     In other words, using the same medicament cartridge (e.g., cartridge  100 ) and pump assembly (e.g., pump assembly  200 ), the user may configure the system for use as “pocket pump” or a “patch pump” by simply selecting the appropriate baseplate  500  or  501  and attaching the baseplate to the pump assembly. The user may also switch from one configuration to another, in many instances without removing the cartridge from the pump assembly, by simply removing one baseplate and replacing it with another baseplate. 
     Whether configured as a “pocket pump” or a “patch pump,” the system may be configured to provide basal delivery of medicament in accordance with a delivery profile provided by a physician by way of a clinician&#39;s programming unit. For example, the system may include a program that stores a number of delivery profiles (e.g. delivery profiles associated a 24-hour delivery cycle and delivery profiles for particular situations such as sleep or illness). Each delivery profile specifies multiple doses (or pump “operations”) over time, e.g. a particular number of doses at particular times or a particular number of doses per unit time. In some implementations, a dose may be the volume associated with the minimum controllable displacement of a cartridge plunger. The system may also be configured to provide bolus delivery in response to an instruction from a patient remote control. A bolus instruction may come in response to a high glucose level measurement in the case of a diabetic patient, an increase in pain level in the case of a pain management patient, or some other symptom. The system may also be configured to perform other functions, such as ending medicament delivery, in response to instructions from a patient remote control. 
     The parts of the present systems that do not come into contact with medicament during normal operation (e.g., operation not associated with a cartridge that is damaged and leaking) may be considered the reusable parts, while the parts that do come into contact with medicament during normal operation, and may define portions of the medicament delivery (or “flow”) path, may be considered the disposable parts. In the illustrated embodiments, the pump assembly  200 , which includes structures such as the motor and various mechanical structures, the controller and the battery (and may be more expensive), is reusable, while the cartridge  100 , baseplates  500 - 502  and cannula  600  (if any) are disposable. 
     The pump assembly  200  in the exemplary system  10  (and  11 ) does not come into contact with medicament because the cartridge  100 , which is accessible from outside the pump assembly  200 , includes its own manifold. Medicament can, therefore, flow directly from the cartridge reservoir to the associated cannula or other device without contacting the pump assembly. Such an arrangement is advantageous for a variety of reasons. For example, portions of the medicament delivery path from the reservoir to the cannula (or infusion set tube) can become clogged or otherwise in need of repair. Such repair may be inconvenient and costly in the context of many conventional infusion pumps because the pump mechanism (e.g., a piston or peristaltic pump) is part of the medicament delivery path. The present systems obviate this unpleasant aspect of some conventional infusion pumps by removing the medicament flow path from the reusable portion of the system. The present systems also provide less expensive long term therapy, as compared to many conventional systems, because the more expensive portions are reusable. 
     The infusion pumps described herein address the accuracy/precision factors and the axial movement factors noted above by providing a more accurate, less compliant infusion pump. For example, the constructions of the cartridge (e.g., the inside diameter is constant, and the plunger is configured to be urged precisely in response to movement of the drive mechanism), the rigidity of the chassis and the precision of the drive mechanism, as well as the operation procedures of the drive mechanism, allow for an amount of medicament of 0.1% or less of the total filled volume of the reservoir to be controllably dispensed with single-dose precisions that range from plus or minus (+/−) 20% to +/−5%. This precision can be obtained after a dispensing period of six to eight hours or less resulting in a dose accuracy of from +/−20% to +/−5%. The dispensed amount can be as low as 0.23-0.27 μl/dose. The dose can be dispensed in as little as two seconds or less for small volumes, or longer times for larger volumes such as those associated with basal delivery. 
     For example, 300 units of U-500 insulin (0.6 mL or 600 μl) can be provided in the reservoir of one of the cartridges described below, and within a two hour or less stabilization (or “time-to-precision”) period, medicament can be controllably dispensed from the cartridge with a precision of +/−5% and with 0.5 unit per dose (1.0 μl/dose). As graphically illustrated in  FIG.  2   , the ability to obtain a single-dose precision of better than +/−5% in as little as six to eight hours or less is vastly superior to the standard set forth in the International Electrotechnical Standard (IEC) for the safety of infusion pumps and controllers (IEC 60601-2-24), which provides for a 24-hour stabilization period before precision measurements are even taken. In other words, although the IEC 60601-2 delivery test provides a twenty-four hour stabilization period during which pump operation is allowed to be untested, the present pumps, from a clinical perspective, may be tested without such a stabilization period. This time-to-precision superiority is especially important in the context of high concentration medicaments because the adverse effects of prolonged over-delivery or under-delivery are magnified. For example, a time-to-precision period of six hours may be appropriate in the context of U-500 insulin and Type-1 diabetics who use basal rates of less than one IU/hour. 
     The precision capabilities associated with the present system, and the corresponding ability to use a very highly concentrated medicament (e.g., U-500 insulin) and relatively highly concentrated medicaments (e.g., U-200 to U-400 insulin) also facilitate, if so desired, a marked decrease in ambulatory infusion pump size as compared to conventional pumps. For example, one exemplary pump assembly  100  described below has dimensions of about 40 mm×32 mm×11 mm, for an overall volume of about 14 cc. This is considerably less than the approximately 47 cc overall volume of the aforementioned OmniPod® insulin pump. 
     III. Exemplary Medicament Cartridges 
     The exemplary system is, as noted above, a cartridge-based system in that medicament cartridges  100  are inserted into the pump assembly  200  and later removed from the pump assembly. The cartridges  100  may also be, but are not required to be, prefilled and disposable. Prefilled cartridges are advantageous for a variety of reasons. By way of example, but not limitation, some users prefer to avoid cartridge filling procedures because they are inconvenient and tend to involve needles. User-based refilling also increases the likelihood that air bubbles will be introduced into the cartridge, while prefilling by the manufacturer of the cartridge and/or the medicament can be accomplished without any substantial introduction of air bubbles using, for example, a vacuum filling procedure. A lack of bubbles is very important in the context of dosage accuracy in that air is compressible and liquid medicament is not. For example, 20 μlof air will have a compressibility of about 6 μlat a 5 psi operating pressure, which can adversely effect pressure sensing in the system. If the system is configured to alert the user of missed dosing equal to approximately 6 μl (3 IUs for U-500 insulin), 6 μl (3 IUs for U-500 insulin) will be delayed before there is a user alert. In addition, the presence of 20 μl of air in the cartridge results in the patient not receiving 10 IUs of U-500 insulin during the life of the cartridge. Prefilled cartridges with less than 5 μl of air bubbles are preferred when U-500 is the stored medicament. 
     As illustrated in  FIGS.  3  and  4   , the exemplary medicament cartridge  100  may include a body portion (or “barrel”)  102 , which defines a medicament reservoir  104 , a plunger  106  that is held by friction within the body portion, and a manifold  108  that may be used to connect the reservoir to, for example, cannulas and baseplate structures in the manner described below with reference to, for example,  FIGS.  57  and  63   . Medicament is identified by reference numeral  101  in  FIG.  23   . The plunger  106  is moved within the body portion  102  to vary the volume of the reservoir  104 . In particular, the plunger  106  moves in a dispensing direction where reservoir volume is decreased, but does not substantially move to increase volume during use of the cartridge  100 . The cartridge  100  may also be provided with a plug  110  that prevents leakage from a prefilled reservoir  104  (e.g., prefilled in a vacuum with U-500 insulin) during packaging, shipping, storage and handling, and can be used in a pusher zeroing procedure as described in Section VIII-B below. 
     Referring first to the body portion  102 , and although the present inventions are not limited to any particular shape, the exemplary body portion  102  is cylindrical in overall shape and has a cylindrical inner surface  112  that defines the cylindrical reservoir  104  ( FIG.  3   ). The body portion  102  and inner surface  112  may be other shapes in other implementations. By way of example, but not limitation, the overall shape of the body portion  102  and the shape of the inner surface  112  may both be oval in cross-section, or the overall shape of the body portion may be rectangular and the shape of the inner surface may be oval or circular in cross-section. The inner surface  112  may also be a non-curved, such as rectangular or square in cross-section. 
     The exemplary manifold  108  illustrated in  FIGS.  3  and  4    has a body portion  114  that defines a through-bore  116  and the front wall  117  of the cartridge. The through-bore  116  is directly connected to a relatively short reservoir outlet port  118  (i.e., is connected without additional tubing). The through-bore  116  and outlet port  118  facilitate a direct fluidic connection between the cartridge  100  and the aforementioned cannulas and baseplates that have a portion thereof inserted into the through-bore. The reservoir outlet port  118  may also be parallel to the direction of plunger movement (note  FIG.  54   ). Such an orientation results in a short, direct and efficient medicament dispensing path as the plunger  106  reduces the volume of medicament in the reservoir  104 . 
     Additionally, as illustrated in  FIG.  4 A , the inner surface of the body portion end wall  119 , i.e., the wall that the plunger  106  abuts when the reservoir is empty, may include an annular recess  121  which traps bubbles that may be present in the reservoir and prevents them from exiting the cartridge  100 . In one exemplary implementation, the annular recess  121  is a 0.25 mm deep semi-circle in cross-section, is 0.5 mmfrom the circumferential edge of the outlet port  118 , and is 0.5 mm wide (i.e., 0.5 mmfrom the ID to the OD). Such bubble entrapment reduces the likelihood that bubbles will be dispensed and, accordingly, reduces the likelihood that medicament dispensing and occlusion sensing will suffer bubble-related decreases in accuracy. Other ways to trap bubbles at the end wall  119  include, but are not limited to, concentric recesses, hydrophilic filters and elevated outlet ports. 
     At least some of the exemplary implementations may employ pressure data in various contexts. For example, a pressure sensor may be used to detect occlusions downstream from the reservoir outlet port  118  that are impeding, or completely preventing, medicament flow. To that end, a medicament cartridge may include some or all of the pressure sensor itself. In the illustrated implementation, the cartridge  100  includes the cartridge portion  120  of the pressure sensor  234  that is described in Section IV-H below with reference to  FIGS.  41  and  42   . The pressure sensor may also be used to detect the presence of a cartridge in the pump assembly, as is also described below. 
     The exemplary pressure sensor cartridge portion  120  illustrated in  FIGS.  3  and  4    includes a pressure sensor housing  122 , which may be integral with (as shown) or otherwise connected to or carried by the manifold  108 , and a detectable structure  124 . The detectable structure (or “fluid force deflectable part”)  124 , whose movement can be detected as described below, is mounted in a pressure sensor housing recess  126  and communicates with the through-bore  116  by way of an aperture  128  so as to expose the detectable structure to the fluid pressure in the through-bore. As shown in  FIG.  5   , the exemplary detectable structure  124  has a deflectable part  130  with a magnet  132  (e.g., a neodymium magnet) or other sensed element, a resilient diaphragm  134  (e.g., a silicone diaphragm) that carries the magnet by way of a sleeve  136 , and a diaphragm retention ring  138  (e.g., an olefin polymer retention ring). The exemplary detectable structure  124  also has a cap  140  with a cylindrical abutment  142 , a bore  144  in which the magnet  132  and sleeve  136  are located, and a flange  146 . During assembly, the detectable structure  124  is inserted into the housing recess  126  until the retention ring  138  abuts the recess wall  148  ( FIG.  4   ). The cap  140  is thereafter inserted into the recess  126  until the cylindrical abutment  142  engages the retention ring  138  and the flange  146  is flush with the pressure sensor housing  122  ( FIG.  1   ). The diaphragm  134 , which is exposed to reservoir pressure by way of the aperture  128 , flexes in response to pressure increases, such as during an occlusion event, thereby moving the magnet  132 . The movement is sensed by the pump assembly portion  236  (e.g., Hall-effect sensor or magnetoresistive sensor) of the pressure sensor (or “fixed sensor part”)  234  as described in Section IV-H below with reference to  FIGS.  41  and  42   . Thus, in this implementation, the cartridge portion  120  may be thought of as the “unpowered” portion of the pressure sensor  234  and the pump assembly portion  236  may be thought of as the “powered portion.” Moreover, the more expensive portion, e.g., a sensor such as a Hall-effect or magnetoresistive sensor, is part of the reusable pump assembly  200 . 
     Generally speaking, air (not medicament) acts on the diaphragm  134  because of the air cushion formed between the plug  110  and diaphragm during manufacture. That said, the sensor  234 , which includes the cartridge portion  120 , can detect a pressure change corresponding to six μl of medicament (i.e., the three IU of U-500 insulin) or less of plunged medicament that is being held up by a blockage. The six μl of medicament generally corresponds to the volume created by deflection of the detectable structure  124  (note also, detectable structure  124   a  in  FIG.  42   ). 
     Another exemplary cartridge portion of a pressure sensor is generally represented by reference numeral  120   a  in  FIG.  6   . The cartridge portion  120   a  may be part of a medicament cartridge  100   a  that is otherwise identical to cartridge  100 . Cartridge portion  120   a  is substantially similar to cartridge portion  120  and similar elements are represented by similar reference numerals. For example, the cartridge portion  120   a  includes a detectable structure  124   a . Here, however, the diaphragm  134   a  includes a post  136   a  on which a cylindrical magnet  132   a  is mounted. In other words, instead of the magnet  132   a  being in a sleeve, this magnet  132   a  defines a sleeve. The diaphragm  134   a  also includes an integral mounting member  138   a  that is press-fit into the recess  126  with a cylindrical wedge  142   a.    
     It should also be noted that the present pressure sensors are not limited to the type of devices described with reference to  FIGS.  5  and  6   . By way of example, but not limitation, a cartridge portion  120   b  ( FIG.  7   ) may include a diaphragm that carries a magnetically permeable structure  132   b  which changes the inductance of a coil in the pump assembly portion PAP of the sensor when moved relative thereto. A similar arrangement may employ an optical element and a corresponding optical sensor, and  FIG.  7    may also be considered a representation thereof (with the optical element represented by reference number  132   b ). Another exemplary pressure sensor may be in the form of an electrical switch that includes a pump assembly portion PAP 1  with a pair of switch contacts and a cartridge portion  120   c  with a diaphragm which carries an electrical conductor  132   c  that connects the contacts when the diaphragm moves a predetermined distance ( FIG.  8   ). 
     With respect to dimensions, the exemplary cartridge  100  may be configured to have a reservoir  104  whose volume is less than or equal to about 1000 μl and, some implementations, between about 500-700 μl. For perspective, and as noted above, a 600 μl (0.600 ml) reservoir would store 300 units of U-500 insulin, which corresponds to about one week&#39;s worth of insulin for a patient using approximately 40 IU of insulin per day. Such volumes may achieved by way of a body portion  102  with an inner diameter of 9.8 mm, with a tolerance+/−1.0 mm in some instances and a tolerance of +/−0.1 mm in others, an outer diameter of 11.8 mm, with a tolerance+/−1.0 mm in some instances and a tolerance of +/−0.10 mm in others, a stroke length (i.e., the distance that the plunger  106  travels from the full position to the empty position) of 8.5 mm+/−2.0 mm, and a length of 17.5 mm, with a tolerance of +/−1.0 mm in some instances and a tolerance of +/−0.10 mm in others. 
     It should be noted here that the stroke length to inner diameter ratio of the present reservoir  104  may be about 1.0 or less. For example, in some implementations, the ratio may be 0.86, or may range from about 0.75 (or less) to about 1.0. 
     The plunger may play a substantial role in the dosage accuracy associated with the present system. The exemplary plunger  106  illustrated in  FIGS.  3  and  9 - 12    includes a plunger body  150 , a seal  152 , and a friction reduction layer  154  that provides a low coefficient of friction between the friction bearing surface of the plunger  106  and barrel inner surface  112 . 
     Referring more specifically to  FIGS.  10  and  12   , the plunger body  150  may be spool-shaped, in that it is a solid structure with a recessed middle portion  156  and circumferential rings  158 . The recessed middle portion  156  and circumferential rings  158  extend circumferentially around the axis A ( FIG.  12   ). Indentations  159  may be provided for a portion of the friction reduction layer  154 . The spacing between circumferential rings  158  and the barrel inner surface  112  may be relatively small, i.e., there is close tolerance, to minimize plunger wobble. For example, the diameter of the rings  158  may be about 9.7 mm with a tolerance of +/−0.06 mm and the spacing can be 0.10 mm with a tolerance of +/−0.073 mm in some instances and a tolerance of +/−0.12 mm in others. The plunger body  150  also has forward and rearward facing (relative to the direction of plunger travel during medicament dispensing) surfaces  160  and  162 . Put another way, with reference to the medicament in the reservoir  104 , the surface  160  is the “wet side” and surface  162  is the “dry side.” The forward facing surface  160  may be provided with a concave recess  164  that is at least substantially aligned with the reservoir outlet port  118 . A generally annular indentation  165  extends into the plunger body  150  from the rearward facing surface  162 . In addition to reducing the weight of the plunger  106 , the indentation facilitates removal of the plunger body from the mold during manufacture. 
     In other implementations, the plunger body may be planar on the wet and/or dry sides. Such a plunger body would resemble the simplified illustration of plunger body  150  in  FIG.  34   . The plunger body surfaces interfacing with the inner surface of the barrel may also be cylindrical, that is, planar in cross section as opposed to rounded. 
     Referring to  FIGS.  10 - 12   , the seal  152  may be located between the plunger body  150  and the friction reduction layer  154 , and within the plunger body recessed middle portion  156  between the circumferential rings  158 . As such, the seal  152  in the illustrated implementation acts on the plunger body  150 , as well as the friction reduction layer  154 , and is radially and axially constrained. The seal  152 , which may include an annular base portion  166  and a pair of o-rings  168 , also provides enough force to press the friction reduction layer  154  outwardly against the inner surface  112  of cartridge body  102  and establishes a seal that will hold under the pressures associated with the present systems and methods. Moreover, given the radial and axial constraints, the amount of seal compression (and the resulting sealing force) is more predictable than it would be otherwise. 
     The seal  152  is under radial and axial compression forces which provide a sealing load on both the friction reduction layer  154  and the plunger body  150 . The radial and partial axial compression forces also force the friction reduction layer  154  outward against the cartridge barrel inner surface  112 . Overcompression is undesirable as the resultant seal has a wide range of static/running forces, so compression is engineered to be within a predictable range. 
     The seal  152  may also be provided with a plurality of protrusions  170  ( FIGS.  11  and  12   ), such as integrally molded protrusions, on the forward facing surface  172  (as shown) and/or on the rearward facing surface (not shown). The protrusions  170  ensure that the seal  152  is axially stable (or properly constrained) between the plunger body circumferential rings  158 , and will typically be compressed into the annular base portion  166  as shown in  FIG.  12   . Constraining the seal  152  in this manner makes it more likely that the seal will accurately track movement of the plunger body  150  and, in turn, facilitates accurate reduction in reservoir volume. The protrusions  170  also prevent overcompression of the exemplary seal  152  in the plunger body  150 , which could lead to unpredictable seating and unpredictable forces on the friction reduction layer  154  and, therefore, on the cartridge barrel  102 . 
     It should also be noted here that the plunger  106  in the illustrated embodiment is not connectable (or “is unconnectable”) to the plunger pusher  250  (note  FIGS.  45 - 47   ) that pushes the plunger forwardly toward the outlet port  118 . Put another way, and referring to  FIG.  12   , the plunger body  150  does not include any structural components that are (or could be) connected to the plunger pusher. For example, the plunger body  150  does not include an unthreaded opening, a threaded opening, a fastener, a magnetic catch, a ratchet, or other such instrumentality. The dry side of the plunger body could also be planar (and noted above). Given the lack of connectability, under no circumstances will reverse movement of the plunger pusher  250  pull the plunger  106  rearwardly and draw medicament back and air (if any) into the reservoir  104 . The plunger  106  can only move forwardly when being contacted by, and/or due to operation of, the plunger pusher  250 . 
     Although there are numerous possible configurations that would not be connectable to a plunger pusher, the exemplary plunger body  150  simply has a smooth rearward facing surface  162  that may be planar (as shown in the simplified illustrated presented in  FIG.  34   ) or curved. Additionally, or alternatively, the plunger pusher  250  (note  FIGS.  18 ,  23  and  25   ) may be unconnectable to the plunger, as is discussed in Section IV-D below, for the same reasons. 
     With respect to materials, the body portion  102 , manifold  108  and plunger body  150  of the exemplary cartridge  100  may be formed from plastic, glass or a combination of glass and plastic, and the seal  152  may formed from rubber, such as bromobutyl rubber. The body portion  102  and manifold  108  may be integrally formed, or formed separately and joined to one another (e.g., by ultrasonically or laser welding). One suitable plastic is cyclic olefin polymer (COP). It should be noted, however, that the particular medicament that is to be stored in the cartridge  100  should be taken into account. For example, each milliliter of Humulin® R U-500 insulin contains 500 units of biosynthetic human insulin, 16 mg glycerin, 2.5 mg Metacresol as a preservative, and zinc-oxide calculated to supplement endogenous zinc to obtain a total zinc content of 0.017 mg/100 units. Sodium hydroxide and/or hydrochloric acid may be added during manufacture to adjust the pH. Other ingredients, such as phenol (preservative), surfactants, and buffering agents may be added as required. As such, Humulin® R U-500 insulin may be better suited for long term storage in glass than it is for long term storage in plastic. In those instances where storage in a plastic cartridge (e.g., a COP cartridge) is desired due to the inherent advantages of plastic as compared to glass (e.g., lighter, less expensive and more durable), a bioequivalent of Humulin® R U-500 may be employed. Here, the formulation of Humulin® R U-500 may be adjusted to increase the stability of the insulin by, for example, changing preservative, changing stabilizers, and changing buffering agents. 
     In at least some implementations, the cartridge body portion  102  may be formed from transparent glass, transparent COP or some other suitable transparent material. There are a variety of advantages associated with a transparent cartridge body portion  102 . For example, as shown in  FIG.  17    and discussed in Section IV below, the pump assembly  200  and cartridge  100  are respectively configured such the body portion  102  will protrude through an opening  226  in the housing top wall  214  when the cartridge is inserted into the pump assembly. In one implementation, the cartridge  100  will protrude less the one mm (which equates to five percent of the volume of reservoir  104 ). The patient will be able to see the medicament in reservoir  104  and readily determine, when for example the medicament is insulin, whether or not the medicament is cloudy (which indicates a loss of effectiveness), as well as roughly estimate what portion of the original medicament volume remains in the reservoir. 
     The friction reduction layer  154  in the exemplary embodiment may be formed in a variety of ways. The friction reduction layer  154  may be, for example, a polytetrafluoroethylene (PTFE) sleeve that is shrink wrapped over the plunger body  150  and seal  152  (as shown in  FIG.  12   ). Ethylene tetrafluoroethylene (ETFE) and fluorinated ethylene propylene (FEP), which are in the same family as PTFE, may also be employed. Alternately, the friction reduction layer  154  can be implemented as a low friction coating or surface modification of the seal  152 . Coatings could be formed from a fluorinated polymers such as FEP and PTFE. When combined with a COP cartridge body portion  102  and the other above-described aspects of the plunger  106 , the present friction reduction layer  154  provides a break force (static friction) of less than five pounds and running forces (dynamic friction) of two to four or five pounds. 
     As to the exemplary plug  110  illustrated in  FIG.  3   , and as alluded to above, the plug is a removable sealing device that is inserted into the cartridge through-bore  116  during manufacture to prevent leakage from a prefilled reservoir  104 , by way of the outlet port  118 , during packaging, shipping, storage and handling. The plug  110  will typically remain in place in the through-bore  116  until the cartridge  100  is in place within the pump assembly  200  and is ready for medicament dispensing. At that point, the plug  110  will be manually removed by the user. Although the plug  110  is not limited to any particular configuration, the implementation illustrated in  FIG.  3    includes a bulbous head  174  and a stem  176 . The head  174  may have a disk portion  178  and a plurality of gripping protrusions  180 , while the stem  176  may have a plurality of spaced sealing rings  182  carried on a cylindrical member  184 . Suitable material for the plug  110  includes, but is not limited to, bromobutyl rubber. An internal core (not shown), such as a fiber core, may be provided in some instances in order to prevent the plug from ripping during manual removal subsequent to the pusher zeroing procedure described in Section VIII-B below. 
     In some instances, long term interaction between the medicament and the pressure sensor diaphragm (e.g., diaphragm  134 ) during shipping and storage may be problematic. Accordingly, in at least some implementations, the respective configurations of the cartridge  100  and plug  110  are such that the pressure sensor aperture  128  will be isolated from the reservoir outlet port  118  by a portion of a fully inserted plug. For example, at least one of the sealing rings  182  may be between the pressure sensor aperture  128  and reservoir outlet port  118  when the plug is fully inserted. 
     Another exemplary plunger, which is generally represented by reference numeral  106   a  in  FIG.  13   , includes a plunger body  150   a , a forward (relative to the direction of travel) o-ring seal  152   a , and a friction control device  152   b  that is spaced from the o-ring seal. The friction control device  152   b  may be in form of an o-ring (as shown) or in the form of an overmolded part in some embodiments. The friction control device  152   b  provides for a consistent, reliable resistance of the plunger  106   a  to pushing force (e.g., from the plunger pusher) and may be configured such that at least one pound of force is required to push and move the plunger. This functionality may be accomplished in a variety of ways. For example, the o-ring seal  152   a  and friction control device  152   b  may be formed from different materials, and/or may be differently shaped, and/or may be differently sized. For example the o-ring seal  152   a  may be made of chlorobutyl rubber or bromobutyl rubber, and the friction control device  152   b  of silicone or polytetrafluoroethylene. 
     At least some embodiments of the present pump assembly  200  include a latch or other mechanism that prevents the cartridge  100  from simply falling out of the pump assembly when the associated baseplate is removed. Here, a small amount of pushing force (via the top opening  226  in  FIG.  15   ) and/or pulling force (via the insertion opening  218  in  FIG.  16   ) is used to remove the cartridge. Turning to  FIG.  14   , a medicament cartridge (e.g., cartridge  100 ) may be provided with a pull tab  186  that allows the user to pull the cartridge from the pump assembly  200  and/or simply makes the cartridge easier to grasp in those instances where pulling force is not required. In the illustrated example, the pull tab  186  has a main portion  188  that is firmly secured to the cartridge  100  and a handle portion  190 . The handle portion  190  may include a low tack adhesive to hold it to the cartridge body until the time of use. Alternatively, the handle portion  190  may simply hang free or may be pushed out of the way (shown by dotted lines). Instead of and/or in addition to the pull tab  186 , an outward bias device (such as one or more springs) may be mounted to the cartridge or within in the cartridge compartment. Pull-out ribbons may also be provided. 
     IV. Exemplary Pump Assemblies 
     Briefly, the exemplary pump assembly  200  may include an external housing (“housing”), which is generally represented by reference numeral  202  in  FIG.  15   , and a pump module, which is generally represented by reference numeral  204  in  FIG.  18   , that is located within the housing. Other structures that may be carried within the housing  202  include, but are not limited to a rechargeable battery  238 , a circuit board controller  240  and an alarm  242 , as are illustrated in  FIG.  18   . When the medicament cartridge  100  is inserted into the pump assembly  200 , as illustrated in  FIG.  23   , the cartridge plunger  106  of the medicament cartridge  100  will be proximate to and facing the plunger pusher  250  of the pump module  204 . The drive mechanism  252  of the pump module may then drive the pusher  250  relative to the cartridge plunger  106  to controllably and precisely dispense medicament from the cartridge reservoir  104 . 
     A. Exemplary Housings 
     Referring first to  FIG.  15 - 17   , the housing  202  has a top portion  206  and a bottom portion  208 . The top portion  206 , which includes two side walls  210 , two end walls  212 , a top wall  214  and rounded corners therebetween, generally defines the internal volume in which the pump module  204  and other pump assembly components are carried, as well as the overall volume of the pump assembly  200 . The bottom portion  208  includes a bottom wall  216 , which functions as a cover for most of the internal volume, and an insertion opening  218  in the bottom wall through which the cartridge  100  is inserted into the cartridge receiving (or “cartridge storage”) area  220 . The outer surface of the top wall  214  defines the “top face” or “top surface” of the housing  202 , and the outer surface of the bottom wall  216  defines the “bottom face” or “bottom surface” of the housing. In the illustrated embodiment, the insertion opening  218  abuts a thin rim  356  that is flush with the exterior surface of the bottom wall. The rim  356  is part of the chassis  244  ( FIG.  14   ) of the pump module  204 . 
     The configuration of the pump assembly  200  generally, and the housing  202  and insertion opening  218  in particular, is such that the cartridge  100  is inserted through the insertion opening  218  and into the cartridge receiving area  220  in a direction that is normal to plunger pusher  250 , as well as the axis along which the plunger pusher travels (note  FIGS.  1  and  80   ). 
     The top wall  214  of the housing  202  may also be provided with one or more openings. For example, a through-bore opening  224  may be provided in the housing top wall  214  to provide access to the cartridge through-bore  116  ( FIGS.  3 - 4   ). Such access may be required during a cannula insertion process, such as that described below with reference to  FIGS.  45 - 48   . 
     The top wall  214  of the housing  202  may also be provided with an opening  226  for the cartridge body  102  (or “cartridge body opening  226 ”) in some implementations. The through-bore opening  224  and cartridge body opening  226  are merged into a single cartridge opening in the illustrated embodiment. Such openings may be separate in other embodiments. As alluded to in Section III in the context of the exemplary cartridge  100 , an opening facilitates observation of the medicament and plunger in a cartridge formed from transparent material. Additionally, in the illustrated embodiment, the pump assembly  200  is configured (i.e., sized, shaped, etc.) such that a portion of the associated cartridge (e.g., cartridge  100 ) may protrude through the cartridge body opening  226  when the cartridge is in the cartridge receiving area  220 . For example, the relative configurations of the cartridge  100  and pump assembly  200  may be such that the cartridge body  102  protrudes slightly (e.g., about 0.40-1.00 mm, or five percent of the reservoir volume) through the opening  226  in the housing top wall  214 , as is illustrated in  FIG.  17   . The cartridge body inner surface  112  will, however, be located below the inner surface of the top wall  214 . The length of the cartridge body opening  226  is substantially equal to the length of the cartridge body  102 , with appropriate clearance, while the width is somewhat less than the diameter of the cartridge body. For example, the width of the opening  226  may be about 60 to 90% of the diameter and is about 83% in the illustrated implementation. 
     One important advantage of the cartridge/pump assembly relationship described in the preceding paragraph is size reduction. Allowing a portion of the cartridge  100  to protrude through the cartridge body opening  226  eliminates the need to accommodate that portion of cartridge below the inner surface of the housing top wall  214 , which in turn allows for a reduction in the overall thickness (or “profile”) of the pump assembly  200 . The reduction is equal to the sum of the length of the protrusion, the thickness of the housing top wall  214 , and any clearance that would have been necessary between the inner surface of the top wall and the cartridge in a “cartridge enclosed” implementation. In the context of ambulatory infusion pumps, where every reduction in size is important, this is a significant savings. 
     The pump assembly  200  may also be configured (i.e., sized, shaped, etc.) such that a portion of the associated cartridge (e.g., cartridge  100 ) protrudes through the insertion opening  218  on the bottom surface of the housing  202  when the cartridge is in the cartridge receiving area  220 . In such an implementation, the associated baseplate (e.g., baseplate  500 ) may be provided with an aperture  508  (or a recess) to accommodate the protruding portion of the cartridge as is discussed in Section V below with reference to  FIGS.  53 - 55   . Typically, although not necessarily, the cartridge  100  will not protrude substantially beyond the bottom surface of the baseplate or will not protrude beyond the bottom surface of the baseplate at all. Protrusion of the cartridge through the insertion opening  218  affords the same size related advantages as the cartridge opening  226  in the housing top wall  214 , which is to reduce the thickness of the housing  202 . 
     A plurality of electrical contacts  228 ,  230  and  232  may extend through (or be carried on) the housing bottom portion  208 , as is illustrated in  FIG.  16   . As discussed in greater detail in Sections IV-J and VI below, two of the contacts (e.g., contacts  228  and  230 ) may be used to electrically connect the pump assembly  200  to a battery recharger (e.g., charger  700  in  FIG.  49   ) and all of the contacts, at least in some implementations, may be used by the pump assembly during a baseplate identification procedure described. 
     With respect to dimensions, some embodiments of the exemplary housing  202  may have the following dimensions: length dimensions of 42 mm+/−1.0, 42 mm+/−0.10, 40+/−1.0 mm, 40+/−0.10 mm or 40+/−5.0 mm; width dimensions of 34 mm+/−1.0, 34 mm+/−0.10 mm, 32 mm+/−1.0 mm, 32 mm+/−0.10 mm or 32 mm+/−5 mm; overall thickness or height dimensions of 11 mm+/−1.0 mm or 11 mm+/−0.10 mm; and wall thickness dimensions on the order of 1.0 mm+/−0.10 mm. Suitable housing materials include, but are not limited to, plastic or other materials having a modulus of elasticity of 0.2-1.0 million psi. 
     B. Exemplary Pump Module Overview 
     As noted above with reference to  FIG.  15   , internal components of the exemplary pump assembly  200  may include, among other things, the pump module  204 , rechargeable battery  238 , circuit board controller  240  and alarm  242 . Exemplary pump modules are described below with reference to  FIGS.  18 - 39   . Other components may include the pump assembly portion  236  of a pressure sensor. 
     C. Exemplary Chassis 
     Briefly, and referring first to  FIG.  18   , the exemplary pump module  204  may have a rigid chassis  244 , which is configured to form a cartridge compartment  246  that defines the cartridge receiving area  220 , a plunger pusher (or “pusher”)  250  that drives the cartridge plunger  106  ( FIG.  25   ) in the dispensing direction, and a drive mechanism  252  that drives the plunger pusher in the dispensing (or “forward”) direction and the retraction direction. The rigid chassis  244  may, among other things, provide a low compliance, very rigid mounting structure for receiving and securely holding the medicament cartridge  100  relative to the plunger pusher  250 , and is shown in  FIGS.  23  and  25   . 
     The chassis  244 , and thereby the pump module  204 , may be molded snap in, hooked, bonded or attached with fasteners to the bottom portion  208  of the pump assembly housing  202 . As can be seen in  FIG.  16   , when the chassis  244  is positioned in the housing  202 , the large bottom opening  248  directly communicates with the medicament cartridge receiving area  220 . The exemplary chassis  244  also includes an opposing, and smaller, top opening  254  that directly communicates with the top wall opening  226  in the housing  202 , as shown in  FIGS.  15  and  17   . 
     Turning to  FIG.  20   , the components of the exemplary chassis  244 , which is described in extensive detail below, may include a first side frame member  256 , a second side frame member  258 , an end gear cap  260 , two long fasteners  262 , two shorter fasteners  264 , a connector bar  266  ( FIG.  21   ), and two spring bias clips  268 . The exemplary rigid chassis  244  is shown in exploded form in  FIGS.  21  and  22    to illustrate the various chassis components and the assembly thereof. 
     The first side frame member  256  illustrated in  FIGS.  21  and  22    may include a first side longitudinal portion  270 , a rear transverse dog leg  272 , a bulging portion  274 , a first forward recessed area  276  defining part of the cartridge compartment  246  and a first forward transverse portion  278  defining another part of the cartridge compartment  246 . The longitudinal portion  270  has an outer elongate recessed area  280  ending at the bulging portion  274 , which has a through-hole  282 . A first half  284  of a circular longitudinal opening  350  ( FIG.  18   ) may be formed at the rear of the cartridge compartment  246  by the first side frame member  256 . The longitudinal portion  270  may have a side through-opening or window  287  at a forward location in the cartridge compartment  246 . In some embodiments, the opening  287  may be sealed with a transparent cover such as a transparent film. The dog leg  272  may have two large fastener openings (or “holes”)  286  and two small fastener openings  288  in a rearward face  290 . Engagement portion  292  extends inwardly from the longitudinal portion  270  and the forward transverse portion  278  and into the cartridge compartment  246 . The forward transverse portion  278  may have a side opening  294 . Top and bottom body plate portions  296 ,  298  extend inwardly from the longitudinal portion  270 , forwardly from the dog leg  272  and rearwardly from the cartridge compartment  246 . 
       102411  The second side frame member  258  illustrated in  FIGS.  21  and  22    may include a second side longitudinal portion  300 , a second forward recessed area  302  defining part of the cartridge compartment  246  and a second forward transverse portion  304  defining part of the cartridge compartment  246  and having a transverse through-hole  306 . An engagement portion  308  extends into the cartridge compartment  246  from the second side longitudinal portion  300  and the second forward transverse portion  304 . As shown in  FIG.  21   , two spaced recessed areas  310  may be formed on the inward surface of the second side longitudinal portion  300  and at the cartridge compartment  246 , and lateral through-openings  312  may be formed at upper ends of these recessed areas, as can be seen in  FIG.  22   . A second half  314  of the large longitudinal opening  350  may be formed at the rear of the cartridge compartment  246 , as shown in  FIG.  21   . A longitudinal through-opening  316  may be near the second half  314  of the opening, as can be seen in  FIG.  21   , and through a wall  318  of the second side frame member  258 . The wall  318  forms a portion of the aft wall  320  ( FIG.  18   ) of the cartridge compartment  246 . The rear end of the second side frame member  258  may include a wall  322  extending between top and bottom body plate portions  324 ,  326  and inward from the second side longitudinal portion  300 . As can be seen in  FIG.  22   , the wall  322  may include upper and lower openings  328 ,  330 . 
     It may be noted here, with reference to  FIGS.  16  and  17   , that the chassis engagement portions  292 ,  308  at least in substantial part define the periphery of the top opening  254  of the chassis  244 . The engagement portions  292 ,  308  may also form abutment surfaces for the medicament cartridge  100  to block a top surface of the medicament cartridge from impacting the housing  202  as a small portion of the cartridge extends through the housing opening  226  ( FIG.  17   ). 
     The exemplary end gear cap  260  illustrated in  FIGS.  21  and  22    may be formed by a body portion  332  having a bulging portion  334  and a flat inward back face  336 . Referring to  FIG.  21   , the inward back face  336  may include two small recess openings  328 ,  330 , a first one in the bulging portion  334  and a second one close to the first one, as well as a central circular large recess opening  338 . The outward rear surface of the body portion  332  may have two recessed wells  340 , each communicating with respective through-openings  342 , and two recessed wells  346 , each communicating with respective through-openings  348 , as shown in  FIG.  21   . 
     The configuration of the exemplary chassis  244  allows the chassis to be subsequently disassembled and reassembled in order to, for example, retrieve, repair and/or replace components of the pump module  204 . 
     The assembly of the chassis components can be understood from a comparison of  FIGS.  21  and  22    to  FIGS.  18  and  20   , with an emphasis on the dotted lines in  FIGS.  21  and  22   . The order of the assembly steps may be varied from those set forth below as would be apparent to those skilled in the art. Operative positions of the components of the drive mechanism  252  ( FIG.  18   ) and drive line  344  ( FIG.  25   ) in and relative to the chassis  244  are described below with reference to  FIGS.  23  and  25   , for example. 
     As part of the exemplary assembly method, bottom ends of the spring clips  268  are fitted into (or otherwise affixed in) bottom ends of the respective recessed areas  310 . The clips  268  are compressed slightly and their upper ends are inserted into the upper ends of the respective recessed areas  310  and into the respective openings  312 . The clips  268  are thereby compressed and bulging slightly into the cartridge compartment  246 , as can be seen in  FIGS.  18  and  19   . Thus, when the medicament cartridge  100  is in the cartridge compartment  246 , the spring clips  268  bias the cartridge  100  to and against the opposite wall of the cartridge compartment. This not only helps to insert and releasably hold the cartridge  100  in the cartridge compartment  246 , but also pushes the cartridge  100  closer to the chassis window  287  to hold occlusion sensor components in fixed relation as is discussed in detail in Section IV-H. 
     The first and second side frame members  256 ,  258  are positioned together as part of the chassis assembly process. When positioned together, the connector bar  266  is inserted in through the through-hole  306  and into the opening  294  to thereby connect the first and second transverse portions  278 ,  304  together. Alternatively, the connector bar  266  may be inserted into the through-hole  306 , the first and second side frame members  256 ,  258  positioned together and the connector bar  266  then pushed into the opening  294 . 
     With the first and second side frame members  256 ,  258  positioned together and the end gear cap  260  positioned against the rearward face  290  of the dog leg  272  of the first side frame member  256 , it can be understood from the drawings that many of the holes or openings will align for operative insertion therein of respective fasteners. Specifically, and referring to  FIG.  22   , holes  286 ,  330 ,  342  will align for receipt therein of fasteners  262  with the heads  263  disposed in the wells  340 ; and holes  288 ,  348  will align for receipt therein of fasteners  264  with the heads  265  disposed in the wells  346 . The heads  263  and  265  are disposed in their respective wells, and do not extend out exposed beyond the outer surface envelope of the end gear cap  260 , as can be seen in  FIG.  20   . 
     Referring to  FIG.  22   , the two longer fasteners  262  pass through respective holes  342  in the end gear cap  260  and the first and second side frame members  256 ,  258 . In contrast, the two shorter fasteners  264  do not extend into the second side frame member  258 , but only through holes in the end gear cap  260  and the first side frame member  256 . This arrangement has the advantage that the fasteners  262 ,  264  not only attach the gear cap  260  to the first and second side frame members  256 ,  258 , but also attach aft ends of the side frame members together and in a relatively compact construction. 
     When the chassis  244  is assembled, the first and second halves  284 ,  314  ( FIG.  21   ) adjoin to form the circular longitudinal opening  350  ( FIG.  18   ). The opening  350  extends between the cartridge compartment  246  and the chassis chamber  352  illustrated in  FIG.  21   . The top surface of chamber  352  is formed by the adjoining top plate portions  296 ,  324  and the bottom surface is formed by the adjoining bottom plate portions  298 ,  326 . The opening  316  ( FIG.  18   ), which is adjacent to the opening  350 , also extends between the cartridge compartment  246  and the chamber  352 . 
     As can be understood from the drawings, including  FIGS.  18 ,  19  and  20   , the bulging portions  274 ,  334  of the first side frame member  256  and the end gear cap  260 , respectively, are similarly configured such that when the end gear cap  260  is attached to the first side frame member  256  the bulging portions  274 ,  334  mate and form a continuous smooth curving surface. 
     The cartridge compartment bottom opening  248  ( FIG.  18   ), which is formed when the first and second side frame members  256 ,  258  are mated, may have a generally rectangular shape with three right angle corners and one rounded corner  354 , which is shown in the bottom perspective views of  FIGS.  18  and  20   . The bottom opening  248  may be formed or defined by a rim  356 , as shown for example in  FIGS.  19  and  20    and described above. The opening  248  and the cartridge compartment  246  itself may be configured to receive therein with a relatively close fit the medicament cartridge  100 . The opening  248 , cartridge compartment  246  and medicament cartridge  100  may be configured so that there advantageously is only one orientation in which the cartridge  100  may be inserted into the cartridge compartment  312 . 
     With respect to materials, the chassis  244  may be made, for example, of ceramic, plastic filled with a stiffening material, glass-reinforced plastic, carbon reinforced plastic, aluminum, steel, titanium or other metal. The chassis  244  may be formed of a material having a modulus of elasticity greater than  1  million psi,  3  million psi,  10  million psi or  10 - 30  million psi. This is considerably more rigid than the material of the housing  202  itself. Turning to dimensions, in some implementations, the chassis  244  may have a length of 40 mm+/−1.0, 40 mm+/−0.10 mm or 37.0-41.0 mm; a thickness of 9 mm+/−1.0, 9 mm+/−0.10 mm or 8.9-9.1 mm; and a width of 16 mm+/−1.0, 16 mm+/−0.10 mm, or 15.8-16.2 mm. The cartridge compartment  246 , in turn, may have a length of 19 mm+/−1.0, 19 mm+/−0.10 mm or 18.8-19.2 mm and a width of 12 mm+/−1.0, 12 mm+/−0.10 mm or 11.8-12.2 mm. The cartridge compartment  246  also may help shield the medicament  101  ( FIG.  23   ) in the medicament cartridge  100  from heat generated by the rechargeable battery  238  ( FIG.  18   ) during dispensing and/or recharging procedures. 
     As an example, the configuration and construction of the present chassis  244  may contribute to a frame and drive line rigidity sufficient to withstand axial loads to ten pounds without extension greater than 0.0005 inch through 200,000 rotational (turns) cycles or 400 axial cycles. Axial cycles refer to the drive nut  364  traveling down the lead screw  360  (discussed below with reference to  FIGS.  23  and  25   ). 
     D. Exemplary Plunger Pushers and Drive Mechanisms 
     The exemplary pump module  204  illustrated in  FIG.  18    includes, as noted above, a plunger pusher  250 , to push the cartridge plunger  106  in the dispensing direction, and a drive mechanism  252  that drives the plunger pusher. Generally speaking, the exemplary drive mechanism  252  may, in some instances, include a motor  358 , a lead screw  360  ( FIG.  23   ), a gear assembly  362  ( FIG.  19   ) operatively between the motor and the lead screw, a drive nut  364  ( FIG.  23   ) attaching the pusher to the lead screw, and a thrust bearing  370  ( FIG.  23   ). Each of these components is discussed in greater detail below. 
     As illustrated for example in  FIG.  23   , the exemplary plunger pusher  250  may be a hollow, generally cylindrical structure that includes a plunger engagement surface  366 . The pusher  250  may, in some instances, have a flange (not shown) that prevents rotation of the pusher with the lead screw  360 . Additionally, as noted in Section III above in the context of exemplary medicament cartridge  100 , the exemplary pusher  250  may be configured such that it is not connectable (or “is unconnectable”) to the cartridge plunger  106 . Put another way, and referring to  FIG.  23   , the exemplary plunger pusher  250  does not include any structural components that are (or could be) connected to the plunger pusher. For example, the plunger pusher does not include external threads, a fastener, a magnetic catch, a ratchet, or other such instrumentality. The plunger engagement surface  366  may, for example, simply be planar as shown. Given the lack of connectability, under no circumstances will reverse movement of the plunger pusher  250  pull the plunger  106  rearwardly and draw medicament back into the reservoir  104 . 
     Suitable materials for the plunger pusher  250  include, but are not limited to, stainless steel, polystyrene and polycarbonate. The dimensions will correspond to the other aspects of the overall system. For example, the plunger pusher  250  may have an outer diameter (or other “thickness” dimension of 6 mm+/−1 mm and a length of travel of 8.5 mm+/−2.0 mm. 
     With respect to the drive mechanism  252 , and referring first to the motor, and although the present inventions are not limited to any particular motor, the exemplary motor  358  may be a stepper motor such as, for example, the Faulhaber ADM 0620 motor. The Faulhaber ADM 0620 motor has a 6 mm diameter, a planetary gearhead of  256  reduction, and the specifications of the motor are set forth at www.faulhaber.com. A stepper motor may in some instances control angular displacement and speed more precisely than a DC motor. Motors other than stepper motors, including DC motors, may be employed in the present pump assemblies. 
     Turning to the lead screw, and referring to  FIG.  23   , the exemplary lead screw  360  is connected to the plunger pusher  350  by a drive nut (or “retaining nut”)  364  such that the rotational motion of the lead screw  360  may be translated into axial movement of the pusher  250 . In other words, the drive nut  364  is in contact with the lead screw  360  and propels the pusher  250 . The exemplary drive nut  364  may be molded with the pusher  250  or may be pressed into a flange of the pusher. Alternatively, the pusher  250  and drive nut  364  may be integrally machined of the same material or the pusher may be molded with internal threads. 
     The lead screw  360  and the drive nut  364  may be made of material that allows axial movement within an exemplary 0.0005 inch overall chassis “stretch” budget under a ten pound load through 200,000 rotational cycles or 400 axial cycles. The lead screw  360  may have a gearform accuracy in rotation of better than 0.0005″ to prevent apparent missed delivery increment, and may have a 70% mechanical efficiency. The diameter of the lead screw  360  may be relatively small (e.g., 3.0 mm) to help minimize the size of the pump module  204 . The threads  368  of the exemplary lead screw  360  may be Acme threads to provide high efficiency and precision, and may have a 0.5 mmlead pitch (approximately 0.020 inch/revolution). 
     An exemplary drive line  344  may be defined, as is illustrated in  FIG.  28   , by the drive nut  364 , lead screw  360  and thrust bearing  370 . The thrust bearing  370  may be on the non-threaded shaft end  372  of the lead screw  360 . The thrust bearing  370  may also be selected, for example, to allow axial movement within an exemplary 0.0005 inch overall chassis “stretch” budget under a 10 pound axial load, and have an axial length of 2 mm, an inner diameter of 2 mm and an outer diameter of 6 mm. 
     The thrust bearing may be a conventional ball bearing, angular contact bearing, or, as illustrated in  FIG.  28   , it may be a combined radial/thrust bearing of the type represented by reference numeral  370 . The thrust bearing  370  may include ball bearings  374 , a retainer  376  that guides the ball bearings, a thrust washer  378 , and radial ball bearings  380  that ride on the thrust washer and also ride on a thrust face of a drive gear  382 . The radial ball bearings  380  may take up the thrust of the lead screw  360  in the retraction direction. The drive gear  382  may be integrally machined with, or welded or bonded to, a portion of the lead screw  360  such as the non-threaded shaft end  372 . The radial bearings  384  may be pressed onto the shaft  372  and, to resist axial force, pressed or bonded into the rear wall of the chassis  244  or more specifically into the opening  338  ( FIG.  21   ) in the gear cap  260 . As an example, the combined radial/thrust bearing  370  may be configured to resist ten pounds of axial force during medicament  101  dispensing from the medicament cartridge  100  and four pounds of axial force during retraction of the pusher  250 . 
     Turning to  FIG.  19   , which shows the exemplary pump module  204  with the gear cap  260  removed therefrom for explanatory purposes, the drive gear  382  on the lead screw  360  is one of three gears of a transverse gear train  384 . The other two gears may be a planetary gearbox output gear  386  and a transverse gear  388  that is operatively positioned between the drive gear  382  and the output gear  386 . As illustrated in  FIG.  21   , the shaft  390  of the transverse gear  388  is fixed in the gear cap opening  392  and the gear  388  freely rotates on the shaft  390 . The gear cap and first side member bulging portions  336 ,  274  define part of a gear box for the transverse gear train  384 . Lubricant may be provided in the gear box to reduce the friction between the gears therein. 
     The transverse gear train  384  may be selected to withstand gearform loads of 10 mNm output torque at the motor  358 . The accuracy of the gearform in rotation may be better than 0.0005 inch to prevent apparent missed delivery increment (decremented by the gear ratio closer to the motor output). The transverse gear train  384  may have a 2:1 gear ratio. 
     The exemplary gear assembly  362  may also include a planetary gearbox  394 . The planetary gearbox  394  may be selected to withstand gearform loads of 10 mNm output torque at the motor  358 , and may have a 256:1 gear ratio. 
     As illustrated for example in  FIGS.  18  and  19   , the drive mechanism  252  may also include an encoder  396  positioned on the shaft of motor  358  opposite the planetary gearbox  394 . The encoder  396  may be used to define/resolve the number of revolutions (or “angular displacement”) and/or the rotational direction of the motor shaft. The displacement/direction information is sent to the controller  240  and used to control various operations of the pump assembly  200 , as is discussed in greater detail in Section IV-L (among others) below. Briefly, during normal operation, the controller  240  sends paired drive signals to the motor  358  (stepping pulses) while monitoring the pulse train back from the encoder  396 . For example, the number of encoder signals (or “ticks”) for a particular dispensing operation may be calculated, encoder  396  is monitored in near real time to determine if it is moving as predicted. The encoder  396  may also be used to detect gear assembly issues as well as motor operation errors. 
     As is also illustrated in  FIGS.  18  and  19   , the motor  358 , planetary gearbox  394 , and encoder  396  together define a cylinder. The cylinder fits in a compact manner partially into and against the outer recessed surface  280  of the chassis first side frame member  256 . Turning to  FIGS.  23  and  25   , when viewed in plan, the exemplary drive mechanism  252  defines a U-shape with one leg of the U being defined by the longitudinal axis of the motor  358 , planetary gearbox  394 , and encoder  396 , while the other leg of the U is defined by the longitudinal axis of the lead screw  360 . The two axes (or legs of the U) are only 9.5+/−1.0 mm apart in the illustrated embodiment. The base of the U is defined at least substantially by the transverse gear train  384 . 
     In at least some instances, it may be desirable to detect when the plunger pusher  250  is in the fully retracted (or “home”) position illustrated in  FIGS.  18  and  29   . This may be accomplished in a variety of ways. One exemplary structure for performing the retracted position detection function is the position detector  398  illustrated in  FIG.  29   . The exemplary position detector  398  includes a switch  400 , which may be mounted to the chassis  244  aft of the opening  350 , and a flange  402  that may be carried by the pusher  250 . When the pusher  250  is in the retracted position illustrated in  FIG.  29   , the switch  400  is closed by the flange  402  and sends a signal to the controller  240  indicating that the pusher  250  is in the home position. The switch is open when the pusher  250  is not in the home position and a portion thereof is within the cartridge compartment  246 . 
     In other embodiments, different types of switches may be employed, or the flange may be omitted and the switch positioned such that it will be closed by the pusher  250  when the pusher  250  is in the retracted position. For example, switch contacts (e.g. a metalized pattern) may be carried on the chassis  244  and a conductive pad may be carried on the flange  402 . Non-mechanical detectors, such as magnetic detectors and optical detectors, may be used in place of a switch. Additionally, regardless of the type of detector employed, the detector may be configured to provide a signal to the controller  240  when the pusher  250  is not in the retracted position. 
     Another alternative is to simply detect that the motor encoder  396  is not turning when running the motor  358  in reverse. To that end, a hard mechanical stop (not shown) may be provided at a location that stops the pusher  250  and stalls drive mechanism  252  when the pusher reaches the home position. Such a hard mechanical stop may be non-binding, i.e., configured such that the drive mechanism  252  can be stalled by the stop but can also easily reverse without mechanism binding. Homing may be accomplished by retracting the pusher  250  with controlled torque and speed until the pusher hits the hard mechanical stop, thereby stalling the motor  358 . Motor stall may be identified in response to the encoder  396  indicating no rotation. The expected stall (home) location may be remembered by the device and compared to the actual stall position for additional control or, in at least some implementations, the motor  358  may be given a reverse displacement command that is larger than the total possible travel of the drive mechanism  252 , and the actual stall (home) position determined based on the stall of the motor. The various techniques described herein for increasing motor torque in response to a motor stall to verify stall position may be employed to improve this technique of home position determination by stalling at the hard stop. 
     E. Exemplary Reservoir Clamping 
     The arrangement, configuration and materials of the chassis  244  and drive line  344  in the exemplary implementation together create a force “clamp” that is generally represented by reference numeral  404  in  FIG.  30   . The clamp  404  clamps the reservoir  104  between the dry side of the plunger  106  and the outer surface of the cartridge front wall  117 . Put another way, both ends of the reservoir  104  are held in such a manner that movement of the reservoir relative plunger pusher  250  (e.g., due to cartridge movement) may be prevented, and the corresponding loss of delivery accuracy prevented. 
     The thick arrow  406  in  FIG.  30    represents the action force associated with the pusher  250  pushing the plunger  106  as a result of rotation of the motor  358 . The thin arrows  408  show the reaction forces originating in the plunger  106 , traveling back in the opposite direction through the drive line  344  and then forward through the fasteners  262  and  264 , and through the chassis  244  to the front wall  117  of cartridge  100 . A reaction force  410  on the outer surface of the front wall  117  and opposite to the action force  406  is thereby created. The force “clamp”  404  may be generally configured as a pair of oppositely-facing C-shaped clamps, as can be understood from  FIG.  30   . 
     The clamping displacement of the reservoir  104  applied by the clamp  404  adjusts incrementally as the cartridge plunger  106  is advanced towards the front wall  117  by the pusher  250 . For example, the clamping displacement may adjust incrementally by 0.001 inch. The exemplary clamp  404  may apply a clamping displacement with, for example, a precision of better than 2% over a force range of zero to ten pounds. 
     F. Exemplary Cartridge Lock and Bias Apparatus 
     In at least some implementations, structure is provided to block removal of a cartridge from the pump assembly when the plunger pusher  250  is in the cartridge  100 , and to allow a cartridge to be inserted into and removed from a compartment within the pump assembly when the pusher is retracted. 
     One example of such as structure is the releasable, linear one-way clutch (or a “latching mechanism,” or an “interlock”) that is generally represented by reference numeral  412  in  FIGS.  23 - 27   . The clutch  412  blocks removal of a cartridge (e.g., cartridge  100 ) from the pump module  204  when the plunger pusher  250  is in the cartridge, but allows the cartridge to be inserted into and removed from the cartridge compartment  246  when the pusher is in a retracted “home” position. 
     Referring first to  FIG.  24   , the exemplary clutch  412  may include a first coil spring  414 , a first pin or elongate member  416 , a second coil spring  418 , a second pin or elongate member  420 , and a “teeter-totter” toggle ball  422 . The second elongate member  420  may include friction-engaging surface  428  ( FIG.  27   ). The first coil spring  414  is positioned inside of the first elongate member  416  to form a spring-biased first member  424 . The second coil spring  418  is positioned in the second elongate member  420  to form a spring-biased second member  426 . 
     In one exemplary implementation, the first and second springs  414 ,  418  may each have one to two pounds of spring force. The first spring  414  may have a one mm diameter, and the second spring  418  may also have a one mm diameter. The first and second elongate members  416 ,  420  may have respective lengths of 12.5 and 7.25 mm. The second elongate member  420  may be a two mm diameter steel rod, and the friction-engaging surface  428  may be a two to five degree beveled surface. 
     With respect to operation of the exemplary clutch  412 , the mode of the spring-biased first member  424  determines whether the clutch  412  is in a locked condition ( FIGS.  23  and  24   ) or an unlocked condition ( FIGS.  25  and  26   ). The spring-biased second member  426 , when the pusher  250  is in a non-retracted position, holds the spring-biased first member  424  in a friction-contact locked condition with the friction-engaging surface  428 . The cartridge  100  is thereby latched in place in the cartridge compartment  246 . 
     The toggle ball  422  toggles when the pusher  250  is moved to the retracted home position. The toggling action moves the spring-biased second member  426  to a position with the friction-engaging surface  426  out of friction contact with the spring-biased first member  424 . In this unlocked or unlatched condition ( FIGS.  25  and  26   ), the cartridge  100  may be removed from or inserted into the cartridge compartment  246 . In this fully retracted mode, the spring-biased first member  424  retracts when the spring force of the first coil spring  414  therein is overcome by the force of a cartridge  100  being inserted into or removed from the cartridge compartment  246 . 
     The spring-biased first member  424  may have a patterned end  430  with a sixty-degree beveled face  432  on the cartridge insertion side, as shown in  FIG.  24    for example. This beveled face  432  facilitates easy cartridge insertion, with a radius where the spring-biased first member  424  engages the cartridge  100  in a small slot (not shown) for detent action.  FIG.  18    shows the end  428  of the spring-biased first member  424  protruding or extending into the cartridge compartment  246  with the sixty-degree beveled face  432  disposed upwards. So positioned, the spring-biased first member  424  will engage the inner surface  112  ( FIG.  23   ) of the cartridge medicament cartridge when the medicament cartridge is in the cartridge receiving area and, given the close fit between the exterior of the cartridge and the interior of the chassis, removal will be prevented. 
     More particularly, when the clutch  412  is in the locked condition illustrated in  FIGS.  23  and  24   , the second member  426  intersects the first member  424  at generally five degrees with a light spring force of 0.1 to 0.5 pound, biasing the spring-biased second member  426  towards the spring-biased first member  424 . That is, the second member  426  is spring biased towards the first member  424 , and thereby operates similar to a one-way roller clutch. Referring to  FIG.  24   , the first member  424  is on top with the second member  426  below and intersecting at generally five degrees with the light spring bias of 0.1 to 0.5 pound. With the pusher  250  in any position other than the fully retracted home position ( FIG.  25   ), the second member  426  is self-energized by friction with the first member  424 , thereby preventing rearward motion of the first member  424 . Then, when the pusher  250  is in a fully retracted position, the second member  426  is moved slightly forward by the half ball toggle  422 , releasing friction contact with the first member  424 . The spring-biased first and second members  424 ,  426  are thereby in the positions shown in  FIG.  26   . 
     In other words, when the pusher  250  is fully retracted, the first member  424  is biased towards the cartridge  100  with a one to two pound spring force and acts like a spring plunger detent. In this fully retracted mode, the first member  424  is able to retract when the spring force is overcome by cartridge insertion or removal. Then when the pusher  250  is not fully retracted, the second member  426  locks the first member  424  from rearward motion and blocks cartridge insertion and removal. 
     The half ball toggle  422  may be formed from a two mm diameter steel ball, and may rest in a spherical recess  434 , such as one machined into a surface of the chassis  244 . The half ball toggle  422  thereby can toggle the second member  426  forward when the pusher  250  retracts fully and engages the half ball toggle  422 , as can be understood from the arrows  436 ,  438 ,  440  in  FIG.  23   . Other toggling or “teeter-totter” constructions may be used instead of the exemplary half-ball toggle  422 . The clutch  412  also self-adjusts for cartridge  100  tolerance. 
     The pusher  250  and the spring-biased first member  424  may be provided with o-ring sealing surfaces (not shown) to help make the clutch  412  waterproof. 
     The pusher  250  may be retracted automatically when the reservoir  104  is empty (see  FIG.  25   ) as discussed elsewhere in this disclosure, which thereby automatically causes the clutch  412  to be unlocked when the reservoir is empty. Alternatively, by operating the remote control  1000  (see, e.g.,  FIG.  81   ), the patient may cause the pusher  250  to be retracted before the reservoir  104  is empty, as when he wants to remove the medicament cartridge  100  before it is empty and replace it with a new cartridge  100 . This retraction of the pusher  250  by the patient&#39;s instructions also causes the clutch  412  to unlock. 
     Another way of describing the mechanism of the clutch  412  is that the mechanism functions as an interlock that prevents removal of the medicament cartridge  100  from the receiving area  220  when the cartridge  100  is in the inserted position and the pusher  250  is in a non-retracted position, and that allows removal of the medicament cartridge  100  from the receiving area  220  when the cartridge  100  is in the inserted position and the pusher  250  is in a retracted position. The interlock/clutch  412  automatically unlocks the cartridge  100  when the pusher  250  is in the retracted position, and automatically locks the cartridge  100  when the pusher  250  is advanced out from the retracted position. 
     Additionally, one exemplary advantage of the aforementioned light spring bias is illustrated in  FIG.  31    in the context of system  10 . When a user of the exemplary patch pump system  10  desires to replace the cartridge  100 , baseplate  500  and cannula  600 , the pump assembly  200  may simply be pulled off the baseplate. The baseplate adhesive (discussed below) will hold the baseplate  500  to the skin, the cannula latch (discussed below) will hold the cannula to the baseplate, and frictional engagement between the cannula and the cartridge through-bore will hold the cartridge to the cannula. In other words, the reusable portion of the system readily and conveniently separates from the disposable portions. 
     A further way to view the operation of the clutch  412  is that by operating the remote control  1000 , a cartridge-biasing member (the spring-biased first member  424 ) may be changed from a blocking condition, where the cartridge-biasing member (the spring-biased first member  424 ) blocks removal of a medicament cartridge  100  from the pump module  204 , to a release condition, where the cartridge-biasing member (the spring-biased first member  424 ) does not prevent the medicament cartridge  100  from being removed from the pump module  204 . The clutch  412  biases the cartridge  100  forwards, acts as a spring plunger detent during insertion of the cartridge  100  into the compartment  246 , and prevents backwards motion during use. 
     When in a locked condition, the spring-biased first member  424  may engage and bias the medicament cartridge  100  forward in the cartridge compartment  246 . The cartridge  100  is thereby biased to a “held” position to secure the cartridge  100  firmly in place, such as against a rigid wall of the chassis, for accurate and precise medicament dispensing. The first member  424  may bias the cartridge  100  forward and thereby closer to the chassis window  287  (see  FIG.  20   ) to fix the relative positions of various occlusion sensor components, as discussed elsewhere in detail in this disclosure. 
     Another exemplary structure that blocks removal of a cartridge from the pump assembly when the plunger pusher is in the cartridge, and allows a cartridge to be inserted into and removed from a compartment within the pump assembly when the pusher is retracted, is the sliding latch mechanism (or “sliding latch”) generally represented by reference numeral  412   a  in  FIGS.  32 - 35 A . The exemplary latch  412   a  is described below in the context of the pump assembly  200 ′ and baseplate  500 ′, which are identical to pump assembly  200  and baseplate  500  but for minor accommodations for the latch  412   a , and similar elements are represented by similar reference numerals. With respect to the minor accommodations, which are discussed below in context, the pump assembly housing  202 ′ includes a bottom portion  208 ′ with a latch slot  209 , the chassis  244 ′ includes minor adjustments, the plunger pusher  250 ′ includes a recess  468 , and the baseplate  500 ′ includes a latch indentation  509 . 
     The sliding latch  412   a  is configured to secure the cartridge  100  in place when the pusher  250 ′ is at least partially in the cartridge  100 , such as during the dispensing process. In addition to securing the medicament cartridge  100  within the pump module  204 ′, the sliding latch  412   a  biases the cartridge forward to a “held position” against the rigid chassis front wall  245  when the pusher  250 ′ is at least partially in the cartridge  100 . Such biasing facilitates accurate and precise medicament dispensing, and ensures that the cartridge will be accurately located relative to the chassis window  287  ( FIG.  20   ). 
     Turning to the components of the exemplary sliding latch  412   a , and referring to the bottom perspective view presented in  FIG.  32   , the sliding latch includes a slidable latch member  442  with a bottom lateral body member  444  as well as a pair of legs  446  (one shown) extending up from opposite ends of the body member. A pair of abutment tabs  448  respectively extend rearwardly from the legs  446 . The bottom lateral body member  444  includes a pair of flange portions  452  and an arched (convex) finger tab  456 , with friction ridges  458 , that is operatively accessible to the user when no baseplate attached ( FIGS.  33  and  34   ). 
     A pair of rods  460  (one not shown) extend longitudinally through holes in the legs  446  and the front ends of the rods are secured in a wall of the chassis  244 , such as the aft wall  320  ( FIG.  18   ). The rear ends of the rods  460  are secured in a chassis flange  462 . A pair of bias springs  464  (one not shown) respectively encircle the rods  460  between the legs  446  and the flange  462 , and bias the slidable latch member  442  forward, towards the chassis cartridge compartment  246  and to a normal forward biased position. 
     When the latch member  442  is in the normal forward biased position, the ends of the flange portions  452  will extend over the opening of the cartridge compartment  246 , thereby blocking insertion of a medicament cartridge (e.g., cartridge  100 ) into the pump assembly  200 ′ as well as the removal of cartridge from the pump assembly. When the pusher  250   a  is in a retracted home position, the slidable latch member  442  is unlocked (as discussed below) and the user can slide the latch member rearward against the bias force of springs  464  ( FIGS.  32  and  33   ) within the housing slot  209 . The latch member  442  reaches the rearward position when the tabs  448  abut the rear flange  462  ( FIG.  32   ). Here, the flange portions  452  no longer overlap the opening of the cartridge compartment  246  and block insertion (or removal) of a cartridge. 
     Turning to  FIG.  33   , the exemplary sliding latch  412   a  may also include a locking apparatus  466 . The exemplary locking apparatus  466  may include a recess  468  in the plunger pusher  250 ′, a recess  470  in the lateral body member  444 , a hole  472  in the chassis  244 ′, and a movable ball  474  carried within the hole. When the latch  412   a  is in the state illustrated in  FIG.  33   , which is the result of the user sliding the lateral body member  444  to the rearward position, the movable ball  474  will be located within the pusher recess  468 . After a cartridge  100  is inserted into the cartridge compartment  246  and the user releases the lateral body member  444 , the springs  464  will push the lateral body member to the position illustrated in  FIG.  34   . Here, movable ball  474  will be aligned with both the pusher recess  468  and the lateral body member recess  470 . Depending on the rotational orientation of the pump assembly  200 ′, the movable ball  474  will either be in the pusher recess  468  or the lateral body member recess  470 . When the baseplate  500 ′ is attached as shown in  FIG.  35   , the user will no longer have access to the latch  412   a  and the finger tab  456  will be located in the baseplate recess  509  ( FIG.  35 A ). After the plunger pusher  250 ′ is moved forwardly by operation of the lead screw  360 , the movable ball  474  will be held in the lateral body member recess  470  and, given that a portion of the ball is also in the chassis hole  472 , the lateral body member  444  will held in place and the latch  412   a  will be in the locked state. The user will not be able to unlock the latch  412   a  until the pusher  250 ′ is returned to the home position. 
     It should be noted that the relationship between the finger tab  456  and the baseplate slot  509  also helps to facilitate proper alignment of the baseplate  500 ′ relative to the pump assembly  200 ′ and, for example, proper alignment of the structures that are associated with the baseplate identification process (described in Section VI below with reference to  FIGS.  66 - 78   ) on the pump assembly (e.g., electrical contacts  228 ,  230  and  232  in  FIG.  16   ) and the baseplate (e.g., identification devices  582 - 0 ,  582 - 1  and  582 - 2  in  FIG.  1   ). 
     Another exemplary structure that blocks removal of a cartridge from the pump assembly when the plunger pusher is in the cartridge, and allows a cartridge to be inserted into and removed from a compartment within the pump assembly when the pusher is retracted, is the sliding latch mechanism (or “sliding latch”) generally represented by reference numeral  412   b  in  FIGS.  36  and  37   . The latch  412   b  may be used in conjunction with, for example, the cartridges, pump assemblies and baseplates described herein with the minor accommodations described below. The exemplary latch  412   b  is described below in the context of the cartridge  100 ′, which is identical to cartridge  100  but for minor accommodations for the latch  412   b , and the pump assembly chassis  244 . Similar elements are represented by similar reference numerals. With respect to the minor accommodations, which are discussed below in context, the cartridge body  102  includes a slot  478  and the chassis wall  318  includes a longitudinal aperture  486 . 
     The exemplary latch  412   b  may include a latch element  476 , which is carried by the chassis  244 , and is biased to a retracted, unblocking position by a spring  480 . In the illustrated embodiment, the latch element  476  includes a flange portion  482  and a thinner extension portion  484 . The spring  480  may be positioned between the chassis wall  318  (or some other fixed structure) and the flange portion  482 . The thinner extension portion  484  extends through the longitudinal aperture  486 . 
     The latch assembly  412   b  may also include a sliding latch tensioner  488  that slides relative to the pusher  250  along a longitudinal axis of the pusher. A flange or other structure  490  may be secured to, or be an integrally formed part of, the pusher  250  and may be positioned aft of the sliding latch tensioner  488 . A tensioner spring  492  may be disposed between the sliding latch tensioner  488  and the flange  490 . The tensioner spring  492  may be stronger than the latch spring  480 . As the pusher  250  is driven into and against the plunger  106 , the latch spring  480  compresses quickly, propelling the extension portion  484  into the cartridge slot  478  ( FIG.  37   ), thereby preventing the cartridge from moving in a direction orthogonal to the longitudinal axis of the plunger  250 . The tensioner spring  492  absorbs additional propelling energy. The biasing force of the spring  480  pulls the extension portion  484  out of the cartridge slot  478 , thereby unlocking the latch, when the plunger  250  returns to the home position ( FIG.  36   ). 
     The clutch  412  ( FIGS.  16 - 20   ) and the sliding latch mechanism  412   a  ( FIGS.  27 - 27 C ), in addition to performing latching/locking functions, also perform a pushing function. The latch assembly  412   b  ( FIGS.  36 - 37   ) may be adapted to perform a pushing function. They all are examples of structures that perform the function of pushing (or “biasing”) a medicament cartridge (e.g., cartridge  100 ) against a wall and, more specifically, engaging an aft end of a cartridge and pushing the medicament cartridge that is in the inserted position within the pump assembly against a rigid wall to a held position. The rigid wall may, for example, be the front wall of the chassis  244 . Other examples structures that performing these function are schematically represented by reference numeral  494  in  FIG.  38   . Such structures include, but are not limited to, coil springs, leaf springs, interfering bumps, interference fits, and deformable resilient members. Such structures may be attached to the aft wall  320  of the cartridge compartment  246  or some other structure. 
     G. Exemplary Encoders 
     One aspect of present system control instrumentalities, which is applicable to variety of individual control methodologies discussed herein, is monitoring the actual movement of the shaft of motor  358 . Specifically, the number of revolutions (or “angular displacement”) and/or the rotational direction of the motor shaft is resolved. For purposes of simplicity, rotation of the shaft of the motor is simply referred to as rotation of the motor. The number of revolutions in the forward direction may be used to determine the amount of medicament that has been dispensed. For example, in some implementations, 14.4 revolutions may equal one μL and, accordingly, may equal 0.50 IU of U-500 insulin dispensed. 
     A wide variety of apparatus may be used to monitor angular displacement and rotational direction of the motor  358  so that the controller  240  can, for example, determine if the motor is moving as predicted. Although the present inventions employ an encoder to perform this function, other apparatus that may be employed include, but are not limited to, monitoring coil current of the motor. It should also be noted that the present inventions are not limited to any particular type of encoder. 
     In the exemplary embodiments, an encoder  396  may be positioned on the shaft of motor  358  in the manner illustrated, for example, in  FIG.  18   . The motor/encoder relationship is schematically represented in  FIG.  39    and various exemplary encoders are described below with reference to  FIGS.  40 A- 401   . Briefly, during normal operation of at least one embodiment, the controller  240  sends paired pulse/phase drive signals (stepping pulses) to the motor  358  while monitoring the pulse train back from the encoder  396 . The pulse trains associated with exemplary encoders are also presented in  FIGS.  40 A- 401   . The encoder  396  is monitored in near real time to determine if its movable portion associated with the motor shaft  357  (and, therefore, the motor  358 ) is moving as predicted. 
     Referring to  FIG.  40 A , an exemplary encoder  396   a  may be an optical encoder. Such encoders may have a light emitter  397 , a photodetector  399 , and one or more optical interrupters  401 . The interrupters  401  are positioned and/or configured so that a different waveform is produced when the portion of the encoder  396   a  with the interrupters is rotated in a forward direction as opposed to a rearward direction, as shown. The optic interrupters  401  in the exemplary encoder  396   a  are in the form of two occluding tabs spaced apart at an angle other than 180 degrees. Turning to  FIG.  40 B , exemplary encoder  396 b has two encoder openings  401   b  spaced apart at an angle other than 180 degrees. An exemplary encoder  396   c  with two reflective surfaces  401   c , also spaced apart at an angle other than 180 degrees, is shown in  FIG.  40 C . The exemplary encoder  396   d  in  FIG.  40 D  has a single encoder opening  401   d  with an asymmetrical shape that forms different forward and reverse waveforms. The occluding tab  401   e  in exemplary encoder  396   e  ( FIG.  40 E ) is also asymmetrical and the waveform produced thereby is different in the forward and reverse directions. The exemplary encoder  396 f in  FIG.  40 F  has openings  401   f  of different size that result in a waveform that is different in the forward and reverse directions. 
     Turning to  FIGS.  40 G- 401   , other exemplary encoders employ magnetic detectors. Such encoders may include a sensor that senses changes in magnetic fields, such as a Hall-effect sensor or a magnetoresistive sensor, and a magnet arrangement on or rotating with the motor shaft to produce magnetic fields that are different in the forward and reverse directions of rotation. To that end, the exemplary encoder  396   g  illustrated in  FIG.  40 G  includes a sensor  403  and a magnet arrangement  405   g , with S-N-S magnetized domains, that produces the illustrated signal waveform. The exemplary encoder  396   h  ( FIG.  40 H ) includes a magnet arrangement  405   h  with S-N-S magnetized domains and N-S-N magnetized domains. Another exemplary encoder, which is generally represented by reference numeral  396   i  in  FIG.  40 I , has a rotation axis that passes through a two-bar magnet arrangement  405   i . Another exemplary encoder  396   j  is illustrated in  FIG.  51   . Here, the rotating portion  405   j  includes a single magnet and there is a pair of sensors  403   a  and  403   b . Another exemplary encoder may be in the form of an optical encoder with a pair of sensors. 
     H. Exemplary Pressure/Occlusion Sensors 
     As discussed in Section III above, pressure sensors may be provided to, among other things, detect occlusions in a cannula or infusion set tube. Occlusions may occur for any number of reasons including, but not limited to, cannula kinks caused by movement of the pump assembly relative to a deployed cannula, kinks in the infusion set tube, or granuloma formation at the outlet end of a cannula. The structures that are used to sense pressure may also be used to, for example, sense medicament cartridge presence and alignment within a pump assembly. In at least some implementations, one portion of the pressure sensor may be part of the medicament cartridge and another portion of the pressure sensor may be part of the pump assembly. With respect to the medicament cartridge pressure sensor portions, a variety of different embodiments are described in Section III above with reference to  FIGS.  3 - 8   . Also, although the term “pressure sensor” is employed because pressure tends to increase when fluid is pumped into a lumen that is completely or partially occluded, the sensor may simply be a device that responds to a predetermined threshold pressure or a predetermined increase in volume within a particular region, as opposed to a sensor that is capable of measuring various pressures within a range of pressures. Also, actual pressure need not be determined. For example, for a sensor that is calibrated to produce a predetermined range of outputs over a predetermined range of pressures, the rate of pressure change (which may be indicative of an occlusion) may be determined without actual pressure determinations. 
     Referring now to  FIGS.  41  and  42   , the exemplary pressure sensor  234  includes the cartridge portion  120   a , which is associated with medicament cartridge  100   a  described in Section III above, and the pump assembly portion  236 . The cartridge portion  120   a  may include, among other things, a detectable structure (or “fluid force deflectable part”)  124   a  with a magnet  132   a  or that is carried by a resilient diaphragm  134   a . The diaphragm  134   a , which is exposed to reservoir pressure by way of the aperture  128 , flexes in response to pressure increases, thereby resulting in movement of the magnet  132   a . The pump assembly portion (or “fixed sensor part”)  236 , whose location is fixed relative to the medicament cartridge  100   a , may be a sensor that responds to changes in the adjacent magnetic field (e.g., a Hall-effect sensor or a magnetoresistive sensor). As the magnet  132   a  moves relative to the pump assembly portion  236 , the sensor responds to the associated changes in the adjacent magnetic field (e.g., with a change in output voltage or a change in resistivity). The pump assembly portion  236  is operably connected to the controller  240 , and the controller may be configured to equate sensor responses to changes in pressure within the through-bore  116 . To that end, the pump assembly portion  236  can be mounted on the circuit board associated with the controller and/or may be thought of as the powered part of the sensor. 
     With respect to operation of the pressure sensor  234 , it should initially be noted that a fluid delivery procedure would be performed with, for example, a cannula connector plug (e.g., plug  602  in  FIG.  57   ) or a connector plug  550  for an infusion set ( FIG.  63   ) located within the cartridge through-bore  116 . Such structures have been omitted from  FIGS.  41  and  42    to simplify the illustrations. The detectable structure  124   a  is shown in the “at rest” position in  FIG.  41   , which may correspond to little or no pressure within the cartridge through-bore  116 . The distance between the magnet  132   a  and the pump assembly portion  236  is D 1 . As pressure within the cartridge through-bore  116  increases, deflection of the diaphragm  134   a  results in the distance between the magnet  132   a  and the pump assembly portion  236  decreasing, and the associated sensor will respond accordingly. A pressure change associated with the missed delivery of six μl of medicament (e.g., 5 psi), which may be considered to be the result of an occlusion, will decrease the distance between the magnet  132   a  and the pump assembly portion  236  by an amount AD to D 2  in the illustrated embodiment. 
     The discussion here is, of course, equally applicable to the exemplary medicament cartridge  100  (with cartridge portion  120   a ) described in Section III. Also, as discussed above in the context of  FIGS.  3 - 8   , other exemplary detectable structure arrangements include, but are not limited to, a magnetically permeable structure carried on a diaphragm and movable relative to a coil; and an optical element carried on a diaphragm and movable relative to an optical sensor; and an electrical conductor carried on a diaphragm and movable relative to a pair of switch contacts. It should also be noted that, with respect to the implementations that include a pressure sensor, the present inventions are not limited to pressure sensor arrangements that include a diaphragm, or to pressure sensor arrangements that include a cartridge portion and a pump assembly portion. For example, a medicament cartridge may include a pressure sensor that communicates with the pump assembly by way of electrical contacts. 
     Given the very short distance that the magnet or other detectable structure travels (e.g., ΔD=about 0.1 to 1 mm), changes in the location of the medicament cartridge (e.g., cartridge  100  or  100   a ) relative to the pump assembly portion  236  of the sensor  234  may adversely effect the accuracy of the measurements. Accordingly, in at least some implementations, various structures are provided to position and hold the medicament cartridge at a predetermined location within the cartridge receiving area  220 , e.g., the spring bias clips  268  and the latches  412  and  412   a  described above with reference to  FIGS.  18 ,  23 - 26  and  32 - 35 A . It should also be noted here that the above-described “low system compliance” aspect of the present pump assemblies contributes to the accuracy of the sensor measurements by maintaining the intended spatial relationships between the sensor components, such as pressure sensor cartridge portion  120   a , pump assembly portion  236 , and the window  287  therebetween ( FIG.  41   ). 
     I. Exemplary Fall-Off Detectors 
     The present inventors have determined that one issue associated with any patch pump is that it may be fully or partially dislodged from the patient&#39;s skin (i.e., “falls off”) without the patient&#39;s knowledge. Such full or partial dislodgement could bend the cannula or otherwise interfere with medicament delivery. 
     A variety of mechanisms that detect when a patch pump has been dislodged, and provide an appropriate signal to the system controller (e.g., controller  240 ), are discussed below with reference to  FIGS.  43 - 47   . The system controller may take various steps, e.g., activation of an alarm and/or stopping of the motor, in response to a fall-off signal. Although not limited to use with any particular type of patch pump, the detection mechanisms are described below in the context of patch pump systems that are otherwise identical to the above-described system  10  ( FIGS.  1  and  54   ) to simplify the explanation. Similar elements are represented by similar reference numerals. Other exemplary implementations include, but are not limited to, patch pumps that do not include a baseplate. 
     As illustrated for example in  FIGS.  43  and  44   , an exemplary pump assembly  200   a  is provided with a switch-type detector  650  within the housing  202   a , and the exemplary baseplate  500   a  is provided with a detector aperture  505  that extends through the plate member  506 . The exemplary detector  650  may include a switch  652  and a movable switch actuator  654 . The switch  652  may be a self-contained structure that is biased to the open state ( FIG.  43   ) and that closes in response to contact with the switch actuator ( FIG.  44   ). In other implementations, some or all of the switch may be carried by the associated switch actuator. The switch actuator  654 , which is biased to an extended position ( FIG.  44   ) by a spring  656  or other bias device, may include an abutment  658  that rests on the skin surface S when the baseplate  500   a  is secured to the skin and the pump assembly  200   a  is secured to the baseplate ( FIG.  43   ). A detector aperture  205  is provided on the housing  202   a  to permit movement of the switch actuator  654 . The abutment  658  is carried on one end of a post  660 , and a stop  662  is carried on the other end. The stop  662  both limits travel of the switch actuator  654  and engages the switch  652  during a “fall-off.” 
     So configured, the actuator  654  will be out of contact with the switch  652  when the baseplate  500   a  is secured to the skin and the pump assembly  200   a  is secured to the baseplate ( FIG.  43   ). As the baseplate  500   a  separates from the skin surface S due to failure of the adhesive  542  ( FIG.  44   ) or a pulling force on the baseplate or pump assembly, or the pump assembly  200   a  separates from the baseplate due to failure of the connection therebetween, the biasing force of the spring  656  will move the stop  662  toward the switch  652  until contact is made, the switch is closed, and a signal is sent to the controller. 
     The exemplary switch-type detector  650  may be calibrated, by adjusting the distance D that the switch actuator  654  must travel prior to closing the switch  656 , to define the magnitude of the separation that will trigger a signal to the controller  240  and, in at least some instances, a subsequent patient alert. In the illustrated implementation, the distance D may about 0.5 to 2.0 mm. 
     Another exemplary fall-off detector arrangement is generally represented by reference numeral  650   a  in  FIG.  45   . The exemplary detector  650   a  includes a sensor  664 , which is carried within or by the housing  202   b  of a pump assembly  200   b , and a movable sensed structure  666  that is carried by the baseplate  500   b . The type of sensor will depend upon the type of structure being sensed. In the exemplary implementation, the sensed structure includes a magnet  668  and, accordingly, the sensor  664  is a sensor that is configured to sense changes in magnetic fields such as, for example, a Hall-effect sensor or magnetoresistive sensor. The housing  202   b  also includes an indentation  207  to accommodate the sensed structure  666 . 
     The manner in which the magnet  668  (or other sensed structure) is carried on the baseplate may vary. As illustrated for example in  FIG.  45   , the magnet  668  is carried on a post  670  that extends through a detector aperture  505  in the plate member  506 . A seal  672  may be carried on the post  670 . A steel disk  674  is carried by the plate member  506 . Elastomeric sheets  676  and  678  may be secured to the plate member  506  to enclose the magnet  668 , post  670  and steel disk  674 . 
     So configured, the sensed structure  666  will be relatively close to the sensor  664  when the baseplate  500   b  is secured to the skin and the pump assembly  200   b  is secured to the baseplate (not shown). As the baseplate  500   b  and attached pump assembly  200   b  separate from the skin surface S due to failure of the baseplate adhesive (not shown), the magnetic attraction between the magnet  668  and steel disk  674  will pull the magnet away from the sensor  664 . When the distance therebetween increases to distance D, the magnitude of the change in the magnetic field experienced by the sensor  664  will be such that a signal is sent to the controller. The sensor  664  will experience a similar change in the adjacent magnetic field should the pump assembly  200   b  separate from the baseplate  500   b  due to failure of the connection therebetween. 
     The exemplary sensor-type detector  650   a  may be calibrated by adjusting the distance D that the appropriate portion of the sensed structure  666  (e.g., magnet  668 ) must travel prior to a signal to the controller being triggered and, in at least some instances, a patient alert being provided. In the illustrated implementation, the distance D may be about 0.5 to 2.0 mm. 
     Another exemplary detector, which is generally represented by reference numeral  650   b  in  FIG.  46   , is in the form of an RF circuit with a transmitting antenna  680 , a receiving antenna  682 , and an RF energy source  684 . The RF energy source may be powered by the system battery  238 . The receiving antenna  682  is positioned relative to the transmitting antenna  680  such that the amplitude of the RF field received changes as the baseplate becomes separated from the user&#39;s skin surface S, as shown by waveforms A 1  and A 2 . For example, A 1  may be about twice A 2 . The received RF field has a greater amplitude against skin than in air. In response to a decrease in amplitude, the RF circuit sends a signal to the controller. The transmitting antenna  680  can be mounted in either one of the baseplate and the pump assembly (not shown), the receiving antenna  682  can mounted in either one of the baseplate and the pump assembly, and transmitting antenna and the receiving antenna can both be embedded in the baseplate  500   c  (as shown). In those instances where the RF energy source is carried by the baseplate, power may be provided by way of the pump assembly electrical contacts  228  and  230  ( FIG.  16   ) and the baseplate contacts  228 BP and  230  BP ( FIG.  66   ) 
     Another exemplary detector, which is generally represented by reference numeral  650   c  in  FIG.  47   , is in the form of an electrical circuit having a first electrical terminal  686  and a second electrical terminal  688 , spaced from the first terminal, and carried on baseplate  500   c ′. The electrical circuit is completed between the first and second terminals  686  and  688  by the user&#39;s skin when the associated baseplate  500   c ′ is adhered to the skin surface S by the baseplate adhesive, and is broken when the baseplate becomes separated from the skin. A signal is sent to the controller when the circuit is broken. In the illustrated embodiment, the first and second terminals  686 ,  688  may be in the form of electrically conductive pads carried on the bottom surface of the baseplate  500   c ′. The “fall-off” signal may be a voltage signal and the exemplary circuit is configured to convert current of the electrical circuit to the voltage signal. 
     J. Exemplary Batteries and Battery Rechargers 
     The battery that drives the motor may be a rechargeable battery, such as a rechargeable lithium polymer battery or a rechargeable lithium ion battery. At least some implementations will employ a rechargeable battery having a fully charged, open circuit voltage of generally 4.2 Volts, or 4.18-4.24 Volts. One advantage of lithium polymer and lithium ion batteries is that they can be recharged quickly by the patient, have high energy density, and have desirable linear decay that facilitates accurate charge state indication. Turning to  FIG.  49   , the exemplary battery  238  may be carried within the pump assembly housing  202  in a compartment that is separate from the cartridge compartment  246 . Additionally, because the battery  238  is rechargeable and the housing includes external recharging contacts  228  and  230 , the exemplary housing  202  does not include a door or a cover to provide access to the battery, and the exemplary housing may be sealed (i.e., it cannot be opened without damage thereto). 
     In at least some instances, the user may seek to recharge the battery  238  when there is medicament in the cartridge  100 . Note that the cartridge  100  will be locked into the pump assembly  200  so long as the plunger pusher  250  is not in the fully retracted position, as is discussed above with reference to, for example,  FIGS.  23 - 26   . So locked, the cartridge  100  and pump assembly  200  will separate from the “patch pump” baseplate  500  and cannula  600  in the manner illustrated in  FIG.  48   , while the baseplate and cannula remain on the skin surface S of the user, when the user pulls the pump assembly off of the baseplate. Similar separation will occur in the context of an “infusion set” baseplate  501  and a “non-delivery” baseplate  502  ( FIG.  1   ). 
     Given the relatively close proximity of the battery  238  to the medicament cartridge  100 , heat from the battery  238  could possibly increase the temperature of the medicament during recharging, especially during rapid recharging. The medicament temperature may be relevant to certain medicaments such as insulin, for example, which can be damaged and have its viability become undefined at about 37° C. Accordingly, a temperature sensor  239  (e.g., a thermistor or thermocouple) may also be carried within the pump assembly housing  202  in such a manner that the temperature sensor can sense the temperature of the medicament in the cartridge  100  (or a temperature that is at least representative thereof). For example, the temperature sensor  239  may be carried on the circuit board associated with the exemplary controller  240  ( FIG.  18   ) or on the chassis  244  ( FIG.  18   ). Temperature sensing apparatus, such as a heat pipe that extends to the reservoir (not shown), may also be included on some cartridge implementations. The temperature information may be provided to the controller  240 , or to another controller, to modulate the battery recharging process as a function of temperature as is described below. 
     One example of a battery recharger, which is generally represented by reference numeral  700  in  FIG.  49   , includes recharging circuitry  702  (e.g., a controller and power circuitry) within a housing  704 . The top portion of the recharger housing  704  may be configured in a manner similar to the baseplate  500 . To that end, the top portion of the housing  704  may include a plate  706 , a cartridge recess  708 , a pair of opposing connectors  712 , a hook  714 , and electrical contacts  228 R and  230 R. In some implementations, a temperature sensor  739  may be provided at or near the recess  708  to sense the temperature of medicament in the cartridge  100  during recharging. Power and data connectors  716  and  718  may also be provided. 
     The respective configurations of the pump assembly  200  and battery recharger  700  are such that, when the pump assembly is placed on the plate  706  with an end wall  212  abutting the hook  714 , the pump assembly recharge contacts  228  and  230  will be electrically connected to the recharger contacts  228 R and  230 R. Also, when the cartridge  100  is within the pump assembly  200  during the recharging procedure, the cartridge barrel  102  will nest in the recess  708  to insure proper alignment of the electrical contacts  228 / 230  and  228 R/ 230 R. The recess  708  may also be configured to accommodate the finger tab  456  associated with the latch  412   a  ( FIG.  32   ). 
     The recharging process may be controlled by circuitry  237  associated with the pump assembly controller  240 , the recharger controller  702 , separate circuitry, or some combination thereof, which are collectively referred to as the “recharge controller.” The recharge controller  702  may modulate the recharging of the battery  238  as a function of the temperature sensed by temperature sensor  239  and/or temperature sensor  739 . For example, and weighing the desire to rapidly recharge the battery  238  against the desire to avoid medicament damage, the recharge controller may be configured to maintain the sensed temperature within a temperature range that is above a predetermined threshold and below a predetermined maximum for the particular medicament. In the exemplary context of insulin and a lithium polymer battery, the threshold temperature can be 37° C. (or range from, for example, 36.6-37.4° C.) and the predetermined maximum temperature can range from, for example, 45-50° C. 
     It should also be noted that it may be difficult for the battery  238  to provide enough current if the temperature within the pump housing  202  is low. The temperature sensor  239  may, therefore, be used to monitor temperature during operation of the pump assembly  200 . An alarm may be actuated by the controller  240  if the temperature is too low. 
     Modulation of the recharging process may be accomplished by, for example, selectively increasing or decreasing the rate at which the battery  238  is recharged (e.g., by controlling current) as a function of sensed temperature. For example, and referring to  FIG.  50   , the modulation process may be designed to perform temperature control in a manner that prevents the sensed temperature from overshooting the predetermined maximum temperature (TMAX) as shown by the dashed lines. To that end, as temperature reaches a modulation temperature (TMOD) below the maximum temperature TMAX, the recharging rate is reduced to keep the temperature at or below the maximum temperature TMAX. 
     In at least some implementations, the charge controller may be configured to identify and/or prevent charging faults, such as battery overcharge that can cause the battery to swell, vent and otherwise stress other components within the pump assembly. 
     It should be noted here that the present pump assemblies and battery rechargers are not limited to those which make a direct electrical connection through the use of electrical contacts. By way of example, but not limitation, inductive coupling may be employed. It should also be noted here that at least some implementations of the present pump assemblies may be configured to accept a replaceable battery. Such implementations would, however, require a waterproof battery compartment cover. 
     K. Exemplary Alarms 
     As noted above with reference to  FIG.  18   , the exemplary pump assembly  200  may include an alarm  242  that is carried within the housing  202 . The alarm may be audible (e.g., a buzzer), palpable (e.g., a vibrator), visible (e.g., an LED with a portion that extends through the housing  202 ) and/or any combination thereof. A number of conditions may result in alarm activation in the exemplary embodiments. For example, as discussed in Section IX below, alarm conditions include, but are not limited to, low or dead battery, occlusion, low or empty reservoir, hardware self-test, firmware error, absence of a baseplate, device fall-off, battery charge over-temperature, unable to find plunger, and/or charging faults. 
     L. Exemplary System Controllers 
     The exemplary pump assemblies described herein may include a controller that is configured to perform the various control functions described herein. The controller may also operate/execute algorithms for periodic safety checks such as memory checksums, hardware verification self tests, and the like. The present inventions are not limited to any particular type of controller and include those currently available or yet to be developed. By way of example, but not limitation, such a controller may be in the form of a microcontroller and stored firmware programs. The microcontroller may include, among other things, some or all of a microprocessor or other central processing unit (CPU), other digital and/or analog control circuitry, digital and/or analog communication circuitry, and memory such as static random access memory (SRAM), flash memory, and synchronous dynamic random access memory (SDRAM). The controller may employ any suitable control principles including, but not limited to, proportional, adaptive, neural network, fuzzy logic, and/or proportional integral derivative (PID). The microcontroller may also support firmware updates through an RF interface. 
     One exemplary controller is generally represented by reference numeral  240  in  FIG.  18    and is described here, in the context of various system components that are connected thereto, with reference to  FIG.  51   . The exemplary controller  240  may include a microcontroller (labeled p-C in  FIG.  51   ) with a CPU, flash memory, SRAM, and a built-in RF transceiver. Building the RF circuitry into the controller decreases the size of the controller by positioning everything on a single chip. One example of a suitable microcontroller is the Texas Instruments CC2530 microcontroller. 
     A pair of oscillator crystals  249  respectively provide clock sources for the RF transceiver and the microcontroller. A filter capacitor for the microcontroller power supply is shown at  247 . 
     As discussed above and below, a variety of devices may be operably connected to the controller  240 . Referring to  FIG.  51   , such devices may include the position detector  398  ( FIG.  29   ) that detects when the plunger pusher  250  is in the fully retracted (or “home”) position, the sensor(s) from an encoder that monitor motor shaft rotation (e.g., sensors  403   a  and  403   b  of encoder  396   j ), and the temperature sensor  239 , which may be a thermistor, creates a variable analog voltage which connects to an analog ADC input. 
     With respect to power, the recharging contacts  228 ,  230  connect the battery  238  to the battery recharger  700  ( FIG.  49   ). The charging voltage is distributed by a distribution circuit  243  to the battery  238  and to a voltage regulator  231 . A protection circuit  241  is provided for the battery  238 , and a regulator  231  regulates the power delivered to the microcontroller. The recharger controller  237 , if present, may be used to control recharging of the battery  238  in those instances where the battery recharger  700  does not perform this function. A voltage divider  245  reduces the voltage to be compatible with the analog input of the microcontroller and allows the microcontroller to read the full range of the output of the battery  238 . To conserve battery power, the divider  245  is only enabled when battery voltage is being sensed. When the divider  245  is enabled, the voltage at the associated pin is BatteryVoltage*Rb/(Ra+Rb). Thus, the voltage is a fractional representation of the actual battery voltage so that the input range of the pin is not exceeded. The analog-to-digital converter input senses this voltage. The microcontroller&#39;s built-in analog-to-digital converter converts the voltage to a digital value (e.g., a 10 bit digital value). 
     In those implementations where a switch-type fall-off detector is employed (e.g., detector  650  in  FIGS.  43  and  44   ), the input to R 4  is a digital input that senses the actuation of associated switch S 3 . This input allows the microcontroller to sense the position of the portion of the detector that protrudes through the housing  202  (e.g. abutment  658 ) and can be programmed to wake the microcontroller up from an extremely low power state. 
     The alarm  242 , which may be audible, palpable and/or visible, has a driver circuit to increase the current drive to it. A mute switch  1004  may also be provided, e.g., on the pump assembly housing  202 , to mute an audible alarm. 
     A sending and receiving antenna  1002  is provided to communicate with, for example, the remote control  1000 . An impedance matching circuit  1003  for the antenna  1002  receives its power from the transceiver. 
     M. Exemplary Motor Control 
     Turning to motor control, and referring to  FIG.  51   , the motor  358  (e.g., a stepper motor) actuated by the phases of the motor coils C 1 , C 2 . The phases are energized in the proper sequence to drive the motor  358  at the desired speed and in the desired direction. The interlock circuit  361  is a simple missing pulse detector which can be implemented with a re-triggerable monostable multivibrator integrated circuit such as a 74HC123 CMOS device from NXP Semiconductors. The interlock circuit  361  is enabled by a pin  365  that continuously toggles from high to low, and software of the microcontroller causes the pin to toggle. Thus, if the software stops functioning, the pin will not toggle and the motor  358  will be automatically disabled for safety reasons by the interlock circuit  361 . More particularly, output  365  enables the motor interlock circuit  361 , protecting against over-delivery of medicament due to a software lockup. 
     Pulse width modulating (PWM) circuit  363  is the motor enable output that enables the drivers DR 1 , DR 2  to the motor  358 . Put another way, the PWM circuit  363  modulates energy from the battery  238  applied to motor coils C 1 , C 2 . This pulse width modulated output enables control of the motor current depending on the programmed torque and the voltage of the battery  238 . Circuit  363  operates at a frequency ten to one hundred times higher than the motor phases, and avoids having to use a regulator for the motor voltage. 
     Drivers DR 1 , DR 2  energize the coils C 1 , C 2  of the motor  358  and change their polarities. Assuming the interlock circuit  361  has been enabled and output F is at a logic 1, driver DR 1  is enabled with positive drive to coil C 1  when output C is a logic 1 and A is a logic 0. Likewise driver DR 2  is enabled with positive drive to coil C 2  when output B is a logic 1 and D is a logic 0. Under the same conditions, driver DR 1  is enabled with negative drive to coil C 1  when output C is a logic 0 and A is a logic 1. Likewise driver DR 2  is enabled with negative drive to coil C 2  when output B is a logic 0 and D is a logic 1. If A=C, driver DR 1  is disabled. Similarly if B=D, driver DR 2  is disabled. If output F is a logic 0 or if the interlock circuit  361  is disabled, both drivers are disabled regardless of the state of outputs A-D. The pulse width modulation occurs when output F of PWM circuit  363  pulses at a given duty cycle. If F pulses at a 75% duty cycle, then the coils will be turned on with the polarity as selected by A-D, with an effective voltage of 75% of the battery voltage. 
       FIG.  51 A  is a block diagram that illustrates the functional relationships of certain elements/components shown in  FIG.  51    and, in particular, the relationship of the battery charging system to the other components of the system. The battery charging system, as shown in the lower left in a dotted line block, includes the battery  238 , the battery protection circuit  241 , the power connectors  228 ,  230  and the charge circuit  237 . As can be seen in  FIG.  51 A , one way the battery charging system connects to the microcontroller is through the voltage divider  245 . The motor drivers DR 1 , DR 2  receive power from the battery and drive the motor  358  whose position is sensed by the position sense encoder  396   j . The interlock circuit  361  provides a safety shutoff of the motor drivers DR 1 , DR 2  when there is a software problem in the microcontroller. Oscillator crystals  249  provide clocking functions for the microcontroller and RF transceiver. The microcontroller controls the operation of the alarm  242 . The antenna  1002  is connected to the microcontroller by way of the antenna circuit  1003 . 
     Energy to the motor  358  may be controlled so as to be within a range having a lower limit that provides sufficient torque to overcome drive line inefficiencies and axial cartridge friction and move the plunger  106 , and an upper limit that is low enough so as to not cause leakage past plunger seals  152 .  FIG.  52    is a flow chart showing an exemplary low torque motor control procedure. Referring thereto, a firmware counter with the number of encoder counts required to advance the pusher a distance corresponding to the desired drug dose is loaded in the controller  240  (Step S 001 ). The motor  358  is excited (Step  5002 ) and the encoder  396  is monitored (Step S 003 ). If no motor rotation is detected (Step S 004 ), then the excitation current is up-regulated to increase the motor torque (Step  5005 ) and the process is returned to the previously-mentioned motor excitation step (Step S 002 ). On the other hand, if motor rotation is detected, the counter is decremented (Step S 006 ). 
     If the counter is not zero (Step S 007 ), then the excitation current is down-regulated to limit the motor torque and to conserve energy (Step S 008 ), and the process is returned to the previously-mentioned motor excitation step (Step S 002 ). If the counter is zero (Step S 007 ), then motor excitation is continued for additional motor steps past the firmware count zero for subsequent detection of motor rotation following cessation of motor excitation (Step S 009 ). Following completion of the additional motor steps, delivery is thereby at an end (Step s 010 ). 
     The excitation current regulation method mentioned in the up-regulate and down-regulate steps above varies with the method used. Examples of methods are (a) pulse width modulation and (b) a programmable linear or switching type voltage regulator. Up and down regulation using a voltage regulator increases or reduces the voltage output to the coil drivers. For a pulse width modulation method, down regulation reduces the duty cycle and up regulation increases the duty cycle. 
     In other words, pulse width modulation is one way to control energy consumption and provide a prescribed (e.g., 10 pound) stall limit. A stall limit that is too low will not provide sufficient performance against drive line and cartridge inefficiencies, while a stall limit that is too high can overdrive the cartridge and, potentially, create excessive reservoir pressure that will cause leakage past the cartridge seals  152  during a pusher “zeroing” procedure (described in Section VIII-B with reference to  FIG.  91   ) or during an occlusive event (described in Section VIII-C with reference to  FIGS.  92  and  93   ). 
     Pursuant to an exemplary embodiment the motor  358  always runs under pulse width modulation or other torque control method, as the motor is designed with excess torque that needs to be controlled. Pulse width modulation is one effective method to control the torque. The electronic drive provided for the motor is important to minimize battery drain as well as to control the torque the motor is providing to the system and what forces the lead screw  360  is putting on the cartridge  100  in all cases, e.g., retracting, homing, zeroing, running, and occlusion detecting. 
     Referring to  FIG.  52 A , one of the drivers DR 1 , DR 2  in  FIG.  51    is shown connected to the associated motor winding. Rs is a current sensing resistor (about 1 Ω) for implementations that directly sense the coil current, and Vs is the current sensing voltage. The inductor (L) is the inductance of the motor winding and the load (R) is the winding resistance. The switch  359   c  is a FET driver, and diodes  359   a  and  359   b  are intrinsic back-diodes within the FET drivers. These components essentially form the elements of a basic buck-type switching regulator, with R being the load. When the ENABLE bar shown in that figure (and in  FIG.  51   ) is a logic 0 (the true condition), the switch  359   c  turns on and power is thereby provided to the rest of the circuit, thereby enabling the coil drivers. If the switch  359   c  is turned on and off at a rate faster than R/L, then the voltage to the load R will be effectively reduced in the manner of a buck-type switching regulator. During the on time of switch  359   c , inductor L charges by ramping up its current, thereby limiting the voltage applied to load R. During the off time of switch  359   c , the inductor L discharges by ramping down its current, thereby continuing to supply voltage to load R. Inductor L discharges through the load R and the intrinsic back-diodes  359   a  and  359   b . This circuit could be further enhanced by adding Schottky diodes across the intrinsic back-diodes  359   a  and  359   b  to reduce the voltage drop when the inductor L discharges through them during the off time of switch  359   c . This is much in the same manner that Schottky diodes are found in buck-type switching regulators. 
     The equation to be relied on is: Veff=D*Vbatt, where Veff is the effective voltage to the coil resistance R, D is the pulse-width modulation duty cycle, and Vbatt is the battery voltage. If the battery  238  is fully charged to 4.0 volts and the motor  358  is to be run as though the battery voltage were only 3.0 volts, pulse-width modulation is done at a 75% duty cycle. The effective voltage to the coil resistance R is 0.75*4.0=3.0 volts. As the battery voltage drops to 3.0 volts the duty cycle will be increased to 100% and no switching will take place. The frequency of the switching will be determined by the L/R time constant. For an exemplary motor L=3.5 mH and R=30 Ohm, so L/R=117 pSec. The frequency has a period less than the time constant to insure a relatively linear ramp-up and down of the inductor current. This ensures that the equation Veff=D*Vbatt holds true. This method can be used to further reduce the effective voltage to the coil resistance if desired. This can be done to limit the pressure within the reservoir. A filter capacitor across the load R used in a traditional buck type switching regulator is not necessary due to conservation of energy. It simply holds charge to reduce voltage ripple, while the motor actually operates on electrical current, not voltage. In the description above, the coil current is directly proportional to the effective voltage Veff, since this voltage is considered to be across the purely resistive portion R of the coil load. Thus, for example, if the effective voltage to R is reduced by 25%, the current will also be reduced by 25%. 
     The pulse width modulation system may include an analog-to-digital (A/D) converter which converts voltage of the battery to a digital representation. The controller (a) operates through a driver circuit to control the operation of the motor and to pulse-width modulate energy from the battery applied to coils of the motor, (b) reads the digital output of the encoder and (c) reads the digital output of the A/D converter. 
     The controller  240  may include a first software algorithm adapted to use the digital representation of the motor position to program a first digital timer/counter circuit in the controller to provide low level signal outputs that enable the drivers DR 1 , DR 2  of the motor  358  to facilitate a sequencing of voltage at the coils C 1 , C 2  of the motor to produce a desired motor rotation. The controller  240  may also include a second software algorithm that uses the output of the A/D converter to program a second digital timer/counter circuit in the controller to provide a low level signal output that further enables the drivers DR 1 , DR 2  of the motor  358  to facilitate the pulse-width modulation of the voltage to the coils C 1 , C 2  of the motor  358 . 
     The steps of the first software algorithm may be as follows: (1) determine the position of the motor shaft by reading the encoder  396 ; (2) determine the direction of rotation (either forward/delivery or reverse/retraction); (3) determine the number of rotations required (how much drug delivery or how far to retract); (4) step the motor  358  according to the sequence defined by the motor manufacturer&#39;s specification by driving coil phase A and B either +or −; and (5) repeat step (4) at a rate, which is determined by analysis and characterization during development, that guarantees movement with normal loads until the desired number of rotations is read from the encoder  396 . Steps (4) and (5) may be performed by the first digital timer/counter circuit where the outputs are connected to the drivers DR 1 , DR 2  for the motor coils C 1 , C 2  while the microcontroller is reading the outputs of the encoder  396 . 
     The steps of the second software algorithm may be as follows: (1) determine the effective motor coil voltage (Veff) required (for example, 2.7 volts to run the motor  358  in the forward direction, 1.1 volts to run the motor in the reverse direction; the actual voltages will be determined after analysis and characterization during development); (2) read the A/D converter output containing the digital representation of the battery voltage (Vbatt); (3) calculate Veff/Vbatt; and (4) program the second digital counter/timer circuit to output a digital pulse waveform with a duty cycle of Veff/Vbatt at a frequency of 10 to 100 times the rate of step (5) of the first software algorithm. The output of the second digital timer circuit will be a global enabling signal for both motor coil drivers DR 1 , DR 2 . 
     Thus, even though the circuit determines, for example, that at a particular time, coil phase A should be driven at +Vbatt and coil phase B should be driven at −Vbatt, the output of the second timer is the gating signal that determines when the drivers are actually enabled to drive the selected levels to the coils. The result will be that coil phase A will be driven at +Vbatt, but on and off at a duty cycle of Veff/Vbatt and likewise for coil phase B. This on and off rate will be much higher than the rate that the drivers DR 1 , DR 2  will switch the polarity of the coil phases to perform the specified sequencing that causes the motor  358  to rotate. The effect is to limit the current to Veff/Vbatt times the amount of current that would be used if the full battery voltage were applied to the coils 100% of the rotation time. 
     Thus, torque can be limited by limiting the current to the motor coils C 1 , C 2 . Other ways to limit the current are to use a constant current source. However, this can be somewhat complex and wasteful of battery energy. A constant voltage source can be used. Since the coil resistance limits the current, limiting the voltage will effectively limit the current. This can be done in either of two ways. A linear voltage regulator may be employed, although this may be an unnecessary drain on the battery. Alternatively, a switching voltage regulator may be employed, which is more efficient in that it uses a coil to store energy, but includes more parts. 
     V. Exemplary Baseplates and Cannulas 
     As noted above, and as illustrated for example in  FIG.  1   , the present infusion systems may include any one of a variety of different baseplates in combination with a cartridge (e.g., cartridge  100 ) and a pump assembly (e.g., pump assembly  200 ). Each baseplate may be configured for a different mode of system operation. Baseplate  500  is a body adherable baseplate that may be used in conjunction with a cannula such as cannula  600  ( FIGS.  56 - 57   ) which is directly connected to the cartridge  100  so that the system may be deployed as a “patch pump.” Baseplate  501  is configured to connect the cartridge  100  to an infusion set  503  so that the system may be deployed as a “pocket pump,” a “belt-worn pump” or some other wearable pump. Baseplate  502  is a medicament non-delivery baseplate that includes a plug  504  which may be used to seal the cartridge  100  during periods of non-use. Additionally, and as discussed in Section VI below, pump assemblies (e.g., pump assembly  200 ) and baseplates (e.g., baseplates  500 - 502 ) may be respectively configured such that a pump assembly can determine which one of a variety of baseplates is attached to the pump assembly and then prepare to proceed in accordance with the operational mode associated with that baseplate. Also, although the exemplary baseplates are described herein in the context of the exemplary cartridge  100  and the exemplary pump assembly  200 , the present baseplates may be used in conjunction with other cartridges, cartridge-based pumps, and pumps that are not cartridge-based. 
     Turning to  FIGS.  53 - 55   , the exemplary body adherable baseplate  500  may include a plate member  506  that is configured to cover the insertion opening  218  ( FIG.  16   ) in the housing bottom portion  208 . A cartridge aperture  508  (or simply a recess) may be provided to accommodate a medicament cartridge such as cartridge  100 , or may be omitted, and a cannula aperture  510  may be provided to permit passage of a cannula in those instances where the plate member  506  would otherwise block the cannula. It should also be noted that the cartridge  100 , pump assembly  200  and baseplate  500  are respectively configured such that a portion of the cartridge manifold  108  will rest on the plate member  506 . 
     The exemplary baseplate  500  also includes structure that perform the function of securing the baseplate to the associated pump assembly. For example, in the embodiment illustrated in  FIGS.  53 - 55   , the baseplate  500  includes a pair of opposing connectors  512  and a hook  514 . The connectors  512  frictionally engage the side walls  210  of the pump assembly housing  202 , and may have an engagement portion  516 , a support portion  518  that connects the engagement portion to the plate member  506 , and a protrusion  520  to engage the user&#39;s finger. Gaps  522 , which are located on either side of the support portion  518 , allow the support portion to pivot in the direction shown by arrow P. The distance between the engagement portions  516  is less than the distance between the outer surfaces of housing side walls  210  when the connectors are in an unstressed state. As such, when the housing  202  and baseplate  500  are pressed together ( FIGS.  54 - 55   ), thereby pivoting the connectors  512  out of their unstressed states, the engagement portions will apply forces F to the housing side walls  210  that are sufficient to provide enough frictional engagement to prevent separation during normal usage. The hook  514  may include an engagement portion  526  and a support portion  524 , and gaps  528  may be located on either side of the support portion  524  if hook flexibility is desired. 
     During attachment of the baseplate  500  to the pump assembly  200 , a bottom corner of the housing end wall  212  may be aligned with the space  528  defined by the hook  514 . The baseplate  500  and pump assembly  200  are then moved relative to one another (e.g., pivoted about the hook  214 ) to the position illustrated in  FIGS.  54 - 55   , where the connectors  512  frictionally engage the housing side walls  210  and secure the baseplate to the pump assembly. 
     In at least some embodiments, the baseplate and associated cannula may be configured to secure themselves to one another. As a result, the pump assembly (e.g., pump assembly  100 ) and medicament cartridge (e.g., cartridge  200 ) may be removed together as unit from the baseplate with the cannula remaining secured to the baseplate as noted above with reference to  FIG.  31   . This allows, for example, the pump assembly battery to be recharged without removing the cartridge. The user may also use this capability to remove the baseplate and cannula from his/her body and then redeploy the system with a new baseplate and cannula at a different location. 
     One exemplary baseplate and cannula configuration is illustrated in  FIGS.  56 - 57 A . The exemplary baseplate  500 ″ is essentially identical to baseplate  500  and similar elements are represented by similar reference numerals. In addition, a recess  511  with a mating surface  513  is positioned around the cannula aperture  510  on the bottom side (i.e., adhesive side) of the plate member  506 . The recess  511  is used to secure a cannula to the baseplate  500 ″ in the manner described below. 
     The exemplary cannula  600  is configured to establish a fluidic connection between a medicament cartridge (e.g., cartridge  100 ) and the patient. The exemplary cannula  600  is also configured to cooperate with the recess  511  such that axial movement of the cannula relative to the baseplate  501  is prevented, at least in the removal direction, after the cannula has been deployed into the patient. 
     With respect to the fluidic connection, the cannula  600  may include a connector plug  602  (or “head”) that is configured to be inserted into the cartridge through-bore  116 . The exemplary connector plug  602  may include a cylindrical member  604  with an internal lumen  606 , at least one inlet port  608  connected to the internal lumen, o-ring or other seals  610  on opposite sides of the inlet port(s)  608 . A cannula tube  612  may be connected to the connector plug  602 . The exemplary seals  610  may be integral with the cylindrical member  604 , or may be separate structures formed from rubber or other appropriate seal materials that are carried thereon. 
     Turning to cooperation with the baseplate recess  511 , the exemplary cannula  600  includes a latch (or “hook”)  614 . Although the latch may be any suitable configuration, the exemplary latch  614  is a resilient structure that includes a latch surface  616  and a frustoconical support  618  below the latch surface. The latch  614  will deflect as the cannula  600  is deployed through the medicament cartridge through-bore  116  in the manner described above with reference to  FIGS.  45 - 49   . Here, the inserter trocar (e.g., trocar  812  in  FIG.  85   ) will push through the top of the cylindrical member  604 , through the internal lumen  606 , and through the cannula tube  612 , while the inserter drive structure (e.g., movable member  802  in  FIG.  85   ) pushes the top of the cylindrical member. Once the resilient latch  614  passes through the cannula aperture  510 , it will return to its relaxed state and the latch surface  616  will abut the mating surface  513  in the baseplate recess  511  ( FIG.  57   ). The frustoconical support  618  will then prevent the cannula  600  from being pulled back through the cannula aperture  510 . 
     It should also be noted that the respective sizes (e.g., diameters) of the recess  511  and the latch surface  616  are essentially the same. This relationship produces a tight fit that helps prevent lateral movement of the baseplate  500 ″ relative to the cannula  600 . 
     It should also be noted that the configuration of the associated inserter, e.g., inserter  800  in  FIG.  85   , prevents downward movement of the cannula  600  beyond that illustrated in  FIG.  57   . In other implementations, a cannula and/or baseplate may be provided with structure that performs this function. 
     The exemplary cannula  600   a  illustrated in  FIGS.  58  and  59    is essentially identical to cannula  600  and similar elements are represented by similar reference numerals. In addition, cannula  600   a  includes a septum  620 . The septum  620 , which is formed from softer material than the cylindrical member  604 , facilitates smooth passage of an inserter trocar to the internal lumen  606 . 
     The dimensions of the exemplary cannulas  600  and  600   a  will depend on the intended patient as well as the configuration of the medicament cartridge. For example, the cylindrical member  604  may have a diameter of  4  mm+/−1 mm and a length of 7 mm+/−1 mm, while the cannula tube  612  may have an outer diameter of 0.5 mm, an inner diameter of 0.2 mm and a length of 6-10 mm. With respect to construction and materials, the plug  602  and cannula tube  612  may be formed as two separate pieces (as shown), and from two different materials, or integrally formed. Suitable materials for an integrally formed single cannula include, but are not limited to, FEP, PTFE, COP, medical grade plastics, and polypropylene. In a two piece arrangement, suitable materials for the cylindrical member  604  and integral resilient latch  614  include, but are not limited to PTFE, COP, medical grade plastics, and polypropylene, while the cannula tube  612  may be formed from materials such as PTFE, FEP and other fluoropolymers, and metals such as stainless steel. 
     Other exemplary instrumentalities for securing a cannula to a baseplate include, but are not limited to, other types of latches, including latches where a deflectable structure is included on the baseplate or both the baseplate and the cannula, as well as devices such as friction devices, adhesive, pivoting structures and sliding structures. A latching arrangement may also be associated with the cannula tube instead or, or in addition to, the cannula plug. The cannula latch may also be omitted and the cartridge through-bore and cannula plug respectively configured such that friction will maintain the relative positioning. One example of such a latch-less arrangement is discussed below with reference to  FIG.  85   . 
     The present baseplates and pump assemblies are not limited to any particular connector arrangement. One alternative is the interlocking latch arrangement illustrated in  FIGS.  60  and  61   , which may be employed in any of the pump assemblies and baseplates described herein. The interlocking arrangement is somewhat similar to the friction arrangement illustrated in  FIGS.  53 - 55    and similar elements are represented by similar reference numbers. Here, however, the connection involves a mechanical interlock instead of mere friction. More specifically, the body adherable baseplate  500 ″′ includes a pair of opposing connectors  512   a  (one shown) and a hook  514  (not shown). The exemplary connectors  512   a  have the aforementioned protrusions  520  as well as apertures  530 . The side walls (one shown) of the associated pump assembly housing  202 ′ have corresponding mating structures  532 , each having a protrusion  534  that is sized and shaped to fit into an aperture  530 . In the illustrated implementation, the mating structures  532  are carried within recesses  536  and have cam surfaces  538  and flat surfaces  540 . As the baseplate  500 ′ is connected to the pump assembly  200 ′, which is otherwise identical to pump assembly  200 , the protrusions  520  will engage the cam surfaces  538 , thereby pivoting the connectors  512   a , until the apertures  530  are aligned with the mating structures  532 . The resilience of the opposing connectors  512   a  will then cause them to move into the recess  536  and produce the mechanical interlock (or latched state) with protrusions  534 . It should also be noted that the arrangements illustrated in  FIGS.  53 - 55 ,  60  and  61    can be reversed, i.e., the connector structures on the housing moved to the baseplate and connector structures on the baseplate moved to the housing, and/or the connector structures can be associated with different housing walls. The number of connectors may also be increased and decreased, and other latching arrangements may be employed. 
     The present baseplates and pump assemblies are not limited to the exemplary structures for securing the baseplate to the associated pump assembly described above. Other suitable structures for securing a baseplate to a pump assembly include, but are not limited to, guided slide attachments, mechanical fasteners, magnet arrangements, hook-and-loop attachments, screw-on configurations, and low tack pressure sensitive adhesives. Also, the pump assembly or the baseplate may be provided with a pocket into which the other may be inserted. 
     The body adherable baseplate  500  will be, before, during and/or after the cartridge  100  and pump assembly  200  are combined therewith, adhered to the patient&#39;s skin. To that end, the bottom surface of the plate member  506  carries an adhesive layer  542  ( FIG.  55   ) that releasably attaches the baseplate  500  to the patient&#39;s skin. The adhesive layer  542  may cover all, or less than all, of the bottom surface. A removable liner  544  ( FIG.  54   ) may be used to cover the adhesive layer  542  until the time of use. 
     The present inventors have determined that it can be difficult to keep the cannula fixed and erect in the wound, given that the skin may be rough and non-planar and the wound area may be soft, wet and flexible, and that the failure to keep the cannula fixed and erect in the wound may cause the cannula to bend and occlude. Strong adhesive close to the cannula keeps the cannula fixed and tight. However, strong adhesive is more likely to irritate and even damage the skin. Thus, although the adhesive layer  542  may consist of a single type of adhesive, the exemplary baseplate  500  may include more than one type of adhesive in the adhesive layer  542 , each serving a different purpose. In the illustrated embodiment, the adhesive layer has a first adhesive  546  and a second adhesive  548  that is stronger (or “more aggressive”) than the first adhesive. The first adhesive  546  occupies the majority of the adhesive layer  542  and holds the majority of the baseplate to the skin with enough strength to prevent separation during normal usage. The second, more aggressive adhesive  548  surrounds the cannula opening  510  and keeps the cannula fixed and tight. 
     In the illustrated example, the second adhesive  546  may cover 0.75-1.25 mm around the cannula opening  510 , bulging out and intersecting the adjacent corner of the plate member  506 . The second adhesive may also cover 1-10% of the bottom surface. With respect to the relative strengths, in one example, the peel strength of the first adhesive  544  may be 60 oz/inch width+/−20 oz/inch width, and the peel strength of the second adhesive may be 50-100% more than that of the first. In another example, the first adhesive can have 80% of the strength of the stronger second adhesive. 
     The dimensions of the baseplate  500  may correspond to those of the associated pump assembly. In the context of the exemplary pump assembly  200  described above, the plate member may be 1 mm thick, with length/width relationships such as 42 mm×34 mm, 40 mm×32 mm, and/or 39.0-43.0 mm×31.0-35.0 mm. 
     The exemplary infusion set baseplate  501  illustrated in  FIGS.  62  and  63    is substantially similar to the body adherable baseplate  500  and similar elements are represented by similar reference numerals. For example, the baseplate  501  may include a plate member  506 ′, a cartridge aperture  508  (or recess), and connectors  512  (or any of the other connector structures described above). Here, however, the baseplate  501  may include an infusion set such as infusion set  503  (as shown) or may simply be configured to be connected to an infusion set. The baseplate  501  may also lack the adhesive layer. 
     The baseplate  501  in the illustrated example includes structures that establish a fluidic connection which extends from the medicament cartridge, such as cartridge  100 , to the infusion set  503 . To that end, and referring to  FIGS.  62  and  63    the baseplate  501  may have a connector plug  550  that is configured to be inserted into the cartridge through-bore  116 . The exemplary connector plug  550  includes a cylindrical member  552  with an internal lumen  554 , a plurality of inlet ports  556  located around the perimeter of the cylindrical member and connected to the internal lumen, and o-ring or other seals  558  on opposite sides of the inlet ports  556 . The exemplary connector plug  550  may be integral with the plate member  506 ′ or may be a separate structure that is secured thereto. The exemplary seals  558  may be integral with the cylindrical member  552  or may be separate structures, formed from rubber or other appropriate seal materials, that are carried thereon. A lumen  560  within the plate member  506 ′ extends to an outlet port  562 . 
     The baseplate  501 , pump assembly (e.g., pump assembly  200 ) and cartridge (e.g., cartridge  100 ) may be respectively configured such that, when the system  11  is assembled, the connector plug  550  will be located within the cartridge through-bore  116  with the connector plug seals  558  on opposite sides of the reservoir outlet port  118 . Fluid flowing into the through-bore  116  from the outlet port  118  will enter the inlet ports  556 , flow through the internal lumen  554 , the baseplate lumen  560 , and the outlet port  562  to the infusion set  503 . 
     The exemplary infusion set  503  ( FIG.  62   ), which may be any conventional infusion set, may have a hub  564 , a cannula  566  extending from the hub, a flexible adhesive-backed wing-type base  568 , and a fluid tube  570 . Infusion sets with disk-type bases may also be employed. The adhesive may be a single type of adhesive, or may be two or more different adhesives as described above. The tube  570  may be removably or permanently connected to the outlet port  562 . The tube  570  may also be any suitable length (e.g., 42 inches). Connectors  572  and  574  may be provided on the hub  564  and fluid tube  570  in those instances where the hub and fluid tube are separable. 
     Turning to the exemplary medicament non-delivery baseplate  502  illustrated in  FIGS.  64  and  65   , there may be instances where the user chooses not to use the pump assembly to deliver medicament and desires to re-plug the medicament cartridge to prevent leakage. Such periods of non-delivery may be associated with, for example, the use of an alternate pump or syringes to deliver medicament, or the shipment of the pump assembly to a service center. 
     The medicament non-delivery baseplate  502  illustrated in  FIGS.  64  and  65    is substantially similar to the body adherable baseplate  500  and similar elements are represented by similar reference numerals. Given the small sizes of the cartridge  100  and pump assembly  200 , users may find it easier to reseal the cartridge with the medicament non-delivery baseplate  502  than with the plug  110 . 
     The exemplary baseplate  502  may include a plate member  506 , a cartridge aperture  508  (or recess), and connectors  512  (or any of the other connector structures described above). Here, however, the baseplate  502  may also include a plug  504  that is configured to prevent flow from a medicament cartridge (e.g., cartridge  100 ) carried in a pump assembly (e.g., assembly  100 ). The baseplate  502  may also lack the adhesive layer. 
     The exemplary plug  504  includes a cylindrical member  578  and two or more o-ring or other seals  580 . The exemplary plug  504  may be integral with the plate member  506  or may be a separate structure that is secured thereto. The exemplary seals  580  may be integral with the cylindrical member  578  or may be separate structures, formed from rubber or other appropriate seal materials, that are carried thereon. The baseplate  502 , a pump assembly (e.g., pump assembly  200 ) and a cartridge (e.g., cartridge  100 ) may be respectively configured such that, when the system  12  is assembled, the plug  504  will be located within the cartridge through-bore  116  with the seals  580  on opposite sides of the reservoir outlet port  118 , thereby preventing flow. 
     It should also be noted that the present inventions include kits which contain various combinations of baseplates, at least two of the baseplates being different. Kits may also include such combinations and, in addition, a pump assembly, and/or a medicament cartridge and/or a cannula. For example, a kit may include one or more of each of baseplates  500  and  502 , a kit may include one or more of each of baseplates  501  and  502 , a kit may include one or more of each of baseplates  500 ,  501  and  502 . Kits may also include any of the combinations recited in the preceding sentence and, in addition, a pump assembly, and/or one or more medicament cartridges and/or one or more cannulas. The baseplates in such kits may also include the detection instrumentalities discussed in Section VI below. The components the present kits (e.g., combination of various baseplates) may be stored in a common package, with individual packages for each component if necessary, and provided to the user in the common package. Other instrumentalities that may be provided in such kits includes, but is not limited to, inserters that are preloaded with a cannula and cleaning swabs. A recharger may also be provided in a kit that includes a pump assembly. 
     VI. Exemplary Baseplate Identification 
     It should be noted here that, but for the issue of priming, the dispensing procedures associated with an infusion system “patch pump” configuration, which may include a pump assembly  200  and a baseplate  500  ( FIG.  53   ), are substantially the same as the dispensing procedures associated with a “pocket pump” configuration, which may include a pump assembly  200  and a baseplate  501  ( FIGS.  62 - 63   ). With a “patch pump” configuration, priming is not necessary because the volume of the associated cannula will be very small and there is a direct connection between the cannula and the medicament cartridge ( FIG.  50   ). Priming is, however, required to fill the infusion set tube (e.g., tube  570  in  FIGS.  62 - 63   ) in a “pocket pump” configuration prior to the onset of medicament delivery. 20-30 μlmay be required to fill the entire infusion set tube and, accordingly, the priming procedure may involve the rapid delivery of 10-15 IUs of U-500 insulin to the tube. The present inventors have determined that it would be advantageous to prevent users from initiating a priming procedure when the system is in the “patch pump” configuration, with a cannula positioned to deliver medicament essentially directly from the medicament cartridge to the patient, because rapidly delivering 10-15 IUs of insulin to the patient could adversely effect patient health. 
     To prevent such undesirable outcomes, at least some of the present baseplates may be provided with a baseplate identification device and at least some of the present pump assemblies may be provided with structure that cooperate with a baseplate identification device in such a manner that the pump assembly controller can make a “baseplate type” determination. For example, the baseplate identification devices may be carried by the baseplates and may be detectable by the pump assembly as well as distinguishable from one another. Once the “baseplate type” determination is made (e.g., baseplate  500  or baseplate  501 ), the pump assembly will proceed in a manner, or mode of operation, that is appropriate for the attached baseplate. For example, if the baseplate  500  is detected, the controller will not including priming as part of the delivery process and, in some implementations, will prevent the user from manually implementing a priming procedure. If, on the other hand, baseplate  501  is detected, then the delivery process may include appropriate priming of the infusion set tube. 
     A wide variety of baseplate identification instrumentalities and identification methodologies may be employed, and the present inventions are not limited to any particular instrumentalities and methodologies. Various illustrative examples of such instrumentalities and identification methodologies are presented below. 
     In the exemplary implementation illustrated in  FIGS.  1  and  66 - 68   , the baseplates  500 ,  501  and  502  respectively have identification devices  582 - 0 ,  582 - 1  and  582 - 2 , each of which includes a pair of electrical contacts. The electrical contacts are located such that each pair will be aligned with (as well as contact or be otherwise electrically coupled to) a respective two of the three electrical contacts  228 ,  230  and  232  associated with the pump assembly ( FIG.  16   ) when a baseplate is secured to the pump assembly. The electrical contacts  228  and  230  may also be used to recharge the pump assembly battery  238 , as is noted above. For example, baseplate identification device  582 - 0  may include electrical contact pair  228 BP/ 230 BP ( FIG.  66   ) that will align with pump assembly electrical contact pair  228 / 230 , baseplate identification device  582 - 1  may include electrical contact pair  230 BP/ 232 BP ( FIG.  67   ) that will align with pump assembly electrical contact pair  230 / 232 , and baseplate identification device  582 - 2  may include electrical contact pair  228 BP/ 232 BP ( FIG.  68   ) that will align with pump assembly electrical contact pair  228 / 232 . The electrical contacts in each pair, which may be located in recesses  584 , are electrically coupled to one another by conductors  586 . The conductors  586  may be formed from a low resistance material and may be covered with an appropriate electrical insulator. 
     During use, and after a baseplate has been secured to the pump assembly (e.g., pump assembly  200 ), the pump assembly controller (e.g., controller  240 ) will cause voltage to be applied across the pump assembly electrical contacts  228 ,  230  and  232  and may measure resistance (or another suitable variable) between contact pairs  228 / 230 ,  230 / 232  and  228 / 232 . The pair that is in contact with two of the baseplate electrical contacts will have low resistance therebetween, while the other two pairs will have extremely high (e.g., infinite) resistance therebetween. The pump assembly controller may store information which indicates that low resistance at contact pair  228 / 230  is indicative of baseplate  500 , low resistance at contact pair  230 / 232  is indicative of baseplate  501 , and low resistance at contact pair  228 / 232  is indicative of baseplate  502 . The “baseplate type” determination may, therefore, be made by simply determining which two of the three pump assembly electrical contacts have a low resistance path therebetween. 
     Turning to  FIGS.  69 - 72   , the exemplary pump assembly  200   d  is essentially identical to pump assembly  200  and the baseplates  500   d ,  501   d  and  502   d  are essentially identical to baseplates  500 ,  501  and  502 , respectively. Similar elements are represented by similar reference numerals. Here, however, the pump assembly  200   d  only includes the two recharging-related electrical contacts  228  and  230 , and the baseplates  500   d ,  501   d  and  502   d  respectively include baseplate identification devices  588 - 0 ,  588 - 1  and  588 - 2  that each have two electrical contacts, i.e., electrical contacts  228 BP and  230 BP. The electrical contacts  228 BP and  230 BP, which will contact or otherwise electrically couple with the contacts  228  and  230  when a baseplate is attached to pump assembly, may be connected by resistors R 1 , R 2  and R 3  with different resistor values. The resistor values may be significantly different to reduce the likelihood of error. For example R 1  may be 10 kΩ, R 2  may be 22 kΩ, and R 3  may be 68 kΩ. Also, in the illustrated implementation, the electrical contacts  228 BP and  230 BP are carried in recesses  590 . Resistor value to baseplate type correspondence information may be stored by the pump assembly controller. During use, and after a baseplate has been secured to the pump assembly (e.g., pump assembly  200   d ), the pump assembly controller will cause voltage to be applied across the electrical contacts  228  and  230  and the resistance between the electrical contacts  228 BP and  230 BP will be measured. The “baseplate type” determination may be made based on this resistance measurement and a comparison of the measured value to the stored information. 
     The exemplary electrical contacts described above may be formed from materials such as copper or nickel. Also, although the surfaces of the electrical contacts are generally planar in the illustrated embodiments, the electrical contacts are not limited to any particular configuration. For example, opposing metallic half balls may be employed with proper accommodation on the pump assembly and baseplate. 
       103941  Other exemplary baseplate identification instrumentalities are illustrated in  FIGS.  73 - 75   . Here, the baseplates  500 e,  501   e  and  502   e , which are otherwise identical to baseplates  500 ,  501  and  502 , respectively, carry baseplate identification devices  591 - 0 ,  591 - 1  and  591 - 2  with different patterns of optically identifiable targets. For example, the optically identifiable targets may be reflective targets  592   a  and occluded targets  592   b . The associated pump assembly (e.g., pump assembly  200   d ) may be provided with an emitter/detector  593  that “reads” the patterns of optically identifiable targets and transmits a pattern signal to the pump assembly controller (e.g., controller  240 ) indicative of the pattern that has been read (e.g., 0,1,1 for the pattern illustrated in  FIG.  74   ). Pattern to “baseplate type” correspondence information may be stored by the pump assembly controller, and the controller may identify the baseplate based on the pattern signal. Additionally, the baseplate identification devices  591 - 0 ,  591 - 1  and  591 - 2  may be carried or formed directly on the baseplate, or may be carried on structures (e.g. decals) that are secured to the baseplate. 
     Other exemplary baseplate identification instrumentalities are illustrated in  FIG.  76   . Here, the baseplates  500 f,  501   f  and  502   f , which are otherwise identical to baseplates  500 ,  501  and  502 , respectively, carry baseplate identification devices  594 - 0 ,  594 - 1  and  594 - 2  in the form of resonant circuits with different resonant frequencies. The associated pump assembly (e.g., pump assembly  200   d ) may be provided with an RF transmitter  595 , including an RF transmitter antenna, a detector-demodulator, and RF electronics. The RF transmitter  595  may be used to detect the frequency of a resonant circuit in proximity thereto and to provide such frequency information to the controller. Exemplary resonant frequencies for the baseplate identification devices  594 - 0 ,  594 - 1  and  594 - 2  include, but are not limited to, 10 kHz, 20 kHz and 30 kHz, and frequency to “baseplate type” correspondence information may be stored by the controller. 
     Still other exemplary baseplate identification instrumentalities are illustrated in  FIG.  77   . Here, the baseplates  500   g ,  501   g  and  502   g , which are otherwise identical to baseplates  500 ,  501  and  502 , respectively, carry baseplate identification devices  596 - 0 ,  596 - 1  and  596 - 2  in the form of magnets that create different magnetic fields. The associated pump assembly (e.g., pump assembly  200   d ) may be provided with a sensor  597 , such as a Hall-effect sensor or a magnetoresistive sensor, that reads the magnetic field of the associated baseplate identification device, and sends a signal corresponding to the sensed magnetic field to the controller. Magnetic field to “baseplate type” correspondence information may be stored by the controller. 
     Turning to  FIG.  78   , the exemplary baseplate identification instrumentalities illustrated therein include baseplate identification devices  598 - 0 ,  598 - 1  and  598 - 2  in the form of RFID tags, each of which emits different identification data in response to being interrogated. The baseplate identification devices  598 - 0 ,  598 - 1  and  598 - 2  are respectively carried by baseplates  500 h,  501 h and  502 h, which are otherwise identical to baseplates  500 ,  501  and  502 . The associated pump assembly (e.g., pump assembly  200   d ) may be provided with an RFID reader  599  that interrogates the associated identification device, and sends a signal corresponding to the identification data to the controller. 
     The present baseplates and pump assemblies are not limited to the exemplary identification instrumentalities described above. By way of example, but not limitation, other identification instrumentalities include protrusions on the plate that depress buttons, or combinations of buttons, on the bottom surface of the pump assembly housing. Another example includes depressible pins that extend from the bottom surface of the pump assembly housing, such that they will be pressed by an attached baseplate. Here, different baseplates may be provided with different combinations of indentations that will be aligned with the pins, to prevent depression thereof, when the baseplate is attached. It should also be noted that the present baseplates and pump assemblies are not limited to identification instrumentalities that require the baseplate to be completely or partially attached to the pump assembly prior to the identification procedure. Instrumentalities that merely require suitable proximity (including those that involve RFID technology) may be employed. 
     VII. Exemplary Basic Operation and Use 
     At the most basic level, use of the exemplary infusion pump system  10  (or  11 ) illustrated in  FIG.  1    involves inserting a new medicament cartridge  100  into the pump assembly, connecting the baseplate  500  (or  501 ) to the pump assembly, gaining subcutaneous access, and initiating a medicament delivery operation. In some instances, use may involve additional steps such as removal of a previously inserted cartridge (whether empty or not) and battery recharging. Various aspects of the basic operation of the present systems are described below. Operation of a system does not require all of the steps each time the system is deployed, and the order of some of the steps may be changed. Operation is also discussed below, in the exemplary context of the above-described cartridge  100 , pump assembly  200 ′ and patch pump baseplate  500 ′, through the use of a flow chart ( FIG.  79   ) as well as through illustrations of the exemplary system itself in various states ( FIGS.  80 - 90   ). The discussion is, however, equally applicable to other patch pump implementations, as well as to pocket pump implementations with minor variations. Also, unless otherwise indicated, the actions and determinations performed by the pump assembly  200 ′ are controlled by controller  240  ( FIGS.  18  and  84   ) and references to the controller are omitted in the interest of brevity. 
     Referring first to  FIG.  79   , use of the present systems may involve removal of a cartridge from a pump assembly. This may occur (in some instances automatically) when the plunger pusher  250 ′ is at the end of the pusher stroke (Step  5101 ) and a “replace cartridge” report is presented (Step S 102 ), or when the controller receives a user-initiated “replace cartridge” signal from the remote control  1000  (Step S 103 ). The user may desire to replace a cartridge before it is empty for a variety of reasons such as, for example, to accommodate the user&#39;s sleep or travel schedule, when the medicament appears cloudy or otherwise exhibits a loss of effectiveness, when a dispensing problem arises, or due to a prescribed change in medicament. Whether automatic or user-initiated, the plunger will be returned to the fully retracted home position (Step S 104 ). The user may then obtain a new cartridge  100 , a new baseplate  500 ′, a new cannula and inserter, the remote control  1000  (if not already at hand), and the battery recharger  700  (Step S 105 ). The cartridge  100 , pump assembly  200 ′, baseplate  500 ′ and cannula may then be removed from the skin, and the baseplate, cartridge and cannula discarded (Steps S 106  and S 107 ). The battery  238  may be recharged with the recharger  700  (Step S 108 ) in the manner described in Section IV-J above with reference to  FIGS.  49 - 50   . 
     A new cartridge  100  may then be inserted in the pump assembly  200 ′ (Step S 109 ). In particular, as illustrated in  FIG.  80   , because the pusher  250 ′ is in a retracted home position, the slidable latch  412   a  is unlocked and the latch member  442  can be pushed to the rearward position, thereby facilitating cartridge insertion, as described in Section IV-F above with reference to  FIGS.  32 - 35 A . The latch member  442  will return to the locked position ( FIG.  81   ) when released, thereby pushing the cartridge  100  against the chassis  244 . 
     The plug  110  may remain in the cartridge through-bore  116  should the user desire to perform the pusher zeroing procedure (or “zeroing procedure”) described in Section VIII-B below with reference to  FIG.  91    (Step S 110 ). The zeroing procedure may also be an automatic aspect of pump operation. The user may use, for example, the remote control  1000  to initiate the zeroing procedure ( FIG.  81   ) which involves briefly advancing the pusher  250 ′ ( FIG.  82   ), thereby locking the latch  412   a  and rigidly fixing the position of the cartridge  100  against the chassis  244  in a held position within the cartridge receiving area  220 . If the results of the zeroing procedure are negative, the pusher  250 ′ is withdrawn ( FIG.  83   ), thereby unlocking the latch  412   a . The medicament cartridge  100  is removed and discarded, a new cartridge is inserted, and the zeroing procedure is repeated (Steps S 111 , S 112 , S 113  and S 114 ). Alternatively, if the results of the zeroing procedure are positive, the pusher  250 ′ is withdrawn, the plug  110  is removed and the baseplate  500 ′ may be secured to the pump assembly  200 ′, as shown in  FIG.  84    (Steps S 115  and S 116 ). As discussed above in Section IV-F above with reference to  FIG.  35 A , the slidable latch member  442  will seat in the baseplate latch indentation  509  to properly align the pump assembly  200 ′ and baseplate  500 ′. 
     A cannula inserter (or “inserter”) may then be secured to the pump assembly  200 ′ (Step S 117 ). One exemplary inserter, which is generally represented by reference numeral  800  in  FIG.  85   , may include a movable member  802  within a housing  804 , and a trigger-type actuator  806  that acts on the movable member. The exemplary actuator  806  may have a rotatable trigger  808  and a compressed spring or other biasing device  810 . A trocar  812  is carried on the movable member  802 . A cannula  600 ′ is pre-mounted on the trocar  812  such that the sharp end of the trocar extends beyond the cannula tube  612 . The inserter  800  may also be configured to withdraw the trocar back into the housing  804  after the cannula is deployed. 
     It should be noted here that the exemplary cannula  600 ′ is substantially similar to the cannula  600  described in Section V above with reference to  FIGS.  56 - 57    and similar elements are represented by similar reference numerals. Here, however, the cannula  600 ′ does not include a latch. Instead, the respective configurations (e.g., shape, size and materials) of the cartridge through-bore  116  and the cannula plug  602 ′ are such that friction therebetween will maintain the relative positioning after cannula deployment. The cannula plug  602 ′ may also be formed from two different materials, e.g., a more rigid inner material to provide structural support and a softer outer material for sealing. The discussion concerning deployment of the cannula  600 ′ is, of course, equally applicable to cannula  600 , cannula  600   a  and/or any other cannula that may be used in conjunction with the present pump assemblies and baseplates. 
     The user may clean the skin surface S onto which the baseplate  500 ′ will be adhered, and the liner  544  may be removed to expose the adhesive layer  542 , as illustrated in  FIGS.  85  and  86    (Steps S 118  and S 119 ). Turning to  FIG.  87   , the unit consisting of the cartridge  100 , pump assembly  200 ′, baseplate  500 ′, cannula  600 ′ and inserter  800  may be adhered to the skin surface S (Step S 120 ). The inserter actuator  806  may then be actuated ( FIG.  88   ) by rotating the trigger  808 , thereby allowing the spring  810  to drive the movable member  802  towards the patient (Step S 121 ). The cannula plug  602 ′ will be properly seated in the cartridge through-bore  116 , and the cannula tube  612  will be subcutaneously deployed, at the end of the movable member stroke. The inserter  800  may then be removed ( FIG.  89   , Step S 122 ). 
     In some implementations, the pump assembly may be provided with structure (not shown) that performs the function of determining whether or not the cannula is properly inserted (Step S 123 ). If not, an error message will be provided to the user (Step S 124 ). 
     Finally, as shown in  FIG.  90   , the remote control  1000  may be used to initiate a particular medicament delivery operation (Step S 125 ). The delivery operation may follow a predetermined delivery profile (e.g. a particular basal rate, a series of time-spaced bolus deliveries, or some combination thereof) that is equated to motor rotations, at particular rates and times, required to deliver medicament in accordance with the profile. The profile may be input by the user with the remote control  1000  and stored by the controller  240 . For example, as described below, the remote control may store a number of different delivery profiles and bolus deliveries from which the patient can choose. Such profiles may correspond to, for example and depending on the medicament, days where vigorous exercise is expected, days where it is not, incidences of increased pain, etc. Alternatively, or in addition, the profile stored in the controller may be set by a clinician&#39;s programming unit. 
     The discussion above is also applicable to use of the “pocket pump” system  11 . Minor variations in the above-described procedure include, for example, use of the baseplate  501 , deploying the infusion set  503  instead of a cannula, and priming of the infusion set tube. 
     VIII. Exemplary Operational Methodologies 
     Various methodologies are presented here in the context of the exemplary structures described in the preceding sections, and illustrated in  FIGS.  1 - 90   , for the purpose of explanation only. Although the present methodologies may employ the structures described above, they are not limited thereto. Additionally, the alarms, reports and other notifications associated with the methodologies described below may be provided in audible, visible and/or tactile form. A pump assembly may provide audible, visible and/or tactile notifications. A remote control may also provide audible, visible and/or tactile notifications as an alternative to, or in addition to, any notifications provided by a pump assembly. Additionally, embodiments of the present inventions may incorporate any one of the methodologies described below, or all of the methodologies described below, or any and all combinations of less than all of the methodologies described below. 
     A. Exemplary Cartridge Position Check 
     Given the relatively small size of the systems described above, the present inventors have determined that it would be desirable to determine whether or not a cartridge (e.g., cartridge  100 ) has been properly inserted into (or “positioned in” or “seated in”) a pump assembly (e.g., pump assembly  200 ) cartridge receiving area. For example, it may be desirable to make such a determination when the cartridge is initially inserted into a pump assembly, and prior to the pusher zeroing procedure discussed in Section VIII-B below. Other procedures, such as pusher zeroing procedure, may also start automatically after the position check. 
     A variety of structures may be employed in such a position check. For example, as discussed in Section IV-H above with reference to  FIGS.  41  and  42   , an exemplary cartridge and pump assembly may be provided with a pressure sensor  234  that includes a detectable structure on the cartridge portion  120  (e.g., a magnet) and a detector on the pump assembly portion  236  that responds to the detectable structure (e.g., a sensor that responds to changes in magnetic fields). The pre-pressurization “at rest” position of the cartridge portion  120  within the cartridge receiving area  228  (and relative to the chassis window  287 ) is also closely controlled by, for example, the spring bias clips  268 , the latches  412  and  412   a  and structures  494  described in Section IV-F above with reference to  FIGS.  18 ,  23 - 26 ,  32 - 35 A and  38   . As a result, the controller  240  may use the signals from the pump assembly portion  236  to determine whether or not the cartridge has been properly positioned. In the exemplary context of magnet-based sensors, the controller would compare the measured magnetic field signals to expected magnetic field signals to determine whether or not the cartridge is properly positioned. 
     Accordingly, and referring to  FIG.  91   , a method of checking cartridge position may include sampling the output of the pump assembly portion  236  of a pressure sensor  234  (Step S 201 ) and determining whether or not the output is above a predetermined threshold and stable (Step S 202 ). If not, then a “cartridge not installed” alert may be provided (Step S 203 ) so that the user can take appropriate action, such as inserting a new cartridge or returning the pump to the manufacturer. If the cartridge is properly positioned, then the system will proceed with subsequent processes such as the pusher zeroing procedure described below. 
     It should also be noted here that in other implementations, structures other than the pressure sensor  234  may be used to determine whether or not the cartridge  100  is properly positioned in the pump assembly  200 . For example, the cartridge barrel  102  may be provided with a pressure responsive structure that will not be isolated from the reservoir, as will the sensor cartridge portion  120  by the plug  110 , during the pusher zeroing procedure described below. Here, a pressure-based cartridge position check may be performed at the onset of a pusher zeroing procedure. Switches, electrical contacts or other devices may also be employed. 
     B. Exemplary Pusher “Zeroing” Procedure 
     As discussed at great length above, precision is very important to dispensing procedures that involve highly concentrated medicaments such as U-500 insulin. The present inventors have determined that one aspect of dispensing precision is associated with the distance that the plunger pusher must travel, from the initial home position, before it will engage the cartridge plunger and begin to drive medicament out of the reservoir. Given that there may be some tolerances associated with cartridge manufacture and initial seating of the cartridge within the pump assembly, this distance may vary. Thus, a dispensing process based on an estimate/measurement of this distance at the time of manufacture may result in under delivery or over delivery in some circumstances. 
     The pusher zeroing procedure described below obviates this issue by precisely determining and/or setting, prior to actual dosing, exactly how far the plunger pusher  250  must travel before it will engage the cartridge plunger  106 . This procedure may be performed each time a cartridge  100  is inserted into a pump assembly  200  and, in at least some instances, is performed after the position of the cartridge is checked in the manner described in the preceding section. Generally speaking, the zeroing procedure is performed when flow from the cartridge  100  is blocked by the plug  110 . A test load (e.g., ten pounds) is applied to the cartridge  100  with the plunger pusher  250  to fully seat the cartridge and to generate a motor stall. Misalignment or misplacement of the cartridge  100  within the pump assembly  200 , such as from a raised chip or other debris on mating surfaces, is either removed or accommodated by local deformation of the cartridge under the test load, thereby precluding subsequent cartridge movement during medicament delivery. The motor stall is presumed to be due to hydraulic lock and, therefore, indicative of the plunger pusher  250  engaging the plunger  106  of a plugged cartridge  100 . 
     Referring again to  FIGS.  81 - 83  and  91   , one exemplary implementation of the zeroing procedure may be practiced in conjunction with pump assembly  200 ′. The zeroing procedure, which is equally applicable to pump assembly  200 , commences by advancing a plunger pusher  250 ′ into engagement with the cartridge plunger  106  ( FIG.  81   ) to increase the fluid path pressure (Step S 204 ). The encoder  396  or other monitoring device is sampled to determine whether a motor stall occurs as the pusher  250 ′ continues to be advanced (Steps S 205  and S 206 ). One example of such a stall is illustrated in  FIG.  82   . The pusher  250 ′ may be advanced up to a predetermined allotted distance (e.g., 0.5 mm) from the home position ( FIG.  18   ), which corresponds to a predetermined number of encoder signals. The allotted distance is a distance that is sufficient to make contact with cartridge plunger  106  under normal conditions. 
     The pusher may be initially advanced at a relatively fast speed, and then advanced at a relatively slow speed (e.g., ½ of the faster speed) until the lack of encoder signals evidences that the motor is not turning. The faster speed can occur over a distance of 0.3 mm and the slower speed can occur over a distance of 0.2 mm. The slower speed is a “searching” speed employed over the portion of the allotted distance where it is anticipated that the pusher  250 ′ will contact the plunger  106 . The lower speed reduces the force of the impact. The faster speed is used to speed up the process over the portion of the allotted distance where it is less likely that the pusher  250 ′ will contact the plunger  106 . Also, the pusher  250 ′ may be advanced at a controlled torque, or limited force, so that the motor will stall with the least amount of force possible for reliable results, in order to reduce the load on the system (e.g., the bearings and the battery). 
     If a motor stall does not occur within the allotted distance, the system controller  240  may determine that the associated cartridge  100  is either not new, not full, was improperly made or filled, or is otherwise defective and may preclude its use (Step S 208 ). In those instances where the cartridge is not full, the preclusion is useful because, for example, the associated dispensing program may be based on a full cartridge with a known volume of medicament. 
     If the motor  358  does stall within an acceptable encoder count range, i.e., at or before the allotted distance, then the pusher  250 ′ is retracted a predetermined distance by running the motor in reverse, which ends the process (Step S 209 ). One example of pusher retraction is illustrated in  FIG.  83   . The retraction distance may be, for example, 0.001 to 0.005 inch (0.025 mm to 0.125 mm). The retraction distance may also be equated to dispensed medicament, e.g., 1 to 20 μl worth, or 5.5 to 6.5 μl worth. In any event, at the onset of dosing, the distance between the plunger pusher and the plunger is precisely set and can be taken into account as movement of the plunger pusher is controlled. 
     The advancing-retracting process can be repeated a few times to account, for example, for variability of the interface between the lead screw  360  and drive nut  364  ( FIG.  23   ). The advancing-retracting process can be also repeated using a light force (e.g., two pounds) followed by a stronger force (e.g., four to five pounds) to confirm that the first motor stall was due to torque and not some other cause. Repeating the process increases the likelihood that the “zero” distance between the plunger pusher  250 ′ and the dry side of the plunger  106  will be precisely established. 
     C. Exemplary Occlusion Detection 
     Various structures in the exemplary cartridges and pump assemblies may be used to detect occlusions in a cartridge, cannula or infusion set tube. Although precise occlusion detection may be desirable in any infusion pump, it is especially desirable in those instances where very high concentration medicament is dispensed. For example, some conventional insulin pumps alert the patient after approximately 30 μl of missed delivery without an undue number of false alarms. While this level of fidelity may be adequate in the context of U-100 insulin, where 30 μl equates to 3 IUs of insulin, it would result in a much more problematic 15 IUs of missed delivery in the U-500 context. Occlusions may also lead to other undesirable outcomes. For example, continuing to drive the motor in the presence of an occlusion may lead to cartridge leakage and/or damage to various aspects of the drive mechanism. The structures described above and methodologies described below address these issues. 
     One exemplary dispensing method, which includes occlusion detection, is illustrated in  FIGS.  92  and  93   . The occlusion detection aspect of the exemplary method includes monitoring of the motor encoder  396  as well as monitoring of the pressure sensor  234 . It should be noted, however, that only one of the two may be monitored in the occlusion detection context in other implementations. 
     Referring first to  FIG.  92   , at the initiation of a dosing operation, the firmware counter of the controller  240  is loaded with the number of encoder counts required to advance the pusher  250  a distance corresponding to the desired drug dose (Step S 301 ). For example, in some implementations, a single dose of 1 μl (or 0.50 IU) of U-500 insulin would equate to 14.4 motor revolutions. In other words, in the context of the exemplary embodiment illustrated in  FIG.  23 ,  14 . 4    motor revolutions will cause the drive screw  360  to drive the plunger pusher  250  (and cartridge plunger  106 ) a distance sufficient to force 1 μl from the reservoir  104 . 
     Motor rotation begins, which causes the pusher  250  to advance, and the counter is decremented in response to signals from the encoder  396  (Step S 302 ). Detected increases in pressure from the pressure sensor  234  and/or signals from the encoder  396  indicative of a stalled motor  358  result in the generation of an “occlusion” report (Steps S 303 , S 304  and S 305 ). In at least some implementations, the motor  358  will also be disabled (i.e., motor excitation ceases). Various exemplary occlusion detectors are discussed in greater detail in Section IV-H above with reference to  FIGS.  41  and  42   . In response to the detection of an occlusion, the user may be instructed to remove and replace the cartridge  100  as well as the baseplate  500  (and associated cannula) or baseplate  501 . Also, in at least some implementations, the plunger pusher  250  will be automatically withdrawn from the cartridge and returned to the home position, as described in Section VIII-F below, in response to a detected occlusion. This readies the system for cartridge removal and replacement. 
     Absent an occlusion, the dispense operation will continue until the counter reaches zero (Step S 306 ), which indicates that the desired dose has been delivered. At that point, the controller  240  will control the motor  358  to rotate until the next step count from the encoder  396 , and will thereafter disable the motor (Steps S 307  and S 308 ). The controller  240  may, however, continue to monitor the encoder  396  (Step S 309 ) to determine whether or not there is encoder (and motor  358 ) rotation in the absence of motor excitation (Step S 310 ). If forward rotation of the motor  358  is detected in the absence of motor excitation (Step S 311 ), which indicates that the motor  358  is at least attempting to drive the plunger pusher  250  in the dispensing direction, an error is reported (Step S 312 ). If reverse rotation is detected in the absence of motor excitation, which is indicative of the plunger pusher moving away from the cartridge plunger due to, for example, system load or compliance, the appropriate number of encoder counts will be added to the next dispense dose (Step S 313 ). 
     As alluded to above, occlusions may be detected by monitoring rotation of the motor  358  (e.g., by way of the encoder  396 ) and/or by monitoring pressure (e.g., with the sensor  234 ). With respect to pressure, a predetermined rate of pressure change (or AP/AT) or pressure above a predetermined threshold may be indicative of an occlusion. The present methods may employ one of, any two of, or all three of rotation, ΔP/ΔT and threshold, as shown in  FIG.  93   . Motor rotation may be monitored during a dispense operation by continuously sampling the encoder  396  with the controller  240  (Step S 401 ). If the encoder  396  does not sense rotation of the motor  358  during a dispense operation, the controller  240  will consider the motor  358  to be stalled due to, among other things, an occlusion (Step S 402 ) and report accordingly (Step S 403 ). Alternatively, or in addition, the controller  240  may repeatedly sample the output of the pressure sensor  234  (Step S 404 ) and use a most recent value, the immediately preceding value, and the time period therebetween to create AP/AT values (Step S 405 ). If the ΔP/ΔT values remain over a predetermined magnitude (e.g., 2 psi/sec.) for a predetermined period of time (e.g., 2 sec.), the controller  240  will consider the pressure increase to be due to an occlusion (Step S 406 ) and report accordingly (Step S 403 ). Alternatively, or in addition, the controller  240  may repeatedly sample the output of the pressure sensor  234  (Step S 407 ) and compare the output to a predetermined threshold value (Step S 408 ). In some instances, the controller  240  will provide a “possible occlusion” alert in response to any sample that is over the threshold value (e.g., the expected “occluded” value) and, regardless of whether the “possible occlusion” alert is provided, subsequent samples will be used to determine whether or not the condition persists (Step S 409 ). If the “over the threshold” condition persists for a predetermined period (e.g., 1 sec.), and if a comparison of subsequent samples to the prior sample is not indicative of a future reduction below the threshold value, then the controller  240  will consider the pressure increase to be due to an occlusion (Step S 410 ) and report accordingly (Step S 403 ). 
     D. Exemplary Accounting for Unpowered Motor Reverse 
     The present inventors have determined that there may be some instances where an unpowered motor unintentionally rotates in reverse due to, for example, system load or compliance. Such load and compliance may be associated with a build-up in force in the gears which releases itself by the gears turning in the reverse direction when the motor is not energized. When this occurs, the motor is rotated in reverse. At the other end of the gear assembly, the plunger pusher, which has previously been brought into engagement with the cartridge plunger, may (or may not) pull away from the plunger. The initial motor turns in the next delivery procedure (or “dose” or “delivery cycle”) will, in essence, simply rebuild the force in the gears and, if not already the case, bring the pusher back into contact with the plunger. As a result, the volume of medicament actually delivered to the patient in that dose will be less than expected. 
     In order to account for, or correct for, the delivery error that would otherwise be associated with this condition, the pump assembly may include an encoder  396  which senses rotations of the motor in both the forward and reverse directions. The controller  240  may be configured to determine from the encoder signals the amount of reverse rotation and to adjust the dispensing program accordingly so that the net result is the overall intended result. 
     One example of such a correction process is illustrated in  FIG.  94   . At the onset of a dispensing procedure (Step S 501 ), the number of motor revolutions corresponding to the intended delivery is calculated and set (Step S 502 ). Using the example above, a single dose of 1 μl (or 0.50 IU) of U-500 insulin may equate to 14.4 motor revolutions. The controller  240  will control the motor  358  to operate for the set number of revolutions (Step S 503 ), unless one of the other alarm conditions described below with reference to  FIG.  100    occurs. The controller  240  will then unpower the motor  358 , and the motor will remain unpowered, until the next dosing (Step S 504 ). Should the motor  358  rotate in reverse, as evidenced by signals from the associated encoder  396 , the number of reverse rotations (or “reverse count”) will be counted and stored until the next dosing (Steps S 505  and S 506 ). When the next dosing commences, the reverse count will be added to calculated and set number of rotations for that next dosing (Step S 503 ). For example, if there were 2 reverse rotations prior to a dosing that equates to 14.4 motor revolutions, the controller would control the motor to perform 16.4 revolutions for that dosing. 
     E. Exemplary Motor Stopping 
     The present inventors have determined that another aspect of motor control which can effect the precision of medicament delivery is motor stopping. Briefly, when a controller cuts off power to a motor, the motor will continue to rotate, in a now uncontrolled state, due to its own momentum and the momentum of other rotating aspects of the drive mechanism. The plunger pusher will continue to travel in the forward dispensing direction, thereby driving the cartridge plunger, as the motor continues to rotate. Although one could simply cut off power a few revolutions prior to the end of a delivery cycle, the precise number of “extra,” post cut-off revolutions is difficult to accurately and consistently estimate. As such, the simple act of turning the motor on and off, from dose to dose, can lead to under delivery and/or over delivery error due to the uncontrolled movement of the plunger pusher. 
     One exemplary method of controlling a motor such as a stepper motor  358  with a controller such as controller  240  is graphically illustrated in  FIG.  95   . In particular, the speed of motor is increased from zero at the beginning of the dispensing procedure (e.g., a single dose) and is then maintained at a constant rate. At a predetermined point prior to the end of the dispensing procedure (e.g., three revolutions prior), which is labeled “begin motor stop process” in  FIG.  95   , the frequency of the power waveform delivered to the motor  358  will be slowly decreased. Positive control over the motor  358  is maintained as the velocity of the plunger pusher  250  decreases from its propelling velocity to a complete stop, where the speed equals zero and the dosing ends. Maintaining positive control of the motor  358  in this manner allows the number of turns associated with a motor stoppage to be precisely controlled as is shown with a solid downwardly sloping line in  FIG.  95   . As a result, the intended number of rotations associated with stoppage will be the actual number of rotations, the distance of pusher travel will be the intended distance, and dispensing precision will be maintained. For purposes of comparison, stopping the motor by simply cutting off power at the same predetermined point may result in too much or too little rotation, as is shown with dashed lines. As a result, the distance of plunger travel (and dispensed volume) may be more or less than intended. 
     Accordingly, by employing the above-described stopping method, the controller can cause the motor  358  to propel the pusher  250  against the medicament reservoir plunger  106  according to a medicament dispensing program, having a plurality of individual dispensing operations, without stoppage related losses in precision. Also, the predetermined point prior to the end of the dispensing procedure at which frequency of the power waveform begins to decrease may vary from system to system. Although a three revolution slow down period is employed in the illustrated example, that number may be increased or decreased, and need not be a whole number. 
     F. Exemplary Automatic Plunger Pusher Retraction Procedures 
     For purposes of convenience and safety, the present pump assembly may be configured such that the plunger pusher is automatically retracted out of the associated medicament cartridge to the home position when the cartridge reaches the empty state, as evidenced by an encoder count or a motor stall, and/or when there is a motor stall due to an occlusion or other mechanical issue. 
     Referring to  FIG.  96   , the controller  240  will monitor the encoder  396  to determine whether the motor  358  has stalled or the encoder count has reached the number that is indicative of an empty cartridge (Step S 601 ). Such a stall would be evidenced by the cessation of encoder counts and could, for example, be the result of the plunger pusher  250  driving the cartridge plunger  106  into the cartridge end wall  119  ( FIG.  25   ), or an occlusion, or a mechanical issue. The “empty” number could reflect the exact number of motor rotations that would result in, for example, the cartridge plunger  106  reaching the end wall  119  ( FIG.  3 A ). However, in order to prevent damage to the drive mechanism that could result from the plunger pusher  250  repeatedly driving cartridge plungers into a fixed wall, the “empty” number could instead reflect slightly less than the exact number of motor rotations. It should also be noted that the encoder count may be adjusted to account for unpowered reverse motor rotations, during the life of the associated cartridge, in the manner described above with reference to  FIG.  94   . 
     Other issues notwithstanding, so long as the motor  358  has not stalled and the encoder count is not indicative of an empty cartridge, dispensing will be allowed to continue (Step S 602 ). If, on the other hand, the motor  358  has stalled or the encoder count is indicative of an empty cartridge, then the controller  240  will control the motor to run in the reverse, pusher retraction direction (Steps S 603  and S 604 ). The retraction speed may be relatively slow, as compared to a user-initiated retraction, so as to conserve battery power. For example, a relatively slow retraction may take 1 minute, or between 1.5 and 2.5 minutes, while a faster user-initiated retraction may take 30 seconds, or between 20 and 40 seconds. The user is not inconvenienced by the slower automatic retraction because it is occurring automatically at a time when the user is most likely not waiting for it to end, as would be the case in a user-initiated retraction. 
     At least initially, the retraction will take place at the full retraction speed (Step S 605 ). The speed may be reduced to a slower speed when the pusher  250  approaches the fully retracted home position (Step S 606 ). For example, the speed may be reduced at a distance from the fully retracted position that corresponds to 10% of the total pusher travel distance (i.e., the distance between fully retracted and fully extended). Withdrawal will continue until the controller  240  determines that the pusher has reached the fully retracted position (e.g., by way of position detector  398  in  FIG.  29   ), at which time the motor  358  will be stopped (Steps S 607  and S 608 ). To that end, it should be noted that the lower speed over the last 10% of pusher travel reduces the likelihood that the pusher  250  will damage the switch  398  or other position detector during impact therewith. 
     G. Exemplary Gear Assembly Verification Procedure 
     One aspect of the present pump assembly  200  that may require periodic operational verification is the gear assembly (e.g., gear assembly  362  in  FIG.  19   ) and, for example, the interfaces thereof. One exemplary gear assembly verification procedure (“GAV procedure”) is illustrated in  FIG.  97   . The exemplary GAV procedure will typically be performed by a controller when there is no medicament cartridge in a pump assembly in order to avoid the possibility of medicament being unintentionally dispensed. For example, controller may be configured to perform the GAV procedure each time the plunger pusher is returned to the fully retraced home position (e.g., against a hard stop), which is commonly associated with cartridge removal, or during a pusher zeroing procedure. Alternatively, or in addition, the GAV procedure may be a user implementable procedure initiated through operation of the remote control  1000 . 
     Upon initiation of the GAV procedure (Step S 701 ), the controller  240  may determine whether or not a cartridge  100  is within the pump assembly  200  by, for example, a method similar to those described in Section VIII-A above. Here, however, the controller need only determine whether a cartridge is in the pump assembly at all, as opposed to determining whether a cartridge is precisely located within the cartridge receiving area. If a cartridge is present, then the procedure is discontinued and an error message is provided to the user (Steps S 702  and S 703 ). If no cartridge is present, then the controller  240  determines whether or not the plunger pusher  250  is in the fully retracted home position and, if for some reason it is not, the controller automatically retracts the plunger pusher (Steps S 704  and S 705 ). Alternatively, the user could be instructed to retract the pusher  250  through operation of the remote control  1000 . 
     Relatively low torque is then applied to the gear assembly  362  by the motor  358  in the reverse direction (Step S 706 ). For example, approximately 20-70% (or 50%), or less than 20%, of the torque (e.g., 5-10 mNm) that is applied in the forward dispensing direction during normal delivery may be applied in the reverse direction. This may be accomplished by controlling power in the manner described in Section IV-M above. It should be noted here that there may be some built-up gear compression that will allow reverse motor rotation despite the fact that the plunger pusher has been fully retracted. Other situations are described below. 
     The power pulses will be sustained for a period corresponding to a predetermined number of motor revolutions (e.g., 50 revolutions). Signals from the encoder  396  and, therefore, motor rotation may be monitored. If the encoder signals indicate that the motor  358  has rotated at least a predetermined number of revolutions (e.g., 20 revolutions), precisely synchronized to motor driving sequence of pulses, the controller  240  determines that the motor is disconnected from the gear assembly  362  and creates a “drive error” signal (Steps S 707  and S 708 ). If, on the other had, the encoder signals indicate that less than the predetermined number of revolutions have occurred and that there is not a 1:1 correlation between the driving pulses and the encoder signals, then the controller determines that gear assembly  362  is intact and creates a “drive OK” signal (Step S 709 ). In other words, and somewhat counter intuitively, the controller  240  determines that the gear assembly  362  is not operating properly if signals from the encoder  396  indicate that the motor  358  is synchronized with the motor driving pulse sequence, and determines that the gear assembly is operating properly if signals from the encoder indicate that the motor is not synchronized with the motor driving pulse sequence. 
     In those instances where the plunger pusher  250  has been fully retracted and there is no built-up gear compression that would allow reverse rotation of the motor  358  under normal circumstances, the process may be adjusted slightly. Here, the motor  358  may be driven first in the forward direction and then in the rearward direction several times to verify whether or not the motor stalls after the same number of pulses (as determined by, for example, the switch  398  in  FIG.  29   ). 
     As alluded to above, a GAV procedure may be performed each time the motor  358  stalls. During zeroing and, in some embodiments, during homing, the motor  358  is stalled at controlled torque either against the plunger (zeroing) or against a hard stop (homing). During this procedure, the motor  358  is controlled to advance the mechanism at a known controlled torque while the motor encoder  396  is monitored for rotation. Correct operation requires the system to stall (encoder  396  ceases to turn while driving the motor  358 ) at a predetermined position. If the encoder  396  continues to indicate motor rotation while drive signals are being sent to the motor  358 , past the region of expected motor stall, it indicates the possibility of gear assembly failure. 
     IX. Exemplary Remote Controls and Associated Methodologies 
     The present infusion pumps may be used in conjunction with a wide variety of remote controls. Such remote controls may be used to, for example, allow the user to transmit instructions to the pump assembly or facilitate communication between the pump assembly and the user (e.g., an alarm condition message or other message concerning the conditions of the pump assembly). 
     The particular type of remote control may depend on the desired level of functionality for a particular user. A key fob type remote control which has one to four buttons may be provided in those instances where the user&#39;s control options are to be limited to, for example, starting and stopping medicament delivery procedures and withdrawing the plunger pusher from the cartridge. On the other end of the spectrum, commercially available devices with full-function user interfaces (e.g., a keyboard and a display, or a touch screen display), such as mobile telephones and personal digital assistants, may be programmed to provide the desired level of remote control functionality. 
     One exemplary remote control, which is generally represented by reference numeral 1000 in  FIGS.  98  and  99   , is configured and dimensioned to be easily grasped and manipulated in the user&#39;s hand. The exemplary remote control  1000  may include a power supply  1006  (e.g., one or more replaceable or rechargeable batteries), a sending and receiving antenna  1008  that is adapted for use with a corresponding sending and receiving antenna in the pump assembly (e.g., antenna  1002  in  FIG.  51   ), and a user interface  1010 . Operations may be controlled by a controller  1012  (e.g. a microprocessor, memory, firmware and/or software). Communication between the pump assembly  200  and remote control  1000  may be in the form of RF based communication (as described above) or other communication mediums such as infrared and magnetic. The user interface  1010  may include a visual display  1014  (e.g., an LCD display) and a plurality of buttons  1016  (e.g., switches, membrane keys, etc.). An alarm device  1018 , which may be audible (e.g., a buzzer), palpable (e.g., a vibrator), visible (e.g., an LED), or any combination thereof, may also be provided. 
     The exemplary remote control  1000  may also include a port or connector  1020  (e.g., a USB connector) that allows communication with, for example, a personal computer, a printer, or a clinician&#39;s programmer. 
     The exemplary remote control  1000  may also be provided with a proximity sensor  1022  that, when active, senses the distance between the remote control and the pump assembly  200 . The controller  1012  may actuate the alarm device  1018  if the distance is too great, in order to remind the user to keep the remote control  1000  close at hand. 
     The exemplary remote control  1000  may be configured to facilitate one, some or all of the following operations: (1) turning the remote control  1000  on or off, (2) associating (or “assigning”) the remote control  1000  to the pump assembly  200 , (3) obtaining status information such as battery charge level, medicament level, and/or alarm conditions, (4) silencing the pump assembly alarm, (5) selecting options that may be associated with the pump assembly alarm such as type of alarm (audible, palpable, and/or visible) and strength/volume of alarm, (6) connecting the remote control to a computer to, for example, update remote control or pump assembly firmware, load and delete delivery profiles stored in the pump assembly or remote control, and otherwise re-program the pump assembly or remote control, and (7) selecting medicament options such as medicament concentrations. 
     Other operations that may be performed through operation of the remote control  1000  include (1) selecting and initiating a stored medicament delivery profile, (2) increasing and decreasing medicament dose rate, (3) retracting the plunger pusher from the cartridge to the home position, and/or (4) pausing a dispensing operation. A user may pause delivery in order to remove or replace a patient applied structure (e.g. a cartridge, cannula or baseplate), adjust for a current or anticipated change body condition (e.g., low glucose, vigorous exercise), follow a physician&#39;s suggestion, or disconnect the pump assembly from the body for any other reason. 
     The exemplary remote control  1000  may be configured to generate an indicator, based on information from the pump assembly controller (e.g., controller  240 ), that is indicative of the amount of time remaining in the current dispensing program and/or the amount of time until the next cartridge replacement and/or the amount of time until the pump assembly battery requires recharging. The indicator may be audible, visible, palpable or combinations thereof. A time remaining indicator, such as the exemplary time indicator  1024  on the remote control visual display  1014  ( FIG.  98   ), may be useful for a variety of reasons. For example, knowledge of the time remaining prior to next cartridge replacement and/or battery recharging allows the patient to determine, based at least in part on the current time of day and upcoming events (e.g., travel or sleep), whether or not it would be more convenient to replace the medicament cartridge at a time prior to the end of the dispensing program and/or recharge the battery prior to the point at which it is necessary. 
     One exemplary type of visible time remaining indicator is the pie chart style “hours left” gauges  1024  and  1025  illustrated in  FIG.  98   . Any other suitable visible indicator may be employed. The visible indicators  1024  and/or  1025  may be displayed whenever the display  1014  is active, displayed in response to a user inquiry, displayed intermittently, and/or displayed in response to predetermined event (e.g., when 8 hours are remaining). 
     The exemplary remote control  1000  may be configured to generate an indicator, based on information from the pump assembly controller, that is indicative of the amount of medicament remaining in the cartridge. The indicator may be audible, visible, palpable, or combinations thereof. The exemplary visible “volume remaining” indicator  1026  may be displayed whenever the display  1014  is active, displayed in response to a user inquiry, displayed intermittently, and/or displayed in response to predetermined event (e.g. 25% remaining). 
     Remaining time calculations may be performed by the pump assembly controller  240  and be based, for example, on the total delivery duration for the associated cartridge (in view of the delivery program and cartridge volume) and the portion of that total delivery duration which has thus far passed based on actual delivery time (i.e., taking into account user stoppages, if any). Alternatively, or in addition, the calculations may be based on the initial volume of the associated cartridge, the total number of motor revolutions necessary to completely deliver the initial volume, the number of motor revolutions that have occurred prior to the calculation (as evidenced by, for example, encoder signals), and amount of time, based on the delivery program, before the total number of revolutions will be reached. Remaining volume (as opposed to remaining time) calculations performed by the controller  240  may be based on the initial volume of the associated cartridge, the number of motor revolutions necessary to completely deliver the initial volume, and the number of motor revolutions that have occurred prior to the calculation (as evidenced by, for example, encoder signals). Here, the information received by the remote control  1000  from the pump assembly controller  240  will be the actual time/volume information to be displayed. 
     It should also be noted that the calculations described above may be performed by the remote control controller  1012 . Here, the information received by the remote control  1000  from the pump assembly controller  240  may simply be encoder information. All other information (e.g. start time, program being implemented, etc.) would be already available at the remote control itself. 
     Additionally, in lieu of actual calculations, the pump assembly controller  240  and/or the remote control controller  1012  may be pre-programmed to automatically generate a time and/or volume indicator based on encoder information and a pre-programmed look-up table associated with the dispensing program. 
     With respect to the amount of time until the battery  238  requires recharging, the pump assembly may be provided with a battery management chip (or other suitable battery management apparatus) that determines when recharging is necessary. For example, recharging may be necessary when the battery voltage is reduced from the fully charged voltage to a predetermined voltage that is less than the fully charged voltage. The amount of time remaining may be estimated by the battery management apparatus based on factors such as battery age, battery temperature, and the dispensing program. The battery management apparatus may be part of, or operably connected to, the pump assembly controller  240 . The controller  240  is configured to generate a signal indicative of the amount of time remaining until the battery will require recharging. 
     One exemplary method that may stem from use of the information provided by a pump assembly and/or a remote control is as follows. The user learns from the remote control (e.g., remote control  1000 ) the amount of time (or medicament) remaining in the medicament dispensing program running on the associated infusion device (e.g., cartridge  100  and pump assembly  200 ). The information may be provided by the remote control  1000  in audible, visible and/or palpable form (e.g., with the time indicator  1024  and/or the volume remaining indicator  1026 ). The patient then determines, based on anticipated activity or activities, whether it would be preferable to remove a not yet empty medicament cartridge and replace it with a new medicament cartridge immediately, in the near future, or after the dispensing program has been completed and the cartridge is empty. It may be that, at the end of the remaining time, the user anticipates activity (e.g., sleeping, traveling, exercising, attending a social or business event) which would render cartridge replacement inconvenient or impossible. Thus, the user may decide that it is better to replace the cartridge before it is empty, and then do so. 
     Turning to  FIG.  100   , the exemplary remote control  1000  may be used to alert the user to, and specifically identify, a variety of alarm causes (or “conditions”). The exemplary remote control  1000  may be used to suggest actions to be taken in response to the alarms. The alarm causes and suggested actions may be provided in audible or visible form. Exemplary alarm causes are identified AC 1 -AC 16  in  FIG.  100   , and are followed by a suggest action. “R and R” is used in  FIG.  100    to represent “remove and replace,” and references to “cannula/baseplate” are references to both “patch pump” style baseplates (e.g., baseplate  500 ), which are used in conjunction with a separate cannula, and “pocket pump” style baseplates (e.g., baseplate  501 ), which may have their own cannula as part of an attached infusion set. 
     The exemplary alarm cause (or “conditions”) may include some or all of, but are not limited to, a pump assembly  100  (and/or a baseplate  500 ) falling off the user&#39;s skin (AC- 1 ), a battery with a low charge level (AC- 2 ), an error associated with an acoustic transducer or other alarm (AC- 3 ), a fully depleted battery (AC- 4 ), a battery fault (AC- 5 ), an occlusion (AC- 6 ), a telemetry fault (AC- 7 ), a motor error, such motor current too low (AC- 8 ), a baseplate/pump assembly disconnection (AC- 9 ), a firmware checksum error (AC- 10 ), a variables checksum error (AC- 11 ), a low reservoir (AC- 12 ), an empty reservoir (AC- 13 ), a battery fault (AC- 14 ), a zeroing procedure error (AC- 15 ), and a temperature (e.g. within the housing  202 ) above a preset limit (AC- 16 ). Other alarm conditions may include an error associated with pressure sensing hardware and delivery decision hardware. 
     Although the inventions disclosed herein have been described in terms of the preferred embodiments above, numerous modifications and/or additions to the above-described preferred embodiments would be readily apparent to one skilled in the art. It is intended that the scope of the present inventions extend to all such modifications and/or additions and that the scope of the present inventions is limited solely by the claims set forth below. 
     Finally, with respect to terminology that may be used herein, whether in the description or the claims, the following should be noted. The terms “comprising,” “including,” “carrying,” “having,” “containing,” “involving,” and the like are open-ended and mean “including but not limited to.” Ordinal terms such as “first”, “second”, “third” in the claims do not, in and of themselves, connote any priority, precedence, or order of one claim element over another or temporal order in which steps of a method are performed. Instead, such terms are merely labels to distinguish one claim element having a certain name from another element having a same name (but for the ordinal term) to distinguish the claim elements. “And/or” means that the listed items are alternatives, but the alternatives also include any combination of the listed items. The terms “approximately,” “about,” “substantially” and “generally” allow for a certain amount of variation from any exact dimensions, measurements, and arrangements, and should be understood within the context of the description and operation of the invention as disclosed herein. Terms such as “top,” “bottom,” “above,” and “below” are terms of convenience that denote the spatial relationships of parts relative to each other rather than to any specific spatial or gravitational orientation. Thus, the terms are intended to encompass an assembly of component parts regardless of whether the assembly is oriented in the particular orientation shown in the drawings and described in the specification, upside down from that orientation, or any other rotational variation therefrom.