Patent Publication Number: US-11664106-B2

Title: Syringe pump

Description:
The present application is a continuation of U.S. patent application Ser. No. 15/059,394, filed Mar. 3, 2016, and entitled Syringe Pump, now U.S. Pat. No. 10,245,374, issued Apr. 2, 2019, which is a continuation of Ser. No. 13/724,568, filed Dec. 21, 2012, and entitled Syringe Pump, now U.S. Pat. No. 9,295,778, issued Mar. 29, 2016, which is a Non-Provisional Application which claims priority to and the benefit of the following: 
     U.S. Provisional Patent Application Ser. No. 61/578,649, filed Dec. 21, 2011 and entitled System, Method, and Apparatus for Infusing Fluid; 
     U.S. Provisional Patent Application Ser. No. 61/578,658, filed Dec. 21, 2011 and entitled System, Method, and Apparatus for Estimating Liquid Delivery; 
     U.S. Provisional Patent Application Ser. No. 61/578,674, filed Dec. 21, 2011 and entitled System, Method, and Apparatus for Dispensing Oral Medications; 
     U.S. Provisional Patent Application Ser. No. 61/679,117, filed Aug. 3, 2012 and entitled System, Method, and Apparatus for Monitoring, Regulating, or Controlling Fluid Flow; and 
     U.S. Provisional Patent Application Ser. No. 61/651,322, filed May 24, 2012 and entitled System, Method, and Apparatus for Electronic Patient Care, each of which is hereby incorporated herein by reference in its entirety. 
     U.S. patent application Ser. No. 13/724,568, filed Dec. 21, 2012, and entitled Syringe Pump, now U.S. Pat. No. 9,295,778, issued Mar. 29, 2016 is also a Continuation In Part Application of the following: 
     U.S. patent application Ser. No. 13/333,574, filed Dec. 21, 2011 and entitled System, Method, and Apparatus for Electronic Patient Care, now U.S. Publication No. US-2012-0185267-A1, published Jul. 19, 2012, and 
     PCT Application Serial No. PCT/US11/66588, filed Dec. 21, 2011 and entitled System, Method, and Apparatus for Electronic Patient Care, both of which are hereby incorporated herein by reference in their entireties. 
     U.S. patent application Ser. No. 15/059,394, filed Mar. 3, 2016, and entitled Syringe Pump, now U.S. Publication No. US-2016-0184510-A1, published Jun. 30, 2016 may also be related to one or more of the following U.S. patent applications filed on Dec. 21, 2012, all of which are hereby incorporated herein by reference in their entireties: 
     Non-provisional application Ser. No. 13/723,238, entitled System, Method, and Apparatus for Clamping, now U.S. Pat. No. 9,759,369, issued Sep. 12, 2017; 
     Non-provisional application Ser. No. 13/723,235, entitled System, Method, and Apparatus for Dispensing Oral Medications, now U.S. Pat. No. 9,400,873, issued Jul. 26, 2016; 
     Non-provisional application Ser. No. PCT/US12/71131, entitled System, Method, and Apparatus for Dispensing Oral Medications, now Publication No. WO-2013/096718, published Jun. 27, 2013; 
     Non-provisional application Ser. No. 13/725,790, entitled System, Method, and Apparatus for Infusing Fluid, now U.S. Pat. No. 9,677,555, issued Jun. 13, 2017; 
     PCT application Ser. No. PCT/US12/71490, entitled System, Method, and Apparatus for Infusing Fluid, now Publication No. WO-2013/096909, published Jun. 27, 2013; 
     Non-provisional application Ser. No. 13/723,239, entitled System, Method, and Apparatus for Electronic Patient Care, now U.S. Pat. No. 10,108,785, issued Oct. 23, 2018; 
     Non-provisional application Ser. No. 13/723,242, entitled System, Method, and Apparatus for Electronic Patient Care, now U.S. Publication No. US-2013-0317753-A1, published Nov. 28, 2013; 
     Non-provisional application Ser. No. 13/723,244, entitled System, Method, and Apparatus for Monitoring, Regulating, or Controlling Fluid Flow, now U.S. Pat. No. 9,151,646, issued Oct. 6, 2015; 
     PCT application Ser. No. PCT/US12/71142, entitled System, Method, and Apparatus for Monitoring, Regulating, or Controlling Fluid Flow, now Publication No. WO-2013/096722, published Jun. 27, 2013; 
     Non-provisional application Ser. No. 13/723,251, entitled System, Method, and Apparatus for Estimating Liquid Delivery, now U.S. Pat. No. 9,636,455, issued May 2, 2017; 
     PCT application Ser. No. PCT/US12/71112, entitled System, Method, and Apparatus for Estimating Liquid Delivery, now Publication No. WO-2013/096713, published Jun. 27, 2013; and 
     Non-provisional application Ser. No. 13/723,253, entitled System, Method, and Apparatus for Electronic Patient Care, now U.S. Publication No. US-2013-0191513-A1, published Jul. 25, 2013. 
    
    
     BACKGROUND 
     Relevant Field 
     The present disclosure relates to pumps. More particularly, the present disclosure relates to a system, method, and apparatus for estimating liquid delivery of a syringe pump. 
     Description of Related Art 
     Syringe pumps are used in a variety of medical applications, such as for intravenous delivery of liquid medications, for example a patient in an intensive-care unit (ICU), for an extended length of time. Syringe pumps may be designed so that needles, tubing, or other attachments are attachable to the syringe pump. Syringe pumps typically include a plunger mounted to a shaft that pushes a liquid out of a reservoir. The reservoir may be a tube-shaped structure having a port at one end such that the plunger can push (i.e., discharge) the liquid out of the syringe pump. Syringe pumps can be coupled to an actuator that mechanically drives the plunger to control the delivery of liquid to the patient. 
     Syringe pumps may also be used to deliver various drugs including analgesics, antiemetics, or other fluids. The medication may be administered via an intravenous liquid line very quickly (e.g., in a bolus) or over a length of time. Syringe pumps may also be used in non-medical applications, such as in microreactors, in laboratory testing, and/or in chemical processing applications. 
     SUMMARY 
     In accordance with one embodiment of the present disclosure, a pump for administering an agent to a patient may comprise a housing. Within said housing may be a motor, a gearbox operatively connected to said motor, a means for sensing rotation of said motor, a controller acting to control operation of said motor and monitor the quantity of said agent delivered to said patient, a pump assembly. The pump may be configured such that the pump is interchangeable from a syringe pump or peristaltic pump respectively to a peristaltic pump or syringe pump via supplanting one pump assembly with a differing pump assembly. 
     In some embodiments, the pump may be field interchangeable from a syringe pump or peristaltic pump respectively to a peristaltic pump or syringe pump via supplanting one pump assembly with a differing pump assembly. 
     In accordance with another embodiment of the present disclosure a syringe pump for administering an agent to a patient may comprise, a housing, a lead screw, and a sliding block assembly. The said sliding block assembly may comprise a cam, a cam projection fixedly coupled to the cam, and a threaded portion capable of engaging and disengaging from said lead screw. The said threaded portion may be configured to be actuated between engagement and disengagement on the lead screw via rotation of the cam and cam projection. 
     In some embodiments, the sliding block assembly may comprise a slot with a straight expanse and an acruated expanse. 
     In some embodiments, rotation of the cam may cause the cam projection to move within the slot. As the cam projection moves within the straight expanse of the slot, the threaded portion may be configured to be actuated between engagement and disengagement with the lead screw. 
     In some embodiments, the syringe pump may further comprise a clamping means configured for clamping any of a range of plunger flange sizes. 
     In some embodiments, the cam projection may not enter the straight expanse of the slot until the largest of the range of plunger flange sizes has been released by the means configured for clamping any of a range of plunger flange sizes. 
     In some embodiments, the syringe pump may further comprise a plunger head assembly coupled to said sliding block and operative to drive a plunger of a syringe into a barrel of said syringe. A plunger tube may couple the plunger head assembly to the sliding block. 
     In some embodiments, the plunger tube may perform at least one or more additional function from a list consisting of: a bushing support for at least one rotating shaft, a channel for electrical conduits to and from the plunger head assembly, and a channel for data transmission conduits to and from the plunger head assembly. 
     In some embodiments, the syringe pump may further comprise a barrel flange clip, said barrel flange clip may be configured to retain a barrel flange of a syringe. 
     In some embodiments, the barrel flange clip may comprise a means of detecting the presence of a barrel flange. The said means of detecting the presence of a barrel flange may comprise an optical sensor and a light source. The said light source may be obscured in the presence of said barrel flange. 
     In some embodiments, the location of the cam of the sliding block assembly may be adjustable such that a user may optimize engagement of the threaded portion on the lead screw. 
     In some embodiments, the sliding block assembly may further include at least one bias member. The said bias member may be configured to bias the threaded portion to one of an engaged position on the lead screw and a disengaged position on the lead screw. 
     In accordance with another aspect of the present disclosure, a syringe pump for administering an agent to a patient may comprise a housing, a lead screw, and a sliding block assembly. The said sliding block assembly may comprise a threaded section configured for engaging and disengaging from the lead screw. The syringe pump may further comprise a plunger head assembly coupled to said sliding block and operative to drive a plunger of a syringe into a barrel of said syringe. The syringe pump may further comprise a clamping means configured for clamping any of a range of plunger flange sizes. The said means configured for clamping any of a range of plunger flange sizes may comprise at least a first plunger flange clamp jaw and a second plunger flange clamp jaw. The first and second plunger flange clamp jaws may be configured to be actuated from a first position to a position in which at least one point of each of the first and second plunger flange clamp jaws abut an edge of the plunger flange forcing the plunger flange against the plunger head assembly and acting as an anti-siphon mechanism. 
     In some embodiments, the means configured for clamping any of a range of plunger flange sizes may comprise a cam, at least one cam follower, at least one bias member. The said bias member may bias said means configured for clamping any of a range of plunger flange sizes toward a first position. In some embodiments, movement of the at least one cam follower along the cam may overcome the bias member and allow the means configured for clamping any of a range of plunger flange sizes to move toward a second position. 
     In some embodiments, the cam, at least one cam follower, and at least one bias member may be coupled to a rotatable shaft. The said cam may not be rotatable with said shaft but may be displaceable along an axial dimension of said shaft. The said at least one cam follower may be fixedly coupled to said shaft and rotatable with said shaft. Rotation of said shaft may cause movement of the at least one cam follower along said cam thereby displacing the cam along the axial dimension of said shaft. 
     In some embodiments, the bias member may automatically return the means configured for clamping any range of plunger flange sizes to the first position in the absence of a force sufficient to overcome the bias member. 
     In some embodiments, the cam may comprise at least one detent, each of said detents being reached by one of the at least one cam followers when the means configured for clamping any range of plunger flange sizes has been allowed to move to the second position. 
     In some embodiments, the plunger head assembly may further comprise a pressure sensor for monitoring the pressure of the agent being dispensed from the syringe. 
     In some embodiments, the plunger flange of the syringe may be held against the pressure sensor by the means configured for clamping any range of plunger flange sizes. 
     In some embodiments, the syringe pump may further comprise a barrel flange clip. The said barrel flange clip may be configured to retain a barrel flange of the syringe. 
     In some embodiments, the barrel flange clip may comprise a means of detecting the presence of a barrel flange. The said means of detecting the presence of a barrel flange may comprise an optical sensor and a light source. The said light source may be obscured in the presence of said barrel flange. 
     In accordance with another aspect of the present disclosure a syringe pump for administering an agent to a patient may comprise a housing a lead screw and a sliding block assembly. The said sliding block assembly may comprise a threaded section configured for engagement and disengagement with said lead screw and movable along said lead screw. The syringe pump may further comprise a plunger head assembly coupled to said sliding block assembly and operative to drive a plunger of a syringe into a barrel of said syringe. The syringe pump may further comprise a clamping means configured for clamping any of a range of plunger flange sizes. The syringe pump may further comprise a means of monitoring the clamping means, the means of monitoring the clamping means may be capable of generating data to determine at least one characteristic of the clamped syringe. 
     In some embodiments, the means of monitoring the clamping means may be a potentiometer. 
     In some embodiments, the data generated by the means of monitoring the clamping means may be evaluated by referencing said data against a database. 
     In some embodiments, the data generated by the means of monitoring the clamping means may be evaluated by referencing said data against a database and data generated by at least one other sensor. 
     In some embodiments, the clamping means may comprise a cam, at least one cam follower, and at least one bias member. The said bias member may bias said clamping means toward a first position. Movement of the at least one cam follower along the cam may overcome the bias member and allow the clamping means to move toward a second position. 
     In some embodiments, the cam, at least one cam follower, and at least one bias member may be coupled to a rotatable shaft. The said cam may not be rotatable with said shaft but may be displaceable along an axial dimension of said shaft. The said at least one cam follower may be fixedly coupled to said shaft and rotatable with said shaft. Rotation of said shaft may cause movement of the at least one cam follower along said cam displacing the cam along the axial dimension of said shaft. 
     In some embodiments, the bias member may automatically return the clamping means to the first position in the absence of a force sufficient to overcome the bias member. 
     In some embodiments the cam may comprise at least one detent. Each of said detents may be reached by one of the at least one cam followers when the means for clamping any range of plunger flange sizes has been allowed to move to the second position. 
     In some embodiments, the plunger head assembly may further comprise a pressure sensor for monitoring the pressure of the agent being dispensed from the syringe. 
     In some embodiments a plunger flange of the syringe may be held against the pressure sensor by the clamping means. 
     In some embodiments, the barrel flange clip may comprise a means of detecting the presence of a barrel flange. The said means of detecting the presence of said barrel flange may comprise an optical sensor and a light source. The said light source may be obscured in the presence of said barrel flange. 
     In accordance with another aspect of the present disclosure, a syringe pump for administering an agent to a patient may comprise a housing, a lead screw, and plunger head assembly operatively coupled to drive a plunger of a syringe into the barrel of a syringe with rotation of said lead screw. The syringe pump may further comprise at least one set of redundant sensors. The redundant sensors may be configured such that if part of a set of redundant sensors is compromised, the syringe pump may function in a fail operative mode for at least the duration of a therapy. A set of the at least one set of redundant sensors monitoring the volume being infused. 
     In accordance with another aspect of the present disclosure, a syringe pump for administering an agent to a patient may comprise a housing and a syringe barrel holder which may be movable between a first position and a second position. The said syringe barrel holder may be biased by a bias member to either the first position or the second position. The syringe pump may further comprise a syringe barrel contacting member. The said barrel contacting member may be coupled to said syringe barrel holder and configured to hold the syringe in place on the housing. The syringe pump may further comprise a detector capable of sensing the position of the syringe barrel holder and generating position data based on the position of the syringe barrel holder. When a syringe is in place on said housing said syringe barrel holder may be biased such that the syringe is held in place on said housing. The position data generated by said detector may be indicative of at least one characteristic of the syringe and evaluated to determine said characteristic. 
     In some embodiments the detector may be a linear potentiometer. 
     In some embodiments, the detector may be a magnetic linear position sensor. 
     In some embodiments, the syringe barrel holder may be configured to be locked in at least one of the first position and second position. 
     In some embodiments, the bias member may cause the syringe barrel holder to automatically adjust to the size of the syringe. 
     In some embodiments, position data generated by the detector may be referenced against a database to determine the at least one characteristic of the syringe. 
     In some embodiments, the position data generated by the detector may be referenced against a database and data from at least one other sensor to determine the at least one characteristic of the syringe. 
     In accordance with another aspect of the present disclosure a method of administering an agent to a patient via a syringe pump may comprise defining one or a number of parameters for an infusion through an interface of the syringe pump. The method may further comprise referencing said parameters against a medical database and placing restrictions on further parameters to be defined through the interface of the syringe pump. One of the further parameters may be an end of infusion behavior to be executed by the syringe pump after a volume to be infused has been infused. The method may further comprise infusing said agent to said patient in accordance with the defined parameters for infusion and executing the specified end of infusion behavior. 
     In some embodiments, the end of infusion behavior may selected from a list consisting of: stopping an infusion, infusing at a keep vein open rate, and continuing to infuse at the rate of the finished infusion. 
     In some embodiments, referencing parameters against a database and placing restrictions on further parameters may comprise referencing the agent against the database. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       These and other aspects will become more apparent from the following detailed description of the various embodiments of the present disclosure with reference to the drawings wherein: 
         FIG.  1    is a illustration of an electronic patient-care system having a syringe pump in accordance with an embodiment of the present disclosure; 
         FIGS.  2 - 5    show several views of a patient bedside system in accordance with an embodiment of the present disclosure; 
         FIG.  6    shows a close-up view of a portion of an interface of a clamp that is attachable to a pump shown in  FIGS.  2 - 5    in accordance with an embodiment of the present disclosure; 
         FIG.  7    shows another close-up view of another portion of the interface shown in  FIG.  6    in accordance with an embodiment of the present disclosure; 
         FIG.  8    shows a perspective view of a pump shown in  FIGS.  2 - 5    in accordance with an embodiment of the present disclosure; 
         FIG.  9    shows a perspective view of a pump shown in  FIGS.  2 - 5    in accordance with an embodiment of the present disclosure; 
         FIGS.  10 - 13    show several views of a syringe pump in accordance with an embodiment of the present disclosure; 
         FIG.  14    shows several of the syringe pump of  FIGS.  10 - 13    mounted on a pole in accordance with an embodiment of the present disclosure; 
         FIGS.  15 - 16    illustrate portions of the operation of the syringe pump of  FIGS.  10 - 13    in accordance with an embodiment of the present disclosure; 
         FIGS.  17 - 18    illustrate several medical devices mounted on a pole in accordance with an embodiment of the present disclosure; 
         FIGS.  19 - 22    show several views of a medical device of  FIGS.  17 - 18    in accordance with an embodiment of the present disclosure; 
         FIG.  23    shows several mounts mounted on a pole in accordance with an embodiment of the present disclosure; 
         FIGS.  24 - 26    show several views of a mount of  FIG.  23    in accordance with an embodiment of the present disclosure; 
         FIG.  27    shows a circuit diagram having a speaker and battery in accordance with an embodiment of the present disclosure; 
         FIG.  28    shows a view of an exemplary embodiment of a syringe pump of the present disclosure; 
         FIG.  29    shows a front view of an exemplary embodiment of a syringe pump of the present disclosure; 
         FIG.  30    is a view of an exemplary embodiment of the syringe pump assembly; 
         FIG.  31    is another view of an exemplary embodiment of the syringe pump assembly; 
         FIG.  32    is another view of an exemplary embodiment of the syringe pump assembly; 
         FIG.  33    is another view of an exemplary embodiment of the syringe pump assembly; 
         FIG.  34    is another view of an exemplary embodiment of the syringe pump assembly; 
         FIG.  35    is a view of an exemplary embodiment of the plunger head assembly, plunger tube, and sliding block assembly of the syringe pump assembly; 
         FIG.  36    is another view of an exemplary embodiment of the plunger head assembly, plunger tube, and sliding block assembly of the syringe pump assembly; 
         FIG.  37    is an exploded view of an exemplary embodiment of the top of the plunger head assembly with half of the plunger head assembly removed; 
         FIG.  38    is an assembled view of an exemplary embodiment of the top of the plunger head assembly with half of the plunger head assembly removed; 
         FIG.  39    is a bottom view of an exemplary embodiment of the top of the plunger head assembly; 
         FIG.  40    is an assembled top view of an exemplary embodiment of the bottom of the plunger head assembly and plunger tube; 
         FIG.  41    is an exploded view of an exemplary embodiment of the dial shaft and related parts of the syringe pump; 
         FIG.  42    is an assembled view of the exemplary embodiment of  FIG.  41   ; 
         FIG.  43    is a partially assembled view of an exemplary embodiment of the plunger head assembly and plunger tube; 
         FIG.  44    is a view of an exemplary embodiment of the plunger head assembly with the plunger head assembly housing top removed; 
         FIG.  45    is a top view of the exemplary embodiment of  FIG.  44   ; 
         FIG.  46    is a partial view of an exemplary embodiment of the plunger head assembly in which the D-shaped connector is shown in cross section; 
         FIG.  47    is a view of an exemplary embodiment of the plunger head assembly, plunger tube, and sliding block assembly in which the sliding block assembly is exploded; 
         FIG.  48 A  is an exploded view of an exemplary embodiment of the sliding block assembly; 
         FIG.  48 B  is a view an exemplary embodiment of the lead screw, half nut, barrel cam, and drive shaft; 
         FIG.  49    is a partial front view of an exemplary embodiment of the half nut and barrel cam in which the half nut is shown as transparent; 
         FIG.  50    is a front view of an exemplary embodiment of the sliding block assembly in which the half nut is in an engaged position; 
         FIG.  51    is a front view of an exemplary embodiment of the sliding block assembly in which the half nut is in the engaged position; 
         FIG.  52    is a front view of an exemplary embodiment of the sliding block assembly in which the half nut is in the disengaged position; 
         FIG.  53    is a cross sectional view of an exemplary embodiment of the sliding block assembly on the lead screw and guide rod; 
         FIG.  54    is a view of an exemplary embodiment of the rear face of the syringe pump assembly; 
         FIG.  55    is another view of an exemplary embodiment of the rear face of the syringe pump assembly with the gearbox in place; 
         FIG.  56    is an interior view of an exemplary embodiment of the syringe pump assembly; 
         FIG.  57    is another interior view of an exemplary embodiment of the syringe pump assembly with the sliding block assembly and linear position sensors in place; 
         FIG.  57 A  is a top view of an embodiment of a magnetic linear position sensor; 
         FIG.  58    is a partially assembled front view of an exemplary embodiment of the sliding block assembly, plunger tube, and plunger head assembly; 
         FIG.  59 A  is a view of an exemplary embodiment of the syringe pump assembly; 
         FIGS.  59 B- 59 J  are electrical schematics of the syringe pump in accordance with and exemplary embodiment of the disclosure; 
         FIG.  60    is a bottom partial view of an exemplary embodiment of the syringe pump assembly; 
         FIG.  61    is a partial view of an exemplary embodiment of the syringe pump assembly in which a barrel flange of a small syringe has been clipped by the barrel flange clip; 
         FIG.  62    is a partial view of an exemplary embodiment of the syringe pump assembly in which a barrel flange of a large syringe has been clipped by the barrel flange clip; 
         FIG.  63    is a view of an exemplary embodiment of the syringe barrel holder; 
         FIG.  64    is a partial view of an exemplary embodiment of the syringe barrel holder; 
         FIG.  65    is a view of an exemplary embodiment of the syringe barrel holder in which the syringe barrel holder is locked in the fully open position; 
         FIG.  66    is a view of an exemplary embodiment the syringe barrel holder linear position sensor in which the linear position sensor printed circuit board is shown as transparent; 
         FIG.  67    is a view of an exemplary embodiment of a phase change detector linear position sensor; 
         FIG.  68    shows a schematic of the exemplary view of a phase change detector linear position sensor in accordance with an embodiment of the present disclosure; 
         FIG.  69    shows a schematic of the exemplary view of a phase change detector linear position sensor in accordance with an embodiment of the present disclosure; 
         FIG.  70    shows a schematic of the exemplary view of a phase change detector linear position sensor in accordance with an embodiment of the present disclosure; 
         FIG.  71    shows a perspective view of a pump with the graphic user interface shown on the screen in accordance with an embodiment of the present disclosure; 
         FIG.  72    shows an example infusion programming screen of the graphic user interface in accordance with an embodiment of the present disclosure; 
         FIG.  73    shows an example infusion programming screen of the graphic user interface in accordance with an embodiment of the present disclosure; 
         FIG.  74    shows an example infusion programming screen of the graphic user interface in accordance with an embodiment of the present disclosure; 
         FIG.  75    shows an example infusion programming screen of the graphic user interface in accordance with an embodiment of the present disclosure; 
         FIG.  76    shows an example infusion programming screen of the graphic user interface in accordance with an embodiment of the present disclosure; 
         FIG.  77    shows an infusion rate over time graphical representation of an example infusion in accordance with an embodiment of the present disclosure; 
         FIG.  78    shows an infusion rate over time graphical representation of an example infusion in accordance with an embodiment of the present disclosure; 
         FIG.  79    shows an infusion rate over time graphical representation of an example infusion in accordance with an embodiment of the present disclosure; 
         FIG.  80    shows an infusion rate over time graphical representation of an example infusion in accordance with an embodiment of the present disclosure; 
         FIG.  81    shows an infusion rate over time graphical representation of an example infusion in accordance with an embodiment of the present disclosure; 
         FIG.  82    shows an example drug administration library screen of the graphic user interface in accordance with an embodiment of the present disclosure; and 
         FIG.  83    shows a block software diagram in accordance with an embodiment of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
       FIG.  1    shows an exemplary arrangement of a system  1  for electronic patient care in accordance with an embodiment of the present disclosure. The system  1  includes a monitoring client  2  that is linked to a number of patient-care devices via docks  3  and  11 , including an infusion pump  4  connected to and delivering from a smaller bag of liquid  5 , an infusion pump  6  connected to and delivering from a larger bag of liquid  7 , a drip detection device  8  connected to tubing from the smaller bag  5 , and a microinfusion pump  9 . System  1  also includes a syringe pump  10  connected wirelessly to the monitoring client  2 . In some embodiments, the monitoring client  2  may communicate with these patient-care devices in a wired fashion, as shown in  FIG.  1    for the infusion pumps  4  and  6 , and the microinfusion pump  9  (via docks  3  and  11 ). Additionally or alternatively, the monitoring client  2  may communicate wirelessly with patient-care devices, as suggested by the absence of a wired connection between the syringe pump  10  and the monitoring client  2 . 
     In some embodiments, a wired connection between the monitoring client  2  and a patient-care device also affords an opportunity for electrical power to be supplied to the patient-care device from the monitoring client  2 . In this exemplary embodiment, the monitoring client  2  may include the electronic circuitry necessary to convert the voltage to power the patient-care device from either a battery attached to the monitoring client  2  or from an Alternative Current (“AC”) line voltage fed into the monitoring client  2  from a power outlet (not shown) in a patient&#39;s room. Additionally or alternatively, the dock  3  supplies power to the infusion pumps  4  and  6 , and to the microinfusion pump  9 , e.g., from a signal generated from an AC line voltage. 
     In an embodiment, the monitoring client  2  is capable of receiving information about each patient-care device with which it is linked either directly from the device itself, or via a docking station, such as, for example, the dock  3  onto which the patient-care device may be mounted. The dock  3  may be configured to receive one or more patient-care devices via a standardized connection mount, or in some cases via a connection mount individualized for the particular device. For example, infusion pumps  4  and  6  may be mounted to the dock  3  via a similar connection mount, whereas the microinfusion pump  9 , for example, may be mounted to the dock  3  via a connection mount configured for the particular dimensions of the microinfusion pump&#39;s  9  housing. 
     The dock  3  may be configured to electronically identify the particular patient-care device being mounted on the docking station, and to transmit this identifying information to the monitoring client  2 , either wirelessly or via a wired connection. Additionally or alternatively, wireless patient-care devices may transmit the identifying information wirelessly to the monitoring client  2 , e.g., during a discovery protocol. Additionally, the particular patient-care device may be preprogrammed with treatment information (e.g., patient-treatment parameters such as an infusion rate for a predetermined infusion liquid) that is transmitted to the monitoring client  2 . For example, the syringe pump  10  may include identity information and treatment information, such as what medication has been prescribed to the patient, what liquid is within the syringe pump&#39;s  10  reservoir, how much and how long the liquid is prescribed to be delivered to the patient, who are the authorized caregivers, etc. In some embodiments of the present disclosure, the monitoring client  2  communicates with EMR records to verify that the preprogrammed treatment information is safe for an identified patient and/or the preprogrammed treatment information matches the prescribed treatment stored in the EMR records. 
     In some embodiments, the drip detection device  8  may communicate with the monitoring client  2  either wirelessly or in a wired connection. If an aberrant liquid flow condition is detected (e.g., because the tubing to the patient has become occluded), a signal may be transmitted to monitoring client  2 , which (1) may display the flow rate of liquid from the liquid container  5  in a user interface either locally on the monitoring client  2 , or more remotely to a user interface at a nurse&#39;s station or a handheld communications device, (2) may trigger an auditory or visual alarm, and/or (3) may cause the monitoring client  2  to alter the rate of infusion of a pump  4  connected to a bag  5 , by either terminating the infusion or otherwise changing the pumping rate The aberrant liquid flow condition may also cause an audible alarm (and/or vibration alarm) on the infusion pump  4  or the drip detection device  8 , or cause the infusion pump  4  to modify or stop the pumping, e.g., when the aberrant liquid flow condition exceed predefined ranges of operation. 
     The alarms may occur simultaneously on several devices or may follow a predetermined schedule. For example, when an occlusion occurs in a line connected to the infusion pump  4 , (1) the drip detection device  8  alarms using its internal speaker and an internal vibration motor, (2) thereafter, the infusion pump  4  alarms using its internal speaker and an internal vibration motor, (3) next, the monitoring client  2  alarms using its internal speaker and an internal vibration motor, and (4) finally, a remote communicator (e.g., a smart phone, blackberry-based phone, Android-based phone, iphone, etc.) alarms using its internal speaker and an internal vibration motor. In some embodiments, the syringe pump  10  may be connected to the drip detection device  8  and detect aberrant liquid flow conditions as described above. 
     In some embodiments, the syringe pump  10  may be programmable to allow for continued operation at a predetermined pumping rate should communications fail between the monitoring client  2  and the syringe pump  10 , either because of a malfunction in the monitoring client  2 , in the communications channel between the monitoring client  2  and the syringe pump  10 , or in the syringe pump  10  itself. In some embodiments, this independent function option is enabled when the medication being infused is pre-designated for not being suspended or held in the event of a malfunction in other parts of the system. In some embodiments, the syringe pump  10  is programmed to operate independently in a fail safe mode and may also be configured to receive information from a drip detection device  8  directly, rather than through a monitoring client  2  (e.g., in embodiment where the drip detection device  8  is used in conjunction with the syringe pump  10 ); with this option, the syringe pump  10  may be programmed, in some embodiments, to stop an infusion if the drip detection device  8  detects an aberrant flow condition (such as, e.g., a free-flow condition or an air bubble present in the infusion line). In some embodiments, one or more of the pumps  4 ,  6 , and  10  may have internal liquid flow meters and/or can operate independently as a stand-alone device. Additionally or alternatively, an internal liquid flow meter of the syringe pump  10  may be independently determined by a flow meter of the drip detection device  8  by the monitoring client  2 , in embodiments where the devices  8  and  10  are used together. 
     The monitoring client  2  may also remotely send a prescription to a pharmacy. The prescription may be a prescription for infusing a fluid using the syringe pump  10 . The pharmacy may include one or more computers connected to a network, e.g., the internet, to receive the prescription and queue the prescription within the one or more computers. The pharmacy may use the prescription to compound the drug (e.g., using an automated compounding device coupled to the one or more computers or manually by a pharmacists viewing the queue of the one or more computers), pre-fill a fluid reservoir or cartridge of a syringe pump  10 , and/or program the syringe pump  10  (e.g., a treatment regime is programmed into the syringe pump  10 ) at the pharmacy in accordance with the prescription. The reservoir or cartridge may be automatically filled by the automated compounding device and/or the syringe pump  10  may be automatically programmed by the automated compounding device. The automated compounding device may generate a barcode, RFID tag and/or data. The information within the barcode, RFID tag, and/or data may include the treatment regime, prescription, and/or patient information. The automated compounding device may: attach the barcode to the syringe pump  10  or to the reservoir, cartridge, or disposable portion of the syringe pump  10 ; attach the RFID tag to the syringe pump  10  or the reservoir, cartridge, or disposable portion of the syringe pump  10 ; and/or program the RFID tag or memory within the syringe pump  10  or the reservoir, cartridge, or disposable portion of the syringe pump  10  with the information or data. The data or information may be sent to a database that associates the prescription with the syringe pump  10  or the reservoir, cartridge, or disposable portion of the syringe pump  10 , e.g., using a serial number or other identifying information within the barcode, RFID tag, or memory. 
     The syringe pump  10  may have a scanner, e.g., an RFID interrogator that interrogates a reservoir, disposable portion, or cartridge of the syringe pump  10  to determine that it is the correct fluid within the fluid reservoir or it is the correct fluid reservoir, disposable portion or cartridge, the treatment programmed into the syringe pump  10  corresponds to the fluid within the fluid reservoir, disposable portion or cartridge, and/or the syringe pump  10  and reservoir, disposable portion or cartridge of the syringe pump  10  are correct for the particular patient (e.g., as determined from a patient&#39;s barcode, RFID, or other patient identification). For example, a serial number of a reservoir, disposable portion as scanned by the syringe pump  10  is compared to a serial number in electronic medical records to determine if it correctly corresponds to a patient&#39;s serial number within the electronic medical records; the syringe pump  10  may scan a RFID tag or barcode of a patient to obtain a serial number of a patient which is also compared to the patient&#39;s serial number within the electronic medical records (e.g., the serial number of a reservoir, disposable portion, or cartridge of the syringe pump  10  or a serial number stored within memory of the syringe pump  10  should be associated with the patient&#39;s serial number as scanned within the electronic medical records). The syringe pump  10  may issue an error or alarm if the serial numbers do not match, in some specific embodiments. Additionally or alternatively, the monitoring client  2  may scan the reservoir, disposable portion, cartridge, or syringe pump  10  to determine that it is the correct fluid within the fluid reservoir, it is the correct fluid reservoir, the treatment programmed into the syringe pump  10  corresponds to the fluid within the fluid reservoir or cartridge, and/or the fluid reservoir and syringe pump  10  are correct for the particular patient (e.g., as determined from a patient&#39;s barcode, RFID, or other patient identification). Additionally or alternatively, the monitoring client  2  or syringe pump  10  may interrogate an electronic medical records database and/or the pharmacy to verify the prescription or download the prescription, e.g., using a barcode serial number on the syringe pump  10 , or a reservoir, cartridge, or disposable portion of the syringe pump  10 . 
     The liquid being delivered to a patient may be monitored by the monitoring client  2  to determine if all the medications being delivered are safe for the patient. For example, the monitoring client  2  may log the medication delivered from the syringe pump  10  as communicated by the syringe pump  10  to the monitoring client  2 , and the monitoring client  2  may also log the medication being delivered by the infusion pumps  4  and  6 , and/or the microinfusion pump  9 . The monitoring client  2  may make a determination from the logged data to determine if the aggregate amounts and types of medication being delivered are safe. For example, the monitoring client  2  may determine if the IV bag  5  is contraindicated with the medication in the syringe pump  10 . Additionally or alternatively, in some embodiments, the monitoring client  2  may monitor the delivery of the liquid in the IV bag  5  and one or more boluses delivered by the syringe pump  10  to determine if the total dose exceeds a predetermined threshold, e.g., the medication in the IV bag  5  and syringe pump  10  may be the same type or class of drug, and the monitoring client  2  may determine if the drugs are safe when combined as delivered to the patient. The syringe pump  10  may also communicate with the infusion pumps  4  and  6 , and/or the microinfusion pump  9  to make the same determination; In this exemplary embodiment, the syringe pump  10  may communicate with the devices directly (via wirelessly or wired communications) or through the monitoring client  2  (via wirelessly or wired communications). In some embodiments of the present disclosures, one or more communication modules (e.g., each having the capabilities to communicate via one or more protocols) may be connected to the syringe pump  10  and/or may be connected together and then connected to the syringe pump  10  to enable the syringe pump  10  to communicate via the communication modules. 
     The syringe pump  10  includes a touch screen interface  11  (which may be detachable), a start button  12 , and a stop button  13 . The user interface  11  may be used to program treatment regimes, such as flow rates, bolus amounts, or other treatment parameters. After a treatment regime is programmed into the syringe pump  10 , the syringe pump  10  may query a database (e.g., Electronic Medical Records (“EMR”), Drug Error Reduction System (“DERS”), or other database) to determine if the treatment regime is safe for the particular patient or for any patient. For example, the syringe pump  10  may query the EMR database (e.g., via a wireless link, wired link, WiFi, cell-phone network, or other communications technology) to determine if the treatment regime from the syringe pump  10  is safe based upon patient information stored (e.g., age, weight, allergies, condition, etc.) in the EMR records. Additionally or alternatively, the syringe pump  10  may query the DERS database (e.g., via a wireless link, wired link, WiFi, cell-phone network, or other communications technology) to determine if the treatment regime from the syringe pump  10  is safe based upon predetermined safety criteria in the DERS records 
     In some embodiments, if the treatment regime is determined to be safe, a prompt may request user confirmation of the treatment regime. After user confirmation, the user (e.g., caregiver, nurse, or other authorized person) may press the start button  12 . In some embodiments, the stop button  13  may be pressed at any time to stop treatment. 
     In some embodiments, if the EMR and/or DERS determines that the treatment regime exceeds a first set of criteria, treatment may continue if the user confirms the treatment (e.g., with an additional warning, user passcode, and/or additional authentication or authorization, etc.); in this embodiment, the EMR or DERS may prevent the treatment from being delivered if the EMR and/or DERS determines that the treatment regime exceeds a second set of criteria, e.g., the treatment is not safe under any circumstances for any patient, for example. 
     Exemplary Bedside Arrangement 
       FIGS.  2 - 9    show various views related to a system  200 .  FIG.  2    shows a system  200  that includes several pumps  201 ,  202 , and  203 . The pumps  201 ,  202 ,  203  can be coupled together to form a group of pumps that are connectable to a pole  208 . The system  200  includes two syringe pumps  201 ,  202  and a peristaltic pump  203 ; however, other combinations of various medical devices may be employed. 
     Each of the pumps  201 ,  202 ,  203  includes a touch screen  204  which may be used to control the pumps  201 ,  202 ,  203 . One of the pumps&#39; (e.g.,  201 ,  202 ,  203 ) touch screen  204  may also be used to coordinate operation of all of the pumps  201 ,  202 ,  203  and/or to control the other ones of the pumps  201 ,  202 ,  203 . 
     The pumps  201 ,  202 , and  203  are daisy chained together such that they are in electrical communication with each other. Additionally or alternatively, the pumps  201 ,  202 , and/or  203  may share power with each other or among each other; For example, one of the pumps  201 ,  202 , and/or  203  may include an AC/DC converter that converts AC electrical power to DC power suitable to power the other pumps. 
     Within the system  200 , the pumps  201 ,  202 , and  203  are stacked together using respective Z-frames  207 . Each of the Z-frames  207  includes a lower portion  206  and an upper portion  205 . A lower portion  206  of one Z-frame  207  (e.g., the lower portion  206  of the pump  201 ) can engage an upper portion  205  of another Z-frame  207  (e.g., the upper portion  205  of the Z-frame  207  of the pump  202 ). 
     A clamp  209  may be coupled to one of the pumps  201 ,  202 ,  203  (e.g., the pump  202  as shown in  FIG.  3   ). That is, the clamp  209  may be coupled to any one of the pumps  201 ,  202 ,  203 . The clamp  209  is attachable to the back of any one of the pump  201 ,  202 ,  203 . As is easily seen in  FIG.  5   , each of the pumps  201 ,  202 ,  203  includes an upper attachment member  210  and a lower attachment member  211 . A clamp adapter  212  facilitates the attachment of the clamp  209  to the pump  202  via a respective pump&#39;s (e.g.,  201 ,  202 , or  203 ) upper attachment member  210  and lower attachment member  211 . In some embodiments, the clamp adapter  212  may be integral with the clamp  209 . 
       FIG.  6    shows a close-up view of a portion of an interface of a clamp (i.e., the clamp adapter  212 ) that is attachable to the pump  202  (or to pumps  201  or  203 ) shown in  FIGS.  2 - 5    in accordance with an embodiment of the present disclosure. The clamp adapter  212  includes a hole  213  in which a lower attachment member  211  (see  FIG.  5   ) may be attached to. That is, the lower attachment member  211  is a curved hook-like protrusion that may be inserted into the hole  213  and thereafter rotated to secure the lower attachment member  211  therein. 
     As is easily seen in  FIG.  7   , the clamp adapter  212  also includes a latch  214 . The latch  214  is pivotally mounted to the clamp adapter  212  via pivots  216 . The latch  214  may be spring biased via springs  218  that are coupled to the hooks  220 . Stop members  219  prevent the latch  214  from pivoting beyond a predetermined amount. After the hole  213  is inserted into the lower attachment member  211  (see  FIGS.  5  and  6   ), the clamp adapter  212  may be rotated to bring the latch  214  towards the upper attachment member  210  such that the latch  214  is compressed down by the upper attachment member  210  until the protrusion  215  snaps into a complementary space of the upper attachment member  210 . The hooks  220  help secure the clamp adapter  212  to the pump  202 . 
     Each Z-frame  207  of the pumps  201 ,  202 ,  203  includes a recessed portion  223  (see  FIG.  5   ) and a protrusion  224  (see  FIG.  8   ). A protrusion  224  of the Z-frame  207  of one pump (e.g., pumps  201 ,  202 , or  203 ) may engage a recessed portion  223  of another pump to enable the pump to be stacked on top of each other. Each of the pumps  201 ,  202 ,  203  includes a latch engagement member  221  that allows another one of the pumps  201 ,  202 ,  203  to be attached thereto via a latch  222  (see  FIG.  8   ). The latch  222  may include a small spring loaded flange that can “snap” into the space formed under the latch engagement member  221 . The latch  222  may be pivotally coupled to the lower portion  206  of the Z-frame  207 . 
     As is seen in  FIG.  3   , the latch  222  of the pump  201  may be pulled to withdraw a portion of the latch  222  out of the space under the latch engagement member  221  of the pump  202 . Thereafter, the pump  201  may be rotated to pull out the protrusion  224  of the pump  201  out of the recessed portion  223  of the Z-frame  207  of the pump  202  such that the pump  201  may be removed from the stack of pumps  202 ,  203  (see  FIG.  4   ). 
     Each of the pumps  201 ,  202 ,  203  includes a top connector  225  (see  FIG.  9   ) and a bottom connector  226  (see  FIG.  8   ). The connectors  225  and  226  allow the stacked pumps  201 ,  202 , and  203  to communication between each other and/or to provide power to each other. For example, if the battery of the middle pump  202  (see  FIG.  2   ) fails, then the top pump  201  and/or the bottom pump  203  may provide power to the middle pump  202  as a reserve while audibly alarming. 
     Exemplary Syringe Pump Embodiment and Related Bedside Arrangement 
       FIGS.  10 - 13    show several views of a syringe pump  300  in accordance with an embodiment of the present disclosure. The syringe pump  300  may have a syringe  302  loaded either facing to the left (as shown in  FIGS.  10 - 13   ) or to the right (refer to  FIG.  16   , described below). That is, the syringe pump  300  is a bidirectional syringe pump. 
     The syringe  302  may be loaded into a syringe holder  306  of the syringe pump  300 . The flange endpiece  310  of the syringe  302  may be placed in the left flange receiver  311  or in the right flange receiver  312 . When the flange endpiece  310  is inserted into the left flange receiver  311 , the syringe  302  faces towards the left outlet  308 , which may hold a tube that is fluidly coupled to the syringe  302 . An engagement member  314  may be coupled to an end fitting  315  of the syringe  302  when or after the syringe  302  is loaded into the syringe holder  306 . A threaded shaft  315  that is coupled to a motor may be rotated to move the engagement member  314  in any direction to discharge fluid from the syringe  302 . 
     The syringe  302  may also be loaded to the right (not shown in  FIGS.  10 - 13   ). The syringe holder  306  may be moved and/or adjusted such that it is moved to the right so the syringe  302  may be loaded. The syringe holder  306  may be manually moved and/or an electric motor may move the syringe holder  306  to the right. In some embodiments of the present disclosure, the syringe holder  306  extends sufficiently to the left and to the right such that no adjustment is used. 
     In the case where the syringe  302  is loaded facing the right, the flange endpiece  310  is loaded into the right flange receiver  312 . The engagement member  314  thereafter moves to the right such that fluid may be discharged through a tube that traverses through a right outlet  309 . 
     The pump  300  may be controlled via a touch screen  304  to set the flow rate, flow profile, and/or to otherwise monitor or control the syringe pump  300 . A clamp  316  may be used to secure the syringe pump  300  to a pole (e.g., using a screw-type clamp). 
       FIG.  14    shows several of the syringe pumps  300  of  FIGS.  10 - 13    mounted on a pole  322  in accordance with an embodiment of the present disclosure. That is,  FIG.  14    shows a system  320  that uses several syringe pumps  300  mounted on the pole  312 . The pole  322  may be used in a hospital and/or in a home setting. 
       FIGS.  15 - 16    illustrate portions  327  of the operation of the syringe pump  300  of  FIGS.  21 - 24    in accordance with an embodiment of the present disclosure.  FIG.  15    shows the syringe  302  loaded facing the left, and  FIG.  16    shows the syringe  302  loaded to the right. As shown in  FIGS.  15 - 16   , a motor  326  is coupled to the threaded shaft  315  such that the motor  326  can rotate the threaded shaft  315 . 
     A left syringe diameter sensor  324  measures the diameter of the syringe  305  to estimate the cross-sectional size of the internal space of the barrel of the syringe  302 . The left syringe diameter sensor  325  may be a bar that is attached to a post such that the bar is lifted to cover the syringe  302 ; the post&#39;s movement out of the body of the syringe pump  300  may be measured by a linear sensor to estimate the diameter of the barrel of the syringe  302 . Any linear sensor may be used including a linear potentiometer technology, an optical linear sensor technology, a hall-effect sensor technology, etc. The motor&#39;s  326  movement may thereby be correlated to fluid discharged from the syringe  302  using the estimate of the diameter of the internal space of the barrel of the syringe  302 . Similarly, the right syringe diameter sensor  325  may be used to estimate the internal diameter of the barrel of the syringe  302 , which may be used to estimate the fluid discharged from the syringe  302  to the right. 
     In some embodiments of the present disclosure, the touch screen  304  requests information from the user when the syringe  302  is loaded into the syringe pump  300  (in either the left or right configuration) and the syringe diameter sensor  324  or  325  is used to estimate the diameter of the internal space of the barrel of the syringe  305 ; The user is prompted by a touch screen  304  request for the user to enter into the touch screen  304  the manufacturer of the syringe  305 . An internal database within the syringe pump  300  may be used to narrow down the range of possible model numbers associated with an estimate of the diameter of the syringe  305 . When the user enters in the manufacturer of the syringe  305 , the database may be used to identify a particular model number of the syringe  305  and/or a subset of possible model numbers corresponding to the estimate of the diameter of the syringe  305  and the user entered information, which in turn, may provide a more accurate internal diameter value (as stored within the database). The user may be prompted by the display on the touch screen  304  to select the syringe model from a list or enter the model of the syringe that will deliver the medication. The user may be guided through a selection process on the touchscreen  304  to identify the syringe loaded into the machine using one or more of the following aspects: syringe barrel size, plunger head size, manufacturer names, images of syringes, and model numbers. The selection process may access a database of syringes including manufacturer, model, internal diameter and image. The syringe pump  300  may use the identified syringe to set the internal diameter value for volume calculations. 
     Exemplary Bedside Arrangements 
       FIGS.  17 - 18    illustrate several medical devices  402  mounted on a pole  403  in accordance with an embodiment of the present disclosure.  FIGS.  19 - 22    show several views of the medical device  402  of  FIGS.  17 - 18   . The medical device  402  is mounted to the pole via the clamp  401 . The clamp  401  allows the medical device  402  to be pulled out and adjusted. The medical device  402  may be any medical device, such as an infusion pump, a syringe pump, a monitoring client, etc. 
     The medical device  402  is coupled to the pole  403  via arms  415  such that the medical device  402  may be pulled away from the pole (see  FIG.  20   ) and/or pivoted on the arms  403 . 
       FIG.  23    shows several mounts  406  mounted on a pole  405 , and  FIGS.  24 - 26    show several views of a mount of  FIG.  23    in accordance with an embodiment of the present disclosure. Each of the mounts  406  includes a clamp  407  (e.g., a screw-type clamp), a first arm  408  pivotally mounted to the clamp  407 , and a second arm  411  pivotally mounted to the first arm  408  via a hinge  409 . The end of the second arm  411  includes a coupling member  410  that can be coupled to a medical device. 
     Exemplary Battery and Speaker Test 
       FIG.  27    shows a circuit diagram  420  having a speaker  423  and a battery  421  in accordance with an embodiment of the present disclosure. The battery  421  may be a backup battery and/or the speaker  423  may be a backup alarm speaker. That is, the circuit  420  may be a backup alarm circuit, for example, a backup alarm circuit in a medical device, such as a syringe pump. 
     In some embodiments of the present disclosure, the battery  421  may be tested simultaneously with the speaker  423 . When a switch  422  is in an open position, a voltmeter  425  may be used to measure the open circuit voltage of the battery  421 . Thereafter, the switch  422  may be closed and the closed-circuit voltage from the battery  421  may be measured. The internal resistance of the battery  421  may be estimated by using the known impedance, Z, of the speaker  423 . A processor may be used to estimate the internal resistance of the battery  421  (e.g., a processor of a syringe pump). The processor may correlate the internal resistance of the battery  421  to the battery&#39;s  421  health. In some embodiments of the present disclosure, if the closed-circuit voltage of the battery  421  is not within a predetermined range (the range may be a function of the open-circuit voltage of the battery  421 ), the speaker  423  may be determined to have failed. 
     In some additional embodiments of the present disclosure, the switch  422  may be modulated such that the speaker  423  is tested simultaneously with the battery  421 . A microphone may be used to determine if the speaker  423  is audibly broadcasting a signal within predetermined operating parameters (e.g., volume, frequency, spectral compositions, etc.) and/or the internal impedance of the battery  421  may be estimated to determine if it is within predetermined operating parameters (e.g., the complex impedance, for example). The microphone may be coupled to the processor. Additionally or alternatively, a test signal may be applied to the speaker  423  (e.g., by modulating the switch  422 ) and the speaker&#39;s  423  current waveform may be monitored by an current sensor  426  to determine the total harmonic distortion of the speaker  423  and/or the magnitude of the current; a processor may be monitored these values using the current sensor  426  to determine if a fault condition exists within the speaker  423  (e.g., the total harmonic distortion or the magnitude of the current are not within predetermined ranges). 
     Various sine waves, periodic waveforms, and/or signals maybe applied to the speaker  423  to measure its impedance and/or to measure the impedance of the battery  421 . For example, a processor of a syringe pump disclosed herein may modulate the switch  422  and measure the voltage across the battery  421  to determine if the battery  421  and the speaker  423  has an impedance within predetermined ranges; if the estimated impedance of the battery  421  is outside a first range, the processor will determine that the battery is in a fault condition, and/or if the estimated impedance of the speaker  423  is outside a second range, the processor will determine that the speaker  423  is in a fault condition. Additionally or alternatively, if the processor cannot determine if the battery  421  or the speaker  423  has a fault condition, but has determined that at least one exists in a fault condition, the processor may issue an alert or alarm that the circuit  420  is in a fault condition. The processor may alarm or alert a user or a remote server of the fault condition. In some embodiments of the present disclosure, the syringe pump will not operate until the fault is addressed, mitigated and/or corrected. 
     Exemplary Syringe Pump Embodiment 
     In an example embodiment, as shown in  FIG.  28   , a syringe pump  500  is depicted. The syringe pump  500  may be used to deliver an agent, such as but not limited to, an analgesic, medicament, nutrient, chemotherapeutic agent, etc. to a patient. The syringe pump may be used to precisely delivery a quantity of an agent to a patient or deliver a precise quantity of an agent over a period of time. The syringe pump  500  may be used in any suitable application, such as though not limited to, intravenous deliver, intrathecal delivery, intra-arterial delivery, enteral delivery or feeding, etc. 
     The syringe pump  500  comprises a housing  502  and a syringe pump assembly  501 . In the example embodiment in  FIG.  28   , the housing  502  is substantially a rectangular box. In alternative embodiments, the housing  502  may take any of a variety of other suitable shapes. The housing  502  may be made of any of a number of materials or combination of materials including, but not limited to, metal or plastic. The housing  502  may be extruded, injection molded, die cast, etc. In some embodiments, the housing  502  may be comprised of a number of separate parts which may be coupled together by any suitable means. In some embodiments, the housing  502  may be taken apart or comprise a removable panel to allow the syringe pump  500  to be easily serviced. 
     As shown in  FIG.  28   , a syringe  504  may be seated on the syringe pump assembly  501 . The syringe  504  may be a glass, plastic, or any other type of syringe  504 . The syringe  504  may be a syringe  504  of any capacity. In some embodiments, including the embodiment in  FIG.  28   , the syringe  504  may be seated on a syringe seat  506  comprising part of the syringe pump assembly  501 . The syringe seat  506  may comprise a contour which allows the syringe  504  to be cradled by the syringe seat  506 . The syringe seat  506  may be made of the same material as the rest of the housing  502 , a different material, or may be made of several materials. The syringe seat  506  may be coupled to the housing  502  by a mount  508  which may also serve as a spill, splash, drip, fluid, or debris guard. 
     In some embodiments, the syringe seat  506  may comprise part of the housing  502 . In the embodiment shown in  FIG.  28   , the syringe seat  506  is part of a syringe pump assembly housing  503  of the syringe pump assembly  501 . In some embodiments the syringe pump assembly housing  503  may be at least partially formed as an extrusion. In such embodiments, the contours of the syringe seat  506  may be formed during extrusion. 
     The syringe pump assembly  501  may be inserted into the housing  502  or may be coupled thereto. In the example embodiment in  FIG.  28   , the syringe pump assembly  501  is mostly disposed inside the housing  502 . The syringe seat  506 , syringe barrel holder  518 , barrel flange clip  520 , plunger head assembly  522 , and plunger tube  524 , each a part of the syringe pump assembly  501 , are not disposed inside the housing  502  in the exemplary embodiment shown in  FIG.  28   . In embodiments where the syringe seat  506  is not part of the housing  502 , the mount  508  may comprise a gasket which functions as a seal to keep unwanted foreign material from entering the housing  502  and getting into portions of the syringe pump assembly  501 , which are disposed inside the housing  502 . In some embodiments, the mount  508  may overhang the syringe seat  506  and may function as a drip edge, splash guard, etc. which will shed liquid off and away from the syringe pump  500   
     In some embodiments, the syringe pump  500  may be converted into a different device such as, though not limited to, a peristaltic large volume pump. This may be accomplished by removing the syringe pump assembly  501  from the housing  502  and replacing the syringe pump assembly  501  with another desired assembly. Replacement assemblies may include for example, other infusion pumps assemblies such as a peristaltic infusion pump assembly. 
     In some embodiments, a clamp  510  may be coupled to the housing  502 . The clamp  510  may be any type of clamp, for example, a standard pole clamp  510  or a quick release pole clamp  510  (shown). The clamp  510  may be used to keep the syringe pump  500  at a desired location on an object such as an I.V. pole. The clamp  510  may be removably coupled to the housing  502  through a clamp mount  512 . In some embodiments, the clamp mount  512  may comprise any of a variety of fasteners such as screws, bolts, adhesive, hook and loop tape, snap fit, friction fit, magnets, etc. In some embodiments, the clamp  510  or a part of the clamp  510  may be formed as an integral part of the housing  502  during manufacture. 
     As shown in  FIG.  28   , the housing  502  may also include a display  514 . The display  514  may function as a graphic user interface and allow a user to program and monitor pump operation. The display  514  may be an electronic visual display such as a, liquid crystal display, touch screen, L.E.D. display, plasma display, etc. In some embodiments, the display may be complimented by any number of data input means  516 . In the example embodiment, the data input means  516  are several user depressible buttons. The buttons may have fixed functions such as “power”, “stop”, “silence”, “emergency stop”, “start therapy”, or “lock”. The lock function may lock all the user inputs to avoid inadvertent commands from being issued to the syringe pump  500 , due to a touch screen display  514  being touched, buttons being depressed or touched, or any other inadvertent gesture. The data input means  516  of other embodiments may differ. In embodiments where the display  514  is a touch screen display, the data input means  516  may include a number of physically depressible buttons. The physically depressible button data input means  516  may be a back-up for the touch screen display  514  and may be used in the event that the touch screen display  514  is compromised or becomes otherwise non-functional. 
     In a non-limiting example embodiment, the data input means  516  may be built into the function of a touch screen display  514 . The touch screen display may detect the position of a user&#39;s finger or fingers on the screen. The touch screen may be a capacitive touch screen or any other type of touch screen. The software may display virtual buttons, slides, and other controls. The software may also detect the user&#39;s touch or the touch of a stylus to control the machine and interact with remote computers that may communicate with the syringe pump  500 . The software may also recognize multi-touch gestures which may control: the display, functioning of the syringe pump  500 , interaction of the syringe pump  500  with one or more remote computers, etc. In some embodiments, the syringe pump  500  may include sensors that detect user gestures when the user is not in contact with the display. These motion detection sensors may comprise a device that transmits invisible near-infrared light, measuring its “time of flight” after it reflects off objects. Such a measurement may allow the syringe pump  500  to detect the location of objects and the distance from the syringe pump  500  to said objects. The syringe pump  500  may thus be able to monitor and take commands via a user&#39;s limbs, hands, and fingers or movements of a user&#39;s limbs, hands, and fingers. One example of a motion detector is the PrimeSense 3D sensor made by the company PrimeSense of Israel. In some embodiments, the display  514  and data input means may be mounted onto the housing  502  during manufacture of the syringe pump  500 . The display  514  may be removed and replaced during servicing if necessary. 
     The syringe pump  500  may include a syringe barrel holder  518 . The syringe barrel holder  518  may securely hold the syringe barrel  540  against the syringe seat  506 . The syringe barrel holder  518  may easily be adjusted by a user to accommodate syringes  504  of various sizes. In some embodiments, the syringe barrel holder  518  may be biased so as to automatically adjust to the diameter of any size syringe  504  after the syringe barrel holder  518  is pulled out by a user. The syringe barrel holder  518  will be further elaborated upon later in the specification. 
     The syringe pump  500  may also include a barrel flange clip  520 . The barrel flange clip  520  in the example embodiment depicted in  FIG.  28    is disposed on an end of the syringe pump assembly housing  503  and is capable of holding the syringe barrel flange  542  in place against the end of the syringe pump assembly housing  503 . The barrel flange clip  520  is also capable of retaining any of a variety of syringe barrel flange  542  types and sizes which may be available to a user. The barrel flange clip  520  will be further elaborated upon later in the specification. For a more detailed description of the barrel flange clip  520 , see  FIG.  61    and  FIG.  62   . 
     The syringe pump  500  may additionally include a plunger head assembly  522 . The plunger head assembly  522  may be attached to the syringe pump assembly  501  by a plunger tube  524 . In the example embodiment depicted in  FIG.  28   , the plunger head assembly  522  and plunger tube  524  extend out of the housing  502  toward the right of the page. 
     The syringe pump  500  may also comprise a downstream pressure sensor  513  as shown in  FIG.  28   . The downstream pressure sensor  513  may comprise part of the syringe pump assembly  501  or the housing  502 . The downstream pressure sensor  513  may take pressure measurements from a fluid line i.e. tubing extending from the syringe  504  to a patient. In some embodiments, the fluid line may include a span of tubing which is different from the rest of the tubing. For example, a span of the fluid line may be made of a deformable PVC material. Such embodiments may make fluid line pressures easier to determine. 
     The downstream pressure sensor  513  may comprise a cradle with a pressure sensor, such as a force sensor. In such embodiments, the fluid line may be held against the cradle and pressure sensor of the downstream pressure sensor  513  by a non-deformable or deflectable structure. The downstream pressure sensor  513  may cause the syringe pump  500  to alarm if the detected pressure falls outside of an acceptable range. The measurement of the downstream pressure sensor  513  may be referenced against a look-up table to determine the pressure in the fluid line. If an abnormal pressure reading (e.g. a high pressure generated during an occlusion event beyond a predetermined threshold) is taken, a control system of the syringe pump  500  may stop delivering fluid. In some embodiments, the syringe pump  500  may be caused to back up and relieve some of the pressure in response to the detection of pressures suggestive of an occlusion. 
       FIG.  29    shows the syringe pump  500  from another perspective. In this view, the display  514  and data input means  516  coupled to the housing  502  face the front of the page. The clamp  510  is coupled to the housing  502  by a clamp mount  512 . The syringe pump assembly  501  is disposed mostly inside the housing  502 . The syringe seat  506 , which comprises part of the syringe pump assembly  501 , forms a substantial part of one side of the housing  502 . The mount  508  retains the syringe pump assembly  501  and helps seal the interior of the housing  502  from exposure to debris. In embodiments where the mount  508  functions as a drip edge the mount  508  may cover the syringe pump assembly  501  and help shed liquid away from the interior of the housing  502 . The syringe barrel holder  518  extends through the syringe seat  506 . In the depicted position in  FIG.  29   , the syringe barrel holder  518  has been pulled away from its resting position and is biased such that it may automatically retract back toward the housing  502 . In some embodiments, the syringe barrel holder  518  may be locked in a non-resting position, such as the position depicted in  FIG.  31   . The barrel flange clip  520  is visible and disposed on the end of the syringe pump assembly housing  503  closest to the plunger head assembly  522 . The plunger tube  524  connects the plunger head assembly  522  to the rest of the syringe pump assembly  501  as described above. The downstream pressure sensor  513  is disposed on the syringe seat  506 . 
       FIGS.  30 - 34    illustrate how a user may place a syringe  504  into the syringe pump assembly  501 . The syringe pump assembly  501  is shown by itself in  FIG.  30   . The syringe  504  is not seated against the syringe seat  506 . As shown, the plunger head assembly  522  comprises two jaws, an upper plunger clamp jaw  526  and a lower plunger clamp jaw  528 . The upper plunger clamp jaw  526  and lower plunger clamp jaw  528  are in the open position. The upper plunger clamp jaw  526  and lower plunger clamp jaw  528  are capable of clamping and retaining the plunger flange  548  on the plunger  544  of the syringe  504 . The upper plunger clamp jaw  526  and lower plunger clamp jaw  528  may be actuated to open or closed positions via rotation of a dial  530  comprising part of the plunger head assembly  522 . The plunger head assembly  522  may also comprise a plunger pressure sensor  532 . 
     In  FIG.  31   , the syringe pump assembly  501  is again shown by itself. The syringe  504  which had not been seated on the syringe seat  506  in  FIG.  30    is seated in place on the syringe seat  506  in  FIG.  31   . The syringe barrel flange  542  is clipped in place by the barrel flange clip  520 . The syringe barrel holder  518 , has been pulled out so the syringe  504  may be placed into the syringe pump assembly  501 , but has not yet been allowed to automatically adjust to the diameter of the syringe barrel  540 . In the example embodiment shown in  FIG.  31   , the syringe barrel holder  518  has been rotated 90° clockwise from its orientation in  FIG.  30    to lock it in position. Alternate embodiments may require counter-clockwise rotation, a different degree of rotation, or may not require rotation to lock the syringe barrel holder  518  in position. The plunger tube  524  and attached plunger head assembly  522  are fully extended away from the rest of the syringe pump assembly  501 . Since the dial  530  has not been rotated from the orientation shown in  FIG.  30   , the upper plunger clamp jaw  526  and the lower plunger clamp jaw  528  are still in the open position. 
     In  FIG.  32   , the syringe pump assembly  501  is again shown by itself. The syringe  504  is seated against the syringe seat  506 . The syringe barrel holder  518  has been rotated out of the locked position and has been allowed to automatically adjust to the diameter of the syringe barrel  540 . The syringe barrel holder  518  is holding the syringe  504  in place on the syringe pump assembly  501 . The syringe  504  is additionally held in place on the syringe pump assembly  501  by the barrel flange clip  520  which retains the syringe barrel flange  542 . The plunger tube  524  and attached plunger head assembly  522  are fully extended away from the rest of the syringe pump assembly  501 . Since the dial  530  has not been rotated from the orientation shown in  FIG.  30   , the upper plunger clamp jaw  526  and the lower plunger clamp jaw  528  are still in the open position. 
     In  FIG.  33   , the syringe pump assembly  501  is again shown by itself. The syringe  504  is seated against the syringe seat  506 . The syringe barrel holder  518  is pressing against the syringe barrel  540  and holding the syringe  504  in place on the syringe pump assembly  501 . The barrel flange clip  520  is holding the syringe barrel flange  542  and helping to the hold the syringe  504  in place on the syringe pump assembly  501 . The amount that the plunger tube  524  extends away from the rest of the syringe pump assembly  501  has been adjusted such that the plunger head assembly  522  is in contact with the plunger flange  548  on the syringe plunger  544 . Since the dial  530  has not been rotated from the orientation shown in  FIG.  30   , the upper plunger clamp jaw  526  and the lower plunger clamp jaw  528  are still in the open position. The plunger flange  548  is in contact with the plunger pressure sensor  532 . 
     In  FIG.  34    the syringe pump assembly  501  is again shown by itself. The syringe  504  is seated against the syringe seat  506 . The syringe barrel holder  518  is pressing against the syringe barrel  540  and holding the syringe  504  in place on the syringe pump assembly  501 . The barrel flange clip  520  is clipping the syringe barrel flange  542  and helping to the hold the syringe  504  in place on the syringe pump assembly  501 . The amount that the plunger tube  524  extends away from the rest of the syringe pump assembly  501  has been adjusted such that the plunger head assembly  522  is in contact with the plunger flange  548  on the syringe plunger  544 . The dial  530  has been rotated from the orientation depicted in  FIGS.  30 - 33   . Consequentially, the upper plunger clamp jaw  526  and lower plunger clamp jaw  528  have moved to a closed position in which the plunger flange  548  of the syringe plunger  544  is retained by the plunger head assembly  522 . Since the upper plunger clamp jaw  526  and lower plunger clamp jaw  528  close about the horizontal centerline of the plunger head assembly  522 , the plunger flange  548  has been centered on the plunger head assembly  522 . 
     In the preferred embodiment, the upper plunger clamp jaw  526  and lower plunger clamp jaw  528  each comprise a fin  529  as illustrated in  FIG.  34   . The fins  529  bow out away from the plunger head assembly  522  and toward the left of the page (relative to  FIG.  34   ). The fins  529  are disposed about the upper plunger clamp jaw  526  and lower plunger clamp jaw  528  such that the fins  529  are the only part of the upper plunger clamp jaw  526  and lower plunger clamp jaw  528  to contact a plunger flange  548  when a syringe  504  is placed on the syringe pump assembly  501 . As the upper plunger clamp jaw  526  and lower plunger clamp jaw  528  are closed down on a plunger flange  548  the thickness and diameter of the plunger flange  548  determine when the upper plunger clamp jaw  526  and lower plunger clamp jaw  528  stop moving. At least some part of the fins  529  will overhang the plunger flange  548  and ensure the plunger flange  548  is retained. Since the upper plunger clamp jaw  526  and lower plunger clamp jaw  528  do not deflect, this forces the plunger flange  548  against the rest of the plunger head assembly  522 . That is, the angle of contact of the upper plunger clamp jaw  526  and lower plunger clamp jaw  528  on the plunger flange  548  results in a force with a component that pushes the plunger flange  548  against the plunger head assembly  522 . This resultant force additionally has a component which centers the plunger flange  548  on the plunger head assembly  522 . This is especially desirable because such an arrangement does not allow for any “play” of the plunger flange  548  between upper plunger clamp jaw  526  and lower plunger clamp jaw  528  and the rest of the plunger head assembly  522 . Additionally, such an arrangement is desirable because it not only securely holds the plunger flange  548  in place against the plunger head assembly  522 , but also doubles as an anti-siphon mechanism. Such an arrangement furthermore, ensures that the plunger flange  548  consistently contacts the plunger pressure sensor  532 . Any force component generated by the upper plunger clamp jaw  526  and lower plunger clamp jaw  528  which may affect readings of the plunger pressure sensor  532  may be predictable and subtracted out or otherwise compensated for. 
     In other embodiments, the upper plunger clamp jaw  526  and lower plunger clamp jaw  528  may not comprise fins  529 . Instead the upper plunger clamp jaw  526  and lower plunger clamp jaw  528  overhang a portion of the plunger flange  548  when in the clamped position. The upper plunger clamp jaw  526  and lower plunger clamp jaw  528  may stop moving when they abut the cruciform which comprises the plunger stem  546 . In other embodiments, the upper plunger clamp jaw  526  and lower plunger clamp jaw  528  may clamp a plunger stem  546  that need not be a cruciform. In another embodiment, the upper plunger clamp jaw  526  and lower plunger clamp jaw  528  may include a wedge, ramp, or tapered rib feature on the surfaces of the jaws that faces the pump head assembly  522 . The wedge, ramp or tapered rib serve to push the plunger flange  548  toward the pump head assembly  522  until the plunger flange  548  is securely held against the pump head assembly  522 . 
     To dispense the contents of the syringe  504 , the syringe pump  500  may actuate the plunger head assembly  522  to thereby push the plunger  544  into the syringe barrel  540 . Since the contents of the syringe  504  may not flow through or past the plunger pusher  550 , the contents of the syringe  504  are forced out of the syringe outlet  552  as the plunger  544  is advanced into the syringe barrel  540 . Any pressure generated as the plunger  544  advances into the syringe barrel  540  is transmitted to the plunger pressure sensor  532 . The plunger pressure sensor  532 , may, in some embodiments, comprise a force sensor such as a strain beam. When an occlusion occurs, fluid within the syringe barrel  540  and/or the fluid lines prevents movement of the plunger  544 . When the plunger head assembly  522  continues to advance, high forces are produced between the plunger  544  and the plunger head assembly  522 . The pressure transmitted to the plunger pressure sensor  532  may have a programmed acceptable range so that possible occlusions may be identified. If the pressure applied to the plunger pressure sensor  532  exceeds a predetermined threshold, the syringe pump  500  may alarm or issue an alert. 
       FIG.  35    shows the plunger head assembly  522  with the upper plunger clamp jaw  526  and lower plunger clamp jaw  528  in the fully closed position. The dial  530  is oriented such that the raised part of the dial  530  is on a plane substantially parallel to the top and bottom faces of the plunger head assembly  522 . The plunger tube  524  is shown extending from the plunger head assembly  522  to the sliding block assembly  800 . One end of a flex connector  562  is attached to the sliding block assembly  800 . A position indicator mark has been placed on the dial  530  for illustrative purposes in  FIG.  35    and  FIG.  36   . 
     The view shown in  FIG.  36    is similar to the view shown in  FIG.  35   . In  FIG.  36   , the dial  530  on the plunger head assembly  522  has been rotated approximately 1350 clockwise. This rotation has in turn caused the upper plunger clamp jaw  526  and lower plunger clamp jaw  528  to separate and move to the fully open position. In alternate embodiments, the dial  530  may require more or less rotation than the approximately 1350 shown in the example embodiment to transition the upper plunger clamp jaw  526  and lower plunger clamp jaw  528  from a fully open position to a fully closed position. The plunger head assembly may be capable of holding itself in this position (described later in the specification). 
     An exploded view of the top half of the plunger head assembly  522  is shown in  FIG.  37   . As shown, the upper plunger clamp jaw  526  comprises two racks  570 . In other embodiments, there may only be one rack  570 . In some embodiments, there may be more than two racks  570 . When the plunger head assembly  522  is fully assembled, the racks  570  may interdigitate with a corresponding number of upper jaw pinion gears  572 . The upper jaw pinion gears  572  spin about the axis of an upper jaw drive shaft  574 . The upper jaw drive shaft  574  may also comprise an upper jaw drive gear  604  which will be elaborated upon later. 
     The plunger head assembly  522  may comprise a number of bearing surfaces for the upper jaw drive shaft  574 . In the example embodiment in  FIG.  37   , the plunger head assembly  522  comprises two upper bearing surfaces  576  and a lower bearing surface  578  for the upper jaw drive shaft  574 . The upper bearing surfaces  576  may be coupled into the plunger head assembly housing top  600 . The upper bearing surfaces  576  may be coupled to the plunger head assembly housing top  600  by any of a variety of means including, but not limited to, screws bolts, adhesive, snap fit, friction fit, welds, a tongue in groove arrangement, pins, or may be formed as a continuous part of the plunger head assembly housing top  600  (shown). The upper bearing surfaces  576  provide a bearing surface for at least a span of the top half of the upper jaw drive shaft  574 . 
     The lower bearing surface  578  is coupled into the plunger head assembly housing top  600 . The lower bearing surface  578  may be coupled to the plunger head assembly housing top  600  by any suitable means such as, but not limited to, screws  580  (shown), bolts, adhesive, snap fit, friction fit, magnets, welds, a tongue in groove arrangement, etc. In some embodiments, the lower bearing surface  578  may be formed as a continuous part of the plunger head assembly housing top  600 . The lower bearing surface  578  provides a bearing surface for at least a span of the bottom half of the upper jaw drive shaft  574 . 
     In some embodiments, there may also be an upper dial shaft bearing surface  651  which couples into the plunger head assembly housing top  600 . The upper dial shaft bearing surface  651  may be coupled into the plunger head assembly housing top  600  by any of a variety of means including, but not limited to, screws, bolts, adhesive, snap fit, friction fit, welds, a tongue in groove arrangement (shown), pins, or may be formed as a continuous part of the plunger head assembly housing top  600 . The upper dial shaft bearing surface  651  will be further elaborated upon later. 
     The upper jaw drive shaft  574  may also comprise a D-shaped span  582 . The D-shaped span  582  may be located on an end of the upper jaw drive shaft  574  as shown in the example embodiment in  FIG.  37   . The D-shaped span  582  of the upper jaw drive shaft  574  may couple into a complimentary shaped orifice in one side of a D-shaped connector  584 . The D-shaped span  582  of the upper jaw drive shaft  574  may not extend all the way through the D-shaped connector  584 . In some embodiments, the orifice may run through the entire D-shaped connector  584 . The other side of the D-shaped connector  584  may couple onto a D-shaped shaft  586  projecting out of a plunger clamp jaws position sensor  588 . Any rotation of the upper jaw drive shaft  574  may cause the D-shaped connector  584  to rotate as well. In turn, this may cause rotation of the D-shaped shaft  586  projecting from the plunger clamp jaws position sensor  588 . In some embodiments, the D-shaped span  582  of the upper jaw drive shaft  574  may extend directly into the plunger clamp jaws position sensor  588 . In such embodiments, the D-shaped connector  584  and D-shaped shaft  586  may not be needed. In some embodiments, the D-shaped span  582 , the D-shaped connector  584 , and D-shaped shaft  586  need not be D-shaped. In some embodiments they may be have a triangular shape, square shape, star shape, etc. 
     In some embodiments, the plunger clamp jaws position sensor  588  may comprise a potentiometer. As the D-shaped shaft  586  projecting from the plunger clamp jaws position sensor  588  rotates, the wiper of the potentiometer is slid across the resistive element of the potentiometer thus varying the resistance measured by the potentiometer. The resistance value may then be interpreted to indicate the position of the upper plunger clamp jaw  526  and lower plunger clamp jaw  528 . Alternatively, the plunger clamp jaws position sensor  588  may comprise a magnet on the end of the upper jaw drive shaft  574  and a rotary encoder such as the AS5030ATSU by Austrianmicrosytems of Austria. Alternatively, the position of the upper jaw  526  and or lower jaw  528  can be measured with a linear encoder or a linear potentiometer. 
     By obtaining a position from the plunger clamp jaws position sensor  588 , the syringe pump  500  may be able to determine a number of things. The position may be used to indicate whether a plunger flange  548  has been clamped by the plunger head assembly  522 . The position may indicate whether a plunger flange has been correctly clamped by the plunger head assembly  522 . This may be accomplished by referencing the determined position against a position or a range of positions which may be acceptable for a specific syringe  504 . The information about the specific syringe  504  being used may be input by a user or may be gathered by one or more other sensors comprising other parts of the syringe pump  500 . 
     Since the position measured by the plunger clamp jaws position sensor  588  depends on the diameter and thickness of a clamped plunger flange  548 , the positional information may also be used to determine information about the specific syringe  504  being used (for example, its type, brand, volume, etc.). This may be accomplished by referencing the measured position against a database of positions which would be expected for different syringes  504 . In embodiments where there are a number of sensors gathering information about the syringe  504 , the positional information generated by the plunger clamp jaws position sensor  588  may be checked against data from other sensors to make a more informed decision on which specific syringe  504  is being utilized. If the position measured by the plunger clamp jaws position sensor  588  does not correlate with data gathered by other sensors, the syringe pump  500  may alarm. 
     As shown in  FIG.  37   , the plunger head assembly housing top  600  may also house the plunger pressure sensor  532  mentioned earlier. The plunger pressure sensor  532  may comprise a plunger pressure sensor push plate  590 . The plunger pressure sensor push plate  590  may be a nub, a disc, or any other suitable shape. The plunger pressure sensor push plate  590  may be flat or rounded. The plunger pressure sensor push plate  590  may extend out of the plunger head assembly  522  such that it may physically contact a plunger flange  548  clamped against the plunger head assembly  522 . The plunger pressure sensor push plate  590  may directly transmit any force applied to it to a plunger pressure sensor input surface  596 . In some embodiments, the plunger pressure sensor push plate  590  may be attached to a plunger pressure sensor lever  592 . The plunger pressure sensor lever  592  may be pivotally coupled to a plunger pressure sensor pivot  594 . The plunger pressure sensor pivot  594  may be disposed at any point along the length of the plunger pressure sensor lever  592 . In the example embodiment in  FIG.  37   , any force applied to the plunger pressure sensor push plate  590  is transmitted through the plunger pressure sensor lever  592  to the plunger pressure sensor input surface  596 . In some specific embodiments, the plunger pressure sensor lever  592  and plunger pressure sensor pivot  594  may serve to constrain the motion of the plunger pressure sensor push plate  590  to a plane perpendicular to the plunger flange  548  and minimize resistance to free movement of the plunger pressure plate  590 . Although the location of the plunger pressure sensor pivot  594  in relation to the plunger pressure sensor push plate  590  does not multiply the force exerted against the plunger pressure sensor input surface  596  in  FIG.  37   , other embodiments may use different arrangements to create a mechanical advantage. 
     The force measurement which is read via the plunger pressure sensor  532  may be interpreted to determine the hydraulic pressure of the fluid being dispensed. This may contribute to safety of operation because the sensed fluid pressure may be useful in identifying possible occlusions so that they may be corrected. The pressure may be monitored such that if the pressure exceeds a predefined value, the syringe pump  500  may alarm. The pressure measurement from the plunger pressure sensor  532  may be checked against the pressure measurement from the downstream pressure sensor  513  (see  FIG.  28   ) in embodiments including both a plunger pressure sensor  532  and a downstream pressure sensor  513 . This may help to ensure greater accuracy. If the pressure measurements do not correlate, an alarm may be generated. Additionally, since the sensors are redundant, if one of the plunger pressure sensor  532  or downstream pressure sensor  513  fails during a therapy, the syringe pump  500  may function on only one of the sensors in a fail operative mode. 
     As shown in  FIG.  37   , a number of electrical conduits  598  run to and from the both the plunger pressure sensor  532  and the plunger clamp jaws position sensor  588 . The conduits  598  provide power to the plunger pressure sensor  532  and plunger clamp jaws position sensor  588 . The electrical conduits  598  also comprise the data communication pathways to and from the plunger pressure sensor  532  and the plunger clamp jaws position sensor  588 . 
       FIG.  38    shows an assembled view of the top half of the plunger head assembly  522 . In  FIG.  38   , the upper plunger clamp jaw  526  is in a closed position. The two racks  570  on the upper plunger clamp jaw  526  are engaged with the two pinion gears  572  on the upper jaw drive shaft  574  such that any rotation of the upper jaw drive shaft  574  translates into linear displacement of the upper plunger clamp jaw  526 . The upper jaw drive shaft  574  is surrounded by the upper bearing surfaces  576  and the lower bearing surface  578 . 
     The D-shaped span  582  of the upper jaw drive shaft  574  and the D-shaped shaft  586  of the plunger clamp jaws position sensor  588  are coupled together by the D-shaped connector  584 . Any rotation of the upper jaw drive shaft  574  will cause rotation of the D-shaped span  582 , D-shaped connector  584 , and D-shaped shaft  586 . As mentioned above this rotation may cause the wiper to slide across the resistive element of the plunger clamp jaws position sensor  588  in embodiments where the plunger clamp jaws position sensor  588  comprises a potentiometer. 
     The plunger pressure sensor  532  is also shown in  FIG.  38   . The plunger pressure sensor push plate  590  may extend out of the plunger head assembly  522  such that it may physically contact a plunger flange  548  (see  FIG.  30   ) clamped against the plunger head assembly  522 . The plunger pressure sensor push plate  590  may directly transmit any force applied to it to a plunger pressure sensor input surface  596 . In some embodiments, including the one shown in  FIG.  38   , the plunger pressure sensor push plate  590  may be attached to a plunger pressure sensor lever  592 . The plunger pressure sensor lever  592  may be pivotally coupled to a plunger pressure sensor pivot  594 . The plunger pressure sensor pivot  594  may be disposed at any point along the length of the plunger pressure sensor lever  592 . In the example embodiment in  FIG.  38   , any force applied to the plunger pressure sensor push plate  590  is transmitted through the plunger pressure sensor lever  592  to the plunger pressure sensor input surface  596 . Although the location of the plunger pressure sensor pivot  594  in relation to the plunger pressure sensor push plate  590  does not multiply the force exerted against the plunger pressure sensor input surface  596  in  FIG.  38   , other embodiments may use different arrangements to create a mechanical advantage. 
     The plunger head assembly housing top  600  also includes the top half of a dial shaft passage  648  for a dial shaft  650  which will be explained later in the specification. In the example embodiment shown in  FIG.  38   , the dial shaft passage  648  passes through the right face of the plunger head assembly housing top  600 . 
       FIG.  39    shows another assembled view of the top half of the plunger head assembly  522 . As shown in  FIG.  39    the plunger head assembly housing top  600  may comprise upper jaw guides  569 . The upper jaw guides  569  are sized and disposed such that they form a track-way in which the upper plunger clamp jaw  526  may move along. In the example embodiment, the upper jaw guides  569  are formed as a continuous part of the plunger head assembly housing top  600  and span the entire height of the side wall of the plunger head assembly housing top  600 . In other embodiments, the upper jaw guides  569  may only span a part of the height of the side wall of plunger head assembly housing top  600 . 
     As shown in  FIG.  39   , the plunger pressure sensor  532  may comprise a plunger pressure sensor force concentrator  595 . In embodiments where the plunger pressure sensor push plate  590  transmits force directly to the plunger pressure sensor input surface  596 , the plunger pressure sensor force concentrator  595  may help to concentrate the force applied to the plunger pressure sensor push plate  590  while exerting it against the plunger pressure sensor input surface  596 . In embodiments where the plunger pressure sensor  532  comprises a plunger pressure sensor lever  592  on a plunger pressure sensor pivot  594 , the plunger pressure sensor force concentrator  595  may be on the end and face of the plunger pressure sensor lever  592  which presses against the plunger pressure sensor input surface  596 . This may help to concentrate the force exerted against the plunger pressure sensor input surface  596  which may increase accuracy. It may also help to concentrate the force at the center of the plunger pressure sensor input surface  596 , making measurements more consistent and accurate. 
     The bottom half of the plunger head assembly  522  and the plunger tube  524  are shown in  FIG.  40   . As shown, the lower plunger clamp jaw  528  comprises two lower plunger clamp jaw racks  610 . In other embodiments, there may only be one lower plunger clamp jaw rack  610 . In some embodiments, there may be more than two lower plunger clamp jaw racks  610 . Each lower plunger clamp jaw rack  610  interdigitates with a lower plunger clamp jaw pinion gear  612 . The lower plunger clamp jaw pinion gears  612  are capable of rotating about the axis of a lower clamp jaw drive shaft  614 . A lower jaw drive gear  620  is also disposed on the lower clamp jaw drive shaft  614 . The lower jaw drive gear  620  will be elaborated upon later. 
     Similar to the upper half of the plunger head assembly  522  the lower half of the plunger head assembly  522  may comprise a number of bearing surfaces for the lower jaw drive shaft  614 . In the example embodiment in  FIG.  40   , the plunger head assembly  522  comprises one upper bearing surface  616  and two lower bearing surfaces  618  for the lower jaw drive shaft  614 . The upper bearing surface  616  is coupled into the plunger head assembly housing bottom  602 . The upper bearing surface  616  may be coupled to the plunger head assembly housing bottom  602  by any of a variety of means including, but not limited to, screws  617  (shown), bolts, adhesive, snap fit, friction fit, welds, a tongue in groove arrangement, pins, or may be formed as a continuous part of the plunger head assembly housing bottom  602 . The upper bearing surface  616  provide a bearing surface for at least a span of the top half of the lower jaw drive shaft  614 . 
     The lower bearing surfaces  618  are coupled into the plunger head assembly housing bottom  602 . The lower bearing surfaces  618  may be coupled to the plunger head assembly housing bottom  602  by any suitable means such as, but not limited to, screws, bolts, adhesive, snap fit, friction fit, magnets, welds, a tongue in groove arrangement, pin (shown), etc. In some embodiments, the lower bearing surfaces  618  may be formed as a continuous part of the plunger head assembly housing bottom  602 . The lower bearing surfaces  618  provide a bearing surface for at least a span of the bottom half of the lower jaw drive shaft  614 . 
     In some embodiments, there may also be a lower dial shaft bearing surface  649  which is coupled to the plunger head assembly housing bottom  602 . The lower dial shaft bearing surface  649  may be coupled into the plunger head assembly housing bottom  602  by any of a variety of means including, but not limited to, screws, bolts, adhesive, snap fit, friction fit, welds, a tongue in groove arrangement, pins, or may be formed as a continuous part of the plunger head assembly housing bottom  602  as shown. The lower half of the dial shaft passage  648  mentioned above is cut through the right face of the plunger head assembly housing bottom  602  The lower dial shaft bearing surface  649  and dial shaft passage  648  will be further elaborated upon later. 
     As shown in  FIG.  40   , the plunger tube  524  may be coupled into the bottom half of the plunger head assembly  522 . In the example embodiment shown in  FIG.  40   , the plunger tube  524  is coupled by two screws  630  onto a plunger tube cradle  631 . In other embodiments, the number or type of fastener/coupling method may be different. For example, the plunger tube  524  may be coupled to the plunger tube cradle  631  by any other suitable means such as, but not limited to, bolts, adhesive, snap fit, friction fit, magnets, welds, a tongue in groove arrangement, pin, etc. The plunger tube cradle  631  may comprise arcuated ribs  633  which are arced such that they are flush with the outside surface of the plunger tube  524  and support the plunger tube  524 . In some embodiments, a portion of the arc of the plunger tube  524  may be eliminated on the span of the plunger tube  524  which is coupled inside of the plunger head assembly  522  when the syringe pump  500  is fully assembled. In the embodiment shown in  FIG.  40   , about a 180° segment, or the upper half of the plunger tube  524  has been eliminated. The end of the plunger tube  524  opposite the end of the plunger tube  524  coupled to the plunger tube cradle  631  may comprise a number of plunger tube cutouts  802  which will be explained later. There may also be a conduit opening  632  near the plunger tube cutouts  802 . 
     In  FIG.  41   , the dial  530  of the plunger head assembly  522  is shown exploded away from a dial shaft  650  to which it couples onto when assembled. As shown, the dial shaft  650  comprises a square shaped end  653 . The square shaped end  653  of the dial shaft  650  fits into a square shaped orifice  655  in the dial  530  such that as the dial  530  is rotated, the dial shaft  650  is caused to rotate as well. In other embodiments, the square shaped end  653  of the dial shaft  650  and square shaped orifice  655  on the dial  530  need not necessarily be square shaped, but rather D-shaped, hexagonal, or any other suitable shape. 
     A dial shaft gear  652  may be disposed about the dial shaft  650 . As the dial shaft  650  is rotated, the dial shaft gear  652  may be caused to rotate about the axis of the dial shaft  650 . A dial shaft cam  654  may be slidably coupled to the dial shaft  650  such that the dial shaft cam  654  is capable of sliding along the axial direction of the dial shaft  650  and the dial shaft  650  freely rotates inside the dial shaft cam  654 . The dial shaft cam  654  may comprise one or more dial shaft cam ears  656 . The dial shaft cam ears  656  may also be referred to as dial shaft cam guides since they perform a guiding function. In the example embodiment, the dial shaft cam  654  comprises two dial shaft cam ears  656 . In the example embodiment, the cam surface of the dial shaft cam  654  is substantially a section of a double helix. At the end of cam surface of the dial shaft cam  654  there may be one or more dial shaft cam detents  660 . The end of the dial shaft cam  654  opposite the cam surface may be substantially flat. 
     A dial shaft cam follower  658  may be coupled into the dial shaft  650  such that it rotates with the dial shaft  650 . In the example embodiment shown in  FIG.  41    the dial shaft cam follower  658  runs through the dial shaft  650  such that at least a portion of the dial shaft cam follower  658  projects from the dial shaft  650  on each side of the dial shaft  650 . This effectively creates two dial shaft cam followers  658  which are offset  1800  from each other. Each end of the dial shaft cam follower  658  follows one helix of the double helix shaped cam surface of the dial shaft cam  654 . 
     A bias member may also be placed on the dial shaft  650 . In the example embodiment, a dial shaft compression spring  662  is placed on the dial shaft  650 . The dial shaft compression spring  662  may have a coil diameter sized to fit concentrically around the dial shaft  650 . In the example embodiment depicted in  FIG.  41   , the dial shaft compression spring  662  is retained on each end by dial shaft washers  664 . A dial shaft retaining ring  665  may fit in an annular groove  666  recessed into the dial shaft  650 . 
     In  FIG.  41   , the end of the dial shaft  650  opposite the square shaped end  653  features a peg-like projection  770 . The peg-like projection  770  may couple into a joint of a double universal joint  772 . The peg-like projection  770  may couple into the double universal joint  772  by any suitable means such as, but not limited to, screws, bolts, adhesive, snap fit, friction fit, magnets, welds, a tongue in groove arrangement, pin (shown), etc. The other joint of the double universal joint  772  may also couple onto a driven shaft  774 . The other joint of the double universal joint  772  may be coupled onto the driven shaft  774  by any suitable means such as, but not limited to, screws, bolts, adhesive, snap fit, friction fit, magnets, welds, a tongue in groove arrangement, pin (shown), etc. The dial shaft  650  and the driven shaft  774  may be oriented approximately perpendicular to each other. 
     In some embodiments, a driven shaft bushing  776  may be included on the driven shaft  774 . In the example embodiment shown in  FIG.  41    the driven shaft bushing  776  is a sleeve bushing. The inner surface of the driven shaft bushing  776  comprises the bearing surface for the driven shaft  774 . The outer surface of the driven shaft bushing  776  may comprise a number of driven shaft bushing projections  778  which extend outwardly from the outer surface of the driven shaft bushing  776 . In the example embodiment in  FIG.  41   , the driven shaft bushing projections  778  are spaced approximately 120° apart from each other along the arc of the outer surface of the driven shaft bushing  776 . In the example embodiment shown in  FIG.  41   , the driven shaft bushing projection  778  which projects toward the top of the page comprises a nub  780  which extends from the top edge of the driven shaft bushing projection  778  toward the top of the page. The driven shaft bushing  776  is held in place on the drive shaft  774  by driven shaft retaining rings  782 . One of the driven shaft retaining rings  782  may be clipped into place on the driven shaft  774  on each side of the driven shaft bushing  776 . The end of the driven shaft  774  not coupled into the double universal joint  772  may comprise a driven shaft D-shaped segment  784 . 
     When assembled, as shown in  FIG.  42   , the dial shaft compression spring  662  biases the dial shaft cam  654  against the dial shaft cam follower  658  such that the ends of the dial shaft cam follower  658  are at the bottom of the cam surface of the dial shaft cam  654 . One dial shaft washer  664  abuts the dial shaft retaining ring  665  and the other dial shaft washer  664  abuts the flat side of the dial shaft cam  654 . Preferably, the distance between the dial shaft washers  664  is at no point greater than or equal to the resting length of the dial shaft compression spring  662 . This ensures that there is no “slop” and that the dial shaft cam  654  is always biased against the ends of the dial shaft cam follower  658 . 
     As shown, the double universal joint  772  connects dial shaft  650  to the driven shaft  774  when assembled. The driven shaft bushing  776  is clipped into place on the driven shaft  774  by driven shaft retaining rings  782  (see  FIG.  41   ). In the embodiment depicted in  FIG.  42    the dial shaft  650  functions as the drive shaft for the driven shaft  774 . Any rotation of the dial shaft  650  generated through rotation of the dial  530  will be transmitted via the double universal joint  772  to the driven shaft  774 . 
       FIG.  43    shows the whole plunger head assembly  522  with the plunger tube  524  coupled in place. The top half of the plunger head assembly  522  is exploded away from the bottom half of the plunger head assembly  522 . The bottom half of the dial shaft  650  is sitting in the lower dial shaft bearing  649  on the plunger head assembly housing bottom  602 . Another span of the bottom half of the dial shaft  650  is seated on the portion of the dial shaft passage  648  located on the plunger head assembly housing bottom  602 . As shown, the dial shaft passage  648  functions as a second bearing surface for the dial shaft  650 . The square shaped end  653  of the dial shaft  650  extends beyond the dial shaft passage  648  and couples into the square shaped orifice  655  on the dial  530 . 
     As shown in  FIG.  43   , the dial shaft gear  652  on the dial shaft  650  interdigitates with the lower jaw drive gear  620 . As the dial  530  is rotated, the dial shaft  650  and dial shaft gear  652  also rotate. Rotation is transmitted through the dial shaft gear  652  to the lower jaw drive gear  620 . Rotation of the lower jaw drive gear  620  rotates the lower clamp jaw drive shaft  614  and the lower clamp jaw pinion gears  612  on the lower clamp jaw drive shaft  614 . Since the lower clamp jaw pinion gears  612  interdigitate with the lower plunger clamp jaw racks  610 , any rotation of the lower clamp jaw pinion gears  612  is translated into linear displacement of the lower plunger clamp jaw  528 . Thus, in the shown embodiment, rotating the dial  530  is the means by which a user may actuate the lower plunger clamp jaw  528  to an open or clamped position. 
     In the embodiment shown in  FIG.  43   , rotation of the dial  530  also causes a linear displacement of the dial shaft cam  654  away from the dial  530  and in the axial direction of the dial shaft  650 . As shown in the example embodiment, the upper bearing surface  616  for the lower clamp jaw drive shaft  614  comprises a dial shaft cam ear slit  690  which functions as a track for a dial shaft cam ear  656 . One of the dial shaft cam ears  656  projects into the dial shaft cam ear slit  690 . This ensures that the dial shaft cam  654  may not rotate with the dial  530  and dial shaft  650  because rotation of the dial shaft cam ear  656  is blocked by the rest of the upper bearing surface  616  for the lower clamp jaw drive shaft  614 . 
     The dial shaft cam ear slit  690  does, however, allow the dial shaft cam  654  to displace linearly along the axial direction of the dial shaft  650 . As the dial  530  and dial shaft  650  are rotated, the dial shaft cam follower  658  also rotates. The dial shaft cam follower&#39;s  658  location on the dial shaft  650  is fixed such that the dial shaft cam follower  658  is incapable of linear displacement. As the ends of the dial shaft cam follower  658  ride up the cam surface of the dial shaft cam  654 , the dial shaft cam  654  is forced to displace toward the right face of the plunger head assembly housing bottom  602  (relative to  FIG.  43   ). The dial shaft cam ears  656  also slide in this direction within the dial shaft cam ear slit  690 . This causes the dial shaft compression spring  662  to compress between the dial shaft washer  664  abutting the dial shaft cam  654  and the dial shaft washer  664  abutting the dial shaft retaining ring  665 . The restoring force of the dial shaft compression spring  662  serves to bias the dial  530 , and all parts actuated by the dial  530  to their original positions prior to any dial  530  rotation. If the dial  530  is released, the dial  530  and all parts actuated by the dial  530  will be caused to automatically return to their original orientations prior to any dial  530  rotation due to the expansion of the compressed dial shaft compression spring  662 . In the example embodiment, the original position prior to any dial  530  rotation, is the position depicted in  FIG.  35    where the upper plunger clamp jaw  526  and lower plunger clamp jaw  528  are fully closed. 
     In some embodiments, including the embodiment shown in  FIG.  43   , the dial shaft cam  654  may comprise a dial shaft cam detent  660  along the cam surface of the dial shaft cam  654 . The dial shaft cam detent  660  may allow a user to “park” the dial shaft cam follower  658  at a desired point along the cam surface of the dial shaft cam  654 . In the example embodiment, the dial shaft cam detent  660  may be reached by the dial shaft cam follower  658  when the dial  530  has been fully rotated. When the dial shaft cam follower  658  is in the dial shaft cam detent  660 , the dial shaft compression spring  662  may not automatically return the dial  530  and all parts actuated by the dial  530  to their orientation prior to any rotation of the dial  530 . A user may need to rotate the dial  530  such that the dial shaft cam follower  658  moves out of the dial shaft cam detent  660  before the restoring force of the compressed dial shaft compression spring  662  may be allowed to expand the dial shaft compression spring  662  to a less compressed state. 
       FIG.  44    shows a similar view to the view illustrated in  FIG.  43   . In  FIG.  44   , the plunger head assembly housing top  600  and some parts comprising the top half of the plunger head assembly  522  are not visible. Among the parts that are visible are the upper dial shaft bearing  651 , upper clamp jaw drive shaft  574 , the upper clamp jaw pinion gears  572 , and the upper jaw drive gear  604 . As shown in  FIG.  44   , when assembled the dial shaft  650  is sandwiched between the upper dial shaft bearing  651  and lower dial shaft bearing  649 , the dial shaft gear  652  on the dial shaft  650  interdigitates with the upper jaw drive gear  604 . As the dial  530  is rotated, the dial shaft  650  and dial shaft gear  652  also rotate. Rotation is transmitted through the dial shaft gear  652  to the upper jaw drive gear  604 . Rotation of the upper jaw drive gear  604  rotates the upper clamp jaw drive shaft  574  and the upper clamp jaw pinion gears  572  on the upper clamp jaw drive shaft  574 . 
     Referring back to  FIG.  38   , the upper clamp jaw pinion gears  572  interdigitate with the upper plunger clamp jaw racks  570 . Any rotation of the upper clamp jaw pinion gears  572  is translated into linear displacement of the upper plunger clamp jaw  526 . Thus rotation of the dial  530  is the means by which a user may actuate the upper plunger clamp jaw  526  (not shown in  FIG.  44   ) to an open or clamped position. 
     The lower bearing surface  578  for the upper jaw drive shaft  574  is also visible in  FIG.  44   . The lower bearing surface  578  for the upper jaw drive shaft  574  may comprise a second dial shaft cam ear slit  690  in embodiments where the dial shaft cam  654  comprises more than one dial shaft cam ear  656 . The second dial shaft cam ear slits  690  may functions as a track for a dial shaft cam ear  656 . One of the dial shaft cam ears  656  projects into the second dial shaft cam ear slit  690 . This ensures that the dial shaft cam  654  may not rotate with the dial  530  and dial shaft  650  because rotation of the dial shaft cam ear  656  is blocked by the rest of the lower bearing surface  578  for the upper clamp jaw drive shaft  574 . 
     The second dial shaft cam ear slit  690  does, however, allow the dial shaft cam  654  to displace linearly along the axial direction of the dial shaft  650 . As the dial  530  and dial shaft  650  are rotated, the dial shaft cam follower  658  also rotates. The dial shaft cam follower&#39;s  658  location on the dial shaft  650  is fixed such that the dial shaft cam follower  658  is incapable of linear displacement. As the ends of the dial shaft cam follower  658  ride up the cam surface of the dial shaft cam  654 , the dial shaft cam  654  is forced to displace toward the right face of the plunger head assembly housing bottom  602  (relative to  FIG.  44   ). A dial shaft cam ear  656  also slides in this direction within the second dial shaft cam ear slit  690 . This causes the dial shaft compression spring  662  to compress between the dial shaft washer  664  abutting dial shaft cam  654  and the dial shaft washer  664  abutting the dial shaft retaining ring  665 . The dial shaft compression spring  662 , dial  530 , and all parts actuated by the dial  530  may then behave per the above description. 
     In some embodiments, the upper jaw drive gear  604  (best shown in  FIG.  37   ) and lower jaw drive gear  620  (best shown in  FIG.  43   ) may be substantially identical gears. Additionally, the upper jaw pinion gears  572  (best shown in  FIG.  37   ) and lower clamp jaw pinion gears  612  (best shown in  FIG.  40   ) may be substantially identical gears. In such embodiments, the upper plunger clamp jaw  526  and lower plunger clamp jaw  528  (see  FIGS.  30 - 34   ) will experience an equal amount of linear displacement per degree of rotation of the dial  530 . Since the point of interdigitation of the upper jaw drive gear  604  on dial shaft gear  652  is opposite the point of interdigitation of the lower jaw drive gear  620  on the dial shaft gear  652 , the upper plunger clamp jaw  526  and lower plunger clamp jaw  528  will linearly displace in opposite directions. 
       FIG.  45    shows a view similar to the view shown in  FIG.  44   .  FIG.  45    depicts an assembled view of the plunger head assembly  522  from a slightly different perspective. As shown in  FIG.  45   , the dial  530  is coupled to the dial shaft  650 . The dial shaft gear  652  is in an interdigitating relationship with both the upper jaw drive gear  604  and the lower jaw drive gear  620 . The upper jaw drive gear  604  is disposed on the upper jaw drive shaft  574  along with two upper jaw pinion gears  572 . The upper jaw pinion gears  572  may be spaced apart by the lower bearing surface  578  for the upper jaw drive shaft  574  as shown in  FIG.  45   . 
     The plunger pressure sensor  532  in the embodiment depicted in  FIG.  45    comprises a plunger pressure sensor push plate  590  which extends out of the plunger head assembly  522  such that it may physically contact a plunger flange  548  (as shown in  FIG.  34   ) clamped against the plunger head assembly  522 . The plunger pressure sensor push plate  590  is attached to a plunger pressure sensor lever  592 . The plunger pressure sensor lever  592  is pivotally coupled to a plunger pressure sensor pivot  594 . The plunger pressure sensor pivot  594  is disposed at the left end of the plunger pressure sensor lever  594  (relative to  FIG.  45   ). In the example embodiment in  FIG.  45   , any force applied to the plunger pressure sensor push plate  590  is transmitted through the plunger pressure sensor lever  594  to the plunger pressure sensor input surface  596 . Although the location of the plunger pressure sensor pivot  594  in relation to the plunger pressure sensor push plate  590  does not multiply the force exerted against the plunger pressure sensor input surface  596  in  FIG.  45   , other embodiments may use different arrangements to create a mechanical advantage. The plunger pressure sensor  532  in  FIG.  45    also comprises a plunger pressure sensor force concentrator  595  which is a small projection extending from the plunger pressure sensor lever  592  to the plunger pressure sensor input surface  596 . The plunger pressure sensor force concentrator  595  concentrates force exerted against the plunger pressure sensor input surface  596  to help promote a more accurate pressure reading. 
       FIG.  46    shows a close up of how the upper jaw drive shaft  574  is connected to the D-shaped shaft  586  projecting from the plunger clamp jaws position sensor  588 . In the embodiment depicted in  FIG.  46   , the upper jaw drive shaft  574  comprises a D-shaped span  582 . The D-shaped span  582  of the upper jaw drive shaft  574  projects into a complimentary shaped orifice in the D-shaped connector  584 . The D-shaped connector  584  in  FIG.  46    is shown in cross-section. A D-shaped shaft  586  projecting out of the plunger clamp jaws position sensor  588  also projects into the D-shaped connector  584 . Any rotation of the upper jaw drive shaft  574  may cause the D-shaped connector  584  to rotate as well. In turn, this may cause rotation of the D-shaped shaft  586  projecting from the plunger clamp jaws position sensor  588 . As mentioned above this rotation may cause the wiper to slide across the resistive element of the plunger clamp jaws position sensor  588  in embodiments where the plunger clamp jaws position sensor  588  comprises a potentiometer. 
       FIG.  46    also shows the dial shaft  650  connected to the double universal joint  772 . As shown in the example embodiment in  FIG.  46   , the driven shaft  774  is also coupled to the double universal joint projects down the interior of the hollow plunger tube  524 . The nub  780  on the driven shaft bushing projection  778  of the driven shaft bushing  776  is seated in a plunger tube notch  786  recessed into the edge of the plunger tube  524  to lock the nub  780  within the plunger tube notch  786 . Seating the nub  780  in the plunger tube notch  786  restricts the driven shaft bushing  776  from rotation because the nub  780  may not rotate through the sides of the plunger tube notch  786 . Each of the driven shaft bushing projection  778  abuts the interior surface of the plunger tube  524  which keeps the driven shaft bushing  776  centered in the plunger tube  524 . 
     The plunger tube  524  may also serve as a channel for the electrical conduits  598  to and from the plunger clamp jaws position sensor  588  and the plunger pressure sensor  532 . Since the plunger tube  524  is sealed to liquid when the syringe pump is fully assembled, the plunger tube  524  protects the electrical conduits  598  from exposure to liquid. The electrical conduits  598  exit the plunger tube  524  through the conduit opening  632  of the plunger tube  524  shown in  FIG.  47   . 
       FIG.  47    depicts an exploded view of a sliding block assembly  800 . As shown, the plunger tube  524  which extends from the plunger head assembly  522  comprises two plunger tube cutouts  802 . The plunger tube cutouts  802  are cut into the front and back sides of the plunger tube  524 . In  FIG.  47   , only the front plunger tube cutout  802  is visible. The plunger tube cutouts  802  allow the plunger tube to be non-rotationally coupled to the sliding block assembly  800 . In the example embodiment, two plunger tube coupling screws  804  run through a plunger tube bracket  806 , down the plunger tube cutouts  802  and into a plunger tube support  808 . The plunger tube  524 , is thus tightly sandwiched between the plunger tube bracket  806  and the plunger tube support  808 . Any rotation of the plunger tube  524  is obstructed by plunger tube coupling screws  804  which abut the top and bottom edges of the plunger tube cutouts  802 . Similarly, any axial displacement of the plunger tube  524  is obstructed by the plunger tube coupling screws  804  which abut the sides of the plunger tube cutouts  802 . In other embodiments, the plunger tube  524  may be coupled to the sliding block assembly  800  by any other suitable means such as, but not limited to, bolts, adhesive, snap fit, friction fit, magnets, welds, a tongue in groove arrangement, pin, etc. 
     A closer exploded view of the sliding block assembly  800  is shown in  FIG.  48 A . The sliding block assembly  800  comprises a number of parts. The sliding block assembly  800  comprises a half nut housing  810 , a barrel cam  820 , a half nut  830 , and a half nut cover plate  840 . The half nut housing  810  may be manufactured from any suitable strong material will not significantly deform under the applied loads such as, metal, nylon, glass-filled plastics, molded plastic, a polyoxymethylene plastic such as Delrin, etc. The half-nut  830  is preferably fabricated from bearing metals such as brass, bronze etc that interact well with stainless steel surfaces typical of lead screws. The barrel-cam  820  is preferably fabricated from a hard metal such as stainless to form a good bearing pair with the half nut  830 . The half nut housing  810  comprises a lead screw void  810 A. The lead screw void  810 A allows the lead screw  850  (not shown, see  FIG.  48 B ) to pass through the half nut housing  810 . The lead screw void  810 A has a diameter larger than the lead screw  850  which ensures that the lead screw  850  passes uninhibited through the lead screw void  810 A irrespective of the point on the lead screw  850  at which sliding block assembly  800  is located. The sliding block assembly  800  includes a flex connector  562  to receive power from and for communications with the circuit board  1150  (refer to  FIG.  58 A ). 
     The half nut housing  810  may also comprise a guide rod bushing  810 B. The guide rod bushing  810 B in the example embodiment depicted in  FIG.  48 A  is formed as continuous piece of the half nut housing. The guide rod  852  (not shown, see  FIG.  48 B ) extends through the guide rod bushing  810 B in the half nut housing  810  with the interior surface of the guide rod bushing  810 B serving as a bearing surface for the guide rod  852 . In some embodiments, the guide rod bushing  810 B may not be formed as a continuous part of the half nut housing  810  but rather coupled to the half nut housing  810  in any number of suitable ways. The guide rod bushing  810 B may be made from a lubricious material such as bronze, brass, PTFE, delrin etc, which provides a low friction surface to mate with a hard surface of a guide rod  852  ( FIG.  48 B ). 
     The half nut housing  810  may also comprise a barrel cam void  810 C. The barrel cam void  810 C may be sized such that it has a diameter slightly larger than the diameter of the barrel cam  820 . When the sliding block assembly  800  is fully assembled, the barrel cam  820  may fit into the barrel cam void  810 C on the half nut housing  810 . In some embodiments, the barrel cam void  810 C may extend all the way through the half nut housing  810 . In the example embodiment shown in  FIG.  48 A , the barrel cam void  810 C does not extend all the way through the half nut housing  810 . The barrel cam void  810 C may function as a bushing for the barrel cam  820  when the sliding block assembly  800  is fully assembled. The barrel cam void  810 C and barrel cam  820  may be manufactured with a clearance fit. In one example the diametrical clearance between the barrel cam void  810 C and the barrel cam  820  is 0.001 to 0.005 inches. 
     In some embodiments, including the embodiment depicted in  FIG.  48 A , the half nut housing  810  may include a half nut void  810 D. The half nut void  810 D, may be recessed into the half nut housing  810  such that the half nut  830  may fit in the half nut void  810 D when the sliding block assembly  800  is fully assembled. In some embodiments, the lead screw void  810 A, barrel cam void  810 C, and half nut void  810 D may all be part of a single void recessed into the half nut housing  810 . 
     The half nut housing  810  may comprise a driven shaft aperture  810 E. The driven shaft aperture  810 E extends through the half nut housing  810  and into the barrel cam void  810 C. In  FIG.  48 A  the driven shaft D-shaped segment or shaft collar  784  is shown protruding into the barrel cam void  810 C through the driven shaft aperture  810 E. 
     The half nut housing  810  may additionally comprise a half nut housing groove  810 F. In the example embodiment in  FIG.  48 A , the half nut housing groove  810 F is recessed into the half nut housing  810 . The half nut housing groove  810 F is recessed along the entire side of the half nut housing  810 . The half nut housing groove  810 F extends in a direction parallel to the direction of elongation of the plunger tube  524 , lead screw  850 , and guide rod  852  (shown, e.g., in  FIG.  48 B ). 
     In some embodiments, the half nut housing  810  may comprise at least one limit switch  810 G. In the example embodiment depicted in  FIG.  48 A , the half nut housing  810  may comprise two limit switches  810 G. One limit switch  810 G is located on the front of the half nut housing  810  and the other limit switch  810 G is located on the back of the half nut housing  810 . The limit switch(es)  810 G may be used to limit the range of movement of the sliding block assembly along the lead screw  850  ( FIG.  48 B ). The limit switches  810 G will be further elaborated upon later. 
     As previously mentioned, the barrel cam  820  fits into the barrel cam void  810 C in the half nut housing  810  when the sliding block assembly  800  is fully assembled. As shown, the barrel cam  820  comprises a D-shaped orifice  820 A which extends through the entire barrel cam  820  along the axial direction of the barrel cam  820 . The D-shaped orifice  820 A is sized and shaped to allow the barrel cam  820  to be coupled onto the driven shaft D-shaped segment  784 . When the D-shaped orifice  820 A of the barrel cam  820  is coupled onto the driven shaft D-shaped segment  784  any rotation of the driven shaft  774  and driven shaft D-shaped segment  784  causes the barrel cam  820  to rotate as well. The barrel cam  820  may be joined to the driven shaft  774  in any of the standard methods including but not limited to set screws, pins, adhesive, friction fit, welds, etc. 
     As shown in  FIG.  48 A  the barrel cam  820  is generally a truncated cylinder, and comprises a barrel cam flat  820 B which is cut into the barrel cam  820  along a chord of the front facing base of the cylinder of the barrel cam  820 . The barrel cam flat  820 B may be cut such that some distance from the barrel cam center-line so that the full diameter of the barrel cam  820  remains. The remaining material of barrel cam  820  on the far side of the centerline relative to the half-nut follower surface  830 B provides a bearing surface to transfer forces from the half-nut  820  to the barrel cam void  810 C along the entire length of the barrel cam  820 . 
     The barrel cam flat  820 B may not extend along the entire barrel cam  820  leaving some of the cylinder of the barrel cam  820  to have an unadulterated, classic cylindrical shape. This is desirable because the classic cylindrically shaped portion of the barrel cam  820  may act as a journal within the barrel cam void  810 C which may act as a bushing. In the example embodiment depicted in  FIG.  48 A , the barrel cam flat  820 B extends along the barrel cam  820  until a barrel cam shoulder  820 C begins. The barrel cam shoulder  820 C may extend perpendicularly from the surface of the barrel cam flat  820 B. In the example embodiment in  FIG.  48 A , the expanse of the barrel cam  820  with the unadulterated, classic cylindrical shape is the barrel cam shoulder  820 C. 
     As shown, the barrel cam  820  may also comprise a barrel cam pin  820 D. The barrel cam pin  820 D in the example embodiment in  FIG.  48 A  projects perpendicularly from the front facing base of the cylinder of the barrel cam  820 . The barrel cam pin  820 D projects from the front facing base of the barrel cam  820  near the chord from which the barrel cam flat  820 B has been extended into the cylinder of the barrel cam  820 . 
     The sliding block assembly  800  may also comprise a half nut  830  as mentioned above. In the example embodiment in  FIG.  48 A , the half nut  830  comprises a half nut slot  835 . The half nut slot  835  is sized such that it may act as a track-way for the barrel cam pin  820 D. The half nut slot  835  comprises an arcuate section  835 A and an end section  835 B which is not curved or arced. The half nut slot  835  may be cut into a half nut slot plate  835 C which extends perpendicularly from a half nut cam follower surface  830 B. The half nut cam follower surface  830 B and the half nut slot  835  will be further elaborated on in the following paragraphs. 
     The half nut  830  may comprise a guide rod bushing void  830 A. The guide rod bushing void  830 A of the half nut  830  allows the guide rod bushing  810 B to pass through the half nut  830 . In the example embodiment shown in  FIG.  48 A , the guide rod bushing void  830 A is substantially larger than the diameter of the guide rod bushing  810 B. Additionally, the guide rod bushing void  830 A in the half nut  830  may have an elliptical shape or stadium shape. Such a shape allows the guide rod bushing  810 B to fit comfortably within the guide rod bushing void  830 A when the half nut  830  is engaged, disengaged, or in transition between either position. 
     The half nut  830  may also comprise a span of half nut threads  830 C. The half nut threads  830 C are capable of engaging the threads of the lead screw  850  (not shown, see  FIG.  48 B ). In the example embodiment shown in  FIG.  48 A , the half nut threads  830 C are V-shaped threads. V-shaped threads may be desirable because such a shape may help to self align the half nut threads  830 C on the lead screw  850 . 
     As mentioned above, the sliding block assembly  800  may also comprise a sliding block cover plate  840 . The sliding-block, cover plate  840  may be coupled onto the half nut housing  810  such that the barrel cam  820  and half nut  830  are kept in place within the sliding block assembly  800  when the sliding block assembly  800  is fully assembled. In the example embodiment shown in  FIG.  48 A  the sliding block cover plate  840  may be coupled onto the half nut housing  810  by sliding block cover plate screws  840 A as shown, or by any suitable means such as, but not limited to, bolts, adhesive, snap fit, friction fit, magnets, welds, a tongue in groove arrangement, pin, etc. The sliding block cover plate  840  may comprise a cover plate groove  840 B to assist in guiding the half nut housing  810 . The cover plate groove  840 B may be recessed into the sliding block cover plate  840 . In the example embodiment shown in  FIG.  48 A  the cover plate groove  840 B is recessed along an entire side edge of the sliding block cover plate  840 . The cover plate groove  840 B may sized and disposed such that it lines up with the half nut housing groove  810 F on the half nut housing  810 . 
     The sliding block cover plate  840  may comprise a guide rod bushing aperture  840 C. The guide rod bushing aperture  840 C is sized and disposed such that the guide rod bushing  810 B may project through the guide rod bushing aperture  840 C. The guide rod bushing aperture  840 C may have a diameter substantially equal to, or slightly larger than, the outer diameter of the guide rod bushing  810 B. 
     The edge of the sliding block cover plate  840  opposite the cover plate groove  840 B, may comprise a lead screw trough  840 D. The lead screw trough  840 D may be an arced section recessed into the edge of the sliding block cover plate  840 . The lead screw trough  840 D, in conjunction with the lead screw void  810 A of the half nut housing  810  allows the sliding block assembly  800  to be placed on the lead screw  850 . 
     In operation, the sliding block assembly  800  may be caused to move along the axial direction of the lead screw  850  and guide rod  852  as a result of lead screw  850  rotation. The sliding block assembly  800  may also be moved along the axial direction of the lead screw  850  and guide rod  852  by a user. For a user to move the sliding block assembly  800  along the axial direction of the lead screw  850  the user may need to adjust the location of the plunger head assembly  522  relative to the rest of the syringe pump assembly  501  as shown and described in relation to  FIGS.  32 - 33   . This may only be done by a user when the half nut  830  is not engaged with the lead screw  850   
       FIG.  48 B  shows the half nut  830  in an engaged position on the lead screw  850 . The half nut housing  810 , and half nut cover plate  840  visible in  FIG.  48 A  have been removed in  FIG.  48 B . When the half nut  830  is in engagement with the lead screw  850 , the half nut threads  830 C may operatively be engaged with the threads of the lead screw  850 . Any rotation of the lead screw  850  may cause the half nut  830  to move in the axial direction of the lead screw  850 . 
     To move the half nut  830  between an engaged and disengaged position on the lead screw  850 , the barrel cam  820  must be rotated. As the barrel cam  820  is rotated, the barrel cam pin  820 D may move along the half nut slot  835  in the half nut slot plate  835 C. In the example embodiment shown in  FIG.  48 B , when the barrel cam pin  820 D is located in the arcuate section  835 A of the half nut slot  835 , the half nut  830  is engaged with the lead screw  850 . The arcuate section  835 A of the half nut slot  835  may be shaped such that any movement of the barrel cam pin  820 D within the arcuate section  835 A of the half nut slot  835  does not result in any movement of the half nut  830 . 
     When the barrel cam  820  is rotated such that the barrel cam pin  820 D enters the straight, end section  835 B of the half nut slot  835 , further rotation of the barrel cam  820  may cause the half nut  830  to disengage from the lead screw  850 . The straight nature of the end section  835 B ensures that the further rotation of the barrel cam  820  causes the barrel cam pin  820 D to pull the half nut  830  away from the lead screw  850  until the barrel cam pin  820 D reaches the end of the end section  835 B. Rotation of the barrel cam  820  in the opposite direction will cause the barrel cam pin  820 D to push the half nut  830  back into engagement with the lead screw  850 . 
     In the example embodiment in  FIG.  48 B , when the barrel cam  820  has disengaged the half nut  830  from the lead screw  850 , the half nut cam follower surface  830 B rests in the void created by the barrel cam flat  820 B. When the half nut  830  is disengaged, the distance between the half nut threads  830 C and their point of full engagement on the lead screw  850  is less than or equal to the length of the sagitta of the cylindrical segment removed from the barrel cam  820  to create the barrel cam flat  820 B. As the barrel cam  820  is rotated to engage the half nut  830  with the lead screw  850 , the pin  820 D in the straight, end section  835 B moves the half-nut toward the lead screw  850  until the half-nut  830  is at least partial engaged with the lead screw  850 . As the pin  820 D exits the end section  835 B, the untruncated arc of barrel cam  820  rotates onto the half nut cam follower surface  830 B of the half nut  830 . The untruncated arc of the barrel may push the half nut  830  into full engagement with the lead screw  850  and supplements the action of the barrel cam pin  820 D in the half nut slot  835 . 
     Referring back to the example embodiment shown in  FIG.  48 A , the driven shaft  774  to which the barrel cam  820  is coupled may not deflect when the barrel cam  820  has engaged, disengaged, or is transitioning the half nut  830  from an engaged or disengaged position on the lead screw  850 . As shown, the barrel cam void  810 C in the half nut housing  810  supports the barrel cam  820  when the sliding block assembly  800  is fully assembled. Consequently, any force promoting deflection of the driven shaft  774  is checked by the barrel cam  820  abutting the sides of the barrel cam void  810 C. This ensures that the half nut threads  830 C may not skip on the threads of the lead screw  850  under high axial loads. It also creates minimal drag as the sliding block assembly  800  travels along the lead screw  850  with rotation of the lead screw  850 . 
     In some embodiments, the fit of the half nut  830  and the barrel cam  820  may be adjustable. In such embodiments, a portion of the barrel cam housing  810  that defines the barrel cam void  810 C may have an adjustable position relative to the guide rod that can be adjusted for example by rotation of a set screw or other adjustment means. This may also allow a user to adjust the barrel cam  820  to an optimal or near optimal position. Alternatively, inserts may be added to the barrel cam void  810 C or the barrel cam  820  may be replaced with different sized barrel cam  820  to position the half-nut  830 D/barrel cam  820  interface at the optimal location. In such a position, the barrel cam  820  may engage the half nut threads  830 C on the lead screw  850  such that there is zero or minimal backlash without loading the half nut threads  830 C against the lead screw  850  and creating excessive drag. 
     In alternate embodiments, the barrel cam pin  820 D may be optional. In some alternate embodiments, the barrel cam pin  820 D may be replaced by one or more bias members. The bias members may bias the half nut  830  to the disengaged position. In such embodiments, rotation of the barrel cam  820  may cause the half nut  830  engage or disengage with the lead screw  850 . When the barrel cam flat  820 B is not contacting the half nut cam follower surface  830 B the one or more bias members may be overcome and the half nut threads  830 C may be engaged with the threads of the lead screw  850 . As the barrel cam flat  820 B rotates onto the half nut cam follower surface  830 B, the bias member(s) may act as a spring return which automatically biases the half nut  830  out of engagement with the lead screw  850  and against the barrel cam flat  820 B. The barrel cam  820  may include a transitional cam surface between the barrel cam flat  820  B and the untruncated arc of barrel cam  820  to facilitate displacing the half nut  830  toward the lead screw  850 . Use of the barrel cam pin  820 D may be desirable because such an arrangement requires less torque to engage or disengage the half nut  830  than embodiments which may employ one or more bias members as a substitute. Some embodiments may use both the barrel cam pin  820 D and one or more bias members to effect engagement or disengagement of the half nut  830 . 
     In some embodiments, the bias member may bias the half nut  830  towards the engaged position, in which case, the barrel cam pin  820  may be configured to lift the half nut threads  830 C off the lead screw  850 . 
     In another alternative embodiment, the barrel cam  820  may not comprise a barrel cam pin  820 D and the half nut  830  may not comprise a half nut slot  835 . In such embodiments, the barrel cam flat  820 B may comprise a magnet and the half nut cam follower surface  830 B may also comprise a magnet. Instead of using the barrel cam pin  820 D to pull the half nut  830  away from the lead screw  850 , the magnet on the half nut cam follower surface  830 B may be attracted to the magnet on the barrel cam flat  820 B and be pulled off the lead screw  850  toward the barrel cam flat  820 B when the barrel cam  820  has been rotated the appropriate amount. In some embodiments, the barrel cam  820  may be a simple two pole magnet. In such embodiments, the barrel cam  820  may be disposed such that it may repel or attract a magnet on the half nut cam follower surface  830 B. When like poles of the magnets face each other, the half nut is forced into engagement with the lead screw  850 . By rotating the driven shaft  774  and therefore the magnetic barrel cam  820 , opposite poles may be made to face each other. In turn, this may cause the half nut  830  to disengage from the lead screw  850  as it is attracted to the magnetic barrel cam  820 . 
     In some embodiments, a magnet may be configured to bias the half nut  830  towards the engaged position, in which case, the barrel cam pin  820  may be configured to lift the half nut threads  830 C off of the lead screw  850 . 
     The guide rod  852  is also visible in  FIG.  48 B . In  FIG.  48 B  the guide rod  852  extends in an axial direction parallel to that of the lead screw  850 . The guide rod passes through the guide rod bushing void  830 A in the half nut  830 . In the example embodiment, the guide rod  852  is made of a hard and durable material. For example, in some embodiments, the guide rod  852  may be made of a material such as stainless steel. In other embodiments, the guide rod  852  may be chromium plated. 
       FIG.  49    shows a close up view of the half nut slot plate  835 C. The half nut slot plate  835 C is transparent in the  FIG.  49   . The half nut slot  835  is shown in the half nut slot plate  835 C. As described above, the half nut slot  835  comprises an arcuate section  835 A and a straight, end section  835 B. The barrel cam  820  is shown behind the transparent half nut slot plate  835 C. As shown, the barrel cam pin  820 D is located in the arcuate section  835 A of the half nut slot  835 . As mentioned above, when the barrel cam pin  820 D is in the arcuate section  835 A of the half nut slot  835  the half nut  830  is engaged with the lead screw  850  as shown in  FIG.  48 B . The barrel cam  820  is disposed in the barrel cam void  810 C in the half nut housing  810 . The barrel cam void  810 C acts as a bushing for the barrel cam  820  and supports the barrel cam  820 . 
       FIGS.  50 - 52    show sliding block assembly  800  with the half nut cover plate  840  and half nut  830  shown as transparent. In  FIGS.  50 - 52   , the half nut  830  transitions from an engaged position ( FIG.  50   ) to a disengaged position ( FIG.  52   ). As shown in  FIG.  50    the half nut  830  is in the engaged position. The barrel cam pin  820 D is located in arcuate section  835 A of the half nut slot  835 . The half nut threads  830 C are at the far left extent (relative to  FIGS.  50 - 52   ) of their range of movement. The guide rod bushing  810 B of the half nut housing  810  projects through the guide rod bushing void  830 A of the half nut  830 . As shown, the guide rod bushing  810 B is located at the far right end of the guide rod bushing void  830 A. In the example embodiment shown in  FIGS.  50 - 52    the guide rod bushing void  830 A in the half nut  830  is roughly stadium shaped. 
     The barrel cam  820  has been rotated such that the barrel cam pin  820 D is about to cross from the arcuate section  835 A of the half nut slot  835  and into the end section  835 B of the half nut slot  835  in  FIG.  51   . As shown, the half nut threads  830 C have not moved from the engaged position and are still at the far left extent (relative to  FIGS.  50 - 52   ) of their range of movement. Similarly, the half nut  830  may not have moved relative to the guide rod bushing  810 B from the position depicted and described in relation to  FIG.  50   . 
     In  FIG.  52    the barrel cam  820  has been rotated such that the barrel cam pin  820 D has moved into the straight, end section  835 B of the half nut slot  835 . As described above, further rotation of the barrel cam  820  once the barrel cam pin  820 D enters the end section  835 B of the half nut slot  835  causes the half nut  830  to disengage. As shown, the half nut  830 , and consequentially the half nut threads  830 C, have moved from the far left extent (relative to  FIGS.  50 - 52   ) of their range of movement and toward the right of the page. The half nut  830  has moved in relation to the guide rod bushing  810 B, such that the guide rod bushing  810 B is now near the far left end of the guide rod bushing void  830 A. 
       FIG.  53    shows a cross section of most of the components comprising an embodiment of the sliding block assembly  800 . The sliding block assembly  800  is depicted fully assembled in  FIG.  53   . The lead screw  850  and guide rod  852  are not depicted in cross section in  FIG.  53   . As shown, the lead screw  850  extends through the lead screw void  810 A in the half nut housing  810  and over the lead screw trough  840 D in the half nut cover plate  840 . The guide rod extends through the guide rod bushing  810 B. The guide rod bushing  810 B extends through both the guide rod bushing void  830 A in the half nut  830  and the guide rod bushing aperture  840 C in the half nut cover plate  840 . 
     In the example embodiment shown in  FIG.  53   , the half nut  830  is in the disengaged position. The half nut threads  830 C are not operatively interdigitated with the threads of the lead screw  850 . The guide rod bushing  810 B is near the top of the guide rod bushing void  830 A in the half nut  830 . The half nut cam follower surface  830 B is near or is abbuting (depending on the embodiment) the barrel cam flat  820 B on the barrel cam  820 . Additionally, the barrel cam pin  820 D is at the end of the straight, end section  835 B of the half nut slot  835  which is cut into the half nut slot plate  835 C. 
       FIG.  53    also shows the D-shaped orifice  820 A of the barrel cam  820  coupled onto the driven shaft D-shaped segment  784  of the driven shaft  774 . The plunger tube  524  through which the driven shaft  774  is disposed can be seen coupled onto the sliding block assembly  800  by means of screws running through the plunger tube cutouts  802  and into the plunger tube support  808 . 
       FIG.  54    shows a view of a portion of an embodiment of the syringe pump assembly  501 . At the left side of  FIG.  54   , a section of the plunger head assembly  522  is visible. As shown in  FIG.  54   , the rear face  900  of the syringe pump assembly  501  may comprise a rear face guide rod hole  901 . The rear face guide rod hole  901  may run through the entire rear face  900  of the syringe pump assembly  501  at an angle perpendicular to the rear face  900  of the syringe pump assembly  501 . As shown, the guide rod hole  901  may be substantially cylindrical. 
     The rear face  900  of the syringe pump assembly  501  may comprise a gearbox depression  902 . As shown, the gearbox depression  902  is recessed into the rear face  900  of the syringe pump assembly  501 . In the example embodiment, the gearbox depression  902  is a roughly rectangular shaped depression. In other embodiments, the gearbox depression  902  may have alternative shapes. 
     As shown in  FIG.  54   , an anti-rotation pin  904  projects out of the gearbox depression  902 . The anti-rotation pin  904  in the example embodiment shown in  FIG.  54    is cylindrical. In alternate embodiments, the anti-rotation pin  904  may take any other suitable shape. As shown in  FIG.  54   , the gearbox depression  902  in the rear face  900  of the syringe pump assembly  501  may also comprise a lead screw void  906 . The lead screw void  906  may be cut all the way through the rear face  900  of the syringe pump assembly  501  and allow at least a portion of the lead screw  850  to project beyond of the rear face  900  of the syringe pump assembly  501 . As shown in the example embodiment, the section of the lead screw  850  which projects beyond the rear face  900  of the syringe pump assembly  501  is not threaded. 
     In the example embodiment shown in  FIG.  54   , the section of the lead screw  850  that is visible is smaller in diameter than the lead screw void  906 . This is desirable because it may allow a rear face lead screw bearing  908  to be placed in the lead screw void  906  to provide a bearing surface for the lead screw  850 . In the example embodiment in  FIG.  54    a lead screw bearing is disposed in the lead screw void  906  to provide a bearing surface for the lead screw  850 . 
     As shown, the end of the of the section of the lead screw  850  which projects out of the rear face  900  may comprise a threaded bore  910 . In the example embodiment shown in  FIG.  54   , a gearbox attachment fastener  912  is coupled into the threaded bore  910  on the end of the lead screw  850 . In the example embodiment, the gearbox attachment fastener  912  is a screw with a hex socket head. In other embodiments, any other suitable fastener, or fastener head may be used. 
     In  FIG.  55   , another view of a portion of an embodiment of the syringe pump assembly  501  is shown. At the left side of  FIG.  55   , part of the plunger head assembly  522  is also visible. The gearbox  940  is shown in place in the gearbox depression  902  on the rear face  900  of the syringe pump assembly  501 . As shown, the anti-rotation pin  904  may project through an anti-rotation pin hole  942  in the gearbox  940 . The anti-rotation pin  904  ensures that the gearbox  940  causes rotation of the lead screw  850  and that the gearbox  940  may not rotate around the axis of the lead screw  850 . As shown, the anti-rotation pin  904  does not help to hold the gearbox  940  against the rear face  900  of the syringe pump assembly  501 . In alternate embodiments, the anti-rotation pin  904  may have a threaded anti-rotation pin bore  944  similar to that of the end of the lead screw  850  described in above in relation to  FIG.  54   . An anti-rotation pin gearbox fastener  946  may be threaded into the thread anti-rotation pin bore  944  to help hold the gearbox  940  against the rear face  900  of the syringe pump assembly  501 . The gearbox  940  may be friction locked onto the lead screw  850  to ensure that rotation of the gears in the gearbox  940  is transmitted to the lead screw  850  with zero or minimal backlash. 
     In embodiments where the syringe pump assembly  501  may be removed from the housing  502  (see  FIG.  28   ) and replaced with another assembly such as a peristaltic large volume pump assembly, the gearbox  940  may be compatible with a replacement assembly. 
       FIG.  56    shows an embodiment of the interior of the syringe pump assembly  501 . As shown, the front face  888  of the syringe pump assembly  501  is shown as transparent. As shown, the guide rod  852  projects perpendicularly from the interior of the rear face  900  of the syringe pump assembly  501  and toward the front of the page. The lead screw  850  may similarly project into the interior of the syringe pump assembly  501  through the rear face lead screw bearing  908  at an angle perpendicular to the interior of the rear face  900  of the syringe pump assembly  501 . The guide rod  852  and lead screw  850  may run parallel to each other. In the example embodiment in  FIG.  56   , the lead screw  850  is offset toward the left of the page from the guide rod  852 . 
     As shown, one end of the guide rod  852  is seated in the rear face guide rod hole  901 . The other end of the guide rod  852  is seated in the front face  888  of the syringe pump assembly  501 . In the example embodiment depicted in  FIG.  56   , the end of the guide rod  852  facing the front of the page is smaller in diameter than the rest of the guide rod  852 . This section of the guide rod  852  may be placed in a guide rod hole  1002  in the front face  888  of the syringe pump assembly  501  when the syringe pump assembly  501  is fully assembled. The guide rod hole  1002  may extend through the entire front face  888  of the syringe pump assembly  501  at an angle substantially perpendicular to the front face  888 . The smaller diameter section of the guide rod  852  may have a diameter slightly though not substantially smaller than the diameter of the guide rod hole  1002  such that the guide rod  852  may fit snuggly in the guide rod hole  1002  when the syringe pump assembly  501  is assembled. The end of the guide rod  852  may be flush with the plane of the front face  888  of the syringe pump assembly  501 . Though both the guide rod hole  1002  and the section of the guide rod  852  seated in the guide rod hole  1002  are cylindrical in the example embodiment shown in  FIG.  56   , their shape may differ in alternate embodiments. 
     The lead screw  850  is seated in a lead screw depression  1000  in the front face  888  of the syringe pump assembly  501 . In the example embodiment shown in  FIG.  56   , the depth of the lead screw depression  1000  is substantially the thickness of the front face  888  of the syringe pump assembly  501 . In embodiments where the depth of the lead screw depression  1000  is substantially the depth of the front face  888 , a circular plateau  1004  may be raised off the front face  888  of the syringe pump assembly  501  to accommodate the depth of the lead screw depression  1000 . The center of the circular plateau  1004  may be concentric with the center of a cylindrical lead screw depression  1000  as shown in  FIG.  56   . In some embodiments, the edges of the circular plateau  1004  may extend perpendicularly from the front face  888  of the syringe pump assembly  501  to the raised circular plateau. In the example embodiment illustrated in  FIG.  56   , the edges of the circular plateau  1004  curve up from the front face  888  of the syringe pump assembly  501  to the circular plateau  1004 . 
     As shown, the lead screw depression  1000  may house a front face lead screw bearing  1006  which surrounds the end of the lead screw  850  and provides a bearing surface for the lead screw  850 . In some embodiments, such as the embodiment depicted in  FIG.  56   , a Belleville washer  1008  may be seated against the bottom of the lead screw depression  1000 . The Belleville washer  1008  may ensure that there is no “play” of the lead screw  850  when the lead screw  850  is seated in the lead screw depression  1000 . 
     In some embodiments, the Belleville washer  1008  may be replaced by non-compliant end cap which loads the front face lead screw bearing  1006  against the lead screw  850 . In such embodiments, the end cap may be threaded on its out diameter. The lead screw depression  1000  may feature complimentary threads to which the end cap may screw into. Again the end cap may also ensure that there is no “play” of the lead screw  850  when the lead screw  850  is seated in the lead screw depression  1000 . 
       FIG.  57    shows a view of the interior of the syringe pump assembly  501 . The front face  888  which is shown as transparent in  FIG.  56   , is not present in  FIG.  57   . As shown, the sliding block assembly  800  described above is in place within the syringe pump assembly  501 . The guide rod  852  extends through the guide rod bushing  810 B in the half nut housing  810 . The when the half nut  830  is disengaged from the lead screw  850 , the sliding block assembly  800  may be free to slide about the axial direction of the guide rod  852 . 
     Movement of the sliding block assembly  800  is also guided by a syringe pump assembly guide rail  1010 . In the example embodiment shown in  FIG.  57   , the syringe pump assembly guide rail  1010  extends from the interior face of the syringe seat  506 . The syringe pump assembly guide rail  1010  is shaped such that the half nut housing groove  810 F and cover plate groove  840 B on the sliding block assembly  800  may fit on the syringe pump assembly guide rail  1010  and slide along the syringe pump assembly guide rail  1010 . The syringe pump assembly guide rail  1010  also ensures that the sliding block assembly  800  may not rotate within the syringe pump assembly  501 . The syringe pump assembly guide rail  1010  may be formed as part of the extrusion in embodiments where the syringe pump assembly housing  503  is formed by extrusion. 
     As shown in  FIG.  57   , when half nut  830  of the sliding block assembly  800  is engaged with the lead screw  850 , the lead screw  850  may cause linear movement of the sliding block assembly  800  along the axial direction of the lead screw  850 . To cause linear movement of the sliding block assembly  800 , the lead screw  850  must be rotated. In the example embodiment in  FIG.  57   , the rotational motion of the lead screw  850  causes the half nut  830  and consequently the sliding block assembly  800  to move along the lead screw  850  due to the pitch of the threads of the lead screw  850 . The amount of linear movement per 360° rotation of the lead screw  850  may vary depending on the pitch of the threads of the lead screw  850  which may differ in various embodiments. 
     As mentioned above, the half nut housing  810  of the sliding block assembly  800  may comprise one or more limit switches  810 G. In the example embodiment in  FIG.  57   , a limit switch  810 G is not shown, although it is indicated that a limit switch  810 G may be located on the front of the half nut housing  810 . In other embodiments, there may be multiple limit switches  810 G which may be disposed about other portions of the sliding block assembly  800 . In embodiments where a limit switch may be disposed on the front of the half nut housing  810 , the limit switch  810 G may prevent the sliding block assembly  800  from being driven into the front face  888  (shown in  FIG.  56   ) of the syringe pump assembly  501 . 
     In embodiments comprising a limit switch  810 G, the limit switch  810 G may be a micro switch, although hall sensors and magnets, optical sensors, etc. could also be used. In embodiments where the limit switch  810 G comprises a micro switch, the micro switch may be actuated when the sliding block assembly  800  nears a predefined location along the lead screw  850 . In some embodiments, when the limit switch  810 G is in the actuated position, the lead screw  850  may not be further rotated to advance the sliding block assembly  800  in the direction of the predefined location. 
     As shown in  FIG.  57   , the syringe pump assembly  501  may additionally comprise a sliding block linear position sensor  1050  to determine the sliding block assembly&#39;s  800  location on the lead screw  850 . In some embodiments, the sliding block linear position sensor  1050  may be used to determine the amount of contents left in a syringe  504  which may be in place on the syringe pump assembly  501 . In such embodiments, the sliding block linear position sensor  1050  may be used to determine a quantified volume of syringe  504  contents or may be used as a “gas gauge” which generates a more general syringe  504  contents volume reading. 
     In some embodiments, the sliding block linear position sensor  1050  may comprise a linear potentiometer. In such embodiments, the wiper of the sliding block linear position sensor  1050  may be disposed such that it slides across the resistive element of the potentiometer with movement of the sliding block assembly  800  along the lead screw  850 . The resistance measured by the sliding block linear position sensor  1050  may be used to determine the location of the sliding block assembly  800  along the lead screw  850 . 
     In some embodiments, including the example embodiment shown in  FIG.  57   , the sliding block linear position sensor  1050  may comprise an array of sliding block magnetic linear position sensors  1054 . The sliding block magnetic linear position sensors  1054  may be any suitable magnetic linear position sensor. An example of a suitable magnetic linear position sensor is the “AS5410 Absolute Linear 3D Hall Encoder” available from Austriamicrosystems of Austria. As shown, the sliding block assembly  800  may include a sliding block assembly magnet  1056  which is mounted a suitable distance away from the sliding block magnetic linear position sensors  1054  and may be used in conjunction with the array of sliding block magnetic linear position sensors  1054  in order to determine the location of the sliding block assembly  800  on the lead screw  850 . In some embodiments, the location of the sliding block magnetic linear position sensors  1054  may differ. As shown, the sliding block assembly  800  includes a second magnet  1057  disposed such that it may interact with the sliding block magnetic linear position sensors  1054  when they are placed in an alternate location. 
       FIG.  57 A  shows an example of a possible linear position sensor  1100  arrangement. In the example linear position sensor  1100  arrangement, the linear position sensor  1100  comprises an array of magnetic linear position sensors  1102  such as the “AS5410 Absolute Linear 3D Hall Encoder” available from Austriamicrosystems of Austria mentioned above. A position changing block  1104  is depicted at a position along a position changing block lead screw  1106 . A position changing block arm  1108  projects off the page as indicated by the broken line defining its rightmost edge. An object attached to the position changing block arm  1108  may be caused to move with the position changing block  1104  as the position changing block  1104  moves along the lead screw  1106 . The position changing block  1104  in  FIG.  57 A  may be considered the sliding block assembly  800  in  FIG.  57   . 
     In the example linear position sensor  1100  arrangement shown in  FIG.  57 A , the position changing block  1104  comprises a position changing block magnet  1110 . As shown, the position changing block magnet is located on the face of the position changing block closest to the array of magnetic linear position sensors  1102 . The position changing block magnet  1110  is a dipole magnet. The north pole of the position changing block magnet  1110  is oriented to face toward the right of the page while the south pole faces the left of the page. As the position changing block  1104  moves along the position changing block lead screw  1106 , the position changing block magnet  1110  also moves. This movement may be measured by the array of magnetic linear position sensors  1102  and analyzed to determine an absolute location of the position changing block  1104  along the position changing block lead screw  1106 . In some embodiments, the array of magnetic linear position sensors  1102  may be used to determine differential movements of the position changing block  1104 . 
     As shown in  FIG.  58    an embodiment of the sliding block assembly  800  is shown assembled with the half nut cover plate  840  (see  FIG.  48   ) removed. The half nut  830  is depicted in the engaged position and is shown as transparent so that the half nut housing  810  and the barrel cam  820  may be seen behind it. The driven shaft D-shaped segment  784  of the driven shaft  774  is shown in the D-shaped orifice  820 A of the barrel cam  820 . The driven shaft  774  extends through the plunger tube  524  which couples the sliding block assembly  800  and plunger head assembly  522  together. 
     Referring back to  FIG.  42   , the driven shaft  774  couples into a double universal joint  772 . The double universal joint  772  translates any rotational motion from the dial  530  which rotates the dial shaft  650  to rotational motion of the driven shaft  774 . Rotational motion of the driven shaft  774  in turn causes rotation of the barrel cam  820 . Rotation of the barrel cam  820  engages or disengages the half nut  830  as described above. 
     As also detailed above, rotation of the dial  530  causes linear displacement of the upper plunger clamp jaw  526  and lower plunger clamp jaw  528 . The dial  530  is thus multi-functional. When rotated, the dial  530  both engages or disengages the half nut  830  and opens or closes the upper plunger clamp jaw  526  and lower plunger clamp jaw  528 . It should be noted that the arcuate section  835 A of the half nut slot  835  is shaped such that the half nut  830  does not begin to disengage until the largest plunger flange  548  which can be accepted by the upper plunger clamp jaw  526  and lower plunger clamp jaw  528  has been released by the upper plunger clamp jaw  526  and lower plunger clamp jaw  528 . When the plunger flange  548  has been released and the half nut  830  has disengaged, the dial shaft cam follower  658  on the dial shaft  650  may sit in the dial shaft cam detents  660  of the dial shaft cam  654  as described in relation to  FIG.  43   . As put forth in the detailed description of  FIG.  43   , this would allow a user to “park” the dial  530  in the fully rotated position where the half nut  830  is disengaged and the upper plunger clamp jaw  526  and lower plunger clamp jaw  528  are in the open position. In the example embodiment depicted in  FIG.  58   , when the dial  530  is in the “parked” position, a user may remove their hand from the dial  530  and easily adjust the plunger head assembly  522  so that a syringe  504  may be inserted onto the syringe pump assembly  501  (see  FIGS.  30 - 34    for example illustrations and discussion of syringe  504  placement onto the syringe pump assembly  501 ). 
       FIG.  59 A  shows an embodiment of the syringe pump assembly  501 . As shown, the syringe pump assembly  501  is fully assembled. A syringe  504  is seated on the syringe seat  506  of the syringe pump assembly housing  503 . The gearbox  940  is shown in place on the syringe pump assembly  501 . The motor  1200  which drives the gearbox  940  is also shown coupled to the gearbox  940 . A main printed circuit board (PCB)  1150  is shown transparently on the syringe pump assembly  501 . The main PCB  1150  is coupled to the top of the syringe pump assembly housing  503 . In the example embodiment, the flex connector  562  extending from the sliding block assembly  800  is connected to the main PCB  1150 . The electrical system comprising the main PCB will be described in  FIGS.  59 A- 59 J . 
     The electrical system  4000  of the syringe pump  500  (see  FIG.  28   ) is described in a block schematic in  FIGS.  59 A- 59 J . The electrical system  4000  controls the operation of the syringe pump  500  based on inputs from the user interface  3700  and sensors  3501 . The electrical system  4000  includes a power system comprised of a rechargeable main battery  3420  and battery charger  3422  that plugs into the AC mains. The electrical system  4000  is architected to provide safe operation with redundant safety checks, and allow the syringe pump  500  to operate in fail operative modes for some errors and fail safe for the rest. 
     The high level architecture of multiple processors is shown in the last block diagram detailing the electrical system  4000 ,  FIG.  59 J . In one example the electrical system  4000  is comprised of two main processors, a real time processor  3500  and a User Interface/Safety Processor  3600 . The electrical system  4000  may also comprise a watch-dog circuit  3460 , motor control elements  3431 , sensors  3501 , and input/output elements. One main processor referred to as the Real Time Processor (hereafter RTP)  3500  may control the speed and position of the motor  1200  that rotates the lead screw  850  (see  FIG.  48 B ). The RTP  3500  may control the motor  1200  based on input from the sensors  3501  and commands from the User Interface &amp; Safety Processor (hereafter UIP)  3600 . The UIP  3600  may manage telecommunications, manage the user interface  3701 , and provide safety checks on the RTP  3500 . The UIP  3600  may estimate the volume pumped based on the output of a motor encoder  1202  and may signal an alarm or alert when the estimated volume differs by more than a specified amount from a desired volume or the volume reported by the RTP  3500 . The watch dog circuit  3460  monitors the functioning of the RTP  3500 . If the RTP  3500  fails to clear the watch dog circuit  3460  on schedule, the watch dog  3460  may disable the motor controller  3431 , sound an alarm and turn on one or a number of failure lights at the user interface  3701 . The RTP  3500  uses the sensor inputs to control the motor  1200  position and speed in a closed-loop controller (further described below). The telecommunications may include a WIFI driver and antenna to communicate with a central computer or accessories, a Bluetooth driver and antenna to communicate with accessories, tablets, cell-phones etc. and a Near Field Communication (NFC) driver and antenna for RFID tasks and a Bluetooth. In  FIG.  59 J  these components are collectively referred to with the reference number  3721 . The user interface  3701  may include a display  514  (see  FIG.  28   ). In some embodiments, the display  514  may be a touch screen. In some embodiments the user interface  3701  may comprise one or more buttons or data input means  516  (see  FIG.  28   ) via which a user may communicate with the syringe pump  500 . 
     The detailed electrical connections and components of the electrical system  4000  are shown in  FIGS.  59 B- 59 I .  FIGS.  59 B- 59 I  also depict a number of line traces  5000 - 5169  running to and from various components. A number of sensors of the syringe pump  500  are shown in  FIG.  59 B . As shown, plunger position sensors  3950 , a barrel diameter sensor  3951 , a plunger capture potentiometer sensor  3952 , a plunger force sensor  3953 , and other sensors  3954  are shown. The plunger position sensors  3950  may be any of the plunger position sensors described herein. The barrel diameter sensor  3951  may be the syringe barrel holder linear position sensors  1540  to be described herein. The plunger capture potentiometer sensor  3952  may not necessarily be a potentiometer sensor in all embodiments. In some embodiments, the plunger capture potentiometer sensor  3952  may be the plunger clamp jaws position sensor  588  described herein. The plunger force sensor  3953  may be the plunger pressure sensor  532  described herein. The plunger capture potentiometer  3952  may be a switch to detect a syringe  504  loaded into the syringe seat  506 . The above sensors may communicate signals respective of and indicative of what they are sensing to the RTP  3500  or another component. 
     As shown in  FIG.  59 C , a thermistor  3540  may provide a signal to the RTP  3500  indicative of the temperature of the infusate in an infusion line. Alternatively the thermistor  3540  may measure a temperature in the syringe pump  500  or the temperature of the circuit  4000 . As shown, the electrical system  4000  defines specific part numbers for various components. For example, the thermistor  3540  is defined as a “2X SEMITEC 103JT-050 ADMIN Set THERMISTOR”. These part numbers should not be construed as limiting in any way whatsoever. In different embodiments, suitable replacement components may be used in place of the specific parts listed in the  FIGS.  59 B- 59 I . For example the thermistor  3540  may not be a “2X SEMITEC 103JT-050 ADMIN Set THERMISTOR”, but rather any suitable replacement thermistor  3540 . In some embodiments, the electrical system  4000  may comprise additional components. In some embodiments the electrical system  4000  may comprises fewer components than the number of components shown in  FIGS.  59 B- 59 J . 
     Two sensors which may be located downstream of the syringe pump  500  are shown in  FIG.  59 C . One sensor is an air-in-line sensor  3545 . The other is an occlusion sensor  3535 . Both are connected to the RTP  3500 . These sensors are optional. The air-in-line sensor  3545  may detect the presence of air in the section of an infusion line in near the air-in-line sensor  3545 . In an example embodiment, the air-in-line sensor  3545  may comprise an ultra-sonic sensor  3545 B, a logic unit  3545 A and a signal conditioning unit  3545 C. In some embodiments, the syringe pump  500  may not comprise an air-in-line sensor  3545 . 
     The occlusion sensor  3535  may measure the internal pressure of an infusate in an infusion line. In some embodiments, the occlusion sensor  3535  may be the downstream pressure sensor  513  described herein. In an example embodiment, the occlusion sensor  3535  may comprise a force sensor  3535 B, an amplifier  3535 A, a signal amplifier  3535 C and a buffer  3535 D. The buffer  3535 D may protect the RTP  3500  from over-voltages due to high forces generated from pressures applied to the force sensor  3535 B. In alternative embodiments, the occlusion sensor  3535  may differ. 
     The watch dog circuit  3460  is shown in  FIG.  59 D . The watch dog circuit  3460  may enabled by an I2C command from the RTP  3500 . The watch dog circuit  3460  may signal an error and disable the motor controller  3430  (e.g., via chip  3434 ) if it does not receive a signal from the RTP  3500  at a specified frequency. The watch dog circuit  3460  may signal the user via an audible alarm. The audible alarm may be issued via an amplifier  3464  and/or backup speaker  3468 . The watch dog circuit  3460  may signal the user with visual alarm LEDs  3750  (shown in  FIG.  59 F ) if an abnormal condition is detected. In one embodiment, the RTP  3500  must “clear” the watchdog  3460  between 10 ms and 200 ms after the watch dog circuit&#39;s  3460  last clear. In some embodiments, the watch dog circuit  3460  is comprised of a window watchdog  3460 A, a logic circuit  3460 B (which may include one or more flip-flop switches) and an IO expander  3460 C that communicates with the RTP  3500  over an I2C bus. A backup battery  3450  (see  FIG.  59 C ) may provide power to the watch dog circuit  3460  and backup speaker system (which may comprise an audio amplifier  3464 , and a backup speaker  3468 ) in case the main battery  3420  (see  FIG.  59 E ) fails. The backup battery  3450  may provide power to the RTP  3500  and UIP  3600  to maintain the internal timekeeping, which may be especially desirable when the main battery  3420  is changed. The RTP  3500  may also monitor the voltage of the backup battery  3450  with a switch such as the “FAIRCHILD FPF1005 LOAD SWITCH”  3452  shown in  FIG.  59 C . 
     The RTP  3500  directly controls the speed and position of the motor  1200 . The motor  1200  may be any of a number of types of motors  1200  including a brushed DC motor, a stepper motor, or a brushless DC motor. In the embodiment illustrated in  FIGS.  59 B- 59 J , the syringe pump  500  is driven by a brushless direct current (BLDC) servo motor  1200 . In one example embodiment, the RTP  3500  receives signals from the hall-sensors  3436  of a brushless DC motor  1200  and does the calculations to commutate power to the winding of the motor  1200  to achieve a desired speed or position. The commutation signals may be sent to the motor controller  3430  which selectively connects the windings to the motor power supply  3434 . The motor  1200  may be monitored for damaging or dangerous operation via current sensors  3432  and a temperature sensor  1200 A. 
     The signals from the hall sensors  3436  may be supplied to both the RTP  3500  and to an encoder  1202 . In one embodiment, three hall signals are generated. Any two of the three hall signals may be sent to the encoder  1202 . The encoder  1202  may use these signals to provide a position signal to the UIP  3600 . The UIP  3600  estimates the total volume of fluid dispensed by the syringe pump  500  from the position signal of the encoder  1202 . In some specific embodiments, each syringe pump  500  may be calibrated during assembly to establish the nominal volume/stroke that may be stored in memory. The UIP  3600  estimated volume may then be compared at regular intervals to the volume which would be expected for a commanded therapy. In some embodiments, the interval between comparisons may be shorter for different infusates, for example short half-life infusates. The therapy may specify, among other parameters, a flow rate, duration, and a total volume to be infused (VTBI). In any case, the expected volume based on the programmed therapy at a given time during that therapy may be calculated and compared to the volume estimated by the UIP  3600 . The UIP  3600  may signal an alert or alarm if the difference between UIP  3600  estimated volume and the expected volume for therapy is outside of a predefined threshold. The UIP  3600  may signal an alarm if the difference between UIP  3600  estimated volume and the expected volume for the therapy is outside another predefined threshold. 
     The UIP  3600  may also compare the estimated volume to the volume reported by the RTP  3500 . The UIP  3600  may signal an alert if the difference between UIP  3600  estimated volume and the RTP  3500  reported volume is outside a predefined threshold. The UIP  3600  may signal an alarm if the difference between UIP  3600  estimated volume and the RTP  3500  reported volume is outside a second threshold. 
     In some embodiments, the UIP  3600  may compare the RTP  3500  reported volume to the expected volume for the therapy and signal an alert if the two values differ by more than a predefined threshold. The UIP  3600  may signal an alarm if the difference between the RTP  3500  reported volume and the expected volume for the therapy differ by more than another predefined threshold. The values of the alert and alarm thresholds may be different for comparisons between different sets of volumes. The thresholds may be stored memory. The thresholds may vary depending on a number of different parameters, such as, but not limited to, medication, medication concentration, clinical usage, patient, therapy type, or location. The thresholds may be predefined in a DERS (Drug Error Reduction System) database and downloaded from the device gateway server. 
     An RFID tag  3670  (see  FIG.  59 E ) may be connected by an I2C bus to the UIP  3600  and to a near field antenna  3955 . The RFID tag  3670  may be used by med-techs or other users or personnel to acquire or store information when the syringe pump  500  is in an unpowered state. The UIP  3600  may store service logs, error codes, etc. in the RFID tag  3670 . The service logs, error codes, etc. may be accessible by an RFID reader. A med-tech, for example, could inspect unpowered syringe pumps  500  in storage or evaluate non-functioning syringe pumps  500  by using an RFID reader to interrogate the RFID tag  3670 . In another example, a med-tech or other personnel may perform service on the syringe pump  500  and store any related service information in the RFID tag  3670 . The UIP  3600  may then cull the latest service information from the RFID tag  3670  and store it in memory  3605  (see  FIG.  59 E ). 
     The main battery  3420  may supply all the power to the syringe pump  500 . The main battery  3420  may be connected via a system power gating element  3424  to the motor power supply  3434 . All of the sensors and processors described herein may be powered by one of the several voltage regulators  3428  (see  FIG.  59 E ). The main battery  3420  may be charged from AC power via a battery charger  3422  and a AC/DC converter  3426 . The UIP  3600  be connected to one or more memory chips  3605 . 
     The UIP  3600  controls the main audio system which comprises a main speaker  3615  and the audio-chips  3610  (audio codec),  3612  (audio amplifier) (see  FIG.  59 E ). The main audio system may be capable of producing a range of sounds indicating, for example, alerts and alarms. The audio system may also provide confirmatory sounds to facilitate and improve user interaction with the display  514  and/or data input means  516  (see  FIG.  28   ). The main audio system may include a microphone  3617  which may be used to confirm the operation of the main speaker  3615  as well as the backup speaker  3468 . The main audio system may produce one or more tones, modulation sequences and/or patterns of sound and the audio codec chip  3610  may compare the signal received from the microphone  3617  to the signal sent to the main speaker  3615 . The use of one or more tones and comparison of signals may allow the system to confirm main speaker  3615  function independently of any ambient noise. Alternatively the UIP  3600  or the audio codec  3610  may confirm that the microphone  3617  produces a signal at the same time a signal is sent to the speaker amplifier  3612 . 
     The UIP  3600  may provide a range of different wireless signals for different uses. The UIP  3600  may communicate with the hospital wireless network via a dual band WiFi using chips  3621 ,  3620 , and  3622  and antennas  3720  and  3722 . The spatially diverse dual antenna may be desirable because in may be capable of overcoming dead spots within a room due to multiple paths and cancellation. A hospital device gateway may communicate DERS, CQI (Continuous Quality Improvement), prescriptions, patient data, etc. to the syringe pump  500  via the WiFi system. 
     The Bluetooth system using, the same chips  3621 ,  3620  and  3622  (see  FIG.  59 E ) and antennas  3720  and  3722  (see  FIG.  59 F ), may provide a convenient method to connect auxiliaries to the syringe pump  500  that may include pulse-oximeters, blood pressure readers, bar-code readers, tablets, phones, etc. The Bluetooth may include version 4.0 to allow low power auxiliaries which may communicate with the syringe pump  500  periodically such as, for example, a continuous glucose meter that sends an update once a minute. 
     The NFC system may be comprised of an NFC controller  3624  (see  FIG.  59 E ) and an antenna  3724  (see  FIG.  59 F ). The NFC controller  3624  may also be referred to as an RFID reader. The NFC system may be used to read RFID chips identifying drugs or other inventory information. The RFID chips may also be used to identify patients and caregivers. The NFC controller  3624  may also interact with a similar RFID reader on, for example, a phone or tablet computer to input information including prescriptions, bar-code information, patient, care-giver identities, etc. The NFC controller  3624  may also provide information to phone or tablet computers such as the syringe pump  500  history or service conditions. The RFID antennas  3720  and  3722  and/or NFC antenna  3724  may preferably be located around or near the display  514  screen, so all interaction with the syringe pump  500  occurs on or near the display  514  whether reading an RFID chip or interacting with a touch screen display  514  or other data input means  516  near the display. 
     The UIP  3600  may include a medical grade connector  3665  (see  FIG.  59 I ) so that other medical devices may plug into the syringe pump  500  and provide additional capabilities. The connector  3665  may implement a USB interface. 
     The display  514  may include the RFID antennas  3720 ,  3722 , the NFC antenna  3724 , the display  514 , the touch screen  3735 , an LCD backlight driver  3727 , a light sensor  3740 , a 16 channel LED driver  3745 , LED indicator lights  3747  and  3749 , and three buttons  3760 ,  3765 ,  3767 . The buttons may collectively be referred to herein as data input means  516 . The display  514  may include a backlight  3727  and an ambient light sensor  3740  to allow the display  514  brightness to automatically respond and/or adjust to ambient light. The first button  3760  may be the “Power” button, while another button  3765  may be an infusion stop button. These buttons  3760 ,  3765  may not provide direct control of the syringe pump  500 , but rather provide a signal to the UIP  3600  to either initiate or terminate infusion. The third button  3767  may silence an alarm or alert at the main speaker  3615  and at the backup speaker  3468 . Silencing the alarm or alert will not clear the fault, but may end the audible alarm or alert. The electrical system  4000  described above, or an alternative embodiment of the electrical system  4000  described above may be used with the syringe pump  500  described herein. 
       FIG.  60    shows an exemplary embodiment of the syringe pump assembly  501 . In  FIG.  60    the syringe pump assembly housing  503  which is shown in  FIG.  59 A  has been removed. As shown, a syringe  504  is in place on the syringe pump assembly  501  and is being held by the syringe barrel holder  518 . The sliding block assembly  800  is located approximately in the middle of the axial length of the lead screw  850 . Since the plunger tube  524  connects the sliding block assembly  800  to the plunger head assembly  522 , the plunger head assembly  522  is at location where it has caused the syringe plunger  544  to dispense about half of the content of the syringe  504 . 
     As shown, a motor  1200  is operatively coupled to the gearbox  940  in  FIG.  60   . Rotation of the motor  1200  is transmitted through the gearbox  940  to drive the rotation of the lead screw  850 . As described above, since the upper plunger clamp jaw  526  and lower plunger clamp jaw  528  are closed on the plunger flange  548 , the half nut  830  is engaged with the lead screw  850 . Consequently, in the embodiment depicted in  FIG.  60    as the motor  1200  causes the lead screw  850  to rotate, the sliding block assembly  800  will travel along the axial length of the lead screw  850 . As motor  1200  rotates the lead screw  850  such that the sliding block assembly  800  moves toward the left of the page (relative to  FIG.  60   ), the sliding block assembly&#39;s  800  movement will additionally cause the plunger tube  524  and plunger head assembly  522  to displace toward the left of the page. As the plunger head assembly  522  displaces toward the left of the page, the syringe plunger  544  is advanced into the syringe barrel  540  of the syringe  504  and the contents of the syringe are dispensed. 
     The motor  1200  may be any suitable motor  1200 . As shown in  FIG.  59 A  a small profile pancake motor  1200  may be used to drive the rotation of the lead screw  850 . The embodiment shown in  FIG.  60    does not use a pancake motor  1200 . The motor  1200  shown in  FIG.  60    is an alternative motor that also has hall sensors  3436  to inform commutation of the motor  1200 . As shown in  FIG.  60   , the motor  1200  may comprise a magnet on the rotor that is detected by a rotary encoder  1202 . The rotary encoder  1202  may be any of a variety of suitable rotary encoders  1202  such as the AS5055 by Austrianmicrosystems of Austria. In some embodiments, the rotary encoder  1202  may be a magnetic. The rotary encoder  1202  may be used to monitor rotation of the lead screw  850 . Information from the rotary encoder  1202  may be used to determine when a given amount of the contents of the syringe  504  has been dispensed. Additionally, the rotary encoder  1202  may be used to determine the location of the sliding block assembly  800  on the lead screw  850 . 
     To ensure that the rotary encoder  1202  is functioning properly, a self test may be preformed. The motor  1200  may be powered to move the sliding block assembly  800  back and forth along a distance of the lead screw  850 . Measurements from the rotary encoder  1202  may be confirmed against the measurements of the sliding block assembly linear position sensor  1050 . The same self test may also be used to confirm the hall sensors  3436  of the brushless motor  1200  are functioning properly. 
     As previously indicated, the syringe pump  500  includes a number of sensor redundancies. This allows the syringe pump  500  to function in a fail operative mode if deemed appropriate. In the event that the rotary encoder  1202  fails, the hall sensors  3436  of the brushless motor  1200  may be used in a fail operative mode to measure the dispensation of syringe  504  contents via the rotation of the motor  1200  and provide a feed-back signal for the motor controller. Alternatively the location of the sliding block assembly  800  along the lead screw  850  may be used in a fail operative mode to measure the dispensation of syringe  504  contents via position of the sliding block assembly  800  and provide a feed-back signal for the controller. Alternatively the sliding block assembly linear position sensor  1050 , may be used to monitor the dispensation of syringe  504  contents via position of the sliding block assembly  800  on the lead screw and to provide a feed-back signal for the controller. In some embodiments, the motor hall sensors  3436  or the linear sliding block assembly linear position sensor  1050  may be used to monitor the position of the sliding block assembly  800  on the lead screw  850  to avoid driving the sliding block assembly  800  against the pump frame. 
     In the event of a failure of the rotary encoder  1202 , the syringe pump  500  may finish a therapy if a therapy is in progress and disallow a user from commencing another therapy until the syringe pump  500  has been serviced. In the event of a failure of the rotary encoder  1202  the syringe pump  500  may alarm. In some embodiments, if the rotary encoder  1202  fails and the motor  1200  is being used to deliver at a low flow rate, the syringe pump  500  may not finish the therapy. If such a failure occurs, the syringe pump  500  may alarm and the syringe pump  500  may finish a therapy if a therapy is in progress and disallow a user from commencing another therapy until the syringe pump  500  has been serviced. The controller of the syringe pump  500  may base its decision to continue a therapy based on the risk level of the infusate being delivered to a patient. If the risk of non-delivery to a user is higher than the risk of delivering with reduced accuracy, the syringe pump  500  will deliver in a fail operative mode. 
       FIG.  61    shows a small volume syringe  504  in place on the syringe pump assembly  501 . Only a small portion of the syringe pump assembly  501  is visible in  FIG.  61   . As shown, the syringe  504  is held in place against the syringe seat  506  by the syringe barrel holder  518 . The syringe barrel flange  542  is clipped in place against the syringe pump assembly  501  by the barrel flange clip  520 . The barrel flange clip  520  is slightly offset from the rest of the syringe pump assembly  501  such that there is small gap between the syringe pump assembly  501  and the barrel flange clip  520 . When a user places the syringe  504  on the syringe seat  506 , the user may also place the syringe barrel flange  542  into the small gap between the syringe pump assembly  501  and the barrel flange clip  520 . 
     As shown in  FIG.  61   , the outward edge of the barrel flange clip  520  bows out toward the left of the page. This helps to guide the syringe barrel flange  542  into the gap between the barrel flange clip  520  and the syringe pump assembly  501 . The barrel flange clip  520  may also include one or a number of cutouts  521 . In the example embodiment in  FIG.  61   , the cutouts  521  of the barrel flange clip comprise two valleys. The first valley is recessed into the center span of the outward edge of the barrel flange clip  520 . The second valley, which is recessed into the lowest span of the first valley, is considerably smaller and shallower. In other embodiments, the cutouts  521  may be different in shape, size, etc. The plunger  544  of the small syringe  504  in  FIG.  61    is located entirely within the cutouts  521  in the barrel flange clip  520 . Without the cutouts  521  in the barrel flange clip  520 , the plunger  544  of the syringe  504  would contact the outward edge of the barrel flange clip  520  and obstruct user placement of the syringe barrel flange  542  into the gap between the barrel flange clip  520  and the syringe pump assembly  501 . 
       FIG.  62    shows a large volume syringe  504  in place on the syringe pump assembly  501 . Only a small portion of the syringe pump assembly  501  is visible in  FIG.  62   . As shown, the syringe  504  is held in place against the syringe seat  506  by the syringe barrel holder  518 . The syringe barrel flange  542  is clipped in place against the syringe pump assembly  501  by the barrel flange clip  520 . The barrel flange clip  520  is slightly offset from the rest of the syringe pump assembly  501  such that there is small gap between the syringe pump assembly  501  and the barrel flange clip  520 . When a user places the syringe  504  on the syringe seat  506 , the user may also place the syringe barrel flange  542  into the small gap between the syringe pump assembly  501  and the barrel flange clip  520 . 
     As shown in  FIG.  62   , the barrel flange clip  520  may also include a roughly semi-circular depression  519  which thins the barrel flange clip  520 . The roughly semi-circular depression  519  may be included to accommodate the plunger flange  548  of a syringe  504 . In embodiments where the barrel flange clip  520  includes the roughly semi-circular depression  519 , the plunger  544  may be advanced a distance equal to the depth of the semi-circular depression  519  further into the syringe barrel  540 . This is desirable because it allows more of the contents of the syringe  504  to be administered to a patient. 
     As shown in  FIG.  62   , the barrel flange clip  520  may include a barrel flange sensor  700 . The barrel flange sensor  700  may be comprised of any number of suitable sensors. In some embodiments, the barrel flange sensor  700  may function in a binary (yes/no) manner to indicate whether a syringe barrel flange  542  is clipped by the barrel flange clip  520 . In some embodiments, the barrel flange sensor  700  may comprise a micro switch which is actuated as the syringe barrel flange  542  is placed in the gap between the syringe pump assembly  501  and the barrel flange clip  520 . In other embodiments, the barrel flange sensor  700  may comprise a photosensor. Insertion of the syringe barrel flange  542  into the gap between the syringe pump assembly and the barrel flange clip  520  may block a light source for the barrel flange sensor  700  in embodiments where the barrel flange sensor  700  comprises a photosensor. In such embodiments, the barrel flange sensor  700  may indicate a syringe barrel flange  542  is clipped in place when the light source is blocked. In other embodiments, the barrel flange sensor  700  may be comprised of a different sensor than those described above. The barrel flange sensor  700  may be caused generate an alarm in the event that other sensors, such as the plunger clamp jaws position sensor  588  (mentioned above) or the syringe barrel holder linear position sensor  1540  (see  FIG.  66   ), detect a syringe  504  in place of the syringe pump assembly  501  when the barrel flange sensor  700  does not detect a syringe  504  in place and an initiation of a therapy is attempted. 
       FIG.  63    shows an embodiment of part of the syringe barrel holder  518 . As shown in  FIG.  63   , the syringe barrel holder  518  comprises a syringe barrel holder housing  1500 . In the example embodiment, the syringe barrel holder housing  1500  has a planate base plate  1502 . The planate base plate  1502  comprises a syringe barrel holder housing member  1504  at its left end (relative to  FIG.  63   ). The syringe barrel holder housing member  1504  projects off the bottom of the syringe barrel holder housing  1500  at an angle substantially perpendicular to the plane of the planate base plate  1502 . The syringe barrel holder housing member  1504  may extend substantially perpendicularly from the entire length of the left end of the planate base plate  1502 . In some embodiments, the syringe barrel holder housing member  1504  may take the form of a rectangular prism. In the example embodiment shown in  FIG.  63   , the syringe barrel holder housing member  1504  has a form close to a rectangular prism, but the bottom edges of the syringe barrel holder housing member  1504  have been rounded off. 
     As shown in  FIG.  63   , the planate base plate  1502  may have a base plate slot  1506  cut into it. The base plate slot  1506  may be cut into the planate base plate  1502  from the left edge (relative to  FIG.  63   ) of the planate base plate  1502 . The base plate slot  1506  may extend into the planate base plate  1502  at an angle substantially perpendicular to the left edge of the planate base plate  1502 . The base plate slot does not extend all the way across the planate base plate  1502  and stops short of the right edge. 
     On the flanks of the base plate slot  1506 , one or more syringe barrel holder housing posts  1508  may be disposed. In the example embodiment shown in  FIG.  63   , four syringe barrel holder housing posts  1508  flank the base plate slot  1506 . The four syringe barrel holder housing posts  1508  are divided up such that there are two syringe barrel holder housing posts  1508  on each flank of the base plate slot  1506 . The syringe barrel holder housing posts  1508  extend substantially perpendicularly from the top face of the planate base plate  1502  toward the top of the page. The syringe barrel holder housing posts  1508  in the example embodiment shown in  FIG.  63    have the form of rectangular prisms. In alternate embodiment, the syringe barrel housing posts  1508  may be cylindrical or have any other suitable shape. 
     The planate base plate  1502  may also comprise one or more syringe barrel holder housing bodies  1510 . In the example embodiment shown in  FIG.  63   , there are two syringe barrel holder housing bodies  1510 . The syringe barrel holder housing bodies  1510  projects perpendicularly from the top of the planate base plate  1502  toward the top of the page. The syringe barrel holder housing bodies  1510  have the form of rectangular prisms. As shown, the syringe barrel holder housing bodies  1510  may overhang the right edge of the planate base plate  1502 . The syringe barrel holder housing bodies  1510  may comprise one side which is flush with the front edge or back edge (relative to  FIG.  63   ) of the planate base plate  1502 . 
     In some embodiments, the syringe barrel holder housing  1500  may comprise a “T” shaped member  1512 . In the example embodiment shown in  FIG.  63   , the stem portion of the “T” shaped member extends toward the right of the page from the right edge of the planate base plate  1502 . The “T” shaped member  1512  may extend on a plane substantially parallel to the plane of the planate base plate  1502 . In the example embodiment, the “T” shaped member  1512  projects from roughly the center of the right edge of the planate base plate  1502 . The cross portion of the “T” shaped member  1512  is roughly parallel with the right edge of the planate base plate  1502 . The cross portion of the “T” shaped member  1512  overhangs the stem equally on both sides of the stem. 
     As shown in  FIG.  63   , syringe barrel holder guide rails  1514  may extend substantially perpendicularly from the right face of the syringe barrel holder housing member  1504  and into the left faces of the overhanging cross portions of the “T” shaped member  1512 . The syringe barrel holder guide rails  1514  may extend substantially parallel to each other. In the example embodiment shown in  FIG.  63   , a coil spring  1516  surrounds each syringe barrel holder guide rail  1514 . One end of each coil spring  1516  may abut the left face of the cross portion of the “T” shaped member  1512 . In the example embodiment, the coil springs  1516  are compression springs. In alternate embodiments, other bias members or bias member arrangements may be utilized. 
     As shown in the embodiment in  FIG.  63   , a syringe barrel holder printed circuit board (PCB)  1518  may be held in place on the syringe barrel holder housing posts  1508 . The syringe barrel holder PCB may be coupled in place on the syringe barrel holder housing posts  1508  by any suitable means. In the example embodiment shown in  FIG.  63   , the syringe barrel holder PCB is coupled to the syringe barrel holder housing posts  1508  by screws. 
       FIG.  64    shows an embodiment of part of the syringe barrel holder  518 . In the embodiment shown in  FIG.  64   , the syringe barrel holder PCB  1518  shown in  FIG.  63    has been removed. As shown in  FIG.  64    the base plate slot  1506  may extend down into the syringe barrel holder housing member  1504 . The base plate slot  1506  may comprise a base plate notch catch  1520 . In embodiments where the base plate slot  1506  comprises a base plate notch catch  1520  the base plate notch catch  1520  may be a void in the planate base plate  1502  of the syringe barrel holder housing  1500 . In the example embodiment, the void of the base plate notch catch  1520  extends out from the right end section of the base plate slot  1506  at an angle substantially perpendicular to the side of the base plate slot  1506 . 
     The syringe barrel holder  518  may also comprise a syringe barrel holder arm rod  1522 . In the example embodiment shown in  FIG.  64   , the syringe barrel holder arm rod  1522  extends through an appropriately sized bore in the approximate center of the “T” shaped member  1512  (only the stem of the “T” shaped member  1512  is visible in  FIG.  64   ). The syringe barrel holder arm rod  1522  may be movably coupled to the syringe barrel holder  518 . In embodiments where the syringe barrel holder arm rod  1522  is movably coupled to the syringe barrel holder  518 , the syringe barrel holder arm rod  1522  may move along a direction parallel to the edges of the stem of the “T” shaped member  1512 . In the example embodiment in  FIG.  64   , the syringe barrel holder arm rod  1522  is able to slide along the bore in the “T” shaped member  1512  and uses the bore in the “T” shaped member  1512  as a linear motion bearing. In the example embodiment, the syringe barrel holder arm rod  1522  is longer than the length of the stem of the “T” shaped member  1512 . 
     As shown in  FIG.  64   , one end of the syringe barrel holder arm rod  1522  may comprise a collar which may be a “U” shaped member  1524 . The “U” shaped member  1524  may be fixedly coupled to the syringe barrel holder arm rod  1522 . In the example embodiment, the bottom span of the “U” shaped member  1524  is thicker than the uprights of the “U” shaped member  1524 . The thick bottom span of the “U” shaped member  1524  comprises a hole which allows the “U” shaped member  1524  to be coupled onto the syringe barrel holder arm rod  1522  when the syringe barrel holder  518  is assembled. In the example embodiment, the uprights of the “U” shaped member  1524  extend up through the base plate slot  1506  and are substantially flush with the plane of the top face of the planate base plate  1502 . The uprights of the “U” shaped member  1524  may constrain the syringe barrel holder arm rod  1522  from rotation since any rotation is blocked by the uprights of the “U” shaped member  1524  abutting the edges of the base plate slot  1506 . 
     In the example embodiment shown in  FIG.  64   , the syringe barrel holder  518  comprises a bias bar  1526 . The bias bar  1526  in the example embodiment, is roughly rectangular in shape. The bias bar  1526  may comprise two holes which allow the bias bar  1526  to be placed on the syringe barrel holder guide rails  1514 . The bias bar  1526  may be capable of guided movement along the axial direction of the syringe barrel holder guide rails  1514 . In the example embodiment, the end of the coil springs  1516  on the syringe barrel holder guide rails  1514  not abutting the cross portion of the “T” shaped member  1512  abuts the front face of the bias bar  1526 . In the example embodiment shown in  FIG.  64    the maximum distance between the face of the bias bar  1526  which one end of the coil springs  1516  abut and the face of the “T” shaped member  1512  which the other end of the coil springs  1516  abut is shorter than the uncompressed length of the coil springs  1516 . This ensures that the bias bar  1526  will always be biased toward the position shown in  FIG.  64   . 
     As shown in  FIG.  64   , the bias bar  1526  may comprise a cutout which allows the bias bar  1526  to fit around at least part of the syringe barrel holder arm rod  1522 . The “U” shaped member  1524  may abut the face of the bias bar  1526  opposite the side which the coil springs  1516  abut. In such embodiments, the action of the coil springs  1516  biasing the bias bar  1526  toward the position depicted in  FIG.  64   , additionally biases the syringe barrel holder arm rod  1522  to the position depicted in  FIG.  64   . 
     In the example embodiment in  FIG.  65   , the syringe barrel holder  518  is shown in the fully open position. To move the syringe barrel holder  518  to the open fully open position, a user may grasp the syringe barrel holder grip  1528 . In the example embodiment shown in  FIG.  65   , the syringe barrel holder grip  1528  is a projection which extends from the barrel contacting structure  1530  of the syringe barrel holder  518  which is fixedly coupled to the syringe barrel holder arm rod  1522 . After grasping the syringe barrel holder grip  1528 , a user may pull the syringe barrel holder arm rod  1522  away from the syringe barrel holder housing  1500 . This action causes the “U” shaped member  1524  which is fixedly attached to the syringe barrel holder arm rod  1522  to move as well. Since the “U” shaped member  1524  may not pass through the bias bar  1526 , the bias bar  1526  moves with the “U” shaped member  1524  and syringe barrel holder arm rod  1522 . As the bias bar  1526  moves along the syringe barrel holder guide rails  1514 , the coil springs become compressed such that if a user releases the syringe barrel holder grip  1528 , the restoring force of the coil springs will automatically return the bias bar  1526 , “U” shaped member  1524 , and syringe barrel holder arm rod  1522  to the positions shown in  FIG.  64   . 
     To hold the syringe barrel holder  518  in the fully open position against the bias of the coil springs  1516 , the syringe barrel holder  518  may be locked in the open position. As shown, the syringe barrel holder  518  may be locked in the open position by rotating the syringe barrel holder arm rod  1522  and all parts fixedly coupled to the syringe barrel holder arm rod  1522 . In  FIG.  65   , the syringe barrel holder arm rod  1522  has been rotated substantially 90° such that the bottom span of the “U” shaped member  1524  is disposed within the base plate notch catch  1520 . When the “U” shaped member is rotated into the base plate notch catch  1520 , the restoring force of the coil springs  1516  is not capable of returning the syringe barrel holder  518  to the position shown in  FIG.  64    because travel of the “U” shaped member  1524  is blocked by the base plate notch catch  1520 . 
     After rotating the syringe barrel holder arm rod  1522  such that the syringe barrel holder  518  is locked in the open position, a user may release the syringe barrel holder grip  1528  to grasp a syringe  504  and put it in place. As mentioned above, the syringe barrel holder  518  will remain in the fully open position. A user may then rotate the syringe barrel holder arm rod  1522  90° back to its original, unlocked position and allow the syringe barrel holder  518  to hold the syringe  504  in place. 
     Referring back to  FIG.  31    the syringe barrel holder  518  is shown fully open and rotated into the locked position. In the fully open position, the syringe barrel contacting structure  1530  and syringe barrel holder grip  1528  are at their furthest possible distance from the syringe seat  506  of the syringe pump assembly  501 . In some embodiments, this distance may be substantially larger than the diameter of the largest syringe  504  which may be accepted by the syringe pump  500 . In  FIG.  31   , a syringe  504  has been put in place against the syringe seat  506  while the syringe barrel holder  518  has be locked in the open position. In  FIG.  32   , the syringe barrel holder has been rotated out of the locked position and has been allowed to automatically adjust to the size of the syringe barrel  540 . As mentioned in the discussion of  FIG.  65   , this automatic adjustment is a result of the restoring force of the coil springs  1516  automatically pushing the bias bar  1526 , “U” shaped member  1524 , and the syringe barrel holder arm rod  1522  toward the position depicted in  FIG.  64   . 
     In  FIG.  66   , an example embodiment of the syringe barrel holder  518  is shown. In the embodiment depicted in  FIG.  66    the syringe barrel holder PCB  1518  is shown as transparent. The syringe barrel holder PCB  1518  may comprise one or a number of syringe barrel holder linear position sensors  1540 . In the example embodiment, there are three syringe barrel holder linear position sensors  1540 . The syringe barrel holder linear position sensors  1518  may be used to determine the size of the syringe  504  which the syringe barrel holder  518  is holding in place. 
     In some embodiments, there may only be a single syringe barrel holder linear position sensor  1540 . In such embodiments, the syringe barrel holder linear position sensor  1540  may be a linear potentiometer. In embodiments where the syringe barrel holder linear position sensor  1540  is a linear potentiometer, the syringe barrel holder linear position sensor  1540  may comprise a barrel sizing wiper  1542  which may slide across the resistive element of the potentiometer with movement of the syringe barrel holder arm rod  1522 . When a syringe  504  is held by the syringe barrel holder  518 , the size of the syringe  504  will determine the position of the barrel sizing wiper  1542  along the linear potentiometer type syringe barrel holder linear position sensor  1540 . Since the location of the wiper  1542  will vary the resistance measured by the linear position sensor  1540 , the resistance measured may be used to establish information (size, volume, brand, etc.) about the syringe  504  being used. In some embodiments, the resistance measurement may be referenced with a database or resistance measurements which would be expected from different syringes  504  to determine information about the syringe  504 . The resistance measurement may additionally be used to determine whether a syringe  504  is properly held by the syringe barrel holder  518 . For example, if the resistance measurement indicates that the syringe barrel holder  518  is in the fully open position (as it is in  FIG.  66   ), an alarm may be generated and a therapy may not be initiated. 
     In some embodiments, including the example embodiment shown in  FIG.  66   , the syringe barrel holder linear position sensors  1540  may be magnetic linear position sensors. Any suitable magnetic linear position sensor may be used for the syringe barrel holder linear position sensor  1540 . The syringe barrel holder linear position sensors  1540  may be the same type of sensors as the sliding block assembly linear position sensors  1050 . An example of a suitable magnetic linear position sensor is the “AS5410 Absolute Linear 3D Hall Encoder” available from Austriamicrosystems of Austria. The syringe barrel holder linear position sensors  1540  gather their positional data from a syringe barrel holder magnet  1544  placed at a suitable distance from the syringe barrel holder linear position sensors  1540 . In the example embodiment shown in  FIG.  66   , the syringe barrel holder magnet  1544  rests on the bottom span of the “U” shaped member  1524  between the two uprights of the “U” shaped member  1524 . The absolute location of the syringe barrel holder magnet may be measured by the syringe barrel holder linear position sensors  1540 . Since the measured absolute location of the syringe barrel holder magnet  1544  may vary depending on the syringe  504  being held by the syringe barrel holder  518 , the absolute location of the syringe barrel holder magnet  1544  can be used to determine specific information (for example, size, volume, brand, etc.) about the syringe  504  being held. In some embodiments, the absolute location of the syringe barrel holder magnet  1544  may be referenced with a database to determine information about the syringe  504  being utilized. In such embodiments, the database may be a database of absolute locations which would be expected with different syringes  504 . The absolute position measurement may also be used to determine whether a syringe  504  is correctly held in place by the syringe barrel holder  518 . For example, if the absolute position measurement indicates that the syringe barrel holder  518  is in the fully open position (as it is in  FIG.  66   ), an alarm may be generated and a therapy may not be initiated. 
     In some embodiments, the data gathered by the syringe barrel holder linear position sensor  1540  may be compared to data gathered by other sensors to make a more informed decision on the specific syringe  504  being used. For example, in embodiments where a plunger clamp jaws position sensor  588  may make a determination on the type of syringe  504  being used (see discussion of  FIG.  37   ) the data from the plunger clamp jaws position sensor  588  and linear position sensor  1540  may be compared. If the data gathered by the syringe barrel holder linear position sensor  1540  does not correlate with data gathered by other sensors, an alarm may be generated. 
     In some embodiments, data from the plunger clamp jaws position sensor  588  may be first referenced against a syringe  504  database to narrow down acceptable syringe barrel  540  measurements. In some embodiments, data from the syringe barrel holder linear position sensor may be referenced against a syringe  504  database to set a range of acceptable plunger flange  548  measurements. 
       FIG.  67    shows a basic example of part of an alternative linear position sensor. The part of the alternative linear position sensor in  FIG.  67    is a line stretcher  1600 . In the example embodiment, the line stretcher  1600  comprises a stationary portion and a moving portion. The stationary portion comprises an FR-4 PCB substrate  1602 . On the substrate  1602  there are two microstrips  1604 . As shown, the microstrips  1604  extend parallel to each other. The microstrips  1604  act as transmission lines for a signal at a known frequency. The microstrips  1604  do not allow the signal to propagate into the ambient environment. The width of the microstrips  1604  is chosen so that it is suitable for the desired impedance. In an example embodiment, the desired impedance is 50Ω. 
     The moving portion in the example embodiment comprises a moving portion FR-4 PCB substrate  1606 . As shown, the moving portion FR-4 PCB substrate comprises a moving portion microstrip  1608 . The moving portion microstrip  1608  may be substantially “U” shaped. The uprights of the “U” shaped moving portion microstrip  1608  extend parallel to each other and are spaced such that when the line stretcher  1600  is assembled they may contact the two microstips  1604  on the stationary portion. The moveable portion microstrips  1608  have a width chosen so that it is suitable for desired amount of impedance (50Ω in the example embodiment). The bottom span of the “U” shaped movable portion microstrip  1608  connects the two uprights of the “U” shaped movable portion microstrip  1608  and is substantially perpendicular to the two uprights. When fully assembled, the bottom span of the “U” shaped movable portion microstrip  1604  forms a bridge between the two microstrips  1604  on the stationary portion of the line stretcher  1600 . Any signal sent through one of the microstrips  1604  on the stationary portion may cross via the moving portion microstrip  1608  to the other microstrip  1604  on the stationary portion. By sliding the moving portion along the direction of extension of the stationary portion microstrips  1604  the signal must travel a greater or shorter distance before crossing from one stationary portion microstrip  1604  to the other. By manipulating the amount of travel of the signal, a user may predictably create a phase change of the signal. To reduce wear on the metal microstrips  1604  and  1608  a thin sheet of insulation  1609  may be placed between the microstrips  1604  and  1608 , creating a capacitive coupling. 
       FIG.  68    shows an example of the line stretcher  1600  being incorporated into a phase change detector  1610 . As shown, the phase change detector  1610  comprises a signal source shown as “RF SOURCE” in the example shown in  FIG.  68   . The source signal in the example shown in  FIG.  68    travels from the “RF SOURCE” to a “POWER SPLITTER”. The “POWER SPLITTER” splits the signal, keeping the two output signals in a constant phase relationship with one another. One of the signals travels directly to a “FREQUENCY MIXER”. The other signal is delayed before it is allowed to reach the “FREQUENCY MIXER”. In  FIG.  68   , the signal is delayed by the line stretcher  1600  (see  FIG.  67   ). Delaying the signal causes the delayed signal to be predictably out of phase with the non-delayed signal which travels directly to the “FREQUENCY MIXER”. The delayed signal travels from line stretcher  1600  to the “FREQUENCY MIXER”. In the example embodiment shown in  FIG.  68    the “FREQUENCY MIXER” is a double balanced frequency mixer. As is well known in the art, two identical frequency, constant-amplitude signals sent to a mixer will result in a DC output which is proportional to the phase difference between the two signals. 
       FIG.  69    depicts a slightly different embodiment of the phase change detector  1610 . In  FIG.  69    the delay means is not a line stretcher  1600  such as the one described in  FIG.  67   . The delay means is a variable open or short. As the object whose linear position is to be measured linearly displaces, the short or open&#39;s location on a transmission line may be caused to move proportionally. As shown, the signal travels through a “DIRECTIONAL COUPLER” which may be any suitable directional coupler. As one of the two signals the signal enters the “DIRECTIONAL COUPLER” from the “POWER SPLITTER” the signal is sent out of another port of the “DIRECTIONAL COUPLER to an open or short. The open or short causes the signal to reflect back to the port from which it traveled to reach the open or short. The signal reflected back into the port is then directed by the “DIRECTIONAL COUPLER” to travel into the “FREQUENCY MIXER”. The delay of the signal caused by the distance traveled to and from the point of reflection causes a phase shift in the signal. The amount of phase shift of the signal is dependent on the distance from the port from which the signal exits the “DIRECTIONAL COUPLER” to the open or short. This distance may be caused to change in consequence to movement of the object whose linear position is to be measured. The second signal output of the “POWER SPLITTER” travels directly to the “FREQUENCY MIXER”. As is well known in the art, two identical frequency, constant-amplitude signals sent to a mixer will result in a DC output which is proportional to the phase difference between the two signals. 
     As shown in  FIG.  70   , the “DIRECTIONAL COUPLER” may be replaced with another piece of equipment such as a circulator. The phase change detector  1610  in  FIG.  70    functions very similarly to the phase change detector  1610  in  FIG.  69   . One signal from the power splitter travels directly to the “FREQUENCY MIXER”. The other signal is delayed. The delay is caused in the same manner as described above. Instead of using a “DIRECTIONAL COUPLER”, however, a “CIRCULATOR” may be used to direct the signal. As the signal enters the “CIRCULATOR” at port  61  the signal is circulated to port  26 . The signal travels from port  26  to the short or open and is reflected back into port  26 . The reflected, phase shifted signal entering port  26  of the “CIRCULATOR” is circulated to port  36 . The signal exits port  36  and travels to the “FREQUENCY MIXER” As is well known in the art, two identical frequency, constant-amplitude signals sent to a mixer will result in a DC output which is proportional to the phase difference between the two signals. Since the phase difference is dependent on the distance of the short or open from port  26  of the “CIRCULATOR” and the distances varies in proportion to the location of the object whose linear location is to be found the DC output of the mixer may be used to determine the objects location. 
     In some embodiments, the phase change detector  1610  may be used to substitute for the syringe barrel holder linear position sensors  1540  (see  FIG.  66   ) or the sliding block magnetic linear position sensors  1054  (see  FIG.  57   ). In some embodiments, only one of the syringe barrel holder linear position sensors  1540  or the sliding block magnetic linear position sensors  1054  may be substituted for with the phase change detector  1610 . In some embodiments, a phase change detector  1610  may be used in conjunction with one or both the syringe barrel holder linear position sensors  1540  or the sliding block magnetic linear position sensors  1054  and function as a cross check or backup. 
     In embodiments where the sliding block assembly linear position sensor  1054  (see  FIG.  57   ) is substituted for with a phase change detector  1610 , the phase change detector  1610  may be used to detect the position of the sliding block assembly  800  along the lead screw  850  (see  FIG.  57   ). If the phase shift detector  1610  uses a line stretcher  1600  (see  FIG.  67   ) the moveable portion of the line stretcher  1600  may be caused to move along the stationary portion of the line stretcher  1600  with movement of the sliding block assembly  800  along the lead screw  850 . In turn this would cause the degree of phase change to reflect the position of the sliding block assembly  800  on the lead screw  850 . Consequently, the DC output voltage of the mixer (see  FIG.  68   ) may be used to determine the position of the sliding block assembly  800 . The positional data generated by the phase change detector  1610  may be used in the same manner as described above in relation to the prior discussion of sliding block assembly  800  linear position sensing. 
     In embodiments where the phase change detector  1610  uses a variable short or open (see  FIG.  69    and  FIG.  70   ), movement of the sliding block assembly  800  along the lead screw  850  may cause the short or open to change its location along the transmission line. In turn this would cause the degree of phase change to specify the position of the sliding block assembly  800  along the lead screw  850 . Consequently, the DC output voltage of the mixer (see  FIG.  69    and  FIG.  70   ) may be used to determine the position of the sliding block assembly  800 . 
     In embodiments where the syringe barrel holder linear position sensors  1540  (see  FIG.  66   ) is substituted for by the phase change detector  1610 , the phase change detector  1610  may be used to may be used to determine the size of the syringe  504  (see  FIG.  28   ). If the phase change detector  1610  uses a line stretcher  1600  (see  FIG.  67   ) the moveable portion of the line stretcher  1600  may be caused to move along the stationary portion of the line stretcher  1600  with movement of the syringe barrel holder arm rod  1522 . In turn this would cause the degree of phase change to reflect the position of the syringe barrel holder arm rod  1522 . Since the position of the syringe barrel holder arm rod  1522  is dependent upon various characteristics of the syringe  504 , the DC output voltage of the mixer (see  FIG.  68   ) may be used to determine the position of the of the syringe barrel holder arm rod  1522  and therefore a number of characteristics of the syringe  504 . 
     In embodiments where the phase change detector  1610  uses a variable short or open (see  FIG.  69    and  FIG.  70   ), movement of the syringe barrel holder arm rod  1522  may cause the short or open to change its location along a transmission line. In turn this would cause the degree of phase change to specify the position of the syringe barrel holder arm rod  1522 . Since the position of the syringe barrel holder arm rod  1522  is dependent upon various characteristics of the syringe  504 , the DC output voltage of the mixer (see  FIG.  69    and  FIG.  70   ) may be used to determine the position of the syringe barrel holder arm rod  1522  and therefore a number of characteristics of the syringe  504 . The positional data generated by the phase change detector  1610  may be used in the same manner as described above in relation to the prior discussion of syringe barrel holder linear position sensing. 
     An example embodiment of the graphic user interface (hereafter GUI)  3300  is shown in  FIG.  71   . The GUI  3300  enables a user to modify the way that an agent may be infused by the syringe pump  500  by customizing various programming options. Though the following discussion mostly details the use of the GUI  3300  with the syringe pump  500 , it should be appreciated that the GUI  3300  may be used with other pumps, including the other pumps mentioned in this specification. For example, the GUI  3300  may be used with the pump  201 ,  202 , or  203  (as shown in  FIG.  71   ) detailed in the discussion of  FIGS.  2 - 9   . For purposes of example, the GUI  3300  detailed as follows uses a screen  3204  which is a touch screen display  514  (see  FIG.  28   ) as a means of interaction with a user. In other embodiments, the means of interaction with a user may be different. For instance, alternate embodiments may comprise user depressible buttons or rotatable dials, audible commands, etc. In other embodiments, the screen  3204  may be any electronic visual display such as a, liquid crystal display, L.E.D. display, plasma display, etc. 
     As detailed in the preceding paragraph, the GUI  3300  is displayed on the display  514  of the syringe pump  500 . Each syringe pump  500  may have its own individual screen  3204 . In arrangements where there are multiple syringe pumps  500  or a syringe pump  500  and one or more other pumps, the GUI  3300  may be used to control multiple pumps. Only the master pump may require a screen  3204 . As shown in  FIG.  71   , the pump  203  is seated in a Z-frame  3207 . As shown, the GUI  3300  may display a number of interface fields  3250 . The interface fields  3250  may display various information about the pump  203 , infusion status, and/or the medication, etc. In some embodiments, the interface fields  3250  on the GUI  3300  may be touched, tapped, etc. to navigate to different menus, expand an interface field  3250 , input data, and the like. The interface fields  3250  displayed on the GUI  3300  may change from menu to menu. 
     The GUI  3300  may also have a number of virtual buttons. In the non-limiting example embodiment in  FIG.  71    the display has a virtual power button  3260 , a virtual start button  3262 , and a virtual stop button  3264 . The virtual power button  3260  may turn the syringe pump  500  on or off. The virtual start button  3262  may start an infusion. The virtual stop button  3264  may pause or stop an infusion. The virtual buttons may be activated by a user&#39;s touch, tap, double tap, or the like. Different menus of the GUI  3300  may comprise other virtual buttons. The virtual buttons may be skeuomorphic to make their functions more immediately understandable or recognizable. For example, the virtual stop button  3264  may resemble a stop sign as shown in  FIG.  71   . In alternate embodiments, the names, shapes, functions, number, etc. of the virtual buttons may differ. 
     As shown in the example embodiment in  FIG.  72   , the interface fields  3250  of the GUI  3300  (see  FIG.  71   ) may display a number of different programming parameter input fields. For the GUI  3300  to display the parameter input fields, a user may be required to navigate through one or a number of menus. Additionally, it may be necessary for the user to enter a password before the user may manipulate any of the parameter input fields. 
     In  FIG.  72   , a medication parameter input field  3302 , in container drug amount parameter input field  3304 , total volume in container parameter input field  3306 , concentration parameter input field  3308 , dose parameter input field  3310 , volume flow rate (hereafter abbreviated as rate) parameter input field  3312 , volume to be infused (hereafter VTBI) parameter input field  3314 , and time parameter input field  3316  are displayed. The parameters, number of parameters, names of the parameters, etc. may differ in alternate embodiments. In the example embodiment, the parameter input fields are graphically displayed boxes which are substantially rectangular with rounded corners. In other embodiments, the shape and size of the parameter input fields may differ. 
     In the example embodiment, the GUI  3300  is designed to be intuitive and flexible. A user may choose to populate a combination of parameter input fields which are simplest or most convenient for the user. In some embodiments, the parameter input fields left vacant by the user may be calculated automatically and displayed by the GUI  3300  as long as the vacant fields do not operate independently of populated parameter input fields and enough information can be gleaned from the populated fields to calculate the vacant field or fields. Throughout  FIGS.  72 - 76   , fields dependent upon on another are tied together by curved double-tipped arrows. 
     The medication parameter input field  3302  may be the parameter input field in which a user sets the type of infusate agent to be infused. In the example embodiment, the medication parameter input field  3302  has been populated and the infusate agent has been defined as “0.9% NORMAL SALINE”. As shown, after the specific infusate has been set, the GUI  3300  may populate the medication parameter input field  3302  by displaying the name of the specific infusate in the medication parameter input field  3302 . 
     To set the specific infusate agent to be infused, a user may touch the medication parameter input field  3302  on the GUI  3300 . In some embodiments, this may cull up a list of different possible infusates. The user may browse through the list until the desired infusate is located. In other embodiments, touching the in medication parameter input field  3302  may cull up a virtual keyboard. The user may then type the correct infusate on the virtual keyboard. In some embodiments, the user may only need to type only a few letters of the infusate on the virtual keyboard before the GUI  3300  displays a number of suggestions. For example, after typing “NORE” the GUI  3300  may suggest “NOREPINEPHRINE”. After locating the correct infusate, the user may be required to perform an action such as, but not limited to, tapping, double tapping, or touching and dragging the infusate. After the required action has been completed by the user, the infusate may be displayed by the GUI  3300  in the medication parameter input field  3302 . For another detailed description of another example means of infusate selection see  FIG.  82   . 
     In the example embodiment in  FIG.  72   , the parameter input fields have been arranged by a user to perform a volume based infusion (for instance mL, mL/hr, etc.). Consequentially, the in container drug amount parameter input field  3304  and total volume in container parameter input field  3306  have been left unpopulated. The concentration parameter input field  3308  and dose parameter input field  3310  have also been left unpopulated. In some embodiments, the in container drug amount parameter input field  3304 , total volume in container parameter input field  3306 , concentration parameter input field  3308 , and dose parameter input field  3310  may be locked, grayed out, or not displayed on the GUI  3300  when such an infusion has been selected. The in container drug amount parameter input field  3304 , total volume in container parameter input field  3306 , concentration parameter input field  3308 , and dose parameter input field  3310  will be further elaborated upon in subsequent paragraphs. 
     When the GUI  3300  is being used to program a volume base infusion, the rate parameter input field  3312 , VTBI parameter input field  3314 , and time parameter input field  3316  do not operate independent of one another. A user may only be required to define any two of the rate parameter input field  3312 , VTBI parameter input field  3314 , and time parameter input field  3316 . The two parameters defined by a user may be the most convenient parameters for a user to set. The parameter left vacant by the user may be calculated automatically and displayed by the GUI  3300 . For instance, if a user populates the rate parameter input field  3312  with a value of 125 mL/hr (as shown), and populates the VTBI parameter input field  3314  with a value of 1000 mL (as shown) the time parameter input field  3316  value may be calculated by dividing the value in the VTBI parameter input field  3314  by the value in the rate parameter input field  3312 . In the example embodiment shown in  FIG.  72   , the quotient of the above calculation, 8 hrs and 0 min, is correctly populated by the GUI  3300  into the time parameter input field  3316 . 
     For a user to populate the rate parameter input field  3312 , VTBI parameter input field  3314 , and time parameter input field  3316  the user may touch or tap the desired parameter input field on the GUI  3300 . In some embodiments, this may cull up a number pad with a range or number, such as 0-9 displayed as individual selectable virtual buttons. A user may be required to input the parameter by individually tapping, double tapping, touching and dragging, etc. the desired numbers. Once the desired value has been input by a user, a user may be required to tap, double tap, etc. a virtual “confirm”, “enter”, etc. button to populate the field. For another detailed description of another example way of defining numerical values see  FIG.  82   . 
       FIG.  73    shows a scenario in which the infusion parameters being programmed are not those of a volume based infusion. In  FIG.  73   , the infusion profile is that of a continuous volume/time dose rate. In the example embodiment shown in  FIG.  73   , all of the parameter input fields have been populated. As shown, the medication parameter input field  3302  on the GUI  3300  has been populated with “HEPARIN” as the defined infusate. As shown, the in container drug amount parameter input field  3304 , total volume in container input field  3306 , and concentration parameter input field  3308  are populated in  FIG.  73   . Additionally, since a volume/time infusion is being programmed the dose parameter input field  3310  shown in  FIG.  72    has been replaced with a dose rate parameter input field  3318 . 
     The in container drug amount parameter input field  3304  is a two part field in the example embodiment shown in  FIG.  73   . In the example embodiment in  FIG.  73    the left field of the in container drug amount parameter input field  3304  is a field which may be populated with a numeric value. The numeric value may defined by the user in the same manner as a user may define values in the rate parameter input field  3312 , VTBI parameter input field  3314 , and time parameter input field  3316 . In the example embodiment shown in  FIG.  73   , the numeric value displayed by the GUI  3300  in the in left field of the in container drug amount parameter input field  3304  is “25,000”. 
     The parameter defined by the right field of the in container drug amount parameter input field  3304  is the unit of measure. To define the right of the in container drug amount parameter input field  3304 , a user may touch the in container drug amount parameter input field  3304  on the GUI  3300 . In some embodiments, this may cull up a list of acceptable possible units of measure. In such embodiments, the desired unit of measure may be defined by a user in the same manner as a user may define the correct infusate. In other embodiments, touching the in container drug amount parameter input field  3304  may cull up a virtual keyboard. The user may then type the correct unit of measure on the virtual keyboard. In some embodiments the user may be required to tap, double tap, etc. a virtual “confirm”, “enter”, etc. button to populate the left field of the in container drug amount parameter input field  3304 . 
     The total volume in container parameter input field  3306  may be populated by a numeric value which defines the total volume of a container. In some embodiments, the GUI  3300  may automatically populate the total volume in container parameter input field  3306  based on data generated by one or more sensors. In other embodiments, the total volume in container parameter input field  3306  may be manually input by a user. The numeric value may defined by the user in the same manner as a user may define values in the rate parameter input field  3312 , VTBI parameter input field  3314 , and time parameter input field  3316 . In the example embodiment shown in  FIG.  73    the total volume in container parameter input field  3306  has been populated with the value “250” mL. The total volume in container parameter input field  3306  may be restricted to a unit of measure such as mL as shown. 
     The concentration parameter input field  3308  is a two part field similar to the in container drug amount parameter input field  3304 . In the example embodiment in  FIG.  73    the left field of the concentration parameter input field  3308  is a field which may be populated with a numeric value. The numeric value may defined by the user in the same manner as a user may define values in the rate parameter input field  3312 , VTBI parameter input field  3314 , and time parameter input field  3316 . In the example embodiment shown in  FIG.  73   , the numeric value displayed by the GUI  3300  in the in left field of the concentration parameter input field  3308  is “100”. 
     The parameter defined by the right field of the concentration parameter input field  3308  is a unit of measure/volume. To define the right field of the concentration parameter input field  3308 , a user may touch the concentration parameter input field  3308  on the GUI  3300 . In some embodiments, this may cull up a list of acceptable possible units of measure. In such embodiments, the desired unit of measure may be defined by a user in the same manner as a user may define the correct infusate. In other embodiments, touching the concentration parameter input field  3308  may cull up a virtual keyboard. The user may then type the correct unit of measure on the virtual keyboard. In some embodiments the user may be required to tap, double tap, etc. a virtual “confirm”, “enter”, etc. button to store the selection and move on to a list of acceptable volume measurements. The desired volume measurement may be defined by a user in the same manner as a user may define the correct infusate. In the example embodiment shown in  FIG.  73    the right field of the concentration parameter input field  3308  is populated with the unit of measure/volume “UNITS/mL”. 
     The in container drug amount parameter input field  3304 , total volume in container input field  3306 , and concentration parameter input field  3308  are not independent of one another. As such, a user may only be required to define any two of the in container drug amount parameter input field  3304 , total volume in container input field  3306 , and concentration parameter input field  3308 . For instance, if a user were to populate the concentration parameter input field  3308  and the total volume in container parameter input field  3306 , the in container drug amount parameter input field may be automatically calculated and populated on the GUI  3300 . 
     Since the GUI  3300  in  FIG.  73    is being programmed for a continuous volume/time dose, the dose rate parameter input field  3318  has been populated. The user may define the rate at which the infusate is infused by populating the dose rate parameter input field  3318 . In the example embodiment in  FIG.  73   , the dose rate parameter input field  3318  is a two part field similar to the in container drug amount parameter input field  3304  and concentration parameter input field  3308  described above. A numeric value may defined in the left field of the dose rate parameter input field  3318  by the user in the same manner as a user may define values in the rate parameter input field  3312 . In the example embodiment in  FIG.  73   , the left field of the dose rate parameter input field  3318  has been populated with the value “1000”. 
     The right field of the dose rate parameter input field  3318  may define a unit of measure/time. To define the right field of the dose rate parameter input field  3318 , a user may touch the dose rate parameter input field  3318  on the GUI  3300 . In some embodiments, this may cull up a list of acceptable possible units of measure. In such embodiments, the desired unit of measure may be defined by a user in the same manner as a user may define the correct infusate. In other embodiments, touching the dose rate parameter input field  3318  may cull up a virtual keyboard. The user may then type the correct unit of measure on the virtual keyboard. In some embodiments the user may be required to tap, double tap, etc. a virtual “confirm”, “enter”, etc. button to store the selection and move on to a list of acceptable time measurements. The desired time measurement may be defined by a user in the same manner as a user may define the correct infusate. In the example embodiment shown in  FIG.  73    the right field of the dose rate parameter input field  3318  is populated with the unit of measure/time “UNITS/hr”. 
     In the example embodiment, the dose rate parameter input field  3318  and the rate parameter input field  3312  are not independent of one another. After a user populates the dose rate parameter input field  3318  or the rate parameter input field  3312 , the parameter input field left vacant by the user may be calculated automatically and displayed by the GUI  3300  as long as the concentration parameter input field  3308  has been defined. In the example embodiment shown in  FIG.  73   , the rate parameter input field  3312  has been populated with an infusate flow rate of “10 mL/hr”. The dose rate parameter input field  3318  has been populated with “1000” “UNITS/hr”. 
     In the example embodiment shown in  FIG.  73    the VTBI parameter input field  3314  and time parameter input field  3316  have also been populated. The VTBI parameter input field  3314  and time parameter input field  3316  may be populated by a user in the same manner described in relation to  FIG.  72   . When the GUI  3300  is being programmed to a continuous volume/time dose rate infusion, the VTBI parameter input field  3314  and the time parameter input field  3316  are dependent on one another. A user may only need to populate one of the VTBI parameter input field  3314  or the time parameter input field  3316 . The field left vacant by the user may be calculated automatically and displayed on the GUI  3300 . 
       FIG.  74    shows a scenario in which the infusion parameters being programmed are those of a drug amount based infusion herein referred to as an intermittent infusion. In the example embodiment shown in  FIG.  74   , all of the parameter input fields have been populated. As shown, the medication parameter input field  3302  on the GUI  3300  has been populated with the antibiotic “VANCOMYCIN” as the defined infusate. 
     As shown, the in container drug amount parameter input field  3304 , total volume in container input field  3306 , and concentration parameter input field  3308  are laid out the same as in  FIG.  73   . In the example embodiment in  FIG.  74   , the left field of the in container drug amount parameter input field  3304  has been populated with “1”. The right field of the in container drug amount parameter input field  3304  has been populated with “g”. Thus the total amount of Vancomycin in the container has been defined as one gram. The total volume in container parameter input field  3306  has been populated with “250” ml. The left field of the concentration parameter input field  3308  has been populated with “4.0”. The right field of the concentration parameter input field has been populated with “mg/mL”. 
     As mentioned in relation to other possible types of infusions which a user may be capable of programming through the GUI  3300 , the in container drug amount parameter input field  3304 , total volume in container input field  3306 , and concentration parameter input field  3308  are dependent upon each other. As above, this is indicated by the curved double arrows connecting the parameter input field names. By populating any two of these parameters, the third parameter may be automatically calculated and displayed on the correct parameter input field on the GUI  3300 . 
     In the example embodiment in  FIG.  74   , the dose parameter input field  3310  has been populated. As shown, the dose parameter input field  3310  comprises a right and left field. A numeric value may defined in the right field of the dose parameter input field  3310  by the user in the same manner as a user may define values for other parameter input fields which define numeric values. In the example embodiment in  FIG.  74   , the left field of the dose parameter input field  3310  has been populated with the value “1000”. 
     The right field of the dose parameter input field  3310  may define a unit of mass measurement. To define the right field of the dose parameter input field  3310 , a user may touch the dose parameter input field  3310  on the GUI  3300 . In some embodiments, this may cull up a list of acceptable possible units of measure. In such embodiments, the desired unit of measure may be defined by a user in the same manner as a user may define the correct infusate. In other embodiments, touching the dose parameter input field  3310  may cull up a virtual keyboard. The user may then type the correct unit of measure on the virtual keyboard. In some embodiments the user may be required to tap, double tap, slide, etc. a virtual “confirm”, “enter”, etc. button to store the selection and move on to a list of acceptable mass measurements. The desired mass measurement may be defined by a user in the same manner as a user may define the correct infusate. In the example embodiment shown in  FIG.  74    the right field of the dose parameter input field  3310  is populated with the unit of measurement “mg”. 
     As shown, the rate parameter input field  3312 , VTBI parameter input field  3314 , and the time parameter input field  3316  have been populated. As shown, the rate parameter input field  3312  has been populated with “125” mL/hr. The VTBI parameter input field  3314  has been defined as “250” mL. The time parameter input field  3316  has been defined as “2” hrs “00” min. 
     The user may not need to individually define each of the dose parameter input field  3310 , rate parameter input field  3312 , VTBI parameter input field  3314 , and the time parameter input field  3316 . As indicated by the curved double arrows, the dose parameter input field  3310  and the VTBI parameter input field  3314  are dependent upon each other. Input of one value may allow the other value to be automatically calculated and displayed by the GUI  3300 . The rate parameter input field  3312  and the time parameter input field  3316  are also dependent upon each other. The user may need to only define one value and then allow the non-defined value to be automatically calculated and displayed on the GUI  3300 . In some embodiments, the rate parameter input field  3312 , VTBI parameter input field  3314 , and the time parameter input field  3316  may be locked on the GUI  3300  until the in container drug amount parameter input field  3304 , total volume in container parameter input field  3306  and concentration parameter input field  3308  have been defined. These fields may be locked because automatic calculation of the rate parameter input field  3312 , VTBI parameter input field  3314 , and the time parameter input field  3316  is dependent upon values in the in container drug amount parameter input field  3304 , total volume in container parameter input field  3306  and concentration parameter input field  3308 . 
     In scenarios where an infusate may require a body weight based dosage, a weight parameter input field  3320  may also be displayed on the GUI  3300 . The example GUI  3300  shown on  FIG.  75    has been arranged such that a user may program a body weight based dosage. The parameter input fields may be defined by a user as detailed in the above discussion. In the example embodiment, the infusate in the medication parameter input field  3302  has been defined as “DOPAMINE”. The left field of the in container drug amount parameter input field  3304  has been defined as “400”. The right field of the in container drug amount parameter input field  3304  has been defined as “mg”. The total volume in container parameter input field  3306  has been defined as “250” ml. The left field of the concentration parameter input field  3308  has been defined as “1.6”. The right field of the concentration parameter input field  3308  has been defined as “mg/mL”. The weight parameter input field  3320  has been defined as “90” kg. The left field of the dose rater parameter input field  3318  has been defined as “5.0”. The right field of the dose rate parameter input field  3318  has been defined as “mcg/kg/min”. The rate parameter input field  3312  has been defined as “16.9” mL/hr. The VTBI parameter input field  3314  has been defined as “250” mL. The time parameter input field  3316  has been defined as “14” hrs “48” min. 
     To define the weight parameter input field  3320 , a user may touch or tap the weight parameter input field  3320  on the GUI  3300 . In some embodiments, this may cull up a number pad with a range of numbers, such as 0-9 displayed as individual selectable virtual buttons. A user may be required to input the parameter by individually tapping, double tapping, touching and dragging, etc. the desired numbers. Once the desired value has been input by a user, a user may be required to tap, double tap, etc. a virtual “confirm”, “enter”, etc. button to populate the field. 
     As indicated by the curved double arrows, some parameter input fields displayed on the GUI  3300  may be dependent upon each other. As in previous examples, the in container drug amount parameter input field  3304 , total volume in container parameter input field  3306 , and concentration parameter input field  3308  may be dependent upon each other. In  FIG.  75   , the weight parameter input field  3320 , dose rater parameter input field  3318 , rate parameter input field  3312 , VTBI parameter input field  3314 , and the time parameter input field  3316  are all dependent upon each other. When enough information has been defined by the user in these parameter input fields, the parameter input fields not populated by the user may be automatically calculated and displayed on the GUI  3300 . 
     In some embodiments, a user may be required to define a specific parameter input field even if enough information has been defined to automatically calculate the field. This may improve safety of use by presenting more opportunities for user input errors to be caught. If a value entered by a user is not compatible with already defined values, the GUI  3300  may display an alert or alarm message soliciting the user to double check values that the user has entered. 
     In some scenarios the delivery of infusate may be informed by the body surface area (BSA) of a patient. In  FIG.  76   , the GUI  3300  has been set up for a body surface area based infusion. As shown, a BSA parameter input field  3322  may be displayed on the GUI  3300 . The parameter input fields may be defined by a user as detailed in the above discussion. In the example embodiment, the infusate in the medication parameter input field  3302  has been defined as “FLUOROURACIL”. The left field of the in container drug amount parameter input field  3304  has been defined as “1700”. The right field of the in container drug amount parameter input field  3304  has been defined as “mg”. The total volume in container parameter input field  3306  has been defined as “500” ml. The left field of the concentration parameter input field  3308  has been defined as “3.4”. The right field of the concentration parameter input field  3308  has been defined as “mg/mL”. The BSA parameter input field  3322  has been defined as “1.7” m 2 . The left field of the dose rate parameter input field  3318  has been defined as “1000”. The right field of the dose rate parameter input field  3318  has been defined as “mg/m2/day”. The rate parameter input field  3312  has been defined as “20.8” mL/hr. The VTBI parameter input field  3314  has been defined as “500” mL. The time parameter input field  3316  has been defined as “24” hrs “00” min. The dependent parameter input fields are the same as in  FIG.  75    with the exception that the BSA parameter input field  3322  has taken the place of the weight parameter input field  3320 . 
     To populate the BSA parameter input field  3322 , the user may touch or tap the BSA parameter input field  3322  on the GUI  3300 . In some embodiments, this may cull up a number pad with a range of numbers, such as 0-9 displayed as individual selectable virtual buttons. In some embodiments, the number pad and any of the number pads detailed above may also feature symbols such as a decimal point. A user may be required to input the parameter by individually tapping, double tapping, touching and dragging, etc. the desired numbers. Once the desired value has been input by a user, a user may be required to tap, double tap, etc. a virtual “confirm”, “enter”, etc. button to populate the field. 
     In some embodiments, a patient&#39;s BSA may be automatically calculated and displayed on the GUI  3300 . In such embodiments, the GUI  3300  may query the user for information about the patient when a user touches, taps, etc. the BSA parameter input field  3322 . For example, the user may be asked to define a patient&#39;s height and body weight. After the user defines these values they may be run through a suitable formula to find the patient&#39;s BSA. The calculated BSA may then be used to populate the BSA parameter input field  3322  on the GUI  3300 . 
     In operation, the values displayed in the parameter input fields may change throughout the course of a programmed infusion to reflect the current state of the infusion. For example, as the infusate is infused to a patient, the values displayed by the GUI  3300  in the in container drug amount parameter input field  3304  and total volume in container parameter input field  3306  may decline to reflect the volume of the remaining contents of the container. Additionally, the values in the VTBI parameter input field  3314  and time parameter input field  3316  may also decline as infusate is infused to the patient. 
       FIG.  77    is an example rate over time graph detailing one behavioral configuration of a syringe pump  500  (see  FIG.  28   ) over the course of an infusion. Though the following discussion mostly details behavioral configurations of a syringe pump  500 , it should be appreciated that the graphs shown in  FIG.  77 - 81    may also detail the behavioral configurations of other pumps, including the other pumps mentioned in this specification. The graph in  FIG.  77    details an example behavioral configuration of the syringe pump  500  where the infusion is a continuous infusion (an infusion with a dose rate). As shown, the graph in  FIG.  77    begins at the initiation of infusion. As shown, the infusion is administered at a constant rate for a period of time. As the infusion progresses, the amount of infusate remaining is depleted. 
     When the amount of infusate remaining reaches a pre-determined threshold, an “INFUSION NEAR END ALERT” may be triggered. The point at which “INFUSION NEAR END ALERT” is issued may be configured by the user. The “INFUSION NEAR END ALERT” may also be configured to be triggered sooner on short-half life drugs. The “INFUSION NEAR END ALERT” may be in the form of a message on the GUI  3300  and may be accompanied by flashing lights, and audible noises such as a series of beeps. The “INFUSION NEAR END ALERT” allows time for the care giver and pharmacy to prepare materials to continue the infusion if necessary. As shown, the infusion rate may not change over the “INFUSION NEAR END ALERT TIME”. 
     When the syringe pump  500  (see  FIG.  28   ) has infused the VTBI to a patient a “VTBI ZERO ALERT” may be triggered. The “VTBI ZERO ALERT” may be in the form of a message on the GUI  3300  and may be accompanied by flashing lights and audible noises such as beeps. As shown, the “VTBI ZERO ALERT” causes the pump to switch to a keep-vein-open (hereafter KVO) rate until a new infusate container may be put in place. The KVO rate is a low infusion rate (for example 5-25 mL/hr). The rate is set to keep the infusion site patent until a new infusion may be started. The KVO rate may be configurable by the group (elaborated upon later) or medication and can be modified on the syringe pump  500 . The KVO rate is not allowed to exceed the continuous infusion rate. When the KVO rate can no longer be sustained and the syringe has reached the end of its stoke, an “END OF STROKE ALARM” may be triggered. When the “END OF STROKE ALARM” is triggered, all infusion may stop. The “END OF STROKE ALARM” may be in the form of a message on the GUI  3300  and may be accompanied by flashing lights and audible noises such as beeps. 
       FIG.  78    shows another example rate over time graph detailing one behavioral configuration of a syringe pump  500  (see  FIG.  28   ) over the course of an infusion. The graph in  FIG.  78    details an example behavioral configuration of a syringe pump  500  where the infusion is a continuous infusion (an infusion with a dose rate). The alerts in the graph shown in  FIG.  78    are the same as the alerts shown in the graph in  FIG.  77   . The conditions which propagate the alerts are also the same. The rate, however, remains constant throughout the entire graph until the “END OF STROKE ALERT” is triggered and the infusion is stopped. By continuing infusion at a constant rate, it is ensured that the blood plasma concentration of the drug remains at therapeutically effective levels. Configuring the pump to continue infusion at a constant rate may be especially desirable in situations where the infusate is a drug with a short half-life. In some embodiments, the end of infusion behavior of the syringe pump  500  may be restricted depending on the defined infusate. For example, when the defined infusate is a short half-life drug the end of infusion behavior of the syringe pump  500  may be limited only to continuing to infuse at the rate of the finished infusion. 
     The syringe pump  500  (see  FIG.  28   ) may also be used to deliver a primary or secondary intermittent infusion. During an intermittent infusion, an amount of a drug (dose) is administered to a patient as opposed to a continuous infusion where the drug is given at a specified dose rate (amount/time). An intermittent infusion is also delivered over a defined period of time, however, the time period and dose are independent of one another. The previously described  FIG.  73    shows a setup of the GUI  3300  for a continuous infusion. The previously described  FIG.  74    shows a setup of the GUI  3300  for an intermittent infusion. 
       FIG.  79    is an example rate over time graph detailing the one behavioral configuration of a syringe pump  500  (see  FIG.  28   ) over the course of an intermittent infusion. As shown, the intermittent infusion is given at a constant rate until all infusate programmed for the intermittent infusion has been depleted. In the example behavioral configuration, the syringe pump  500  has been programmed to issue a “VTBI ZERO ALERT” and stop the infusion when all the infusate has been dispensed. In this configuration, the user may be required to manually clear the alert before another infusion may be started or resumed. 
     Depending on the group (further elaborated upon later) or the medication, it may be desirable to configure the syringe pump  500  to behave differently at the end of an intermittent infusion. Other configurations may cause a syringe pump  500  (see  FIG.  28   ) to behave differently. For example, in scenarios where the intermittent infusion is a secondary infusion, the pump  201 ,  202 ,  203  (see  FIG.  2   ) may be configured to automatically switch back to the primary infusion after issuing a notification that the secondary intermittent infusion has been completed. In alternate configurations, the a syringe pump  500  may be configured issue a “VTBI ZERO ALERT” and drop the infusion rate to a KVO rate after completing the intermittent infusion. In such configurations, the user may be required to manually clear the alert before a primary infusion is resumed. 
     A bolus may also be delivered as a primary intermittent infusion when it may be necessary or desirable to achieve a higher blood plasma drug concentration or manifest a more immediate therapeutic effect. In such cases, the bolus may be delivered by a pump  201 ,  202 ,  203  (see  FIG.  2   ) executing the primary infusion. The bolus may be delivered from the same container which the primary infusion is being delivered from. A bolus may be performed at any point during an infusion providing there is enough infusate to deliver the bolus. Any volume delivered via a bolus to a patient is included in the value displayed by the VTBI parameter input field  3314  of the primary infusion. 
     Depending on the infusate, a user may be forbidden from performing a bolus. The dosage of a bolus may be pre-set depending on the specific infusate or infusate concentration being used. Additionally, the period of time over which the bolus occurs may be pre-defined depending on the infusate being used. After performing a bolus, the bolus function may be locked for a pre-defined period of time. In some embodiments, a user may be capable of adjusting these pre-sets by adjusting various setting on the GUI  3300 . In some situations, such as those where the drug being infused has a long half-life (vancomycin, teicoplanin, etc.), a bolus may be given as a loading dose to more quickly reach a therapeutically effective blood plasma drug concentration. 
       FIG.  80    shows another rate over time graph in which the flow rate of the infusate has been titrated to “ramp” the patient up on the infusate. Titration is often used with drugs which register a fast therapeutic effect, but have a short half life (such as norepinephrine). When titrating, the user may adjust the delivery rate of the infusate until the desired therapeutic effect is manifested. Every adjustment may be checked against a series of limits defined for the specific infusate being administered to the patient. If an infusion is changed by more than a pre-defined percentage, an alert may be issued. In the exemplary graph shown in  FIG.  80   , the rate has been up-titrated once. If necessary, the rate may be up-titrated more than one time. Additionally, in cases where titration is being used to “wean” a patient off of a drug, the rate may be down-titrated any suitable number of times. 
       FIG.  81    is another rate over time graph in which the infusion has been configured as a multi-step infusion. A multi-step infusion may be programmed in a number of different steps. Each step may be defined by a VTBI, time, and a dose rate. Multi-step infusions may be useful for certain types of infusates such as those used for parenteral nutrition applications. In the example graph shown in  FIG.  81   , the infusion has been configured as a five step infusion. The first step infuses a “VTBI 1” for a length of time, “Time 1”, at a constant rate, “Rate 1”. When the time interval for the first step has elapsed, the pump moves on to the second step of the multi-step infusion. The second step infuses a “VTBI 2” for a length of time, “Time 2”, at a constant rate, “Rate 2”. As shown, “Rate 2” is higher than “Rate 1”. When the time interval for the second step has elapsed, the pump moves on to the third step of the multi-step infusion. The third step infuses a “VTBI 3” for a length of time, “Time 3”, at a constant rate, “Rate 3”. As shown “Rate 3” is the highest rate of any steps in the multi-step infusion. “Time 3” is also the longest duration of any step of the multi-step infusion. When the time interval for the third step has elapsed, the pump move on to the fourth step of the multi-step infusion. The fourth step infuses a “VTBI 4” for a length of time, “Time 4”, at a constant rate, “Rate 4”. As shown, “Rate 4” has been down-titrated from “Rate 3”. “Rate 4” is approximately the same as “Rate 2”. When the time interval for the fourth step of the multi-step infusion has elapsed, the pump move on to the fifth step. The fifth step infuses a “VTBI 5” for a length of time, “Time 5”, at a constant rate, “Rate 5”. As shown, “Rate 5” has been down-titrated from “Rate 4” and is approximately the same as “Rate 1”. 
     The “INFUSION NEAR END ALERT” is triggered during the fourth step of the example infusion shown in  FIG.  81   . At the end of the fifth and final step of the multi-step infusion, the “VTBI ZERO ALERT” is triggered. In the example configuration shown in the graph in  FIG.  81   , the rate is dropped to a KVO rate after the multi-step infusion has been concluded and the “VTBI ZERO ALERT” has been issued. Other configurations may differ. 
     Each rate change in a multi-step infusion may be handled in a variety of different ways. In some configurations, the syringe pump  500  (see  FIG.  2   ) may display a notification and automatically adjust the rate to move on to the next step. In other configurations, the syringe pump  500  may issue an alert before changing the rate and wait for confirmation from the user before adjusting the rate and moving on to the next step. In such configurations, the pump  500  may stop the infusion or drop to a KVO rate until user confirmation has been received. 
     In some embodiments, the user may be capable of pre-programming infusions. The user may pre-program an infusion to automatically being after a fixed interval of time has elapsed (e.g. 2 hours). The infusion may also be programmed to automatically being at a specific time of day (e.g. 12:30 pm). In some embodiments, the user may be capable of programming the syringe pump  500  (see  FIG.  28   ) to alert the user with a callback function when it is time to being the pre-programmed infusion. The user may need to confirm the start of the pre-programmed infusion. The callback function may be a series of audible beeps, flashing lights, or the like. 
     In arrangements where there is more than one pump  201 ,  202 ,  203  (see  FIG.  2   ), the user may be able to program a relay infusion. The relay infusion may be programmed such that after a first pump  201 ,  202 ,  203  has completed its infusion, a second pump  201 ,  202 ,  203  may automatically being a second infusion and so on. The user may also program a relay infusion such that the user is alerted via the callback function before the relay occurs. In such a programmed arrangement, the relay infusion may not being until confirmation from a user has been received. A pump  201 ,  202 ,  203  may continue at a KVO rate until user confirmation has been received. 
       FIG.  82    shows an example block diagram of a “Drug Administration Library” data structure. The data structure may be stored in any file format or in any database (e.g., an SQL database). In the upper right hand corner there is a box which is substantially rectangular, though its edges are rounded. The box is associated with the name “General Settings”. The “General Settings” may include settings which would be common to all devices in a facility such as, site name (e.g. XZY Hospital), language, common passwords, and the like. 
     In  FIG.  82   , the “Drug Administration Library” has two boxes which are associated with the names “Group Settings (ICU)” and “Group Settings”. These boxes form the headings for their own columns. These boxes may be used to define a group in within a facility (e.g. pediatric intensive care unit, emergency room, sub-acute care, etc.) in which the device is stationed. Groups may also be areas outside a parent facility, for example, a patient&#39;s home or an inter-hospital transport such as an ambulance. Each group may be used to set specific settings for various groups within a facility (weight, titration limits, etc.). These groups may alternatively be defined in other manners. For example, the groups may be defined by user training level. The group may be defined by a prior designated individual or any of a number of prior designated individuals and changed if the associated patient or device is moved from one specific group within a facility to another. 
     In the example embodiment, the left column is “Group Settings (ICU)” which indicates that the syringe pump  500  (see  FIG.  28   ) is stationed in the intensive care unit of the facility. The right column is “Group Settings” and has not been further defined. In some embodiments, this column may be used to designate a sub group, for example operator training level. As indicated by lines extending to the box off to the left of the block diagram from the “Group settings (ICU)” and “Group Settings” columns, the settings for these groups may include a preset number of default settings. 
     The group settings may include limits on patient weight, limits on patient BSA, air alarm sensitivity, occlusion sensitivity, default KVO rates, VTBI limits, etc. The group settings may also include parameters such as whether or not a review of a programmed infusion is necessary for high risk infusates, whether the user must identify themselves before initiating an infusion, whether the user must enter a text comment after a limit has been overridden, etc. A user may also define the defaults for various attributes like screen brightness, or speaker volume. In some embodiments, a user may be capable of programming the screen to automatically adjust screen brightness in relation to one or more conditions such as but not limited to time of day. 
     As also shown to the left of the block diagram in  FIG.  82   , each facility may have a “Master Medication List” defining all of the infusates which may be used in the facility. The “Master Medication List” may comprise a number of medications which a qualified individual may update or maintain. In the example embodiment, the “Master Medication List” only has three medications: Heparin, 0.9% Normal Saline, and Alteplase. Each group within a facility may have its own list of medications used in the group. In the example embodiment, the “Group Medication List (ICU)” only includes a single medication, Heparin. 
     As shown, each medication may be associated with one or a number of clinical uses. In  FIG.  82    the “Clinical Use Records” are defined for each medication in a group medication list and appear as an expanded sub-heading for each infusate. The clinical uses may be used to tailor limits and pre-defined settings for each clinical use of the infusate. For Heparin, weight based dosing and non-weight based dosing are shown in  FIG.  82    as possible clinical uses. In some embodiments, there may be a “Clinical Use Record” setting requiring the user to review or re-enter a patient&#39;s weight (or BSA) before beginning an infusion. 
     Clinical uses may also be defined for the different medical uses of each infusate (e.g. stroke, heart attack, etc.) instead of or in addition to the infusate&#39;s dose mode. The clinical use may also be used to define whether the infusate is given as a primary continuous infusion, primary intermittent infusion, secondary infusion, etc. They may also be use to provide appropriate limits on the dose, rate, VTBI, time duration, etc. Clinical uses may also provide titration change limits, the availability of boluses, the availability of loading doses, and many other infusion specific parameters. In some embodiments, it may be necessary to provide at least one clinical use for each infusate in the group medication list. 
     Each clinical use may additionally comprise another expanded sub-heading in which the concentration may also be defined. In some cases, there may be more than one possible concentration of an infusate. In the example embodiment in  FIG.  82   , the weight base dosing clinical use has a 400 mg/250 mL concentration and an 800 mg/250 mL concentration. The non-weight based dosing clinical use only has one concentration, 400 mg/mL. The concentrations may also be used to define an acceptable range for instances where the user may customize the concentration of the infusate. The concentration setting may include information on the drug concentration (as shown), the diluents volume, or other related information. 
     In some embodiments, the user may navigate to the “Drug Administration Library” to populate some of the parameter input fields shown in  FIGS.  72 - 76   . The user may also navigate to the “Drug Administration Library” to choose from the clinical uses for each infusate what type of infusion the syringe pump  500  (see  FIG.  28   ) will administer. For example, if a user were to select weight based Heparin dosing on  FIG.  82   , the GUI  3300  might display the infusion programming screen shown on  FIG.  75    with “Heparin” populated into the medication parameter input field  3302 . Selecting a clinical use of a drug may also prompt a user to select a drug concentration. This concentration may then be used to populate the concentration parameter input field  3308  (see  FIGS.  72 - 76   ). In some embodiments, the “Drug Administration Library” may be updated and maintained external to the syringe pump  500  and communicated to the syringe pump  500  via any suitable means. In such embodiments, the “Drug Administration Library” may not be changeable on the syringe pump  500  but may only place limits and/or constraints on programming options for a user populating the parameter input fields shown in  FIG.  72 - 76   . 
     As mentioned above, by choosing a medication and clinical use from the group medication list, a user may also be setting limits on other parameter input fields for infusion programming screens. For example, by defining a medication in the “Drug Administration Library” a user may also be defining limits for the dose parameter input field  3310 , dose rate parameter input field  3318 , rate parameter input field  3312 , VTBI parameter input field  3314 , time parameter input field  3316 , etc. These limits may be pre-defined for each clinical use of an infusate prior to the programming of an infusion by a user. In some embodiments, limits may have both a soft limit and a hard limit with the hard limit being the ceiling for the soft limit. In some embodiments, the group settings may include limits for all of the medications available to the group. In such cases, clinical use limits may be defined to further tailor the group limits for each clinical usage of a particular medication. 
     The software architecture of the syringe pump  500  is shown schematically in  FIG.  83   . The software architecture divides the software into cooperating subsystems that interact to carry out the required pumping action. The software is equally applicable to all the embodiments described herein. It is also possible to apply the software to other pumps not described herein. Each subsystem may be composed of one or more execution streams controlled by the underlying operating system. Useful terms used in the art include operating system, subsystem, process, thread and task. 
     Asynchronous messages  4130  are used to ‘push’ information to the destination task or process. The sender process or task does not get confirmation of message delivery. Data delivered in this manner is typically repetitive in nature. If messages are expected on a consistent schedule, the receiver process or task can detect a failure if a message does not arrive on time. 
     Synchronous messages  4120  may be used to send a command to a task or process, or to request (‘pull’) information from a process or task. After sending the command (or request), the originating task or process suspends execution while awaiting a response. The response may contain the requested information, or may acknowledge the receipt of the sent message. If a response is not received in a timely manner, the sending process or task may time out. In such an event, the sending process or task may resume execution and/or may signal a error condition. 
     An operating system (OS) is a collection of software that manages computer hardware resources and provides common services for computer programs. The operating system may act as an intermediary between programs and the computer hardware. Although some application code may be executed directly by the hardware, the application code may frequently make a system call to an OS function or be interrupted by it. 
     The RTP  3500  may run on a Real Time Operating System (RTOS) that has been certified to a safety level for medical devices. An RTOS is a multitasking operating system that aims at executing real-time applications. Real-time operating systems often use specialized scheduling algorithms so that they can achieve a deterministic nature of behavior. The UIP  3600  may run on a Linux operating system. The Linux operating system is a Unix-like computer operating system. 
     A subsystem is a collection of software (and perhaps hardware) assigned a specific set of (related) system functionality or functionalities. A subsystem has clearly defined responsibilities and a clearly defined interface to other subsystems. A subsystem is an architectural division of the software that uses one or more processes, threads or tasks. 
     A process is an independent executable running on a Linux operating system which runs in its own virtual address space. The memory management hardware on the CPU is used to enforce the integrity and isolation of this memory, by write protecting code-space, and disallowing data access outside of the process&#39; memory region. Processes can only pass data to other processes using inter-process communication facilities. 
     In Linux, a thread is a separately scheduled, concurrent path of program execution. On Linux, a thread is always associated with a process (which must have at least one thread and can have multiple threads). Threads share the same memory space as its ‘parent’ process. Data can be directly shared among all of the threads belonging to a process but care must be taken to properly synchronize access to shared items. Each thread has an assigned execution priority. 
     A Task on an RTOS (Real Time Operating System) is a separately scheduled, concurrent path of program execution, analogous to a Linux ‘thread’. All tasks share the same memory address space which consists of the entire CPU memory map. When using an RTOS that provides memory protection, each task&#39;s effective memory map is restricted by the Memory Protection Unit (MPU) hardware to the common code space and the task&#39;s private data and stack space. 
     The processes on the UIP  3600 , communicate via IPC calls as shown by the one-way arrows in  FIG.  83   . Each solid-lined arrow represents a synchronous message  4120  call and response, and dotted-line arrows are asynchronous messages  4130 . The tasks on the RTP  3500  similarly communicate with each other. The RTP  3500  and UIP  3600  may be bridged by an asynchronous serial line  3601 , with one of an InterComm Process  4110  or InterComm Task  4210  on each side. The InterComm Process  4110  presents the same communications API (Application Programming Interface) on both sides of the bridge, so all processes and tasks can use the same method calls to interact. 
     The Executive Process  4320  may invoked by the Linux system startup scripts after all of the operating system services have started. The Executive Process  4320  then starts the various executable files that comprise the software on the UIP  3600 . If any of the software components should exit or fail unexpectedly, the Executive Process  4320  may be notified, and may generate the appropriate alarm. 
     While the system is running, the Executive Process  4320  may act as a software ‘watchdog’ for various system components. After registering with the Executive Process  4320 , a process is required to ‘check in’ or send a signal periodically to the Executive Process  4320 . Failure to ‘check in’ at the required interval may be detected by the Executive Process  4320 . Upon detection of a failed subsystem, the Executive Process  4320  may take remedial action of either: do nothing, declaring an alarm, or restarting the failed process. The remedial action taken is predetermined by a table entry compiled into the Executive Process  4320 . The ‘check-in’ interval may vary from process to process. The amount of variance between ‘check-in’ times for different processes may be based in part on the importance of the process. The check-in interval may also vary during syringe pump  500  operation to optimize the pump controller response by minimizing computer processes. In one example embodiment, during syringe  504  loading, the pump controller may check-in less frequently than during active pumping. 
     In response to the required check-in message, the Executive Process  4320  may return various system status items to processes that checked-in. The system status items may be the status of one or more components on the syringe pump  500  and/or errors. The System Status items may include: battery status, WiFi connection status, device gateway connection status, device status (Idle, Infusion Running, Diagnostic Mode, Error, Etc.), technical error indications, and engineering log levels. 
     A thread running in the Executive Process  4320  may be used to read the state of the battery  3420  from an internal monitor chip in the battery  3420 . This may be done at a relatively infrequent interval such as every 10 seconds. 
     The UI View  4330  implements the graphical user interface (GUI  3300  see  FIG.  71   ), rendering the display graphics on the display  514 , and responding to inputs on the touch screen in embodiments comprising a touch screen or to inputs communicated via other data input means  516 . The UI View  4330  design is stateless. The graphic being displayed may be commanded by the UI Model Process  4340 , along with any variable data to be displayed. The commanded graphic may be refreshed periodically regardless of data changes. 
     The style and appearance of user input dialogs (Virtual keyboard, drop down selection list, check box etc.) may be specified by the screen design, and implemented entirely by the UI View  4330 . User input may be collected by the UI View  4330 , and sent to the UI Model  4340  for interpretation. The UI View  4330  may provide for multi-region, multi-lingual support with facilities for the following list including but not limited to: virtual keyboards, unicode strings, loadable fonts, right to left entry, translation facility (loadable translation files), and configurable numbers and date formats. 
     The UI Model  4340  implements the screen flows, and so controls the user experience. The US Model  4340  interacts with the UI View  4330 , specifying the screen to display, and supplies any transient values to be displayed on the screen. Here screen refers the image displayed on the physical display  514  and the defined interactive areas or user dialogs i.e. buttons, sliders, keypads etc, on the touch screen  3735 . The UI Model  4340  interprets any user inputs sent from the UI View  4330 , and may either update the values on the current screen, command a new screen, or pass the request to the appropriate system service (i.e. ‘start pumping’ is passed to the RTP  3500 ). 
     When selecting a medication to infuse from the Drug Administration Library, the UI Model  4340  interacts with the Drug Administration Library stored in the local data base which is part of the Database System  4350 . The user&#39;s selections setup the run time configurations for programming and administering the desired medication. 
     While the operator is entering an infusion program, The UI Model  4340  may relay the user&#39;s input values to the Infusion Manager  4360  for validation and interpretation. Therapeutic decisions may not be made by the UI Model  4340 . The treatment values may be passed from the Infusion Manager  4360  to the UI Model  4340  to the UI View  4330  to be displayed for the user. 
     The UI Model  4340  may continuously monitor the device status gathered from the Infusion Manager  4360  (current infusion progress, alerts, etc.) for possible display by the UI View  4330 . Alerts/Alarms and other changes in system state may provoke a screen change by the UI Model  4340 . 
     The Infusion Manager Process (IM)  4360  may validate and controls the infusion delivered by the syringe pump  500 . To start an infusion, the user may interact with the UI View/Model  4330 / 4340  to select a specific medication and clinical use. This specification selects one specific Drug Administration Library (DAL) entry for use. The IM  4360  loads this DAL entry from the database  4350 , for use in validating and running the infusion. 
     Once a Drug Administration Library entry is selected, the IM  4340  may pass the dose mode, limits for all user enterable parameters, and the default values (if set) up to the UI Model  4340 . Using this data, the UI Model  4340  may guide the user in entering the infusion program. 
     As each parameter is entered by the user, the value may sent from the UI View/Model  4330 / 4340  to the IM  4360  for verification. The IM  4360  echoes the parameters back to the UI View/Model  4330 / 4340 , along with an indication of the parameter&#39;s conformance to the DAL limits. This allows the UI View/Model  4330 / 4340  to notify the user of any values that are out of bounds. 
     When a complete set of valid parameters has been entered, the IM  4360  also may return a valid infusion indicator, allowing the UI View/Model  4330 / 4340  to present a ‘Start’ control to the user. 
     The IM  4360  may simultaneously make the infusion/pump status available to the UI View/Model  4330 / 4340  upon request. If the UI View/Model  4330 / 4340  is displaying a ‘status’ screen, it may request this data to populate it. The data may be a composite of the infusion state, and the pump state. 
     When requested to run the (valid) infusion, the IM  4360  may pass the ‘Infusion Worksheet’ containing user specified data and the ‘Infusion Template’ containing the read-only limits from the DAL as a CRC&#39;d binary block to the Infusion Control Task  4220  running on the RTP  3500 . The Infusion Control Task  4220  on the RTP  3500  takes the same user inputs, conversions and DERS inputs and recalculates the Infusion Worksheet. The Infusion Control Task  4220  calculated results may be stored in a second CRC&#39;d binary block and compared to the first binary block from the UIP  3600 . The infusion calculations performed on the UIP  3600  may be recalculated and double checked on the RTP  3500  before the infusion is run. 
     Coefficients to convert the input values (ie. □l, grams, %, etc.) to a standard unit such as ml may be stored in the UIP  3600  memory or database system  4350 . The coefficients may be stored in a lookup table or at specific memory locations. The lookup table may contain 10&#39;s of conversion values. In order to reduce the chance that flipping a single bit will resulting in the wrong conversion factor being used, the addresses for the conversion values may be distributed among the values from zero to 4294967296 or 2 32 . The addresses may be selected so that the binary form of one address is never just one bit different from a second address. 
     While an infusion is running, the IM  4360  may monitor its progress, sequences, pauses, restarts, secondary infusions, boluses, and KVO (keep vein open) scenarios as needed. Any user alerts requested during the infusion (Infusion near complete, KVO callback, Secondary complete callback, etc) may be tracked and triggered by the IM  4360 . 
     Processes on the UIP  3600  may communicate with each other via a proprietary messaging scheme based on a message queue library that is available with Linux. The system provides for both acknowledged (synchronous message  4120 ) and unacknowledged (asynchronous message  4130 ) message passing. 
     Messages destined for the Real-time Processor (RTP)  3500  may be passed to the InterComm Process  4310  which forwards the messages to the RTP  3500  over a serial link  3601 . A similar InterComm Task  4210  on the RTP  3500  may relay the message to its intended destination via the RTP  3500  messaging system. 
     The messaging scheme used on this serial link  3601  may provide for error detection and retransmission of flawed messages. This may be needed to allow the system to be less susceptible to electrical disturbances that may occasionally ‘garble’ inter-processor communications. 
     To maintain a consistent interface across all tasks, the message payloads used with the messaging system may be data classes derived from a common baseclass (MessageBase). This class adds both data identity (message type) and data integrity (CRC) to messages. 
     The Audio Server Process  4370  may be used to render sounds on the system. All user feedback sounds (key press beeps) and alarm or alert tones may be produced by playing pre-recorded sound files. The sound system may also be used to play music or speech if desired. 
     Sound requests may be symbolic (such as “Play High Priority Alarm Sound”), with the actual sound file selection built into the Audio Server process  4370 . The ability to switch to an alternative soundscape may be provided. This ability may be used to customize the sounds for regional or linguistic differences. 
     The Device Gateway Communication Manager Process (DGCM)  4380  may manage communications with the Device Gateway Server over a Wi-Fi network  3620 ,  3622 ,  3720 . The DGCM  4380  may be started and monitored by the Executive Process  4320 . If the DGCM  4380  exits unexpectedly, it may be restarted by the Executive Process  4320  but if the failures are persistent the system may continue to function without the gateway running. 
     It may be the function of the DGCM  4380  to establish and maintain the Wi-Fi connection and to then establish a connection to the Device Gateway. All interactions between the DGCM  4380  and the Device Gateway use a system such as the system described in the cross referenced Non-provisional application Ser. No. 13/723,253, entitled System, Method, and Apparatus for Electronic Patient Care. 
     If the connection to the gateway is unavailable or becomes unavailable, the DGCM  4380  may discontinue any transfers in progress, and attempt to reconnect the link. Transfers may be resumed when the link is reestablished. Network and Gateway operational states are reported periodically to the Executive Process  4320 . The Executive Process  4320  distributes this information for display to the user. 
     The DGCM  4380  may function as an autonomous subsystem, polling the Device Gateway Server for updates, and downloading newer items when available. In addition the DGCM  4380  may monitor the logging tables in the database, uploading new log events as soon as they are available. Events that are successfully uploaded may be flagged as such in the database. After a reconnection to the Device Gateway Server, the DGCM  4380  may ‘catch up’ with the log uploads, sending all items that were entered during the communications disruption. Firmware and Drug Administration Library updates received from the Gateway may be staged in the UIP&#39;s  3600  file system for subsequent installation. Infusion programs, clinical advisories, patient identification and other data items destined for the device may be staged in the database. 
     The DGCM  4380  may report connection status and date/time updates to the Executive Process  4320 . There may not be other direct connections between the DGCM  4380  and any of the other operational software. Such a design decouples the operational software from the potentially transient availability of the Device Gateway and Wi-Fi network. 
     The Motor Check  4383  software may read a hardware counter or encoder  1202  ( FIG.  60   ) that reports motor  1200  rotation. The software in this module may independently estimate the motor&#39;s  1200  movements, and compare them to the expected motion based on the user inputs for rate of infusion. This may be an independent check for proper motor control. However, the primary motor  1200  control software may executed on the RTP  3500 . 
     Event information may be written to a log via the Logging Process  4386  during normal operation. These events may consist of internal machine status and measurements, as well as therapy history events. Due to the volume and frequency of event log data, these logging operations may be buffered in a FIFO queue while waiting to be written to the database. 
     A SQL database (PostgreSQL) may be used to store the Drug Administration Library, Local Machine Settings, Infusion History and Machine Log data. Stored procedures executed by the database server may be used to insulate the application from the internal database structures. 
     The database system  4350  may be used as a buffer for log data destined for the Device Gateway server, as well as a staging area for infusion settings and warnings sent to the pump from the Gateway. 
     Upon requesting the start of an infusion, the DAL entry and all user selected parameters may be sent to the Infusion Control Task  4220 . All of the DAL validations and a recalculation of the infusion rate and volume based upon the requested dose may be performed. The result may be checked against the results calculated by the IM  4360  on the UIP  3600 . These results may be required to match to continue. 
     When running an infusion, the Infusion Control Task  4220  may control the delivery of each infusion ‘segment’; i.e. one part of an infusion consisting of a volume and a rate. Examples of segments are: a primary infusion, KVO, bolus, remainder of primary after bolus, primary after titration, etc. The infusion segments are sequenced by the IM Process  4360  on the UIP  3600 . 
     The Pump Control Task  4250  may incorporate the controllers that drive the pumping mechanism. The desired pumping rate and amount (VTBI) may be specified in commands sent from the Infusion Control Task  4220 . 
     The Pump Control  4250  may receive periodic sensor readings from the Sensor Task  4264 . The new sensor readings may be used to determine the motor speed and position, and to calculate the desired command to send to the Brushless Motor Control IRQ  4262 . The receipt of the sensor message may trigger a recalculation of the controller output. 
     While pumping fluid, the Pump Control Task  4250  may perform at least one of the following tasks: controlling pumping speed, measuring volume delivered, measuring air detected (over a rolling time window), measuring fluid pressure or other indications of occlusions, and detecting upstream occlusions. 
     Relevant measurements may be reported to the RTP Status Task  4230  periodically. The Pump Control  4250  may execute one infusion segment at a time, stopping when the commanded delivery volume has been reached. The Sensor Task  4264  may read and aggregate the sensor data used for the dynamic control of the pumping system. 
     The sensor task  4264  may be scheduled to run at a consistent 1 kHz rate (every 1.0 ms) via a dedicated counter/timer. After all of the relevant sensors are read, the data may be passed to the Pump Control Task  4250  via an asynchronous message  4120 . The periodic receipt of this message may be used as the master time base to synchronize the syringe pump&#39;s  500  control loops. 
     The RTP Status Task  4230  may be the central repository for both the state and the status of the various tasks running on the RTP  3500 . The RTP Status Task  4230  may distribute this information to both the IM  4360  running on the UIP  3600 , as well as to tasks on the RTP  3500  itself. 
     The RTP Status Task  4230  may also be charged with fluid accounting for the ongoing infusion. Pump starts and stops, as well as pumping progress may be reported to RTP Status  4230  by the Pump Control Task  4256 . The RTP Status Task  4230  may account for at least one of the following: total volume infused, primary volume delivered, primary VTBI (counted down), volume delivered and VTBI of a bolus while the bolus is in progress, and volume delivered and VTBI of a secondary infusion while the secondary infusion is in progress. 
     All alerts or alarms originating on the RTP  3500  may be funneled through the RTP Status Task  4230 , and subsequently passed up to the UIP  3600 . 
     While the unit is in operation, the program flash, and RAM memory may be continually tested by the Memory Checker Task  4240 . This test may be non-destructive. This test may be scheduled so that the entire memory space on the RTP  3500  is tested every few hours. Additional periodic checks may be scheduled under this task if needed. 
     Tasks running on the RTP  3500  may be required to communicate with each other as well as to tasks that are executing on the UIP  3600 . 
     The RTP  3500  messaging system may use a unified global addressing scheme to allow messages to be passed to any task in the system. Local messages may be passed in memory utilizing the facilities of the RTOS&#39; message passing, with off-chip messages routed over the asynchronous serial link  3601  by the InterComm Task  4210 . 
     The InterComm Task  4210  may manage the RTP  3500  side of the serial link  3601  between the two processors. The InterComm Task  4210  is the RTP  3500  equivalent of the InterComm Process  4310  on the UIP  3600 . Messages received from the UIP  3600  may be relayed to their destination on the RTP  3500 . Outbound messages may be forwarded to InterComm Process  4310  on the UIP  3600 . 
     All messages between the RTP  3500  and the UIP  3600  may be checked for data corruption using an error-detecting code (32 bit CRC). Messages sent over the serial link  3601  may be re-sent if corruption is detected. This provides a communications system that is reasonably tolerant to ESD. Corrupted messages within the processor between processes may be handled as a hard system failure. All of the message payloads used with the messaging system may be data classes derived from a common baseclass (MessageBase) to assure consistency across all possible message destinations. 
     Brushless Motor Control IRQ  4262  may not run as a task; it may be implemented as a strict foreground (interrupt context) process. Interrupts are generated from the commutator or hall sensors  3436 , and the commutation algorithm may be run entirely in the interrupt service routine. 
     Various alternatives and modifications can be devised by those skilled in the art without departing from the disclosure. Accordingly, the present disclosure is intended to embrace all such alternatives, modifications and variances. Additionally, while several embodiments of the present disclosure have been shown in the drawings and/or discussed herein, it is not intended that the disclosure be limited thereto, as it is intended that the disclosure be as broad in scope as the art will allow and that the specification be read likewise. Therefore, the above description should not be construed as limiting, but merely as exemplifications of particular embodiments. And, those skilled in the art will envision other modifications within the scope and spirit of the claims appended hereto. Other elements, steps, methods and techniques that are insubstantially different from those described above and/or in the appended claims are also intended to be within the scope of the disclosure. 
     The embodiments shown in the drawings are presented only to demonstrate certain examples of the disclosure. And, the drawings described are only illustrative and are non-limiting. In the drawings, for illustrative purposes, the size of some of the elements may be exaggerated and not drawn to a particular scale. Additionally, elements shown within the drawings that have the same numbers may be identical elements or may be similar elements, depending on the context. 
     Where the term “comprising” is used in the present description and claims, it does not exclude other elements or steps. Where an indefinite or definite article is used when referring to a singular noun, e.g., “a,” “an,” or “the,” this includes a plural of that noun unless something otherwise is specifically stated. Hence, the term “comprising” should not be interpreted as being restricted to the items listed thereafter; it does not exclude other elements or steps, and so the scope of the expression “a device comprising items A and B” should not be limited to devices consisting only of components A and B. This expression signifies that, with respect to the present disclosure, the only relevant components of the device are A and B. 
     Furthermore, the terms “first,” “second,” “third,” and the like, whether used in the description or in the claims, are provided for distinguishing between similar elements and not necessarily for describing a sequential or chronological order. It is to be understood that the terms so used are interchangeable under appropriate circumstances (unless clearly disclosed otherwise) and that the embodiments of the disclosure described herein are capable of operation in other sequences and/or arrangements than are described or illustrated herein.