Patent Publication Number: US-2023160379-A1

Title: Modular valve apparatus and system

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation application of U.S. patent application Ser. No. 16/839,548, filed Apr. 3, 2020, entitled Modular Valve Apparatus and System and will be U.S. Pat. No. 11,549,502, issuing on Jan. 10, 2023 (Attorney Docket No. AA230), which is a divisional application of U.S. patent application Ser. No. 14/967,093, filed Dec. 11, 2015, entitled Modular Valve Apparatus and System, now U.S. Pat. No. 10,613,553, issued on Apr. 7, 2020 (Attorney Docket No. P82), claiming the benefit of U.S. Provisional Application Ser. No. 62/091,351 filed Dec. 12, 2014 and entitled Modular Valve Apparatus and System (Attorney Docket No. P33), which is hereby incorporated herein by reference in its entirety. 
     U.S. patent application Ser. No. 14/967,093, filed Dec. 11, 2015, entitled Modular Valve Apparatus and System, now U.S. Pat. No. 10,613,553, issued on Apr. 7, 2020 (Attorney Docket No. P82) is also a Continuation-in-Part of U.S. patent application Ser. No. 14/327,206 filed Jul. 9, 2014 and entitled Valve Apparatus and System, Abandoned on Jun. 23, 2021 (Attorney Docket No. M66), which claims the benefit of U.S. Provisional Application Ser. No. 61/844,202 filed Jul. 9, 2013 and entitled Valve Apparatus and System (Attorney Docket No. K61), each of which is hereby incorporated herein by reference in its entirety. 
    
    
     FIELD OF THE INVENTION 
     This application relates generally to fluid flow control valves or manifold valves, and more particularly to modular valved manifold systems. 
     BACKGROUND 
     Controlling the flow of a liquid may be accomplished by using a manifold connected to a pressurized fluid source—pneumatic or hydraulic—that distributes the pressurized fluid to a fluid-actuated liquid pumping or liquid flow control apparatus. Liquid flow valves or pumps (e.g., in medical devices) may be fluidically actuated in a selective manner—either hydraulically or pneumatically—through the use of controller-managed electromagnetic valves in a manifold assembly coupled to one or more fluid sources under positive or negative pressure. The manifold valves selectively direct positive or negative fluidic pressure to the liquid flow control apparatus. 
     A manifold assembly is typically custom-designed and assembled for the specific liquid flow control apparatus to which it is connected, and re-purposing the manifold for other applications (e.g. other pumping devices, or modified devices) is generally not feasible. ces. 
     Power consumption, heat generation and valve reliability can be a significant problem in valved manifolds, particularly in systems requiring the manifold valves to frequently change states. The manifold valves may require a constant source of current to maintain a particular position or state. In contrast, a bistable valve—stable in either of its positions or states—may only require energy input to change its state. However, integrating bistable valve assemblies into a pressure distribution manifold system may be overly complex and expensive. 
     Among some of the inventive improvements described herein: A modular manifold assembly is described that can be readily modified by the addition or subtraction of individual manifold modules in a concatenated manner, and may allow for rapid and convenient re-purposing of the manifold system. Manifold modules forming the building blocks for a manifold assembly are described that have standardized dimensions, inputs, outputs, and valve assemblies. Adding a standardized on-board controller to each module may additionally permit the manifold system to locally perform readily programmable and highly specialized functions in various pump/valve devices. A controller connected to a valved manifold is described that can be used to measure the amount of pressure delivered to or present in the liquid flow control apparatus, can control the rate of pressure delivery—either positive or negative, and can allow for the venting of fluidic pressure in the liquid flow control apparatus. Manifold modules are also described that can accommodate specialized bistable valve sets so that each valved manifold module (with or without an on-board controller) can operate without undue power consumption or heat generation, and allow for individual valve assemblies to be easily replaceable. 
     SUMMARY OF THE INVENTION 
     A manifold module comprises: a manifold base reversibly connectable to a pressure line containing pressurized fluid; a first valve assembly mounted to the manifold base; a controller mounted to the manifold base and connected to the valve assembly; the manifold base being configured to fluidically connect a pressure line inlet port of the manifold base to an inlet of the valve assembly, to fluidically connect a cavity of the valve assembly to a pressure sensing port of the manifold base, to fluidically connect an outlet of the valve assembly to an outlet of the manifold base, and to fluidically connect the pressure line inlet port to a pressure line outlet port of the manifold base. The first valve assembly is configured to be electrically actuated by the controller to either open or block communication between the inlet of the valve assembly and the cavity of the valve assembly, and the cavity of the valve assembly is in fluid communication with the outlet of the valve assembly. The controller comprises a pressure sensor mounted on a control board, the pressure sensor configured to form a reversible sealed connection with the pressure sensing port of the manifold base, the control board having one or more electrical output connectors for connection to an electromagnetic coil to actuate the valve assembly, and the control board having a first electronic communications connector for sending and receiving electronic communications to or from a communications bus on a first side of the manifold module, and having a second electronic communications connector for sending and receiving electronic communications to or from the communications bus on a second side of the manifold module. The manifold module is thereby configured to reversibly connect with a second manifold module via the first or second electronic communications connector and via the pressure line inlet port or the pressure line outlet port of the manifold base. 
     In another aspect, a modular manifold assembly comprises a plurality of concatenated manifold blocks, each manifold block having a flowpath connecting a pressure line inlet port on a first side of the manifold block to a pressure line outlet port on a second side of the manifold block via a fluidic bus in the manifold block, the pressure line outlet port of a first manifold block being connected to the pressure line inlet port of an adjacent second manifold block. The first and second manifold blocks are each reversibly connected to each other, and are each separately reversibly connected to a pressurized fluid line; each manifold block having a valve assembly receiving station for mounting a pre-determined number of valve assemblies; each valve assembly comprising an inlet configured to fluidically communicate with a respective fluidic bus port of the manifold block; each valve assembly configured to be electrically actuated to open or block fluid communication between a cavity of the valve assembly and the inlet of the valve assembly, the cavity of each valve assembly in fluid communication with a respective outlet of the manifold block and in fluid communication with a respective pressure sensing port of the manifold block; and each valve assembly having electrical contacts for actuating the respective valve assemblies, the electrical contacts configured to connect to a programmable controller board mounted on the manifold block. The controller board comprises pressure sensors configured to reversibly and sealably connect to respective sensing ports on the manifold block. And each of the plurality of manifold blocks is tasked by its programmable controller to control one of a plurality of pumps or valves of a liquid flow control apparatus. 
     In another aspect, a manifold module for controlling a pneumatically actuated diaphragm pump comprises: a manifold base reversibly connectable via a first pressure line inlet port to a first pressure line containing positively pressurized gas and a second pressure line inlet port to a second pressure line containing negatively pressurized gas; first, second, third and fourth valve assemblies, each mounted to a valve assembly receiving station on the manifold base; and a controller mounted to the manifold base and connected to the four valve assemblies. The manifold base is configured to fluidically connect the first pressure line inlet port of the manifold base to a first inlet respectively of the first, second and third valve assemblies, to fluidically connect the second pressure line inlet port of the manifold base to a second inlet respectively of the first, second and fourth valve assemblies, to fluidically connect a cavity of each of the third and fourth valve assemblies to a respective pressure sensing port of the manifold base, to fluidically connect an outlet of each of the valve assemblies to a respective outlet of the manifold base, and to fluidically connect the first and second pressure line inlet ports of the manifold base to respective first and second pressure line outlet ports of the manifold base. Each of the first and second valve assemblies is configured to be electrically actuated by the controller to establish fluid communication between the cavity of the first or second valve assemblies and the first inlet of the first and second valve assemblies, or establish fluid communication between the cavity of the first or second valve assemblies and the second inlet of the first and second valve assemblies. The third valve assembly is configured to be electrically actuated by the controller to open or close communication between the cavity of the third valve assembly and the first inlet of the third valve assembly. The fourth valve assembly is configured to be electrically actuated by the controller to open or close communication between the cavity of the fourth valve assembly and the second inlet of said fourth valve assembly. The first valve assembly is configured to fluidically connect to a first fluid inlet diaphragm valve of the diaphragm pump, the second valve assembly is configured to fluidically connect to a second fluid outlet diaphragm valve of the diaphragm pump, and the third and fourth valve assemblies are configured to fluidically connect to a control chamber of the diaphragm pump. The controller comprises first and second pressure sensors mounted on a control board, the pressure sensors configured to form a reversible sealed connection respectively with the pressure sensing ports of the manifold base connected to the cavities of the third and fourth valve assemblies. Thus the controller is configured to coordinate actuation of the four valve assemblies to open the inlet valve, close the outlet valve and generate a fill stroke in the diaphragm pump, or close the inlet valve, open the outlet valve and generate a deliver stroke in the diaphragm pump. 
     In another aspect, a manifold pressure measurement module comprises: a manifold base having a first pressure line inlet port for connection to a first pressure line containing positively pressurized gas, a second pressure line inlet port for connection to a second pressure line containing negatively pressurized gas, a third inlet port for venting to atmospheric pressure; and a fourth inlet port for connection to a control chamber of a pneumatically actuated diaphragm pump. There are first, second third and fourth valve assemblies, each mounted to a valve assembly receiving station on the manifold base. A controller is mounted to the manifold base and connected to the four valve assemblies. The manifold base is configured to fluidically connect the first pressure line inlet port to a first inlet of the first valve assembly, to fluidically connect the second pressure line inlet port to a first inlet of the second valve assembly, to fluidically connect the third inlet port to a first inlet of the third valve assembly, and to fluidically connect the fourth inlet port to a first inlet of the fourth valve assembly. The manifold base is also configured to connect valve cavities of each valve assembly to respective pressure sensing ports of the manifold base, and to connect each of the valve cavities to a reference reservoir of known volume. The first, second, third and fourth valve assemblies are configured to be selectively electrically actuated by the controller to open or close communication between the cavities of the valve assemblies and the first inlets of the valve assemblies. The controller comprises first, second, third and fourth pressure sensors mounted on a control board, the pressure sensors configured to form a reversible sealed connection respectively with the pressure sensing ports of the manifold base. The controller is thereby configured to operate the first, second, third and fourth valve assemblies to charge the reference reservoir with positive or negative pneumatic pressure, or to open the reference reservoir to atmospheric pressure, and to fluidically connect the reference reservoir with the control chamber of the diaphragm pump to equalize pressures between the control chamber and the reference reservoir, and to record pressures in one or more valve chambers before and after pressure equalization. This procedure allows the controller to calculate a volume of the pump control chamber (and thus a volume of the liquid in the pumping chamber) using one or more models based on the ideal gas laws. 
     In another aspect, a valve assembly comprises a shuttle within a valve cavity configured to move linearly from a first position blocking a first inlet of the valve cavity to a second position allowing the first inlet to fluidly communicate with the valve cavity, the movement of the shuttle being actuated electromagnetically, magnetically, or through a biasing force applied by a spring. A molded insert having an outer wall is configured to conform to an inner wall of the valve cavity, and has an inner wall configured to surround the shuttle and permit the shuttle to move from the first position to the second position. The molded insert has an inlet orifice configured to mate with the first inlet of the valve cavity and to be interposed between the first inlet of the valve cavity and a first face of the shuttle. The molded insert has an outlet orifice configured to fluidly communicate with a fluid outlet of the valve cavity. The first molded insert is manufactured from an elastomeric or plastic material that reduces acoustical noise generated by movement of the shuttle. 
     In another aspect, a fluid pumping system comprises a cassette having a flexible diaphragm; a system controller; and a manifold module. The manifold module comprises: a manifold base reversibly connectable to a pressure line containing pressurized fluid; a first valve assembly mounted to the manifold base; and a module controller mounted to the manifold base and connected to the valve assembly. The manifold base is configured to fluidically connect a pressure line inlet port of the manifold base to an inlet of the valve assembly, to fluidically connect a cavity of the valve assembly to a pressure sensing port of the manifold base, to fluidically connect an outlet of the valve assembly to an outlet of the manifold base, and to fluidically connect the pressure line inlet port to a pressure line outlet port of the manifold base. The first valve assembly is configured to be electrically actuated by the module controller to either open or block communication between the inlet of the valve assembly and the cavity of the valve assembly, and the cavity of the valve assembly being in fluid communication with the outlet of the valve assembly. The module controller comprises a pressure sensor mounted on a control board, the pressure sensor configured to form a reversible sealed connection with the pressure sensing port of the manifold base, the control board having one or more electrical output connectors for connection to an electromagnetic coil to actuate the valve assembly, and the control board has a first electronic communications connector for sending and receiving electronic communications to or from a communications bus on a first side of the manifold module. The control board also has a second electronic communications connector for sending and receiving electronic communications to or from the communications bus on a second side of the manifold module. The control board is configured to receive a summary command from the system controller, the control board is configured to generate, based on the summary command, at least one module command addressed to the first valve assembly, the at least one module command enabling selective application of pressure to the flexible diaphragm. The manifold module is thereby configured to reversibly connect with a second manifold module via the first or second electronic communications connector and via the pressure line inlet port or the pressure line outlet port of the manifold base. 
     In another aspect, a fluid flow control system for controlling a pump cassette comprises: a pump cassette including a diaphragm pump having an inlet valve and an outlet valve; a system controller; a manifold base reversibly connectable via a first pressure line inlet port to a first pressure line containing positively pressurized gas and a second pressure line inlet port to a second pressure line containing negatively pressurized gas; first, second, third and fourth valve assemblies, each mounted to a valve assembly receiving station on the manifold base; and an on-board controller mounted to the manifold base and connected to the four valve assemblies. The manifold base is configured to fluidically connect the first pressure line inlet port of the manifold base to a first inlet respectively of the first, second and third valve assemblies, to fluidically connect the second pressure line inlet port of the manifold base to a second inlet respectively of the first, second and fourth valve assemblies, to fluidically connect a cavity of each of the third and fourth valve assemblies to a respective pressure sensing port of the manifold base, to fluidically connect an outlet of each of the valve assemblies to a respective outlet of the manifold base, and to fluidically connect the first and second pressure line inlet ports of the manifold base to respective first and second pressure line outlet ports of the manifold base. Each of the first and second valve assemblies is configured to be electrically actuated by the on-board controller to establish communication between the cavity of said first or second valve assemblies and the first inlet of the first and second valve assemblies, or establish communication between the cavity of the first or second valve assemblies and the second inlet of the first and second valve assemblies. The third valve assembly is configured to be electrically actuated by the on-board controller to open or close communication between the cavity of the third valve assembly and the first inlet of the third valve assembly. The fourth valve assembly is configured to be electrically actuated by the on-board controller to open or close communication between the cavity of the fourth valve assembly and the second inlet of the fourth valve assembly. The first valve assembly is configured to fluidically connect to the inlet valve of the diaphragm pump, the second valve assembly is configured to fluidically connect to the outlet valve of the diaphragm pump, and the third and fourth valve assemblies are configured to fluidically connect to a control chamber of the diaphragm pump. The on-board controller comprises first and second pressure sensors mounted on a control board, the pressure sensors configured to form a reversible sealed connection respectively with the pressure sensing ports of the manifold base connected to the cavities of the third and fourth valve assemblies. And the on-board controller is configured to coordinate actuation of the four valve assemblies to open the inlet valve, close the outlet valve and generate a fill stroke in the diaphragm pump, or close the inlet valve, open the outlet valve and generate a deliver stroke in the diaphragm pump, with the system controller being configured to provide commands to the on-board controller that may include a start pumping command, a stop pumping command, or a command to pump a pre-determined quantity of liquid. 
     The details of one or more embodiments are set forth in the accompanying drawings and the description below. Other features and advantages will become apparent from the description, the drawings, and the claims. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1 A  is a perspective view of the one embodiment of a bistable valve; 
         FIG.  1 B  is a cross-sectional view of one embodiment of a bistable valve with a shuttle capable of being actuated by electromagnets; 
         FIG.  1 C  is another cross-sectional view of the embodiment of  FIG.  1 A ; 
         FIG.  1 D  is a partial cross-sectional view of the embodiment of  FIG.  1 A  with a more detailed view of the shuttle; 
         FIG.  1 E  is a top view of a ring plate according to one embodiment; 
         FIG.  2 A  is a perspective view of one embodiment of a shuttle; 
         FIG.  2 B  is a cross-sectional view of the shuttle of  FIG.  2 A , showing two disk magnets oriented back-to-back; 
         FIG.  2 C  is a view of the magnetization vector and magnetic flux path of one embodiment of a shuttle; 
         FIG.  2 D  is a view of the magnetic flux path of one embodiment when the shuttle is acted upon by an electromagnetic coil; 
         FIG.  2 E  is a view of the magnetic flux path of one embodiment, when the shuttle is acted upon by an electromagnetic coil in the presence of a ring plate; 
         FIG.  2 F  is a perspective view of one embodiment of a shuttle having mechanical retainers; 
         FIG.  2 G  is a cross-sectional view of the shuttle of  FIG.  2 F , showing mechanical retainers; 
         FIG.  3 A  is a perspective view of one embodiment of a shuttle showing two stacked ring magnets; 
         FIG.  3 B  is a cross-sectional view of the shuttle of  FIG.  3 A ; 
         FIG.  4 A  is a perspective view of one embodiment of a shuttle showing radially-oriented magnets; 
         FIG.  4 B  is a cross-sectional view of the shuttle of  FIG.  4 A ; 
         FIG.  4 C  is a top cross-sectional view of the shuttle of  FIG.  4 A ; 
         FIG.  4 D  is a cross-sectional view of one embodiment of a shuttle showing radially-oriented magnets; 
         FIG.  5 A  is a perspective view of one embodiment of a shuttle showing radially-oriented magnets in a stacked pattern; 
         FIG.  5 B  is a cross-sectional view of the shuttle of  FIG.  5 A ; 
         FIG.  5 C  is another cross-sectional view of the shuttle of  FIG.  5 A ; 
         FIG.  6 A  is a front view of one embodiment of a shuttle having guide posts on either side of the shuttle; 
         FIG.  6 B  is a cross-sectional view of one embodiment of a shuttle having elastomer guide posts; 
         FIG.  6 C  is a cross-sectional view of one embodiment of a shuttle having conical elastomer guide posts; 
         FIG.  7    is a cross-sectional view of one embodiment of a valve apparatus and system with the shuttle encased in a membrane; 
         FIG.  8    is a cross-sectional view of one embodiment of a valve apparatus and system including stacked electromagnetic coil geometry; 
         FIG.  9 A  is a cross-sectional view of one embodiment of a valve apparatus and system, utilizing a cantilever armature instead of a shuttle; 
         FIG.  9 B  is a cross-sectional view of one embodiment of a valve apparatus and system, using an axially-oriented magnet in conjunction with a cantilever armature; 
         FIG.  9 C  is a cross-sectional view of another embodiment of a valve apparatus and system, using a radially-oriented magnet in conjunction with a cantilever armature; 
         FIG.  10 A  is a perspective view of one embodiment of a valve apparatus and system arranged in an array; 
         FIG.  10 B  is a top view of a circuit board having multiple flat electromagnetic coils according to one embodiment; 
         FIG.  10 C  is a cross-sectional view of one embodiment of a valve apparatus and system arranged in an array; 
         FIG.  11 A  is a cross-sectional view of one embodiment of a valve apparatus and system integrated into a pumping system; 
         FIG.  11 B  is a cross-sectional view of another embodiment of a valve apparatus and system integrated into a pumping system; 
         FIG.  12 A  is a cross-sectional view of one embodiment of a valve apparatus and system arranged in an array; 
         FIG.  12 B  is another cross-sectional view of one embodiment of a valve apparatus and system arranged in an array; 
         FIG.  13    is a top view of an outer plate for use in an array geometry embodiment; 
         FIGS.  14 A- 14 C  are a perspective view and two cross-sectional views of an embodiment of a valve apparatus; 
         FIGS.  15 A- 15 B  are a perspective view and a cross-sectional view of an embodiment of a valve apparatus; 
         FIGS.  16 A- 16 B  are a perspective view and a cross-sectional view of an embodiment of a valve apparatus; 
         FIGS.  17 A- 17 B  are a perspective view and a cross-sectional view of an embodiment of a valve apparatus; 
         FIGS.  17 C- 17 D  are a perspective view and a cross-sectional view of a shuttle for the valve apparatus of  FIGS.  17 A- 17 B ; 
         FIG.  17 E  is a cross-sectional view of the valve apparatus of  FIGS.  17 A and  17 B ; 
         FIGS.  18 A- 18 B  are a perspective view and a cross-sectional view of an embodiment of a valve manifold; 
         FIGS.  19 A- 19 B  are a perspective view and a cross-sectional view of an embodiment of a valve assembly configured as a pressure regulator; 
         FIGS.  20 A- 20 C  are a cross-sectional view and perspective views of an embodiment of a valve apparatus; and 
         FIGS.  21 A- 21 C  are a cross-sectional view and perspective views of an embodiment of a valve apparatus. 
         FIG.  22    depicts a representational view of an interior cavity of an example bistable valve apparatus; 
         FIG.  23    is a perspective view of an example coil assembly for a bistable valve assembly; 
         FIG.  24    is a perspective view of an valve assembly showing connectors attached to coil assembly terminals; 
         FIG.  25 A-C  are a cross-sectional view and perspective views of an embodiment of a valve apparatus; 
         FIG.  26 A  is a plan view of a valve assembly; 
         FIG.  26 B  is a cross-section view of the valve assembly of  FIG.  26 A   
         FIG.  26 C  is an exploded view of the valve assembly of  FIGS.  26 A and  26 B ; 
         FIG.  27 A  is a plan view of a valve assembly; 
         FIG.  27 B  is a cross-sectional view of the valve assembly of  FIG.  27 A ; 
         FIG.  27 C  is an exploded view of the valve assembly of  FIGS.  27 A and  27 B ; 
         FIG.  27 D  is a cross-sectional view of a portion of an insert for a valve assembly; 
         FIG.  28 A  is a plan view of a valve assembly; 
         FIG.  28 B  is a cross-sectional view of the valve assembly of  FIG.  28 A ; 
         FIG.  28 C  is an exploded view of the valve assembly of  FIGS.  28 A and  28 B ; 
         FIG.  28 D  is a perspective view of a monolithic valve gasket which may be included in a bi-stable valve assembly; 
         FIGS.  29 A-D  are cross-sectional and perspective views of an embodiment of a valve apparatus; 
         FIG.  30 A  is a plan view of a valve assembly; 
         FIGS.  30 B-C  are perspective views of the valve assembly of  FIG.  30 A ; 
         FIGS.  30 D-E  are cross-sectional views of the valve assembly of  FIGS.  30 A-C ; 
         FIG.  31    is a cross-sectional view of an interior cavity of a bi-stable valve in which the shuttle includes a keyed alignment feature; 
         FIGS.  32 A- 32 C  are perspective, cross-sectional and exploded views of an example shuttle which includes a number of keyed alignment features; 
         FIGS.  33 A- 33 B  are perspective views of an example shuttle; 
         FIG.  33 C  is a cross-sectional view of an exemplary valve cavity in which the shuttle of  FIGS.  33 A-B  is positioned; 
         FIG.  34 A  depicts an abstracted block diagram of a valve module; 
         FIG.  34 B  depicts an abstracted block diagram of a manifold comprising a number of valve modules; 
         FIGS.  34 C- 34 G  depict a number of representational block diagrams of pneumatic pump/valve systems controlled by modular manifold assemblies; 
         FIG.  34 H  depicts a representational block diagram of a modular manifold assembly controlling a variety of electrical or electronic components or devices; 
         FIG.  35 A  is a perspective view of a programmable valved manifold module; 
         FIG.  35 B  is a perspective view of two connected or concatenated programmable valved manifold modules; 
         FIG.  35 C  shows a programmable valved manifold module of  FIG.  35 A  with the controller board disconnected from the valve assemblies and the module base; 
         FIG.  35 D  is a perspective view of the programmable valved manifold module of  FIG.  35 A  showing pneumatic output lines of the module; 
         FIG.  35 E  is a perspective view of manifold assembly comprising a stack of four banks of grouped or concatenated programmable valved manifold modules; 
         FIG.  35 F  depicts a block diagram of the connections of a manifold assembly comprising a stack of four banks of grouped or concatenated programmable valved manifold modules; 
         FIG.  36    depicts a pneumatic schematic diagram of a valve manifold module controlling a pump/valve unit; 
         FIG.  37    depicts a block diagram of the pneumatic connections of a pressure measurement valved manifold module; 
         FIG.  38 A  depicts a block diagram of a pumping valved manifold module that is paired with a fluid pressure measurement valved manifold module; 
         FIG.  38 B  shows a block diagram of a pressure measurement valved manifold module connected to a reference reservoir and a pump control chamber; 
         FIG.  39    depicts a block diagram of a regulator valve manifold module with pressure reservoirs or accumulators; 
         FIG.  40    is a perspective view of an example of a pneumatic isolation assembly mountable to a valve slot of a valved manifold module; 
         FIGS.  41 A-B  depict a schematic representation of a group of valved manifold modules configured to control pumping of fluid through a fluid handling cassette; 
         FIGS.  42 A-B  depict another schematic representation of a group of valved manifold modules configured to control pumping of fluid through a fluid handling cassette; 
         FIGS.  43 A and  43 B  depict a schematic representation of an implementation of a manifold assembly comprising a group of programmable valved manifold modules operating various pumps and valves of a hemodialysis system; 
         FIG.  44    depicts a flowchart outlining a procedure for initiating automatic enumeration of manifold modules in a manifold assembly; 
         FIG.  45    depicts a flowchart outlining a procedure for automatically enumerating manifold modules on a communications bus; 
         FIG.  46    depicts a flowchart outlining a procedure for enumerating a new module being installed onto a communications bus that has already been enumerated; 
         FIG.  47    depicts a flowchart outlining a procedure which may be used to assign tasks to various modules in a manifold assembly; 
         FIG.  48    depicts a flowchart outlining a procedure for commanding operation of a module; 
         FIG.  49    depicts a flowchart outlining a procedure of transmitting feedback data from a valve module to a main controller; 
         FIG.  50    depicts a flowchart outlining another example method for providing feedback from a module; 
         FIG.  51    depicts a flowchart outlining a procedure for commanding operation of a valve within a valve module; 
         FIGS.  52 A-B  depict a flowchart outlining a procedure for a valve manifold module actuating the pumping of fluid through a pump chamber of a cassette; 
         FIG.  53    depicts a flowchart outlining a procedure for commanding a pump stroke from a pump chamber of a cassette via a number of valve modules; 
         FIG.  54    depicts a flowchart outlining a procedure for commanding coordinated pumping of fluid through multiple pump chambers; 
         FIG.  55    depicts a flowchart outlining a pumping command set having been sent from a main controller and a procedure for commanding pumping of fluid with one pumping chamber in a filled state; 
         FIG.  56    shows an exemplary graph depicting pressure of a control chamber of a pump over time during a pump stroke; 
         FIG.  57    depicts a flowchart outlining a procedure for detecting an end-of-stroke condition with a chamber control module controller; 
         FIG.  58    depicts a flowchart outlining a procedure for detecting an end-of-stroke condition with a chamber control module controller; 
         FIG.  59    depicts a flowchart outlining a procedure for limiting the toggle frequency of a valve within a valve module; and 
         FIG.  60    depicts a flowchart outlining a procedure that may be used to control the amount of pressure delivered to a pump control chamber. 
     
    
    
     Like reference symbols in the various drawings indicate like elements. 
     DETAILED DESCRIPTION 
     Bistable Valve Embodiments 
     One aspect of a valve apparatus and system is illustrated in  FIGS.  1 A- 1 E . This aspect of the bistable valve  13  includes a first pressure inlet  12 , a second pressure inlet  14 , a shuttle  16 , circuit boards  18 , each having an electromagnetic coil  34  to actuate the shuttle  16 , a valve manifold  20  having an interior valve cavity  32 , and a common output orifice  22  in fluid communication with the valve cavity  32 . 
     The first pressure inlet  12  may have a hollow post portion  28  extending into the valve cavity  32 . In some embodiments, this may be constructed of a ferrous material. Similarly, the second pressure inlet  14  has a hollow post portion  30  extending into the valve cavity  32  substantially opposite from the first pressure post  28 , and may also be constructed of a ferrous material. In some aspects, the first pressure post  28  may include a first pressure orifice  24 , which is in fluid communication with the first pressure inlet  12 . Similarly, the second pressure post  30  may have a second pressure orifice  26  which may be in fluid communication with the second pressure inlet  14 . 
     A first circuit board  18  having a first electromagnetic coil  34  is disposed around the first pressure post  28  such that, when energized, the first electromagnetic coil  34  supplies a magnetic charge to the first pressure post  28 . Similarly, a second circuit board  18  having a second electromagnetic coil  34  is disposed around the second pressure post  30  such that, when energized, the second electromagnetic coil  34  supplies a magnetic charge to the second pressure post  30 . An outer plate  19  constructed of a ferrous material may be disposed around each of the first pressure post  28  and the second pressure post  30 , and abutting an insulating layer on the outer edge  21  of each of the circuit boards  18 . In some aspects, each of the outer plates  19  may be connected to each other by way of fasteners  17  also constructed of a ferrous material. A ring plate  23  may be included, constructed of a ferrous material and having a central opening  25  defined by an inner edge  27 , disposed in the valve manifold  20  such that the ring plate  23  is in contact with each fastener  17 . The central opening  25  surrounds the shuttle  16  within the interior valve cavity  32 . The outer plates  19  and fasteners  17  form a box of ferrous material surrounding the electromagnetic coils  34 , the first pressure post  28 , the second pressure post  30 , the ring plate  23 , and the shuttle  16 . The outer plates  19 , fasteners  17 , ring plate  23 , first pressure post  28  and second pressure post  30  may all be constructed of a ferrous material including, but not limited to, iron, stainless steel or a nickel-iron alloy such as mu metal or, more specifically, a  42  nickel-iron alloy, the composition of which contains approximately 42% nickel. 
     The shuttle  16  may be sealed against the first pressure orifice  24  in a first stable position such that the second pressure orifice  26  is in fluid communication with the interior valve cavity  32 . One or more magnets (e.g., see magnets  38 ,  FIG.  2 B ) may be mounted or attached to the shuttle  16  to provide an attractive force between the shuttle  16  and components surrounding the pressure orifice  24  or  26 . Alternatively, the shuttle  16  may be sealed against the second pressure orifice  26  in a second stable position such that the first pressure orifice  24  is in fluid communication with the interior valve cavity  32 . In each static sealing position, the shuttle  16  is held in place by a magnetic attraction from the shuttle  16  to either the first pressure post  28  or the second pressure post  30 , whichever is being sealed. 
     To switch the position of the shuttle  16  from sealing against the first pressure orifice  24  to sealing against the second pressure orifice  26 , the electromagnetic coils  34  disposed around each of the second pressure post  30  and the first pressure post  28  are energized such that the first pressure post  28  exerts a repellant force on the shuttle  16 , while the second pressure post  30  exerts an attractive force on the shuttle  16 . One or both forces may be sufficient to actuate movement of the shuttle  16 . In one embodiment, both the attractive and repellant forces working together are enough to overcome the static magnetic force currently holding the shuttle  16  to the first pressure orifice  24 . Once this occurs, the shuttle  16  moves linearly through the valve cavity  32  from sealing the first pressure orifice  24  to sealing the second pressure orifice  26 . Once this switch occurs, the electromagnetic coils  34  cease to be energized and the shuttle  16  is retained against the second pressure orifice  26  through a static magnetic attraction. 
     Similarly, to switch the position of the shuttle  16  from sealing against the second pressure orifice  26  to sealing against the first pressure orifice  24 , the electromagnetic coils  34  disposed around each of the first pressure post  28  and the second pressure post  30  are energized such that the second pressure post  30  exerts a repellant force on the shuttle  16 , while the first pressure post  28  exerts an attractive force on the shuttle  16 . Either or both forces may be sufficient to actuate movement of the shuttle. In an embodiment, both the attractive and repellant forces working together are enough to overcome the magnetic force statically holding the shuttle  16  to the second pressure orifice  26 . Once this occurs, the shuttle  16  moves linearly through the valve cavity  32  from sealing the second pressure orifice  26  to sealing the first pressure orifice  24 . Once this switch occurs, the electromagnetic coils  34  cease to be energized and the shuttle  16  is retained against the first pressure post  28  through a static magnetic attraction. 
     In an exemplary implementation, the electromagnetic coils  34  are both energized in series in one polarity to actuate the shuttle  16  in one direction. Similarly, to actuate the shuttle  16  in the opposite direction, both electromagnetic coils  34  are energized together in series in the opposite polarity. 
     Optionally, the coils  34  may be energized by discharging current from a charged capacitor. Once the capacitor is discharged, current ceases to charge the respective coil  34 , and the shuttle  16  is held against either the first pressure post  28  or the second pressure post  30 , by way of static magnetic attraction while the capacitor recharges. Use of a capacitor to charge the electromagnetic coils  34  may have certain safety-related advantages. It may help to limit the amount of continuous current flowing through the coils  34  to reduce the possibility of over-heating. It may also reduce the size, complexity and cost of the apparatus. In one example, a single capacitor may be used to energize multiple valves. In alternate embodiments, the electromagnetic coils  34  may be energized individually by separate sources of electrical current or separate charging devices. 
     In a yet simpler implementation, actuation of the shuttle  16  may only require activation of a single electromagnetic coil to move the shuttle  16  in either direction or sealing position. 
     To reduce the acoustic noise generated during displacement of a shuttle  16 , the interior valve cavity  32  may be sized to minimize the travel distance of the shuttle  16  when actuated from one sealing position to another sealing position. Reduction of shuttle travel may help to increase the life of a valve, as less shuttle kinetic energy is used in operating the valve. A shorter shuttle  16  excursion may also reduce the possibility of misalignment with the valve seats during displacement. In an example, the shuttle  16  may be sized such that it need only displace ˜5% or less of the length of the interior valve cavity to transition from one sealing position to another sealing position. More specifically, for example, the interior valve cavity  32  may measure about 0.200″ long and the shuttle  16  may measure about 0.190″ long. 
     Optionally, a shuttle for a bistable valve may include at least one elastomeric layer. An elastomeric layer may be present on the outward faces of the shuttle that seal the inlets to an interior valve cavity of a bistable valve. The thickness as well as the material comprising the elastomer layer(s) can vary. In some examples, the thickness of the elastomer layer may be between about 0.0010″ and 0.0030 thick. More specifically, for example, the thickness of the elastomer layer may be about 0.0020″ thick. 
     Referring now also to  FIGS.  2 A and  2 B , the shuttle  16  may include a carrier  36  and two magnets  38 , aligned concentrically and oriented back-to back with their opposing faces  40  having the same polarity. As such, they will exhibit a repelling force against each other. The shuttle  16  may include an elastomer layer  42  disposed on each magnet&#39;s outward face  44  and can provide a seal when the shuttle  16  is actuated against either the first pressure orifice  24  or the second pressure orifice  26 . The elastomer layer  42  may be constructed of a pliant material which may include, for example, silicone and/or polyurethane. Each elastomer layer  42  may be retained in the shuttle  16  mechanically, for example, by portions of the shuttle  16  that overlap the edge of each elastomer layer  42  and sandwich it to the corresponding magnet&#39;s outward face  44 . In other implementations, each elastomer layer  42  may be retained in the shuttle  16  by an adhesive holding the elastomer to each magnet&#39;s outward face  44 . Alternatively, the elastomer layers  42  may be secured to each magnet&#39;s outward face  44  by way of overmolding the entire magnet  38  with the elastomer material, or applying a two-part elastomer material to the magnet  38 . For example, each elastomer layer  42  may be constructed by sandwiching each magnet  38  between two sheets of elastomer material and melting portions of the sheets to each other in order to create a pocket of elastomer in which each magnet  38  resides. Optionally, the elastomer layer on one side of the shuttle  16  may be thicker than the other side in order to decrease the sealing stability on the thicker side. This may be advantageous, for example, when a failsafe valve operation is desired, the thicker membrane allowing for easier disengagement of the shuttle from the port to be opened. 
     When a magnet is entirely overmolded by an elastomeric material, the magnet material optionally may first have the elastomeric material overmolded onto it before magnetizing the magnet material. In other examples, the elastomeric overmolded material may comprise a magnetic (e.g. ferrite filled) material. 
     In some examples, the seal between the first or second pressure orifice  24 ,  26  and the shuttle can be enhanced by the first or second pressure post  28 ,  30  having a flat surface with rounded edges surrounding the first pressure orifice  24  and the second pressure orifice  26 . Alternatively, the shuttle  16  may seal against a pressure post having a conical geometry surrounding the first pressure orifice  24  and the second pressure orifice  26 . Optionally, the conical geometry of the pressure post may terminate with a flat surface with a width of about 0.005 inches immediately surrounding both the first pressure orifice  24  and the second pressure orifice  26 . In some embodiments, the shuttle  16  may seal against a pressure post having a hemispherical tip geometry surrounding both the first pressure orifice  24  and the second pressure orifice  26 . 
     In some embodiments, the carrier  36  of the shuttle  16  may include a guide element  46  and/or  48  having a cavity  50  enclosing each elastomer layer  42  such that the guide cavity  50  envelopes a portion of both the first pressure post  28  or the second pressure post  30 , depending on which is being sealed. In an exemplary embodiment, the guide elements may enclose or surround at least partially both pressure posts regardless of which is being sealed. This may be beneficial/desirable, for example, to maintain proper alignment of the shuttle  16  with each pressure post  28 ,  30 . Optionally, the guide elements  46 ,  48  may also include a plurality of air flow notches  52  that enable fluid communication between the valve cavity  32  and either the first pressure orifice  24  or the second pressure orifice  26 , whichever is not being sealed, by way of the corresponding guide cavity  50 . 
     Optionally, the shuttle  16  magnets may be constructed to use the attractive magnetic force with each pressure post to maintain proper alignment. In some cases, this may obviate the need for guide elements  46  and/or  48 . 
     In a shuttle having two magnets (such as that shown in  FIG.  2 A  for example), the distance between the two magnets of the shuttle may vary. For example, the distance or gap between the magnets of the shuttle may be between about 0.0010″ and 0.0110″. In an exemplary embodiment, the distance or gap may be about 0.0040″. 
     Referring now also to  FIG.  2 C , the magnetic flux path present in some embodiments of the shuttle  16  is shown. The magnets  38  may be oriented back-to-back with their opposing faces  40  having the same polarity, and as such, exhibit a repelling force against each other. When the magnets  38  are oriented in this manner, a radial magnetic vector  39  is created by the interaction of the magnets&#39; respective flux leakage paths  29 . These direct switching of the position of the shuttle  16  when the electromagnetic coils  34  are sufficiently energized, as shown in  FIG.  2 D . When the shuttle  16  is positioned against the second pressure orifice  26  and the electromagnetic coils  34  are energized such that they supply an attractive magnetic force to the first pressure post  28  and a repellant magnetic force to the second pressure post  30 , the flux leakage paths  29  of the shuttle  16  will cause the attractive and repellant magnetic forces of the posts  28 ,  30  to repel the shuttle  16  away from the second pressure post  30  and attract it towards the first pressure post  28 . 
     Similarly, when the shuttle  16  is positioned against the first pressure orifice  24  and the electromagnetic coils  34  are energized such that they supply an attractive magnetic force to the second pressure post  30  and a repellant magnetic force to the first pressure post  28 , the flux leakage paths  29  of the shuttle  16  will cause the attractive and repellant magnetic forces of the posts to repel the shuttle  16  away from the first pressure post  28  and attract it towards the second pressure post  30 , positioning it against the second pressure orifice  26 . 
     Referring now also to  FIG.  2 E , a ring plate  23  may optionally be used to assist in switching the position of the shuttle  16 . In an example, the ring plate  23  may be disposed around the shuttle  16  such that its inner edge  27  is in close proximity to the shuttle  16  in either sealing position. When the first pressure post  28  and the second pressure post  30  are energized such that they induce the shuttle  16  to switch sealing positions, the ring plate  23  may help to focus the magnetic flux from the first pressure post  28  and the second pressure post  30  more effectively through the fasteners  17  and the outer plates  19  to assist in attracting one side of the shuttle  16  and repelling the opposite side of the shuttle  16 . This may assist in the shuttle  16  switching positions. 
     Referring now to  FIGS.  2 F and  2 G , the shuttle  16  may optionally include layers of elastomer  42 , which in an example are retained to the magnet faces  44  through mechanical retainers  41 . Magnetic force from each of the pressure posts may help to maintain alignment of the shuttle and may not require the use of any guide elements. 
     Referring now also to  FIGS.  3 A and  3 B , the shuttle  54  may optionally include a carrier  56  and two ring magnets  58 , aligned concentrically and oriented back-to back with their opposing faces  59  having the same polarity. As such, the two ring magnets  58  exhibit a repelling force against each other. A layer of elastomer  60  or other material may also be disposed between the two ring magnets  58 , so that the central aperture  61  of one ring magnet is separated from the central aperture of the other. 
     Referring to  FIGS.  4 A and  4 B , another example of the shuttle  62  may include a carrier  64 , with a plurality of magnets  66  arranged radially around a central axis  76 . Two central guide cavities  70  are aligned coaxially with the central axis  76 , one extending to a top surface  72  and the other extending to a bottom surface  74 . Each radially-oriented magnet  66  is arranged to have a magnetization vector through its thickness, giving the shuttle  62  an overall radial magnetization vector. Optionally, the shuttle  62  may further include a layer of elastomer  68  or other material disposed in each of the central guide cavities  70 . In some embodiments, and as shown in  FIG.  4 D , two central guide cavities  70  may be formed by positioning a layer of elastomer  69  in a central channel  71  that extends through the entire thickness of the shuttle  62  such that the elastomer  69  bisects the channel  71  and fluidically separates the top surface  72  from the bottom surface  74 . 
     Referring to  FIGS.  5 A and  5 B , in another example, the shuttle  78  may include a carrier  80 , comprising two or more concentrically-stacked layers  82 , each having a plurality of magnets  84  arranged radially around a central axis  90 . Each radially-oriented magnet  84  is arranged to have a magnetization vector through its thickness, thereby giving the shuttle  78  an overall radial magnetization vector. The shuttle  78  may include a central cavity  88  disposed along the central axis  90  and extending through the entire thickness of each layer  82 . Optionally, the shuttle  78  may include a layer of elastomer  86  positioned between each of the concentrically-stacked layers  82  and fluidically separating the central cavity  88  of one layer  82  from the central cavity  88  of another layer  82 . 
     Referring now to  FIG.  5 C , in some examples, the shuttle  78  may include two central guide cavities  92 , aligned coaxially with a central axis  90 , one extending into a top surface  96  of the shuttle  78 , and the other extending into a bottom surface  98  of the shuttle  78 . Optionally, the shuttle  78  may also include a layer of elastomer  94  positioned in each of the two central guide cavities  92 . 
     In an alternate example, the shuttle  78  shown in  FIGS.  5 A and  5 B  may comprise two shuttles  62  as shown in  FIGS.  4 A- 4 D  that have been aligned coaxially and mated together. 
     Referring now to  FIG.  6 A , in another example, the shuttle  100  may include two magnets  104  oriented back-to-back and two posts  102  extending from the outward faces  106  of each magnet  104 . Each post  102  is arranged so that when the bistable valve  13  is assembled, the posts  102  may be disposed in both the first hollow post portion  28  and the second hollow post portion  30 . This may eliminate the need for guide elements in the shuttle. Optionally, each post  102  has a cutout  108  to facilitate fluid flow (pneumatic or hydraulic) from the unsealed orifice to the interior valve cavity. 
     As shown in  FIGS.  6 B and  6 C , the post  103  may be constructed of an elastomer material and can seal against a shelf  105  within a cavity  107  of the applicable post  109 . In another example, the elastomer post  103  shown in  FIG.  6 B  may have a conical geometry, and seals against the shelf  105  within the cavity  107  which may be shaped to have a mating conical geometry as seen in  FIG.  6 C . 
     Referring now to  FIG.  7    in another example, the shuttle  110  may be encased in a flexible membrane portion  112  and suspended or held in place by a membrane portion  114  in an interior valve cavity  116 . The membrane portion  114  optionally may be perforated or fenestrated to allow pressure equalization in the interior valve cavity  116 . Alternatively, the membrane portion  112  encasing the shuttle  110  may not be perforated or fenestrated, and may act as a seal to prevent fluid communication between the interior valve cavity  116  and either a first pressure orifice  118  or a second pressure orifice  120 . In an alternative construction, the membrane may be sandwiched between halves of the shuttle instead of enveloping the shuttle  110 . 
     Referring now to  FIG.  8   , a cross-sectional view showing another example of the shuttle  124  is shown. In this example, the shuttle  124  is actuated to seal either a first pressure orifice  126  or a second pressure orifice  128  through the use of traditional wound-coil electromagnets  122  instead of flat circuit board-based electromagnetic coils  34 . 
     As shown in  FIG.  9 A , a valve manifold  130  may include an interior valve cavity  131 , a first pressure inlet  132 , a second pressure inlet  134 , a cantilever armature  146  constructed of a ferrous or magnetic material, at least two electromagnetic coils  144 , and a common output orifice  148 . The first pressure inlet  132  may include a first pressure post  136 , which optionally may be constructed of a ferrous material, and extends into the interior valve cavity  131 , the interior wall of the first pressure post  136  defining a first pressure orifice  140 . The first pressure post  136  may be hollow so that the first pressure inlet  132  is in fluid communication with the interior valve cavity  131  via the first pressure orifice  140 . The second pressure inlet  134  may include a second pressure post  138 , which optionally may be constructed of a ferrous material, and extends into the interior valve cavity  131  substantially opposite of the first pressure post  136 , the interior wall of the second pressure post  138  defining a second pressure orifice  142 . The second pressure post  138  may be hollow so that the second pressure inlet  134  is in fluid communication with the interior valve cavity  131  via the second pressure orifice  142 . The cantilever armature  146  may extend into the interior valve cavity  131  so that it is disposed between the first pressure orifice  140  and the second pressure orifice  142 . 
     A first electromagnetic coil  144  may be positioned around the first pressure post  136  so that when the coil  144  conducts a current, it energizes the first pressure post  136 , exerting an attractive force on the cantilever armature  146 . A second electromagnetic coil  144  may be positioned around the second pressure post  138  so that, when the coil  144  conducts a current, it energizes the second pressure post  138 , exerting an attractive force on the cantilever armature  146 . 
     The cantilever armature  146  may be either sealed against the first pressure orifice  140  in a first position, or sealed against the second pressure orifice  142  in a second position. In each sealing position, the armature  146  is held in place by a continuous magnetic attraction from the armature  146  to either the energized first pressure post  136  or the energized second pressure post  138 , respectively, blocking fluid communication between the interior valve cavity  131  and the corresponding first pressure orifice  140  or the second pressure orifice  142 . To switch the armature  146  from sealing against the first pressure orifice  140  to sealing against the second pressure orifice  142 , the electromagnetic coil  144  positioned around the first pressure post  136  ceases to be energized and the electromagnetic coil  144  positioned around the second pressure post  138  is energized so that it applies a magnetic force to the second pressure post  138  sufficient to attract the armature  146  against the second pressure orifice  142 . Similarly, to switch the armature  146  from sealing against the second pressure orifice  142  to sealing against the first pressure orifice  140 , the electromagnetic coil  144  positioned around the second pressure post  138  ceases to be energized and the electromagnetic coil  144  positioned around the first pressure post  136  is energized so that it applies a magnetic force to the first pressure post  136  sufficient to attract the armature  146  against the first pressure orifice  140 . 
     Referring now to  FIG.  9 B , the valve assembly shown in  FIG.  9 A  further includes a magnet  150  disposed on the cantilever armature  146  with the magnetic force vector  155  substantially aligned with an axis  152  defined by the first pressure post  136  and the second pressure post  138 . In an example, the valve system shown in  FIG.  9 B  may function as a bistable valve so that the electromagnetic coils do not need to continuously energize the pressure post  136 ,  138  having the currently-sealed pressure orifice. The armature  146  is held against the sealed orifice  140 ,  142  through a static magnetic attraction with the magnet  150 . 
     Referring now to  FIG.  9 C , the valve assembly shown in  FIG.  9 A  further includes a magnet  154  disposed on the cantilever armature  146  with the magnetic force vector  156  substantially perpendicular to the axis  152 . The arrangement in  FIG.  9 C  may also function as a bistable valve. 
     In some embodiments, the valve may be actuated by passing a current through an electromagnetic coil, whose magnetic flux acts on a ferro fluid. 
     In various embodiments, the bistable valve may be actuated by a plurality of arrays in which a first array comprises a row of alternating polarity magnets, disposed adjacent to a second array comprising a row of alternating ferrous and non-ferrous material such that in one stable position, the ferrous material allows conductance of one polarity of the magnets, and in a second stable position, the arrays have shifted so the ferrous material allows conductance of the opposite polarity of the magnets. Depending on the magnetic polarity being conducted by the ferrous material, an adjacent ferrous or magnetic body is either pushed towards or pulled away from the plurality of arrays. It is this action on the ferrous body that causes a first stable position in the valve to occur or a second stable position in the valve to occur. By suspending the ferrous or magnetic body in an over-molded elastomer, a seal against one or more orifices can be obtained in either position. The arrays may be shifted by running a current through a plurality of piezoelectric crystals attached to each array. Alternatively, the arrays may be shifted by other means/mechanisms/devices such as, for example, one or more of the following: servos, motors, solenoids, hydraulic means, pneumatic means, and/or NITINOL wire. 
     Optionally, the action of the above magnetic body may be used to compress fluid in a closed system against a thin membrane that will then deform into a bubble-like geometry. This action may be used to actuate a valve by sealing the deformed membrane against an orifice in one position and allowing fluid communication through the orifice in another, non-deformed geometry. 
     In another example, the valve may be actuated using an electroactive polymer. When current is passed through the electroactive polymer, the polymer may expand in one direction while compressing in another direction and allow an attached seal to separate from a valve orifice. This separation allows fluid communication through the valve from that orifice. Terminating current flow through the electroactive polymer allows the electroactive polymer to return to its original shape, expanding in the direction in which it previously compressed, and causing the attached seal to return to the valve orifice, blocking fluid communication from that orifice. Energizing the electroactive polymer may be accomplished by overmolding electrodes into contact with the electroactive polymer. In some examples, the electroactive polymer may be energized through the use of etched or printed electrodes oriented flat against the electroactive polymer. Multiple layers of these electrodes may be used to achieve optimal control of the electroactive polymer. 
       FIG.  10 A  shows a perspective view of a plurality of bistable valves  13  arranged in an array  158 , wherein a valve manifold  20  incorporates the plurality of bistable valves  10 . FIG.  10 B shows a top view of a circuit board  18  comprising multiple electromagnetic coils  34  for use in an arrangement of bistable valves  13  arranged in an array  158  as shown in  FIG.  10 A .  FIG.  10 C  shows a cross-sectional view showing a plurality of bistable valves  13  arranged in a valve array  158  and utilizing a common valve manifold  20 , wherein the valve manifold  20  includes multiple interior valve cavities  32 . 
     Optionally, the electromagnetic coils  34  may be mounted in a flexible circuit board instead of a rigid circuit board. Each of the valve arrays may include two or more bistable valves. 
     Referring now to  FIG.  11 A , one or more bistable valves  13  may be integrated into a liquid flow control system  160 . The bistable valve  13  may be connected to a system manifold  162  in a vertical orientation such that the common output orifice  22  is in fluid communication with the flow control system pressure input  168 . The flow control system  160  is connected to a first pressure source  164  and a second pressure source  166  for use in the bistable valve  13 , for example, as shown in  FIGS.  1 A- 1 D . The first pressure source  164  and the second pressure source  166  may be integrated into a system manifold  162 , or may be standalone components to which the flow control system  160  can connect, or from which it can be disconnected. In an embodiment, either the first pressure source  164 , the second pressure source  166 , or both may provide a common source of pressure to a plurality of valves (e.g., bistable valves  13 ) integrated into a system manifold  162 . 
     As shown in  FIG.  11 B , at least one bistable valve  13  may be integrated into a liquid flow control system  160 , or two or more bistable valves  13  may be integrated into the system  160 . The bistable valve  13  may be positioned in a horizontal orientation and directly connected to the system manifold  162  so that the common output orifice  22  is in direct fluid communication with the liquid flow control system&#39;s pressure input  168 . The system  160  may further include a first pressure source  170  and a second pressure source  172  for connection to the bistable valve  13  as shown in  FIGS.  1 A- 1 D . The first pressure source  170  and the second pressure source  172  may be integrated into the system manifold  162 , or may be arranged as common lines to which individual valve modules or manifold modules can be connected. Either the first pressure source  170 , the second pressure source  172 , or both may serve as a common pressure source for one or a plurality of bistable valves  13  integrated into the system  160 . 
     Referring now to  FIGS.  12 A and  12 B , a plurality of bistable valves  13  may be arranged in an array  180 . This array  180  utilizes common components between the plurality of bistable valves  13 , such as a valve manifold comprising an first manifold half  182  and a second manifold half  184 . The first and second manifold halves  182 ,  184  define multiple interior valve cavities  186 , each interior valve cavity  186  corresponding to one bistable valve assembly. Other common components may include a first track  190  including a first track pressure rail  194  and a second track  192  including a second track pressure rail  196 . The first track pressure rail  194  provides the same pressure input to each of the first set of pressure input posts  198 , each such pressure input post  198  connecting to one of the plurality of bistable valves  13  in the array  180 . Similarly, the second track pressure rail  196  provides the same pressure input to each of the second set of pressure input posts  200 , each such pressure input post  200  connecting to one of the plurality of bistable valves  13  in the array  180 . As seen in  FIG.  12 B , adjacent bistable valves  13  optionally may further share common fasteners  188  constructed of a ferrous material, the fasteners being integral to the magnetic return path in the function of each bistable valve  13  in the array  180 . 
     In various embodiments, the first manifold half  182  and second manifold half  184  may be ultrasonically welded together, for example, to create an airtight union between the two. Similarly, each of the first track  190  and the second track  192  may be ultrasonically welded together to create an airtight union around the respective first track pressure rail  194  and second track pressure rail  196 . The valve manifold and each of the first track  190  and second track  192  components may then be joined to each other using laser welding or other methods. As seen in  FIG.  12 B , the assembly optionally may include an outer plate  202  constructed of a ferrous material. First and second outer plates  202  may be connected by a plurality of common fasteners  188 , which also may comprise a ferrous material. 
     Referring now to  FIG.  13   , an outer plate  202  optionally may be fastened to an array  180  of bistable valves. In the example shown, a plurality of fasteners  188  surrounds each pressure post  204  of each valve in the array. Optionally, each outer plate  202  may also include a plurality of directional slits  206 . The directional slits  206  can be arranged so that the magnetic flux paths of two adjacent valves are directed towards different fasteners  188  to help isolate each valve&#39;s function when adjacent valves are actuated simultaneously. In an exemplary implementation, the actuation of adjacent valves can be staggered to optimize each valve&#39;s magnetic flux path flow. 
     Referring now to  FIGS.  14 A- 14 C , another embodiment of a bistable valve  1400  structure is shown. The valve  1400  includes an interior valve cavity  1420  defined by a first housing  1402 , a second housing  1404 , and a midbody  1406 . Additionally, the valve  1400  includes a plurality of end plates  1408 , a shuttle  1410 , a first post  1412 , a second post  1414 , first pressure inlet  1416 , a second pressure inlet  1418 , and a common output orifice  1422 . Further, the bistable valve  1400  includes a first electromagnetic coil  1424  and a second electromagnetic coil  1426  disposed around the first and second posts  1412  and  1414 , respectively. In one example, the electromagnetic coils  1424  and  1426  may be flat electromagnetic coils disposed in a printed circuit board (PCB), or they may be vertically-oriented wire coils with wire leads as shown in  FIG.  14 B . The common output orifice  1422  is in constant fluid communication with the valve cavity  1420 , regardless of which position the valve is in. Conversely, the first and second pressure inlets  1416  and  1418  are either in fluid communication with the interior valve cavity  1420 , and thus, the common output orifice  1422 , or they are sealed from fluid communication with the interior valve cavity  1420  by the shuttle  1410 . When one of the two pressure inlets  1416  and  1418  is in fluid communication with the interior valve cavity, the other pressure inlet is sealed by the shuttle  1410 . 
     The first pressure inlet  1416  and the second pressure inlet  1418  may in one example extend through the same side of the valve  1400  as the common output orifice  1422 , as shown in  FIG.  14 B . Moreover, the first and second posts  1412  and  1414  may each have an additional pressure inlet  1428  and  1430 , respectively, as shown in  FIG.  14 C . The third pressure inlet  1428  may be in constant fluid communication with the first pressure inlet  1416 , while the fourth pressure inlet may be in constant fluid communication with the second pressure inlet  1418 . In some embodiments, the valve  1400  may feature a third pressure inlet  1428  and a fourth pressure inlet  1430 , each extending through their respective first and second posts, without the additional first and second pressure inlets  1416  and  1418 . 
     Referring now to  FIGS.  15 A- 15 B , in another example, a bistable valve  1500  may include a shuttle  1502  comprising a magnet. The valve  1500  may further include a first membrane portion  1508  abutting a first post  1504 , and a second membrane portion  1510  abutting a second post  1506 , the first and second membrane portions  1508  and  1510 , as well as the shuttle  1502  being disposed in an interior valve cavity  1516 . The first post  1504  and the first membrane portion  1508  may be configured to provide fluid communication from a first pressure inlet  1512  to the interior valve cavity  1516  when the shuttle  1502  is not sealed against the first membrane portion  1508 . Similarly, the second post  1506  and the second membrane portion  1510  may be configured to provide fluid communication from a second pressure inlet  1514  to the interior valve cavity  1516  when the shuttle  1502  is not sealed against the second membrane portion  1510 . A common output orifice  1518  is in constant fluid communication with the interior valve cavity  1516 , regardless of which position the shuttle  1502  is in. Conversely, the first and second pressure inlets  1512  and  1514  are either in fluid communication with the interior valve cavity  1516 , and thus, the common output orifice  1518 , or they are sealed from fluid communication with the interior valve cavity by the shuttle  1502 . When one of the two pressure inlets  1512 ,  1514  is in fluid communication with the interior valve cavity  1518 , the other pressure inlet is sealed by the shuttle  1502 . 
     Referring now to  FIGS.  16 A- 16 B , in another example, a bistable valve  1600  may include a shuttle  1602  comprising ferrous metal. The first post  1604  and the second post  1606  are each magnets. The valve  1600  may further include a first membrane portion  1608  abutting a first post  1604 , and a second membrane portion  1610  abutting a second post  1606 , the first and second membrane portions  1608  and  1610 , as well as the shuttle  1602  being disposed in an interior valve cavity  1616 . The first post  1604  and the first membrane portion  1608  may be configured to provide fluid communication from a first pressure inlet  1612  to the interior valve cavity  1616  when the shuttle  1602  is not sealed against the first membrane portion  1608 . Similarly, the second post  1606  and the second membrane portion  1610  may be configured to provide fluid communication from a second pressure inlet  1614  to the interior valve cavity  1616  when the shuttle  1602  is not sealed against the second membrane portion  1610 . Output orifices  1618 ,  1620  are in constant fluid communication with the interior valve cavity  1616 , regardless of which position the shuttle  1602  is in. Conversely, the first and second pressure inlets  1612  and  1614  are either in fluid communication with the interior valve cavity  1616 , and thus, the output orifices  1618 ,  1620  or they are sealed from fluid communication with the interior valve cavity  1616  by the shuttle  1602 . When one of the two pressure inlets  1612 ,  1614  is in fluid communication with the interior valve cavity  1616 , the other pressure inlet is sealed by the shuttle  1602 . In an exemplary implementation, as shown in  FIG.  16 B , the shuttle  1602  may be spherical or spheroidal and may be made from any material as described above with respect to various embodiments of the shuttle. The bistable valve  1600  may include contact terminals  1622 ,  1624 . A spherical or spheroidal shuttle can optionally be suspended in the interior valve cavity by an elastomeric membrane similar to the embodiment shown in  FIG.  7   . 
     Referring now to  FIGS.  17 A- 17 E , a bistable valve  1700  in another example may include a shuttle  1702  comprising a magnet portion  1724 . The shuttle  1702  may further include a first membrane portion  1708  configured to abut a first post  1704 , and a second membrane portion  1710  configured to abut a second post  1706 , the first and second membrane portions  1708  and  1710  attached to the magnet portion  1724 , and the shuttle  1702  is disposed in an interior valve cavity  1716 . The first and second membrane portions  1708 ,  1710  may be attached to the magnet portion  1724  using any type of adhesive, including, but not limited to, double sided tape, glue or other adhesive. 
     The first post  1704  and the first membrane portion  1708 , which is attached to the magnet portion  1724 , may be configured to provide fluid communication from a first pressure inlet  1712  to the interior valve cavity  1716  when the shuttle  1702  is not sealed against the first post  1704 . Similarly, the second post  1706  and the second membrane portion  1710 , which is attached to the magnet portion  1724 , may be configured to provide fluid communication from a second pressure inlet  1714  to the interior valve cavity  1716  when the shuttle  1702  is not sealed against the second post  1706 . Output orifices  1718 ,  1720  are in constant fluid communication with the interior valve cavity  1716 , regardless of which position the shuttle  1702  is in. Conversely, the first and second pressure inlets  1712  and  1714  are either in fluid communication with the interior valve cavity  1716 , and thus, the output orifices  1718 ,  1720  or they are sealed from fluid communication with the interior valve cavity by the shuttle  1702 . When one of the two pressure inlets  1712 ,  1714  is in fluid communication with the interior valve cavity  1716 , the other pressure inlet is sealed by the shuttle  1702 . In an exemplary configuration, the shuttle  1702  may be cylindrical and may be made from any material as described above with respect to other versions of the shuttle. The bistable valve  1700  may include contact terminals  1721 ,  1722  as well as coils  1726 ,  1728 , end bodies  1730 ,  1732 , and end plates  1734 ,  1736  attached to the end bodies  1730 ,  1732 . 
     The first and second posts  1704 ,  1706  shown in  FIGS.  17 B and  17 E  show two different configurations of pressure inlets  1712 ,  1714 . In  FIG.  17 B , the first and second posts  1704 ,  1706  include a hole machined in, whereas, in  FIG.  17 E , the first and second posts  1704 ,  1706  include a machined groove, which is a slot and/or curve cut  1742 ,  1744 . 
     Optionally, stabilizing features  1740  ( FIG.  17 E ) may be added to the membrane and/or to the valve seat to assist in seating the shuttle properly on the valve seat. Stabilizing features may include, for example, bumps, nubs, posts, or other protuberances. Although not shown in all figures, stabilizing features may be included in any embodiment or version of a bistable valve assembly. 
     Referring now to  FIGS.  18 A- 18 B , a plurality of any of the various configurations of a bistable valve may be combined into an array in a manifold assembly  1800 . The array  1800  includes one or more bistable valves having any of the shuttle  1802  configurations described herein. The manifold  1800  includes end plates  1804 ,  1806  and coil assemblies  1808 , surrounding the shuttles  1802  within the interior valve cavities  1810 . 
     A manifold assembly comprising bistable valves or valve systems according to the various embodiments described may be used in many different applications in which fluidic pressure (pneumatic or hydraulic) is used to drive pumps and/or valves in a device. Examples include any liquid pumping apparatus such as a blood pump, hemodialysis machine, peritoneal dialysis machine, intravenous pump, or any liquid flow control device used in medical or industrial fields. Other uses include inflatable devices, such as a seat cushion. For example, a manifold assembly comprising bistable valves or valve systems can be used to inflate a seat cushion in a powered wheelchair, air bladders in a prosthetic device or other inflatable devices. A bistable valve or valve system according to the various embodiments described may be used in any application requiring the employment of a traditional standalone pneumatic or electronically-actuated valve. 
     The electromagnetic activation features described above may be applied to a monostable valve as well. Instead of the shuttle having a first and a second pressure position, the monostable valve is configured to have an on and an off position with respect to one pressure source. 
     Referring now to  FIGS.  19 A- 19 B , various configurations of a bistable valve may be integrated into various assemblies. In the example shown in  FIGS.  19 A- 19 B , a bistable valve  1906  is integrated into a regulator for a medical device, for example, a hemodialysis machine. A regulator PCB  1900  is connected to the bistable valve  1906 , and the apparatus includes outlet tubing  1902 , inlet tubing  1904 , a pressure sensor  1910  and a PCB valve adapter block  1908 . In practice, one pressure inlet to the valve cavity is blocked and the pressure between the inlet tubing  1904  and the outlet tubing  1902  is regulating by operation of the valve to make or break a connection between the two. 
     Referring now also to  FIGS.  20 A- 20 C , a bistable valve  2000  may include a shuttle comprising a magnet portion  2024 . The shuttle may further include a first membrane portion  2008  which will abut a first post  2004 , and a second membrane portion  2010  which will abut a second post  2006 , the first and second membrane portions  2008  and  2010  attached to the magnet portion  2024 , with the shuttle being disposed in an interior valve cavity  2016 . The first post  2004  and the first membrane portion  2008 , which is attached to the magnet portion  2024 , may be configured to provide fluid communication from a first pressure inlet  2012  to the interior valve cavity  2016  when the shuttle is not sealed against the first post  2004 . Similarly, the second post  2006  and the second membrane portion  2010 , which is attached to the magnet portion  2024 , may be configured to provide fluid communication from a second pressure inlet  2014  to the interior valve cavity  2016  when the shuttle is not sealed against the second post  2006 . Output orifices  2018 ,  2020  are in constant fluid communication with the interior valve cavity  2016 , regardless of which position the shuttle is in. Conversely, the first and second pressure inlets  2012  and  2014  are either in fluid communication with the interior valve cavity  2016 , and thus, the output orifices  2018 ,  2020  or they are sealed from fluid communication with the interior valve cavity  2016  by the shuttle. When one of the two pressure inlets  2012 ,  2014  is in fluid communication with the interior valve cavity  2016 , the other pressure inlet is sealed by the shuttle. In an example, the shuttle may be cylindrical and made from any of the materials described above. The bistable valve  2000  may include contact terminals  2022 ,  2023  as well as coils  2026 ,  2028 , end bodies  2030 ,  2032 , and end plates  2034 ,  2036  attached to the end bodies  2030 ,  2032 . Optionally, the bistable valve  2000  may also include at least one gasket seal  2038  and at least one face seal  2040 . Optionally, the bistable valve  2000  may also include locating pins  2042 ,  2044  as well as a tie bar/screw  2046  and an end body housing  2048 . In some embodiments, the tie bar/screw  2046  attaches the end plates  2034 ,  2036  to the end body housing  2048 . Other methods of attachment may be used including adhesive, bolts, screws, pins, etc. 
     Referring now also to  FIGS.  21 A- 21 C , A bistable valve  2100  may include a shuttle  2102  comprising two opposing magnet portions  2124 ,  2125 . The shuttle  2102  may further include a first membrane portion  2108  attached to the first magnet portion  2125  configured to abut a first post  2104 , and a second membrane portion  2110  attached to the second magnet portion  2124  configured to abut a second post  2106 . The shuttle  2102  is disposed in an interior valve cavity  2116 . The first post  2104  and the first membrane portion  2108 , which is attached to the first magnet portion  2125 , may be configured to provide fluid communication from a first pressure inlet  2112  to the interior valve cavity  2116  when the shuttle  2102  is not sealed against the first post  2104 . Similarly, the second post  2106  and the second membrane portion  2110 , which is attached to the second magnet portion  2124 , may be configured to provide fluid communication from a second pressure inlet  2114  to the interior valve cavity  2116  when the shuttle  2102  is not sealed against the second post  2106 . The first post  2104  and second post  2106  optionally may each include a pneumatic port  2152 ,  2154 . Output orifice  2118  is in constant fluid communication with the interior valve cavity  2116 , regardless of which position the shuttle  2102  is in. Conversely, the first and second pressure inlets  2112  and  2114  are either in fluid communication with the interior valve cavity  2116 , and thus, the output orifice  2118  or they are sealed from fluid communication with the interior valve cavity  2116  by the shuttle  2102 . When one of the two pressure inlets  2112 ,  2114  is in fluid communication with the interior valve cavity  2116 , the other pressure inlet is sealed by the shuttle  2102 . In one example, the shuttle may be cylindrical and made from any of the materials described above with respect to various shuttles. The bistable valve  2100  may include contact terminals  2122 ,  2123  as well as coils  2126 ,  2128 , end bodies  2130 ,  2132 , and end plates  2134 ,  2136  attached to the end bodies  2130 ,  2132 . Optionally, the bistable valve  2100  may also include at least one gasket seal  2138  and at least one face seal  2140 . In an exemplary configuration, the bistable valve  2100  may also include locating pins as well as a tie bar/screw (not shown) and an end-body housing  2148 . The tie bar/screw attaches the end plates  2134 ,  2136  to the end body housing  2148 . Other methods of attachment may also be used including adhesive, bolts, screws, pins, etc. 
     Any of the magnets shown as part of the shuttle may comprise stacked magnets: more than one magnet forms the magnetic portion of the shuttle. Various sizes, shapes and thicknesses of the magnet may alter its magnetic force, whether opposing or attracting. 
       FIG.  22    depicts a representational view of an interior cavity  2200  of an example bistable valve. As shown, a shuttle  2202  is positioned in the interior cavity  2200 . The shuttle  2202  includes a magnet  2204  which is overmolded with an elastomeric material  2206 . In some configurations, multiple magnets may be enveloped by the overmolded elastomeric material  2206 . Any of the shuttles such as any of those described in  FIGS.  2 A- 5 C  may be similarly overmolded. 
     The elastomeric material  2206  also includes a number of radial arms or offshoots  2208  which extend from the magnet  2204  to the walls of the interior cavity  2200 . These radial offshoots  2208  may serve to hold the magnet  2204  substantially along the central axis of the interior cavity  2200  and may inhibit rotation of the magnet  2204 . The radial offshoots  2208  may also act as a damper during actuation of a valve, which may help to minimize the acoustic noise generated as the shuttle  2202  is displaced or toggled back and forth. 
     In the example embodiment, the elastomeric radial offshoots  2208  roughly resemble the arms of a cross, though they may be of any convenient shape and/or any number. For example the radial offshoots  2208  may be spoke-like. The amount of open space between each of the radial offshoots  2208  may also vary. In an exemplary manufacturing process, the radial offshoots  2208  may be laser cut out of a larger piece of elastomeric material. In an alternate arrangement, instead of radial offshoots  2208 , the magnet  2204  may be kept in place by a web-like diaphragm. Such a diaphragm may include a number of generally concentric rings of elastomeric material connected to a number of radial offshoots extending outwardly from the magnet  2204 . In such an embodiment, pressure would be allowed to equalize on each side of the shuttle  2202  through the openings in the web-like diaphragm. 
     In various embodiments of the various bistable valves described herein, the coil may be PCB-based flat coils (i.e., coils on a printed circuit board) or wire wound coils. The coils may be potted into a valve assembly. Any suitable potting material, such as a low Q material may be used. This may help to reduce acoustic noise generated during operation of a valve. It may also help to make the magnetic coil reliability more robust. 
     Wound wire coils may have an air core. Optionally, the coils may be wound around a supporting structure. This may help to simplify manufacture and assembly of a coil and a valve. Any suitable supporting structure may be used, such as a spool, reel, or bobbin. The supporting structure may also have one or more coupling or engagement features that help to simplify installation of the coil into a bistable valve. For example, a supporting structure may include a snap fit feature or a guide feature which interacts with a complementary feature of the bistable valve. Such interaction may ensure that a coil is seated in a desired or prescribed orientation in the valve assembly. The support structure may also be dimensioned and/or made of a material which helps to generate a desired magnetic flux path. 
     An example coil assembly  2300  is shown in  FIG.  23   . The coil assembly  2300  includes a bobbin  2302 . The bobbin  2302  may be made from any suitable material and may, for example, be a molded part made from injection molded plastic. The coil may be wound around the bobbin  2302  so that a magnetic field is created when current passes through the wire. Two leads  2306  which are attached to respective contacts  2308  are also shown in  FIG.  23   . The contacts  2308  may be contact pins as shown, or the contacts  2308  may include a pad or strip that allows for greater tolerances when assembling a bistable valve. 
       FIG.  24    depicts an example embodiment of a bistable valve  3900 . As shown, the bistable valve  3900  includes optional conductive or metal strips  3902 A-C which may be placed or crimped onto the contacts  3908 . Alternatively, the metal strips may be attached (e.g soldered) or integral with the contacts  3908 . The metal strips  3902 A-C may allow a larger contact area/patch when placing a current source into communication with the valve  3900 . This may obviate the need to align pin contacts with a connector on the current source, simplifying assembly and allowing for larger tolerances. As shown, one of the metal strips  3902 C connects a contact  3908  from one coil assembly  3904  to a contact on another coil assembly  3908 . The other two metal strips  3902 A, B may act as positive/negative terminals for the coils depending on the desired direction of current flow through the coil assemblies  3904 . The metal strips  3902 A-C may be made of any suitable material such as, for example, copper. 
     Referring now to  FIGS.  25 A- 25 C , in some embodiments, a bistable valve  2400  may include a shuttle  2402  comprising a magnet  2425 . The shuttle  2402  may further include a first membrane portion  2408  attached to a first face of the magnet  2425 . The shuttle  2402  may also include a second membrane portion  2410  attached to a second face of the magnet  2425  which is opposite the first face. The shuttle  2402  is disposed in an interior valve cavity  2416 . The bistable valve  2400  also includes a first post  2404  and a second post  2406 . The first post  2404  and second post  2406  may act to direct magnetic flux pathways within the bistable valve  2400 . The first post  2404  and second post  2406  may also act as cores for the electromagnetic coils  2426 ,  2428  of the bistable valve  2400 . The first post and second post may be made from a material with a desired magnetic permeability. 
     The example embodiment in  FIGS.  25 A- 25 C  includes a plurality of output orifices. As shown, the bistable valve  2400  embodiment includes a first output orifice  2418  and a second output orifice  2419 . When the shuttle  2402  is sealing over a first pressure inlet  2412 , the first output orifice  2418  and second output orifice  2419  are placed into fluid communication with a second pressure inlet  2414  through the interior valve cavity  2416 . When the shuttle  2402  is sealing over the second pressure inlet  2414 , the first output orifice  2418  and second output orifice  2419  are placed into fluid communication with the first pressure inlet  2412 . When one of the two pressure inlets  2412 ,  2414  is in fluid communication with the interior valve cavity  2416 , the other pressure inlet is sealed by the shuttle  2402 . In various embodiments, the shuttle  2402  may be cylindrical and may be made from any material as described above with respect to various embodiments of the shuttle. The first output orifice  2418  and second output orifice  2419  may connect to a common fluid line or may each be connected to separate and isolated fluid lines in various embodiments. In the example embodiment, the pressure inlets  2412 ,  2414  are not included in or part of the first and second posts  2404  and  2406 . This may help to simplify manufacturing of the bistable valve  2400 . 
     In various embodiments, a bistable valve  2400  may include valve bodies  2430 ,  2432 . These valve bodies  2430 ,  2432  may be coupled together to form the various flow paths and cavities of the bistable valve  2400 . The valve bodies  2430 ,  2432  may be molded parts which include voids for the pressure inlets  2412 ,  2414 , the interior valve cavity  2416 , and the output orifices  2418 ,  2419 . The valve bodies  2430 ,  2432  may be coupled together in any suitable manner which creates sealed flow paths for fluid passing through the bistable valve  2400 . 
     In various embodiments, a bistable valve  2400  may include contact terminals  2422 ,  2423  as well as coils  2426 ,  2428 . As shown, the coils  2426 ,  2428  may be included on a coil assembly  2450  which is placed into a receiving structure in the valve bodies  2430 ,  2432  during assembly. In the example embodiments, the coils  2426 ,  2428  are included on bobbin-like coil assemblies  2450  similar to that depicted in  FIG.  23   . 
     The bistable valve  2400  shown in  FIGS.  25 A-C  also includes end plates  2434 ,  2436  which are attached to the valve bodies  2430 ,  2432 . One or more fastener  2444  may pass through or couple into the end plates  2434 ,  2436 , and may help to hold the valve bodies  2430 ,  2432  together. As described elsewhere, any suitable type of fastener may be used. For example, the fastener may be a bolt, screw, rivet, etc. In various embodiments, the bistable valve  2400  may also include at least one gasket or sealing member which may be any type of seal. In various embodiments, the bistable valve  2400  may also include locating pins  2440 ,  2442 . 
       FIGS.  26 A- 26 C  depict another embodiment of a bistable valve assembly  3800 . The bistable valve assembly  3800  includes a shuttle  3802  made of a magnetized material. The shuttle  3802  is disposed in an interior valve cavity  3816 . The bistable valve  3800  includes a first post  3804  and a second post  3806 . The first post  3804  and second post  3806  are configured to direct magnetic flux pathways within the bistable valve  3800 . The first post  3804  and second post  3806  may also act as cores for the electromagnetic coils  3826 ,  3828  of the bistable valve  3800 . 
     As best shown in  FIG.  26 C , two inserts  3880  may be included in a bistable valve assembly  3800 , or in any other type of valve assembly in which a moving shuttle is used to mechanically block or open communication between an inlet of the valve assembly and the valve cavity. When assembled, these inserts  3880  surround the shuttle  3802  and fit within the interior valve cavity  3816 . In an exemplary construction, the inserts  3880  have a substantially cup-like shape. 
     The inserts  3880  may be made of an elastomeric or other soft or compliant material. For example, the inserts  3880  may be made of Viton® or a similar material. The inserts may also be molded from sound-absorbing plastics that, when formed and solidified, provide both soundproofing qualities as well as structural support to withstand repeated movement of a shuttle within the insert. The inserts  3880  may help to dampen any noise generated as the valve toggles between positions and may allow for better sealing of the shuttle  3802  over pressure inlets  3812 ,  3814 . Thus the inserts may eliminate a need for a separate flexible or elastomeric membrane on either the shuttle face or the valve seat to achieve a seal between the valve seat and the surface of the shuttle. 
     Each of the inserts  3880  may include a sealing flange  3882 . When assembled, the sealing flanges  3882  abut and compress against each other. The valve bodies  3840 ,  3842  can be coupled together to form the bistable valve  3800  by means of one or more fasteners  3844  passing through end plates  3834  and  3836 . As best shown in  FIG.  26 B , mating or mutual compression of the flanges  3882  may fluidically seal the interior valve cavity  3816  as the two valve bodies  3840 ,  3842  of the bistable valve  3800  are joined together. 
     The example embodiment in  FIGS.  26 A- 26 C  includes one or more pressure inlets  3812 ,  3814  and output orifices  3818 ,  3819 . The pressure inlets  3812 ,  3814  and output orifices  3818 ,  3819  are formed as part of the valve bodies  3840 ,  3842 . As shown, the bistable valve assembly  3800  includes a first output orifice  2418  and a second output orifice  2419 . It also includes a first pressure inlet  3812  and a second pressure inlet  3814 . The inserts  3880  include fluid pathways  3884 ,  3886  which extend through the inserts  3880 . First pressure inlet  3812  and second pressure inlet  3814  align with fluid pathways  3886  of their respective inserts  3880 . The first fluid output orifice  3818  and second fluid output orifice  3819  align with fluid pathways  3884  of their respective insert  3880 . Each insert  3880  may also include a valve seat  3888  against which the shuttle  3802  may form a seal. 
     When the shuttle  3802  is sealing the valve seat  3888  of first pressure inlet  3812 , the first output orifice  3818  and second output orifice  3819  are placed into fluid communication with a second pressure inlet  3814  through the interior valve cavity  3816 . When the shuttle  3802  is sealing the valve seat  3888  of the second pressure inlet  3814 , the first output orifice  3818  and second output orifice  3819  are placed into fluid communication with the first pressure inlet  3812 . When one of the two pressure inlets  3812 ,  3814  is in fluid communication with the interior valve cavity  3816 , the other pressure inlet is sealed by the shuttle  3802 . In some examples, the shuttle  3802  is cylindrical and may be made from any material as described above with respect to other examples of the shuttle. The first output orifice  3818  and second output orifice  3819  can be configured to connect to a common fluid line or may each be connected to separate and isolated fluid lines, depending on the desired application. Optionally, the pressure inlets  3812 ,  3814  are not included in or part of the first and second posts  3804  and  3806 . This may help to simplify manufacturing of the bistable valve assembly  3800 . Optionally, the inserts  3880  may include an asymmetric feature that allows the inserts  3880  to be installed in the bistable valve  3800  in only a particular orientation. The asymmetric feature may for example ensure that the inserts  3880  are installed in a manner in which fluid pathways  3884 ,  3886  align with the pressure inlets  3812 ,  3814  and output orifices  3818 ,  3819 , helping to simply assembly of the bistable valve  3800 . 
     A bistable valve assembly  3800  may include contact terminals  3822 ,  3823  as well as coils  3826 ,  3828 . As shown, the coils  3826 ,  3828  may be mounted on a coil assembly  3850  that can be placed into a receiving structure in the valve bodies  3840 ,  3842  during assembly. In the example shown, the coils  3826 ,  3828  are wound on bobbin-like coil assemblies  3850  similar to that depicted in  FIG.  23   . 
       FIGS.  27 A- 27 D  depict another embodiment of a bistable valve  4000 . The bistable valve  4000  may include a shuttle  4002 , that can be made of a magnetized material. The shuttle  4002  is disposed in an interior valve cavity  4016 . The bistable valve  4000  may also include a first post  4004  and a second post  4006 . The first post  4004  and second post  4006  may act to direct magnetic flux pathways within the bistable valve  4000 . The first post  4004  and second post  4006  may also act as cores for the electromagnetic coils  4026 ,  4028  of the bistable valve  4000 . In an exemplary configuration, a bistable valve  4000  may include contact terminals  4022 ,  4023  connected to coils  4026 ,  4028 . As shown, the coils  4026 ,  4028  may be included on a coil assembly  4050  which is placed into a receiving structure in the valve bodies  4040 ,  4042  during assembly. In the example shown, the coils  4026 ,  4028  are wound on bobbin-like coil assemblies  4050  similar to that depicted in  FIG.  23   . 
     As best shown in  FIG.  27 C , two inserts  4080  may be included in a bistable valve  4000 . The inserts  4080  include a cavity portion  4090 . When assembled, the cavity portion  4090  of each insert  4080  may cooperatively surround the shuttle  4002  and define the interior valve cavity  4016 . The inserts  4080  may be made of an elastomeric or other compliant material such as Viton or comparable material. This type of material may allow the inserts  4080  to dampen noise generated as the valve toggles back and forth, and may allow for better sealing of the shuttle  4002  over pressure inlets  4012 ,  4014 . In the example embodiment, the inserts  4080  also include the pressure inlets and outlets for the valve  4000 , which tends to simplify manufacturing of the valve assembly. As shown, pressure inlets  4012 ,  4014  and output orifice  4018 ,  4019  are molded as part of each insert  4080 . All inserts  4080  can be designed to have uniform dimensions and features, allowing them to be manufactured using the same mold. 
     Each of the inserts  4080  may include a sealing flange  4082 . When assembled, the sealing flanges  4082  can abut and compress against each other. The valve bodies  4040 ,  4042  can be coupled together to form the bistable valve assembly  4000  by using one or more fasteners  4044  passing through end plates  4034 ,  4036 . As best shown in  FIG.  27 B , abutment and/or mutual compression of the flanges  4082  may fluidically seal the interior valve cavity  4016  as the two valve bodies  4040 ,  4042  of the bistable valve  4000  are joined together. 
       FIG.  27 D  depicts a cross sectional view taken through the cavity portion of an insert  4080 . As shown, the insert includes a valve seat  4088  surrounding the first pressure inlet  4012 . Surrounding the valve seat  4088  are a number of raised elements  4092 . The raised elements  4092  can be arranged to circumferentially surround the valve seat  4088  (e.g. continuously or at spaced angular intervals). The valve seat  4088  is slightly proud of the raised elements  4092 . When the shuttle  4002  is in a sealing position over the valve seat  4088 , the shuttle  4002  may be retained in that position via magnetic attraction. This magnetic attraction may cause some compression of the valve seat  4088  material. The height difference between the valve seat  4088  and the raised elements  4092  can be chosen so that the expected compression of the valve seat  4088  places it at substantially even height with the raised elements  4092 . As a result, the shuttle  4002  can rest on both the valve seat and the surrounding raised elements  4092 . The raised elements  4092  may help to support the edges of the shuttle  4002  and encourage it to sit flat against the valve seat  4088 , helping optimize the seal created. 
     Referring back to  FIG.  27 B , when the shuttle  4002  is positioned against the valve seat  4088  of first pressure inlet  4012 , the first output orifice  4018  and second output orifice  4019  are placed into fluid communication with a second pressure inlet  4014  through the interior valve cavity  4016 . When the shuttle  4002  is positioned against valve seat  4088  of the second pressure inlet  4014 , the first output orifice  4018  and second output orifice  4019  are placed into fluid communication with the first pressure inlet  4012 . When one of the two pressure inlets  4012 ,  4014  is in fluid communication with the interior valve cavity  4016 , the other pressure inlet is sealed by the shuttle  4002 . 
       FIGS.  28 A- 28 D  depict another embodiment of a bistable valve assembly  4100 . The bistable valve assembly  4100  includes a shuttle  4102  preferably made of a magnetized material. The shuttle  4102  is disposed in an interior valve cavity  4116 . The bistable valve assembly  4100  also includes a first post  4104  and a second post  4106 . The first post  4104  and second post  4106  act to direct magnetic flux pathways within the bistable valve assembly  4100 . The first post  4104  and second post  4106  also act as cores for the electromagnetic coils  4126 ,  4128  of the bistable valve assembly  4100 . An exemplary bistable valve assembly  4100  may include contact terminals  4122 ,  4123  connected to coils  4126 ,  4128 . As shown, the coils  4126 ,  4128  may be included on a coil assembly  4150  which is placed into a receiving structure in the valve bodies  4140 ,  4142  during assembly. In the example embodiments, the coils  4126 ,  4128  are wound on bobbin-like coil assemblies  4150  similar to that depicted in  FIG.  23   . 
     The example embodiment in  FIGS.  28 A- 28 D  includes a plurality of output orifices. As shown, the bistable valve assembly  4100  includes a first output orifice  4118  and a second output orifice  4119 . When the shuttle  4102  is positioned over a first pressure inlet  4112 , the first output orifice  4118  and second output orifice  4119  are placed into fluid communication with a second pressure inlet  4114  through the interior valve cavity  4116 . When the shuttle  4102  is positioned over the second pressure inlet  4114 , the first output orifice  4118  and second output orifice  4119  are placed into fluid communication with the first pressure inlet  4112 . When one of the two pressure inlets  4112 ,  4114  is in fluid communication with the interior valve cavity  4116 , the other pressure inlet is sealed by the shuttle  4102 . An exemplary shuttle  4102  may be cylindrical and may be made from any material as described above with respect to various configurations of the shuttle. The first output orifice  4118  and second output orifice  4119  may connect to a common fluid line, or may each be connected to separate and isolated fluid lines, depending on the desired application. In the example shown, the pressure inlets  4112 ,  4114  are not included in or part of the first and second posts  4104  and  4106 , which may help to simplify manufacturing of the bistable valve assembly  4100 . 
     As best shown in  FIG.  28 C , a valve assembly such as the bistable valve assembly  4100  may use a monolithic gasket  4180  to simplify construction of the valve assembly. The monolithic gasket  4180  is shown in greater detail in  FIG.  28 D . The monolithic gasket  4180  includes a loop portion  4182  which is coupled to an input/output seal portion  4184  by a connecting region  4186 . During assembly the valve bodies  4140 ,  4142  are coupled together to form the bistable valve assembly  4100  by passing one or more fasteners  4144  through end plates  4134 . As best shown in  FIG.  28 B , compression of the loop portion  4182  may fluidically seal the interior valve cavity  4116  as the two valve bodies  4140 ,  4142  of the bistable valve  4100  are joined together. The loop portion  4182  may differ in shape depending on the geometry of the shuttle  4102  and other internal components, with the shape additionally being chosen based on the cross-sectional dimension of the interior valve cavity  4116 . The input/output seal portion  4184  is configured to seal against a manifold into which the valve assembly  4100  is installed. By molding each sealing member together as a monolithic gasket  4180 , part count can be reduced and manufacturing/assembly is simplified. 
     In some embodiments, a bistable valve such as or similar to any of those described herein may be modified to create a mono-stable valve.  FIGS.  29 A- 29 C  depict an example mono-stable valve  2500  embodiment. As shown, the mono-stable valve  2500  includes a shuttle  2502  comprising a magnet  2525 . The shuttle  2502  may further include a first membrane portion  2508  attached to a first face of the magnet  2525 . The shuttle  2502  may also include a second membrane portion  2510  attached to an opposite, second face of the magnet  2525 . The shuttle  2502  is disposed in an interior valve cavity  2516 . The example embodiment shown in  FIGS.  29 A-C  includes a first post  2104  only a single electromagnetic coil  2526 . The coil  2526  may be supported on a bobbin-like support structure  2528  as best shown in  FIGS.  29 B-C . 
     Various embodiments, a mono-stable valve  2500  may include contact terminals  2522 ,  2523  (best shown in  FIGS.  29 B-C ). In the example, the contact terminal  2522 ,  2523  are pad-like which as mentioned above, may allow for more forgiving tolerances. The example mono-stable valve includes two valve bodies  2530 ,  2532  similar to those shown in  FIGS.  25 A-C . End plates  2534 ,  2536 , attached to the valve bodies  2530 ,  2532  are also included. A fastener  2550  may be used to couple the valve bodies  2530 ,  2532  and end plates  2534 ,  2536  together. In various other embodiments, any suitable method of attachment or coupling may be used in place of a fastener  2550  including adhesive, chemical bonding, RF welding, etc. 
     In a first position (shown in  FIG.  29 A ) of the shuttle  2502 , the first membrane portion  2508 , which is attached to the magnet  2525 , may be configured to create a seal over a first pressure inlet  2512 . In this position, fluid communication from the first pressure inlet  2512  to the interior valve cavity  2516  is blocked. In the first position, fluid communication from a second pressure inlet  2514  into the interior valve cavity  2116  may occur. In a second position, the magnet  2525  may be configured to seal over the second pressure inlet  2514 . In this position, fluid communication from the second pressure inlet  2514  into the interior valve cavity  2516  is blocked. In the second position, fluid communication from the first pressure inlet  2512  into the interior valve cavity  2516  may occur. As described elsewhere herein, fluid may be communicated from the interior valve cavity  2516  to one or more output orifice  2518 . 
     In the example embodiment, the shuttle  2502  is stable in the first position. In the first position, the shuttle  2502  is held in place by static magnetic attraction. To transition the mono-stable valve  2500  from the first position to the second position, the coil  2526  may be appropriately energized to repel the magnet  2525  in the shuttle  2502  such that the shuttle  2502  displaces from a sealing position over the first inlet  2512  to a sealing position over the second inlet  2514 . A holding current may be supplied to the coil to keep the shuttle  2502  sealed against the second inlet  2514 . Current may then be passed through the coil  2526  in the opposite direction to attract the shuttle  2502  such that the shuttle  2502  displaces back to the first position. In an alternative embodiment shown in  FIG.  29 D , a second post  2506  may be included. The second post  2506  may help to lower the holding current necessary to hold the shuttle  2502  in the second position. Such an embodiment may also generate less heat during operation. 
       FIGS.  30 A- 30 E  depict an example of a bi-stable 2 way valve assembly  3700 . Such a valve  3700  may not require a holding current when operated. The example embodiment shown in  FIGS.  30 A- 30 E  includes a first post  3712  and an electromagnetic coil  3726 . The coil  3726  may be supported on a bobbin-like support structure  3728  as shown in  FIGS.  30 B and  30 C . The valve assembly  3700  may include contact terminals  3722 ,  3723  (best shown in  FIG.  30 B ) for supplying current to the electromagnetic coil  3726  from an external source. The example valve assembly  3700  includes a valve body  3730 , an input/output body  3732  and end plates  3734 ,  3736 . A fastener  3750  may be used to couple the valve body  3730 , input/output body  3732  and end plates  3734 ,  3736  together. Rather than a fastener  3750 , other methods of coupling may include use of an adhesive, chemical bonding, RF welding, etc. A sealing gasket  3738  may be compressed between the valve body  3730  and the input/output body  3732  when the valve  3700  is assembled. 
     As shown, the valve assembly  3700  includes a shuttle  3702  that includes a magnet  3725 . The shuttle  3702  is disposed in an interior valve cavity  3716 . The shuttle  3702  may further include a membrane portion  3708 , in addition to a shuttle body  3706 . The shuttle body  3706  has a shuttle face  3704  to which the membrane portion  3708  is attached. The membrane portion  3708  may be attached in any suitable manner. For example, the membrane portion  3708  may be overmolded to the shuttle face  3704 . The shuttle body  3706  may also include a shuttle stem  3710 . The magnet  3725  may be ring or O shaped with a substantially central opening sized so that the magnet  3725  may be slid over the shuttle stem  3710  and attached to the shuttle body  3706 . 
     A biasing member  3714  may also be included in the interior valve cavity  3716 . The biasing member  3714  in the example shown is a compression spring. The biasing member  3714  is seated against a wall of the interior valve cavity  3716  opposite the valve seat  3718  and contacts a surface of a flange  3724  on the shuttle body  3706 . The biasing member  3714  applies a biasing force on the shuttle  3702  to a first position within the interior valve cavity  3716 . 
     In a first position (shown in  FIG.  30 D ) of the shuttle  3702 , the first membrane portion  3708 , is configured to press against and create a seal over a valve seat  3718 . In this position, fluid communication from a pressure inlet  3713  to the interior valve cavity  3716  is blocked. In the first position, a pressure outlet  3715  is in fluid communication with the interior valve cavity  3716 . In a second position, the shuttle  3702  is displaced away from the valve seat  3718 . In this position, fluid communication between the pressure inlet  3715  and the pressure outlet  3715  via the interior valve cavity  3716  is established. 
     In the example shown, the shuttle  3702  is stable in the first position due to the biasing force exerted by the biasing member  3714 . Optionally, the shuttle may be stabilized in the first position by the addition of a magnet to provide magnetic attraction between the shuttle  3702  and the input/output body  3723  and/or end plate  3736 . To transition the valve  3700  from the first position to the second position ( FIG.  30 E ), the coil  3726  can be energized to attract the magnet  3725  in the shuttle  3702  so that the shuttle  3702  is no longer in a sealing position over the valve seat  3718 . The electromagnetic attraction is sufficient to overcome the biasing force of the biasing member  3714 . The shuttle  3702  can then be retained in the position against the restoring force of the bias member  3714  by the magnet&#39;s  3725  magnetic attraction with the first post  3712 . Thus a holding current is not necessary to hold the shuttle  3702  in either the first or second positions. Current may be passed through the coil  3726  in the opposite direction to repel the shuttle  3702  such that the shuttle  3702  displaces back to the first position. 
     Shuttle Constraining Features 
     In some embodiments, a bistable valve such as, though not limited to any of those described herein may include one or more feature(s) which serve to constrain the shuttle about one or more degrees of freedom. This may help to ensure that a magnet of the shuttle has its poles oriented in a prescribed manner. It may help to ensure that the shuttle will repeatedly and reproducibly make a proper seal on the fluid inlets to an interior valve cavity. Additionally, a constraining feature may help simplify assembly of a bistable valve since a constraining feature may help to ensure that a shuttle can only be installed in the valve in a proper orientation. In some specific embodiments, all but one degree of freedom of the shuttle may be substantially constrained. For example, all of the shuttle&#39;s rotational degrees of freedom may be constrained while all but one of the shuttles translational degrees of freedom may be constrained. The translational degree of freedom which is not constrained may be a degree of freedom which allows the shuttle to displace about the axis of the interior valve cavity. 
     In some embodiments, a shuttle may have one or more keyed alignment features that serve as a constraining feature. Each of the one or more keyed alignment features cooperate with the interior valve cavity to constrain the shuttle to the desired degrees of freedom. A keyed alignment feature may take any of a variety of forms. For example, the cross sectional shape of a shuttle may be chosen to inhibit motion about unwanted degrees of freedom. A shuttle may be polygonal, ovoid, or irregularly shaped and may displace within a cooperatively shaped interior valve cavity. Alternatively, the interior valve cavity may include one or more guide projection which extends from the wall of the interior valve cavity into the volume of the interior valve cavity. Each guide projection may fit into a respective corresponding recess in the shuttle and serve to constrain the shuttle from undesired movement. The guide projection may or may not be dovetailed depending on the embodiment. The keyed alignment feature used may be selected so as to provide suitable magnetic flux paths within a bistable valve. Alternatively, the keyed alignment feature may not be a continuous part of the magnet of the shuttle. For example, the keyed alignment feature may be a non ferrous or non-magnetic insert or attachment which is coupled into, onto, or around the magnet. Such an insert or attachment may be made of any suitable metal of plastic. In embodiments with a plurality of magnets, the keyed alignment feature may be included on a piece of material which is captured or retained between two of the magnets of the shuttle. Alternatively, the piece of material including the keyed alignment feature may as serve to retain the magnets of the shuttle. The keyed alignment feature may or may not extend through the entire thickness of the shuttle. 
     In other embodiments, such as the embodiment depicted in  FIGS.  31   , the shuttle  2602  of a bistable valve  2600  may include a guide or tab projection  2604 . This projection  2604  may fit into a corresponding recess  2606  in the side wall of the interior valve cavity  2608 . The recess  2606  may include rollers or ball bearings (not shown) in some embodiments to minimize friction. As mentioned above, this guide tab or projection  2604  may be dovetailed although in the example embodiment, a dovetailed feature is not present. As shown, the guide tab or projection  2604  would substantially prevent yawing of the shuttle  2602 . The footprint of the interior valve cavity  2608  is only slightly larger than the footprint of the shuttle  2602 . Due to the thickness of the shuttle  2602 , the interior valve cavity  2608  will substantially prevent roll and pitching of the shuttle  2602 . The footprint of the interior valve cavity  2608  will also substantially prevent translational displacement of the shuttle  2602  in directions other then the axial direction of the interior valve cavity  2608 . 
       FIGS.  32 A- 32 C  depict an example shuttle  2700  which includes a number of keyed alignment features  2702 . As shown, the keyed features  2702  are small pegs which project outwardly from a magnet retaining structure  2704  of the shuttle  2700 . As best shown in  FIG.  32 C , two crown members  2706  may be placed over the ends of the magnet retaining structure to hold the magnets  2708  in place in the magnet retaining structure  2704 . The crown members  2706  may also each capture a piece of pliant material  2710  against the magnet retaining structure  2704  when the shuttle  2700  is assembled. The crown members  2706  may be held in place by any suitable means. For example, the crown members  2706  may be solvent bonded, glued, high frequency welded, ultrasonically welded, etc. onto the magnet retaining structure  2704 . The pegs extend outwardly from the magnet retaining structure  2704  such that the width of the shuttle  2700  is greatest at the location of the pegs. Thus the shuttle  2700  may ride along peg receiving tracks in an interior valve cavity and be substantially restrained from undesired movement. In alternate embodiments, it should be noted that the keyed feature may be a projection from any other part of a shuttle. For example, the keyed feature may be a projection on one or both of the crown members  2706  of a shuttle. 
       FIGS.  33 A- 33 C  depict an example embodiment of shuttle  3600  including a number of notches  3602 A, B which act as constraining features. The notches  3602 A, B may be formed in an overmolded coat  3604  which covers a magnetic or metal body  3606  of the shuttle  3600 . The overmolded coat  3604  optionally, either in whole or in part, is made of an elastomeric material which may further help to ensure that a proper seal is made over valve seats of a valve as it is toggled between positions. As shown the notches  3602 A, B are included in aligned pairs which are separated by ridges  3608 . A first set of notches  3602 A extend toward the ridges  3608  from a first face  3610 A of the shuttle  3600 . The second set of paired notches  3602 B extends toward the ridges  3608  from a second, opposing face  3610 B of the shuttle  3600 . Though the notches  3602 A, B are aligned in the example embodiment, in other embodiments, notches  3602 A can be angularly offset from notches  3602 B. 
     Referring now primarily to  FIG.  33 C , a cross section is shown depicting the shuttle  3600  in an example interior valve cavity  3616 . The notches  3602 A, B cooperate with one or more guide structures  3618  which extend from the interior wall  3620  of the interior valve cavity  3616  toward the shuttle  3600 . The guide structures  3618  may be dimensioned so as to be received in the notches  3602 A, B when a valve is assembled. The ridges  3608  may also act as constraining features. The ridges  3608  may extend into tracks  3622  within the interior valve cavity  3616  of a valve. In some embodiments, the length of the tracks  3622  may serve to limit travel of the shuttle  3600  within the interior valve cavity  3616 . As the shuttle  3600  is displaced, it may move, for example, until it is inhibited by the ridges  3608  abutting an end of their receiving tracks  3622  in the interior valve cavity  3616 . 
     As best shown in  FIG.  33 C , the portion of the overmolded coat  3604  over the faces  3630 A, B of the magnetic of metal body  3606  optionally is thicker than those covering the sides of the metal body  3606 . In one example, the portion of the overmolded coat  3604  over the faces  3630 A, B is about 20-30% (e.g. 25%) the thickness of the metal body  3606 . In a specific example, the portion of the overmolded coat  3604  over the faces  3630 A, B is about 0.03″ thick. 
     Valve/Controller Manifold Modules 
     Valves such as binary valves, vari-valves, or any of the valves described herein may, in some embodiments, be supplied as modular that can be plugged into a manifold frame or base to provide pneumatic, hydraulic or electrical control of external devices, such as fluid flow control devices, heaters, motors, or hydraulic or pneumatic devices. An abstracted block diagram of such a valve module or valve manifold module  2800  is shown in  FIG.  34 A . Each valve module  2800  may comprise one or more valves  2802 . Additionally, each valve module  2800  may include electronic components necessary to operate the valves  2802  included in the valve module  2800 . These can include an electronic controller equipped to perform a number of programmed commands to the valves to allow the valve module  2800  to actuate or control an external device in at least a partially autonomous manner. A valve module  2800  may thus be an assembly of one or more valves  2802  connected to one or more on-board PCBs (printed circuit or electronic control boards) populated with electronic components  2808  suitable for operating the valves autonomously or semi-autonomously with respect to a main or central controller. This may help to offload some of the computing resources necessary to run the valves  2802  from a main processor of a device. The main processor may then only need to send a valve module  2800  higher level commands. These high level commands may include, for example, start commands, stop commands, pause/resume commands, commands to perform a measurement, commands to reverse liquid flow in an associated flow control device, commands to properly sequence the operation of on-board valves, commands to coordinate valve actions among a local group of modules, and commands to perform template functions pre-programmed on the PCB  2808 . Once a higher level control program has been received, the PCB  2808  may command a valve module  2800  perform a valve function (e.g., opening or closing a port in a prescribed sequence or at a prescribed rate) in an autonomous manner without further input from an external controller. Alternatively, the PCB may be programmed to operate a valve module  2800  to perform a valve function in an entirely autonomous manner without any input from an external controller. 
     In embodiments in which a valve manifold module  2800  includes a plurality of valve assemblies  2802 , the PCB  2808  may be configured such that all of the valves  2802  in the module  2800  may be operated using a common power source or bus. Additionally, in embodiments in which a module  2800  includes multiple valve assemblies  2802 , each of the valve assemblies  2802  may be mounted on a modular manifold base  2804  which includes or is connected to manifold fluidic (hydraulic or pneumatic) flow paths (fluid buses) for those valves  2802 . An integrated manifold assembly comprising a plurality of concatenated valve manifold modules  2800  can thus be assembled (attached or connected together, for example by fasteners), and configured for control or operation of an external device, such as a liquid flow control device (e.g. pump and valve device for transfer of a liquid). A modular valve/manifold assembly constructed in this manner can permit maintenance, repair or replacement of individual valve modules  2800  by plugging in or unplugging the valve module  2800  from the manifold. Also, within each valve module  2800  are a bank of valve assemblies  2802  whose ports and electrical connections (as well as housing dimensions) can be sufficiently identical to be interchangeable among the designated receptacles in the module  2800 . A particular valve manifold module  2800  can also be readily re-configured for operation of an external device having different features or functions (e.g., a different array of fluid flow control pumps and valves, or a system with additional electronic, electrical, hydraulic or pneumatic functions). 
     Each PCB  2808  may include, for example, a pressure sensor which is configured to read the pressure of a fluid volume in the module. In some embodiments, the pressure sensors may read the pressure from wells in the module manifold or block  2804  which fluidically communicate with the fluid pathways in the module block  2804 . O-rings, gasketing, or another suitable seal may be included to provide a seal between the volume of the wells in the module block  2804  and the ambient environment. In some embodiments, one of more o-rings or gaskets may be compressed to create the seal as the PCB  2808  is coupled to a module block  2804 . In other embodiments, the pressure sensors of the PCB  2808  may communicate with the interior valve cavities of respective valves  2802  via any suitable fluid path. In the representational embodiment shown, the PCB  2808  pressure sensors may for example be in fluid communication with the interior valve cavities directly through a fluid path in each of the respective valves  2802 . Alternatively, the PCB  2808  pressure sensors may be in communication with the flow paths leading from the valve  2802  outlets via a flow path through the end blocks  2806  on the ends of the module  2800 . Other arrangements may also be used. 
     Other sensors may also be included on the PCB  2808 . Such sensors may include current sensors. These current sensors may be configured to sense the current running through the electromagnetic coils of a valve  2802  for example. Data provided by these current sensors may allow for a determination to be made about whether or not a valve  2802  is functioning properly. The PCB  2808  may also be equipped to receive electronic signals from remote sensors, and to convert these signals to digital form using any suitable A/D converter mounted to the PCB. Such signals may be derived from remote pressure sensors, conductivity sensors, temperature sensors, air-in-line sensors, fluid level sensors, flow sensors, as well as other types of sensors depending on the application to which the application to which the valve/controller module is directed. 
     Additionally, a processor or processing components may be included on the PCB  2808  and may allow a valve module  2800  to autonomously carry out or execute various valve-related applications. Thus a module  2800  may require little or no direction from an external processor included in the device in which the module  2800  is installed. The processor or processing components of the PCB  2808  may make use of and analyze data collected from other components (e.g. pressure sensors) of the PCB  2808  to meet the needs of a particular application. 
     There may be different modules  2800  for different valve applications that are populated with different electronic components suitable for a particular application. Additionally or alternatively, modules  2800  may be programmed in a variety of different ways depending on intended application. Some individual modules  2800  may be programmed such that they may perform a multiplicity of tasks. In some specific embodiments, the valve(s)  2802 , the PCB  2808 , and other components of the valve module  2800  may be overmolded together such that all of the components of the module  2800  are physically attached to one another and form a single unit. In some applications, a valve/control module may be permanently programmed to perform basic functions (e.g. coordinating the opening and closing of inlet and outlet valves while driving a pump, regulating the flow or pumping rate of the pump, detecting aberrant flow conditions, etc.), but may be automatically assigned more specific or detailed tasks upon connection of the valve/control module to a particular location on a communications control bus, such as a controller area network (‘CAN’) bus. 
     Referring now also to the representational embodiment shown in  FIG.  34 B , each module  2800  may be configured such that it may be connectable to another module  2800 . This would allow a user to easily assembly a manifold  2850  which will suit a particular desired application. To facilitate such interaction, the valve modules  2800  may be arranged such that fluid pathways of each module  2800  may be connectable or coupleable to fluid pathways of another module  2800 . End blocks  2806  may be placed on the ends of the manifold  2850  to allow an assembled manifold  2850  to interface with other components such as a pressure reservoir or bus of a device, and electronic communication bus of a device, and/or a power bus of a device. An o-ring, gasket, or seal may be provided to ensure integrity of the fluid paths within the manifold  2850 . 
     When connected together, the electronic components of each connected module  2800  may be placed into communication with one another. This allows for a number of connected modules  2800  to utilize power from a single source (e.g. a device power bus). Communication also allows for sharing of valve state/pressure data between valves  2802  and facilitates module to module synchronization. Additionally, this may allow for some modules  2800  to be made with fewer or less complex electronic components making it more economical to build up a manifold  2850  out of a number of valve modules  2800 . Module-to-module and system or main controller to module communication may be accomplished with any suitable communication scheme, including, in some specific embodiments, a CAN-bus. It may be desirable to utilize a CAN-bus communication scheme as it is low power and is of relatively low complexity. Each module  2800  may include a terminating resistor which can be switched on and off to terminate the manifold  2850  if the module  2800  is at the end of the manifold  2850  (and/or at the end of the CAN-bus communications chain). 
     A manifold  2850  of one or more valve modules  2800  may communicate with other components of a device wirelessly or via wired connection to a device communication bus. In embodiments in which a manifold  2850  of one or more valve module(s)  2800  is controlled remotely or wirelessly, inter-modular communication within the manifold  2850  optionally may also be wireless. 
     In some embodiments, each valve module  2800  may be configured as specializable, but without a preset assigned functionality. That is, the module  2800  may have the hardware capability to perform a full set of valve-related tasks or applications. Tasks may include, but are not limited to, synchronization of inter-modular operations, functioning as master module for a multi-module manifold  2850 , functioning as a pumping module by supplying pressure to a pneumatically or hydraulically driven fluid pump, functioning as a pneumatic or hydraulic valve controller by supplying pressure to a pneumatic/hydraulic valve interface, etc. In some specific implementations, tasks may include supplying pressure to an interface for a pumping cassette to effect pumping of fluid in the pumping cassette, supplying pressure to an interface for a pumping cassette to actuate valves of the pumping cassette, supplying pressure to an interface for a pumping cassette to direct fluid flow through the pumping cassette, etc. 
     As modules  2800  are added onto a manifold  2850  carrying hydraulic or pneumatic supply lines, the modules  2800  may be specialized to particular tasks or applications, which in an embodiment may be automatically determined by the location of the module along an interconnected chain of modules on a communications bus, such as a CAN-bus. Further specialization may also be imposed during operation by a system controller as required by particular applications. For example, a module  2800  specialized to act as a pumping module may be further programmed to pump at a specific pressure or flow rate. 
     By making each valve module  2800  specializable, manifolds  2850  assembled from the interconnection or concatenation of such modules  2800  would be easily scalable. Such a module  2800  would allow for custom manifolds  2850  to be easily built up and assembled with reduced development effort. Additionally, modules  2800  would be easily swappable due to their interchangeability, thus facilitating replacement of a module  2800  within a pre-existing multi-module manifold  2850 . In an embodiment, the specific task assigned to a replaced module may be automatically assigned to the new module by ( 1 ) its location along the chain of modules on the communications bus, and/or ( 2 ) by a system controller that has been alerted to the presence of the new module (e.g. by a unique identifier) and its location on the communications bus or along the manifold assembly. 
     In some embodiments, modules  2800  may be self-enumerating and may be assigned a unique identifier after a module  2800  has been installed onto a manifold  2850 . A processor included on a PCB  2808  of a master module may take a census of the modules  2800  connected to one another in a manifold  2850 . As mentioned above, any module  2800  may be assigned as the master module. This census may be updated as additional modules  2800  are added to the manifold  2850  or as modules  2800  are removed from the manifold  2850 . The processor of the master module may also assign one or more specialization(s) to each module  2800  forming the manifold  2850 . The specialization assigned may depend on the physical position of a module  2800  within the manifold  2800 . In one example implementation, when the census of the manifold  2850  modules  2800  is taken, each module  2800  may be assigned a unique identifier (e.g. module 1 ,  2  . . . n). The census may also determine the spatial arrangement of modules  2800 . For example, a processor of the master module may determine, during the census, that module  2  is adjacent side A of module  1  and also adjacent side B of module  3 . This spatial arrangement data aids in automatic assignment of module  2800  tasks. In some embodiments, spatial arrangement may be implied from identities of the modules  2800  after they are given their identifier. This may be an effect of the manner in which the modules are assigned identifiers. Alternatively, automatic enumeration of modules  2800  in a manifold  2850  need not be orchestrated by a master module, but may be accomplished by each module  2800  determining its own identity in the manifold  2850  (described later in the specification). 
     In some embodiments, new modules  2800  which are added to a manifold  2850  either as replacements for old modules  2800  or to expand the size of the manifold  2850  may be automatically enumerated. As an example, if module  2  has a fault and needs to be replaced with a new module  2800 , the processor of the master module may detect when the new module  2800  has been installed and automatically assign it as module  2 . Alternatively, the new module  2800  may determine its own identity. The new module  2800  may then assume the identity and task set of the original module  2 , executing commands issued for module  2  and communicating with other modules  2800  the same as the previous module  2 . 
     Fault conditions may be communicated in an intermodular manner within a multi-module  2800  manifold  2850 . This may allow a manifold  2850  to adapt to certain faults depending on the manifold  2850  configuration. A processor of a master module may command that the manifold  2850  operate in a “limp home” mode in the event of particular fault conditions. For example, in the event that the manifold  2850  includes two pumping modules and one has a fault, the processor of the master module may determine the most efficient manner to continue pumping with the remain pumping module and command the modules  2800  of the manifold  2850  to operate in that manner. 
     In a scenario in which a communications bus of a manifold  2800  has a fault and is interrupted, but the power bus remains functional, modules  2800  of the manifold  2850  may identify the fault and switch to operation in a fail safe mode. Fluid valves may, for example, be commanded to automatically close. Any other desirable fail safe mode could also be implemented. For example, a module  2800  could be programmed to continue pumping of fluid at a previously programmed or commanded flow rate. In this way, the failure of one module in the manifold assembly may result in loss of communications to the downstream modules, but some of the modules may be allowed to operate in an autonomous manner until the system is wound down in an orderly manner. For example, a blood pump module could be allowed to continue to operate for a designated period of time if a dialysate pump module were to fail in a hemodialysis system. 
     In some embodiments, modules  2800  may also be able to detect and reacted to various conditions of interest. For example, in embodiments where at least one of the modules  2800  of a manifold  2850  is a pumping module, a processor of a module  2800  may be able to detect flow condition related information. In the event that an abnormal flow condition is detected (e.g. a reduced or no flow condition), the module  2800  may arrange for and/or perform troubleshooting or may request that the processor of the master module command troubleshooting be performed. This troubleshooting may determine, for example, if an occlusion exists. The manifold  2850  may then cease pumping and signal that an error condition exists if an occlusion is detected. 
       FIG.  34 C  depicts a representational example diagram of a number of valve modules  2800  installed in a pneumatic system  2852 . Each module  2800  includes a controller  2854  which may be included on a PCB of a module  2800  as described above. Each module  2800  also includes a pneumatic block  2856 . The pneumatic block  2856  may include various pneumatic components of a module  2800  such as one or more valves  2802  (see, for example,  FIG.  34 A ), a module block  2804  (see, for example,  FIG.  34 A ) including fluid flow paths, and an end block  2806  (see, for example,  FIG.  34 A ) if the module  2800  is at the end of a multi-module manifold. 
     Each module  2800  may connect to various buses of a device. As shown in the example in  FIG.  34 C , a data/communications bus  2864  and power bus  2866  are depicted. The data/communications bus  2864  may allow for data or commands to be communicated from module  2800  to module  2800  within a multi-module manifold. This allows for synchronization and coordination of module  2800  activities in a multi-module manifold. Additionally, commands and data may be conveyed to or from the manifold to an external board or processor via the data/communications bus  2864 . The power bus  2866  may supply power to the various modules  2800  in a manifold. This power may pass to the manifold via the power bus  2866  from a source external of the manifold. The data/communication bus  2864  and the power bus  2866  may interface with a connector on a PCB  2808  (see, for example,  FIG.  28 A ) of a module  2800 . 
     A first pneumatic bus  2868 , second pneumatic bus  2870 , and third pneumatic bus  2872  are also shown. The first, second, and third pneumatic buses  2868 ,  2870 ,  2872  may each be connected to a pressure reservoir which is at a different pressure. Pneumatic buses  2868 ,  2870 ,  2872  may interface with a connector on an end block  2806  (see, for example  FIG.  28 A ) of a multi-module manifold. Alternatively, pneumatic buses  2868 ,  2870 ,  2872  may interface with a connector anywhere on a pneumatic block  2856  of a module  2800 . This module  2800  to bus connection may be accomplished in a plug and play fashion. Once a module  2800  is connected to the appropriate buses, an identity for the module  2800  may be determined and the module  2800  will be ready for operation. 
     As represented by the buses of the  FIG.  34 C  running through each module  2800  and on to the next, each bus may be conveyed through the modules  2800  of a multi-module manifold. Electrical power and data communication may be conveyed through a module to module connector on a PCB  2808  (see, for example,  FIG.  34 A ) of each module  2800 . Pneumatic buses  2868 ,  2870 ,  2872  may be conveyed through bus flow paths in the pneumatic block  2856  which align with bus flow paths on the pneumatic block  2856  of an adjacent module  2800 . Alternatively, each module  2800  in a manifold may be individually connected to each bus. In certain embodiments, some pneumatic buses  2868 ,  2870 ,  2872  may only be in fluid communication with selected modules  2800  of a manifold. Some modules  2800  may have occludable ports to the pneumatic block, or may be constructed with a limited array of ports. 
     As shown, the controller  2854  of each module  2800  may issue valve commands  2858  to control the valve(s)  2802  (see, for example,  FIG.  34 A ) of that module  2800 . The controller  2854  may also receive pressure data  2860  from one or more pressure sensor(s)  2862  in a module  2800  which sense the pressure of flow paths within the pneumatic block  2856 . The pressure data  2860  may be used by the controller  2854  to inform control of the valve(s)  2802 . In the example diagram, each module  2800  is shown as a pumping module which the controller  2858  may control to cause fluid to pumped by the pneumatic system  2852 . 
     A first variable volume  2882  and a second variable volume  2884  are included for each module  2800  in the example pneumatic system  2852 . A change in volume of the first variable volume  2882  may in turn cause a change in volume of the second variable volume  2884 . An increase in volume of the first variable volume  2882  may cause a corresponding decrease in volume of the second variable volume  2884 . A decrease in volume of the first variable volume  2882  may cause an increase in volume of the second variable volume  2884 . Two pneumatically driven inlet/outlet valves  2892  for the second variable volume  2884  are included and may be actuated to allow for the variable volumes  2882 ,  2884  to change in volume. 
     As shown, the first variable volume  2882  and two inlet/outlet valves  2892  are connected to the outputs of their respective modules  2800 . The valves  2802  (see, for example,  FIG.  34 A ) of each module  2800  may be actuated to increase or decrease the volume of the first variable volume  2882 . When the volume of the first variable volume  2882  is decreased, one inlet/outlet valve  2802  is open, and the other inlet/outlet valve  2892  is closed, fluid will be drawn into the second variable volume  2884 . When the volume of the first variable volume  2882  is increased, one inlet/outlet valve  2892  is closed, and the inlet/outlet valve  2892  is open, fluid will be forced out of the second variable volume  2884 . As would be appreciated by one skilled in the art, pumping of fluid in either direction may be accomplished by appropriate actuation of the inlet/outlet valves  2892 . 
     The first and second variable volumes  2882 ,  2894  may be configured in any suitable arrangement which would allow a change in volume in one to be tied to a change in volume of the other. For example, the first variable volume  2882  may surround or be surrounded by the second variable volume  2884 . The first variable volume  2882  may be separated from the second variable volume  2884  by a displaceable intermediary structure which acts on the second variable volume  2884  as the first variable volume  2882  increases or decreases in volume. The intermediary structure may be any suitable structure such as a piston, arm or lever, etc. The first and second variable volume  2882 ,  2884  may also be separated from one another by a displaceable wall  2888  such as a diaphragm or a membrane made of a flexible material. 
     In some embodiments, there may be greater number of variable volumes. In such embodiments, a change in volume of the first variable volume  2882  may cause a change in volume of a plurality of other variable volumes. Likewise, change in volume of a plurality of variable volumes may cause a change in volume of one or more additional variable volumes. 
     In the representational diagram depicted in  FIG.  34 C , the first variable volume  2882  is defined by a fixed wall  2886  and a displaceable wall  2888 . The second variable volume  2884  is adjacent the first variable volume  2882  and is defined by a second fixed wall  2889  and the displaceable wall  2888 . As the volume of the first variable volume  2882  increases, the displaceable wall  2888  is pushed toward the second fixed wall  2889 . As the volume of the first variable volume  2882  decreases, the displaceable wall  2888  is pulled toward the first fixed wall  2886 . 
     Another example pneumatic system  2852  is depicted in the representational diagram in  FIG.  34 D . The example pneumatic system  2852  is similar to that depicted in  FIG.  34 C , however, a fourth pneumatic bus  2873  is included. The fourth pneumatic bus  2873  may be connected to a vent reservoir such as the atmosphere. The other three pneumatic buses  2868 ,  2870 ,  2872  may be connected to pressure reservoirs. For example the first pneumatic bus  2868  may be connected to a negative pressure reservoir, the second pneumatic bus  2870  may be connected to a low positive pressure reservoir, and the third pneumatic bus  2872  may be connected to a high positive pressure reservoir. Including a vent or atmospheric bus may be desirable as it may help to minimize the amount of pumping necessary to maintain reservoirs for the other buses  2868 ,  2870 ,  2872 . For example, when switching a volume from positive pressure to a negative pressure or vice versa, it may be desirable to vent the volume to ambient pressure. This would avoid excessive depletion of the pressure reservoirs as it lowers the pressure difference between the volume and the reservoir. It should be appreciated that any other number of pneumatic buses may be included in various embodiments. Additionally, the number of electrical buses may vary as well. 
     Another example pneumatic system  2852  is depicted in the representational diagram in  FIG.  34 E . The example pneumatic system  2852  is similar to that depicted in  FIG.  34 C , however, module to module connectors  2865  are depicted on the data/communication bus  2864  in  FIG.  34 E . The module to module connectors  2865  may consist of cooperating pieces of hardware on each module  2800  which serve to create an electrical communication pathway from module  2800  to module  2800  in a multi-module manifold. 
     As shown the module-to-module connectors  2865  may allow for the connection established to be interruptible in response to commands from the controller  2854  of each module  2800 . This is signified by a switch in each of the module-to-module connectors  2865 . This may be particularly desirable when a manifold is being auto-enumerated or when a new module  2800  is being installed in the manifold as a replacement. In a specific embodiment, a module  2800  may interrupt communications coming from one side of the manifold. That is, the module may interrupt communications in a first direction while leaving communications in a second direction enabled. In the example diagram shown, the third module  2800  from the left has interrupted communications to and from modules  2800  to its right or downstream side. This may be a default configuration of each module  2800  upon installation into a manifold. When communication has been interrupted, a terminating resistor on the module  2800  may also be switched in. 
     Each message sent on the data/communication bus  2864  may be uniquely marked according to the module  2800  from which it originated. After interrupting communications, a module  2800  may then poll modules  2800  on the portion of the manifold that the module  2800  is still in communication with. These modules  2800  may respond to the new module  2800  and the new module  2800  will determine its identity or function based upon the responses received. For example, if the module  2800  only receives responses from modules  1  and  2 , the new module  2800  will determine that it must be module  3 . Messages addressed with the unique marker for module  3  may then be received and acted upon by the new module  2800 . Communication with the rest of the manifold may be reestablished and the next module  2800  may repeat the process to determine its identity or function, and so on. When communications are reestablished, a terminal resistor included on newly enumerated module  2800  may also be switched off. 
     Alternatively, after a module  2800  interrupts communications to one side of the manifold, the module  2800  may wait for a period of time and receive messages sent across the data/communication bus  2864 . The module  2800  may then determine its identity or function based upon the unique markers of the messages sent across the data/communication bus  2864 . If the new module  2800  only receives messages from module  1  and  2 , the new module  2800  may then determine that it must be module  3 . As above, communication with the rest of the manifold may be reestablished and this process may repeat until each module  2800  in a manifold has auto-enumerated. A terminal resistor which may be switched in and out may be included on each module  2800  and operate as described above. 
     As would be appreciated by one skilled in the art, any other scheme involving interruption of the communication bus to facilitate auto-enumeration of modules  2800  in a multi-module manifold may also be used. Also as mentioned above, this process need not be performed by each individual module  2800  in the manifold. In some embodiments, the process may be conducted or coordinated by a master controller in the manifold. 
       FIG.  34 F  depicts another example pneumatic system  2852  similar to that depicted in  FIG.  34 C . As shown, the example pneumatic (or hydraulic) system  2852  in  FIG.  34 F , includes a number of modules  2800  which are arranged to perform a plurality of different valve related tasks. It should be appreciated that the tasks shown are only exemplary. 
     The third module  2800  from the left is arranged as a pumping module similar to those shown in  FIG.  34 C . The two left-most modules  2800  are arranged to control a two chamber fluid pump  2896 . The controllers  2854  of the two left most modules  2800  may operate in tandem, coordinating or synchronizing pumping operations between one another to optimize fluid throughput or achieve substantially continuous pumping, for example. The controllers  2854  may communicate over the data/communication bus  2864  to synchronize with one another. Each controller  2854  may also send commands  2858  to their respective pneumatic blocks  2856  in order to effect pumping of fluid in each module&#39;s  2800  respective chamber of the fluid pump. In one synchronization scheme, the controller  2854  of one module  2800  may be synchronized such that it commands filling of its associated chamber while the other commands delivery of its associated chamber. Thus fluid may be pumped to one of a first or second reservoir  2890 ,  2895  in a substantially continuous fashion from the other reservoir. Modules  2800  may similarly coordinate to synchronize operations between a greater number of fluid pumping chambers as well. For example, a three chamber fluid pump may be controlled by three modules  2800  which communicate over a data/communication bus  2864  to synchronize pumping. 
     The rightmost module  2800  is configured as a pneumatic (or, in other systems, hydraulic) valve module and controls only valves in the example diagram shown in  FIG.  34 G . As shown, the outputs of the module  2800  are connected to a number of fluid valves  2897  which control fluid communication to various fluid pathways  2898  in the pneumatic system. The number of fluid valves  2897  may be greater or less than the number shown. Depending on the number of valves included in a module  2800 , the amount of fluid valves  2897  the module is capable of controlling independently will differ. 
       FIG.  34 G  depicts another example pneumatic system  2852  similar to that depicted in  FIG.  34 C . As shown, the example pneumatic system  2852  in  FIG.  34 G , includes a number of modules  2800  which are arranged to perform a plurality of exemplary valve related tasks including fluid pumping and pneumatic fluid valve  2897  actuation. As in  FIG.  34 F , the fluid valves are shown controlling communication to various flow paths  2898  in the pneumatic system  2852 . Also as shown in  FIG.  34 F , the third module  2800  from the left is shown controlling a fluid pump. 
     The leftmost and second leftmost module  2800  are depicted as cooperatively controlling a single fluid pump. Having a plurality of modules  2800  cooperatively controlling a single fluid pump may allow for manifolds to be made smaller and may allow for manifolds to operate more efficiently depending on the scenario. Additionally, such cooperative control may allow for a greater range of pressures to be used while pumping. For example, a first module  2800  may provide fluid at a first negative pressure and a second negative pressure while a second module may provide fluid at a first positive pressure and a second positive pressure. Another benefit of cooperative control is that it allows for control of a fluid pump requiring a greater number of valves  2802  than a single module includes. 
     As shown in the specific example, the leftmost module  2800  controls the state of two inlet/outlet valves  2892  of the second variable volume  2884  of fluid pump. The leftmost module  2800  also controls a pressure input to the first variable volume  2882  of the fluid pump. The other module  2800  controls another pressure input to the first variable volume  2882  as well as another inlet/outlet valve  2892  of the second variable volume  2884 . To coordinate pumping operations for the fluid pump, the processor  2854  of each cooperating module  2800  may synchronize valve activity related to the fluid pump over the data/communication bus  2864 . This allows a manifold assembled from modules  2800  each including four valves  2802  to run a fluid pump requiring five valves  2802 . 
     While the above description relates to use of modules  2800  to control various pneumatic components (e.g. pneumatically driven pumps and/or valves), it should be recognized that such modules  2800  may be easily modified to control a wide range of components or devices. A similar arrangement may be used to control hydraulically actuated pumps and/or valves, with the manifold valve module  2800  making a hydraulic connection to one or more pressurized hydraulic lines in a system. Such a connection may be made using, for example, quick-connect fittings to allow for ready replacement of manifold valve modules  2800  in need of maintenance or repair, or replacement with manifold valve modules  2800  configured for different combinations of pumps or valves. 
     As illustrated in the representation diagram in  FIG.  34 H , a module  2800  may include a PCB  2808  with a processor  2854  which is programmed to self sufficiently command operation of one or more motors  2841 . The PCB  2808  may include electrical outputs to each winding of the motor  2841 . In some embodiments, the motor  2841  and PCB  2808  may be included as a single package and the PCB  2808  may be overmolded onto a portion of the motor  2841 . Similarly a module  2800  may be modified to self sufficiently control operation of one or more pump  2842 . The PCB  2808  of the module  2800  may include electrical outputs which interface with the pump. In some configurations, the pump  2842  and PCB  2808  may be included as a single package and the PCB  2808  may be overmolded onto a portion of the pump  2842 . A module  2800  may be programmed to control illumination of one or more light emitters  2843  as well. 
     Modules  2800  may be configured such that the PCB  2808  includes a controller  2854  which is programmed to control operation of one or more electromagnets  2844  based on a pre-defined program. The PCB  2808  may include an electrical output which interface with the contacts of the electromagnets  2844  to energize the electromagnets  2844  in any desired fashion. Additionally, modules  2800  may be modified to self sufficiently control operation of one or more heater elements  2845 . In such embodiments, a module  2800  may include a PCB  2808  with a controller  2854  that is capable of switch current flow through the heater element  2845  on and off in any desired manner. Again, this may be accomplished based upon a pre-defined program or based on high level commands from an external main controller. For example, the main controller may command that the heater element  2845  warm a surface to a temperature set point. The module  2800  may then execute all of the necessary control functions to get the surface to the commanded temperature set point using the heater element  2845  and feedback signals from a suitably located temperature sensor. The on-board module controller  2854  may be configured to provide analog control of the heater element  2845 , or digital control through, for example, application of pulse-width-modulated current to the heater element  2845 . In some embodiments, a module  2800  may not directly mediate current flow through the module  2800  to the heater element  2845 . Instead, the module  2800  may control a relay making or breaking a connection between a current source and a heater element  2845 . This may be desirable in scenarios in which the heater element  2845  is run at high voltages (e.g. mains voltage). Modules  2800  may control relays used in other applications as well. Such relays may comprise high speed digital devices, such as thyristors, TRIACS, or silicon controlled rectifiers. 
     A module  2800  may include a PCB  2808  with any of a variety of sensors  2840  suited for particular applications. For example, modules  2800  may be populated with current sensors, temperature sensors, pressure sensors, encoders, optical sensors, magnetic sensors, inertial sensors, or any other sensor as required by the module  2800  application. 
     As described above, modules  2800  used for control of other devices or components can be configured to share power transmitted through a shared power bus  2866 . Such modules are also able to coordinate or synchronize operation via a shared data/communication bus  2864 . This coordination may be between similar or dissimilar devices or components. For example, such coordination may help to limit or manage peak power loads among other benefits. 
       FIG.  35 A  depicts a specific example embodiment of a valve module  2900 . As shown, the example embodiment includes four valve assemblies  2902 . In other embodiments, a valve module  2900  may include any suitable number of valve assemblies. The valves  2902  may be any of a variety of types of valves including binary valves, variable valves, or bi-stable valves such as any of the embodiments described herein. The valves  2902  can be mounted on a manifold module base or block  2904  as shown. The module block  2904  includes a number of fluid channels or flow paths which interface with the fluid inlets and outlets of each valve  2902 . The module block  2904  may thus form a manifold for the valve assembly  2902 . In embodiments comprising bi-stable valves such as those described herein, one of the inlet ports for one or more valve assemblies in the module  2900  can be blocked. This may allow the bi-stable valve to effectively function as a two-way valve. Additionally, a module base or block  2904  may include one or more fluid buses—flow paths which can convey pressurized fluid (e.g. pneumatic or hydraulic) from a pressurized fluid source line to a series of interconnected manifold modules. Any number of manifold modules can be concatenated or connected in series, each having a fluid bus connecting a pressure line inlet port on one side of the module to a pressure line outlet port on another side of the module. Modules can be connected together by standard fasteners, with inlet and outlet ports joined via gaskets or O-rings, for example. Thus in a pneumatic system, one or more pneumatic buses can be assembled in a manifold assembly from module  2800  to module  2800  in a multi-module manifold assembly. 
     Also shown in  FIG.  35 A  are manifold module end blocks  2906 . The end blocks  2906  may be attached to the ends of a manifold assembly assembled from a number of valve modules  2900 . The end blocks  2906  may include connection ports  2907  connecting one or more pressure line inputs or outputs to corresponding pressure line input or output ports of the valved module(s)  2900  making up a manifold. For example, the connection ports  2907  may connect to pressurized fluidic components such as pneumatic lines or buses from one or more positive pressure sources or reservoirs, negative pressure reservoirs, a vented source or reservoir (e.g. atmosphere), or other reservoir. Any suitable connector fitting may be incorporated into the connection ports  2907 , including, for example quick-connect fittings. If not all of the connection ports  2907  of a module  2900  are to be used, the unused connection ports  2907  may be plugged, blocked, or otherwise sealed off. In the example embodiment shown, three connection ports  2907  are included. In other embodiments, the number of connection ports  2907  may differ. For example, some embodiments, may only include two connection ports  2907  ( FIG.  35 E ). The module end blocks may function as a terminal block in a series or bank of connected modules, in which case the connection ports are closed or blocked. Alternatively, the terminal block connection ports may be connected to one or more fluid lines leading to an end block forming an input block of another bank of manifold modules in a larger manifold assembly. In some embodiments, an assemblage of module banks may be stacked as shown in  FIG.  35 E , allowing input end blocks to be interconnected to supply each bank of modules with one or more pressurized fluid lines. In this case, the connection ports of the terminal blocks of each bank of modules can be sealed closed or blocked. 
     An exemplary on-board controller board (PCB)  2908  is included in the module depicted in  FIG.  35 A . As shown, the example PCB  2908  of the valve module  2900  includes capacitors  2910 . FIG. The capacitors  2910  may be selected to have a capacitance sufficient to power the valves  2902  to a known or desired state in the event that power to the valve module  2900  is lost. If the electrical power and/or communications bus voltage of a device sensed by the PCB  2908  of the valve module  2900  drops below a predetermined level, valve(s)  2902  may be transitioned to a preferred or pre-determined configuration (i.e. a valve state that closes a specified fluid port or opens a specified fluid port). This could, for example, represent a fail-safe configuration for the apparatus controlled by the module (e.g. a fluid flow control device such as a pump and/or valves in a medical device). In the event that power from the device is unavailable, the capacitors  2910  of the valve module  2900  may be relied upon to transition the valve(s)  2902  to the preferred default configuration. 
     A number of processing components are included on the PCB  2908  as well. These processing components may include, for example, FGPAs (field programmable gate arrays), microprocessor chips, etc., or a combination thereof. Preferably, the processing components are capable of performing signal processing of data provided at a relatively high sampling rate (e.g. pressure data from on-board pressure sensors  2918  connectable to ports  2916  on the module block communicating with the valve cavities of the individual valve assemblies). The PCB controller can thus control the valve(s)  2902  or electrical outputs in the module  2900  more accurately or at a correspondingly high rate. 
     The PCB  2908  may include a number of connectors  2912 . In the example embodiment, only two connectors  2912  are shown. In other embodiments there may be a greater or smaller number of connectors  2912  included in a valve module  2900 . Referring now also to  FIG.  35 B , the connectors  2912  allow a valved module controller  2908  to be connected to additional neighboring or adjacent valved module controllers  2908  to interconnect valved manifold modules  2900  into a manifold  2950  of any desired size or complexity. The connectors  2912  allow for a communications and/or electrical power bus to be assembled in a bank of manifold modules, allowing for communication of power and/or data between various valve modules  2900  comprising a manifold assembly  2950 . Additionally, the connectors  2912  may allow for electronic communication (power and/or data) between valve modules  2900  in a manifold assembly  2950  and an external (e.g. main or system) controller (not shown) included in a device in which the manifold assembly  2950  is installed. 
     Each module block  2904  may include one or more coupling features which may facilitate connecting modules  2900  together to form a bank of modules or manifold assembly  2950 . In the example embodiment shown in  FIG.  35 A-B , the module blocks  2904  include a number of holes  2914  through which a suitable fastener (not shown) may be placed to couple the module blocks  2904  together. The fastener may be any suitable variety of fastener. A suitable fastener may also be used to couple the end blocks  2906  of a manifold  2950  to the valve modules  2900  at the ends of the manifold  2950 . As mentioned above, where various fluid pathways between the valves  2902 , module blocks  2904 , and/or end blocks  2906  interface with one another, a sealing member such as an o-ring, gasket, or the like may be used to ensure leak-free connections. In a typical assembly procedure, module bases or blocks are first mated side-to-side, aligning the pressure line input ports and pressure line output ports of adjacent blocks. The blocks are fastened together, using gaskets or O-rings as appropriate to form a seal between the input and output ports. One or more valve assemblies may also be installed in each module, either before or after the modules are concatenated. Valve assemblies are positioned over designated receiving stations on the manifold base or block, aligning the inlets of the valve assemblies with pressure ports communicating with the appropriate fluidic pressure bus in the module block, and aligning the outlet of each valve assembly with a port on the module block that fluidly communicates with an outlet of the module block. A gasket (see, e.g. gasket  4602  in  FIG.  40   , or gasket  4184  in  FIG.  28 C ) having appropriately located ports or holes may be interposed between the face of the valve assembly and the mating receiving face of the module block. In some embodiments, the gasket may not have ports communicating with all fluidic pressure buses passing through the module block. Once the module blocks are interconnected and the valve assemblies are installed, the controller board may be mounted on the module and valve assemblies. Alternatively, each controller board can be installed on a valved module block before the individual modules are interconnected, resulting in externally uniform, programmable valved manifold modules that can be readily assembled together, forming an expandable manifold assembly having standardized fluidic and electronic inputs, outputs, valve mating dimensions and similar controllers that can be programmed for various tasks. In installing the electronic control board, pressure sensors mounted on the board are aligned with pressure sensing ports or wells on the module block that communicate with the cavity of the valve assembly. If electromagnetic coils are mounted on the valve assembly, electrodes on the electronic control board are also aligned with corresponding receptacles or electrodes connected to the coils. The valve assemblies may be securely fastened to the module block, and the control board may be securely fastened to the module block using standard methods, such as screws, for example. In the examples shown, a typical module has four valve receiving stations onto which a controller board positions four pressure sensors—one for each installed valve. Modules can be constructed to have fewer receiving stations without necessarily compromising the expandability of the manifold module system. A greater number of valve assembly receiving stations may necessitate changes in the module block and control board to accommodate the additional valve assemblies, and may also require modifications to any rack or mounting frame used to assemble banks of manifold modules. 
     In many applications, a four-valve manifold module can function independently to operate a single pump. For example, a liquid inlet valve and outlet valve of the pump can each be assigned and connected to the output of a separate manifold valve, which can toggle between a positive fluidic pressure bus and negative fluidic pressure bus in the module to either close or open the inlet/outlet pump valve. A third manifold valve can be arranged to toggle on or off a connection of the positive pressure bus to the pump control chamber to perform a pump deliver stroke, and a fourth manifold valve can be arranged to toggle on or off a connection of the negative pressure bus to the pump control chamber to perform a pump fill stroke. The pump control manifold valves can be converted to two-way valves (on/off) by installing them on the module block using a modified gasket having no port to the positive pressure bus if used as a fill control valve, or having no port to the negative pressure bus if used as a deliver control valve. The on-board controller can be programmed to independently operate the liquid pump/valve unit by coordinating the inlet and outlet pump valves to permit filling the pump chamber with liquid and then expelling the liquid from the pump chamber in the direction assigned by the program. The controller can also receive pressure data from the pump control chamber to determine rate of fluid volume movement and end-of-stroke conditions. It can also be programmed to vary the rate or amount of pressure delivered to the pump control chamber. The on-board controller can also receive command sets locally from other manifold module controllers, or from an external main or system controller. 
       FIG.  35 C  depicts a partially exploded view of the example valve module  2900  depicted in  FIGS.  35 A-B . As shown, the PCB  2908  includes a number of pressure sensors  2918 . In the example embodiment, the number of pressure sensors  2918  is equal to the number of valves  2902  included in the valve module  2900 . In other embodiments, the number of pressure sensors  2918  may vary. When the PCB  2908  is attached to the module base or block  2904 , the pressure sensors  2918  are disposed in respective sensing wells or ports  2916  included as a part of the module base or block  2904 . As mentioned above, o-rings, gaskets, or any other suitable sealing member may be used to seal the sensing wells  2916  from the ambient environment. 
     Each of the sensing wells  2916  is in fluid communication with the interior valve cavity of one of the valves  2902 . The sensing wells  2916  may thus allow for the pressure sensors  2918  on the on-board PCB  2908  to sense the pressure of the interior cavity of the valves  2902 . The collected pressure data may be supplied to the processing components or controller included on the PCB  2908  for signal processing. The valve cavity pressure may be measured periodically or monitored in real time, acquired and stored by the on-board controller, and used by the on-board controller to control the valves  2902  of a valve module  2900  to execute particular tasks, such as selected delivery of one or another pressurized fluid (e.g. air) to a controlled device, such as a pump and/or valve in a liquid flow control apparatus. If the valve controls a single pressure line, or if it is configured to be able to simultaneously block more than one pressure line, then the on-board controller can receive pressure data that represents the pressure present in the controlled device (the valve cavity being in fluid communication with a control chamber, for example, of a controlled membrane pump). Using the specific example of a valve module  2900  which is assigned the task set of a pumping module, the pressure data may be used to determine, among other things, an amount of liquid transferred and a flow rate of the liquid being transferred in the liquid flow control apparatus. Pressure data may also be used, for example, during troubleshooting. 
     As shown in  FIG.  35 B , a series of interconnected (or bank) of manifold modules  2900  causes the on-board controllers to be interconnected  2912  on a communications and/or power bus. This allows each manifold module  2900  to be assigned a specific task or set of tasks by an external main or system controller, or additionally or alternatively allows a bank of on-board controllers to establish a ‘master-slave’ or primary-secondary hierarchical relationship. Through the transmission of identifying data to or from each module controller, any or all of the module controllers can detect the presence of and/or function of any other module in the bank or in an entire manifold assembly  2950 . If a controlled device has a plurality of functions or plurality of pump/valve combinations, a primary module controller can be assigned, which can then coordinate or synchronize the functions of a group of secondary modules with respect to the controlled device. In some cases, a linked control group of modules may only be a subset of a plurality of manifold modules in a bank or manifold assembly. 
       FIG.  35 D  depicts a top, back, left perspective view of the example module  2900  shown in  FIG.  35 A . As shown, the example module includes a number of output ports  2955 . These output ports  2955  may allow for tubing to be connected to the module  2900 . This tubing may then run to a destination for the module&#39;s  2900  outputs. In various embodiments, the destination may, for example, be a fluid pump, pneumatic valve, fluid reservoir, etc. Any suitable connector fitting may be included as part of the output ports  2955 . If not all output ports  2955  of a module  2900  are to be used, the unused output ports  2955  may be plugged, blocked, or otherwise sealed off. 
       FIG.  35 E  shows a perspective view of a number of modules  2900  that have been incorporated together to form a manifold assembly  2950 . Banks of modules  2900  are placed on a number of individual module racks or frames  2970 . The module racks or frames  2970  each hold a group or bank of modules  2900 . In the example shown, each group includes four modules  2900  though alternative racks or frames  2970  may hold any desired number of modules  2900 . Each rack  2970  may include mating or coupling features that allow it to be easily stacked upon another rack  2970 , forming a rack or frame assembly. For example, a first side of each rack  2970  may include a pin or projection. A second side of each rack  2970  opposite the first side may include a receiving structure which can retain the projection from the first side of an adjacent rack  2970  connecting the two racks  2970  together. A cap  2972  optionally may be placed on the top or terminal rack  2970 . 
     Each rack may include tracks  2974  or a frame in which modules  2900  may be retained. These tracks  2974  may be designed such that modules  2900  may be easily slid in and out of a rack  2970  during assembly of an integrated manifold  2950 . In some embodiments, the tracks  2974  ensure that modules  2900  may only be installed in one orientation to ensure that all modules  2900  face the same direction. The tracks  2974  may also aid in alignment of connectors  2912  as a manifold  2950  is assembled. In an embodiment, the end blocks  2906  shown in  FIGS.  35 A-E  can be modified to form at least part of the supporting structure of a rack or frame  2970 . Any individual track  2974  can accommodate any number of manifold modules in a bank, each module having a slot in the rack or frame into which it can be placed. Individual modules can be concatenated in a bank by mating the pressure line inlet port of one module with pressure line outlet port of an adjacent module to form the fluidic pressure bus, and by installing the module control boards so that they interconnect via adjacent electronic communications connectors to form the communications/power bus. Thus a manifold assembly  2950  formed from a stack of modules can be readily modified to accommodate any number or combination of manifold modules  2900 , depending on the complexity or needs of the device being fluidically or electrically controlled by the manifold assembly. 
     A communications/power bus extension line  2913  may extend between modules  2900  on one rack  2970  to modules on the next rack  2970 . This may allow for the same communication/power bus to be used for all of the modules  2900  in the manifold assembly  2950 . In some aspects, the communications/power bus extension line  2913  may be integrated in each rack  2970 . As modules  2900  are installed in the rack  2970  they may connect to a communications/power bus which is housed within the rack  2970  structure. As racks  2970  are stacked upon one another, the integral communications/power bus lines for each rack  2970  may be placed into communication or connected with one another. This connection may be automatically established when the racks  2970  are properly attached to one another. This may help to allow for rack  2970  to rack  2970  communication to be easily established when assembling a manifold  2950 . 
     Similarly, pneumatic (or in other systems, hydraulic) communication between modules  2900  on different racks  2970  may be established with pneumatic distribution lines housed or integrated within each rack  2970  (e.g. via modified end blocks  2906 ). The modules  2900  may connect and draw from these lines when installed in each rack  2970 . Additionally, as racks  2970  are stacked, fluidic (e.g. pneumatic) communication from rack  2970  to rack  2970  may be automatically established. The connections may be made, for example, by press-fit plug/receptacle pairs having suitable leak-proof contact surfaces (such as, e.g., elastomeric gaskets or O-rings). Alternatively, pneumatic lines may run individually to each rack  2970  of a manifold. This may be desirable in some embodiments, as it may allow for different groups of modules  2900  of a manifold  2950  to draw from a variety of different pressure sources. 
     Referring now to  FIG.  35 F  a representational diagram showing a number of modules  2900  arranged in a manner similar to that shown in  FIG.  35 E . The modules  2900  are split into a number of groups  2980 A-D. Each module  2900  is connected by connectors  2912  and each group is connected by a communications/power bus extension line  2913  so that all modules may be connected on the same communications/power bus. In the example embodiment in  FIG.  35 F , the groups of modules  2900  of the manifold  2950  draw from different pressure sources  2982 A-D. Groups  2980 A and  2980 B draw from pressure sources  2982 D and  2982 C. Group  2980 C draws from pressure sources  2982 B and  2982 C. Group  2980 D draws from pressure sources  2982 A and  2982 B. Such an arrangement may, for example, allow for module manifold blocks  2904  ( FIG.  29 C ) to be simplified as the number of fluid pathways required in each manifold block  2904  ( FIG.  29 C ) can be reduced. One group  2980 A-D may, for example, be connected to a first positive pressure line. Modules  2900  within that group  2980 A-D may be assigned as pump chamber controlling modules  2900 . Another group  2980 A-D may be connected to a second, higher positive pressure line. Modules  2900  within that group  2980 A-D may be assigned as fluid valve controlling modules  2900 . 
     An example schematic of a pneumatic pumping system  3000  including a manifold  3050  consisting of a single valve module  3060  is shown in  FIG.  36   . In the specific example shown, the valved module  3060  is configured as a pumping module and is similar to the valved module  2900  depicted in  FIG.  35 A . The example module  3060  shown in  FIG.  36    includes four valves  3002 A,  3002 B. The valves  3002 A,  3002 B may be any suitable type of valves, such as any of the bi-stable valves described herein, binary valves, or even variable aperture valves. Each of the valves  3002 A,  3002 B (or more specifically valve cavities or valve outlet ports) can be placed in fluid communication with a pressure sensor  3018 . The valves  3002 A,  3002 B of the module  3060  are commanded by a controller (which may be an on-board controller, or optionally an external controller), and the pressure sensors  3018  are configured to communicate with the controller. The controller may command the valves  3002 A,  3002 B to particular valve states based upon data collected by the pressure sensors  3018 . 
     A first variable volume  3082  separated from a second variable volume  3084  by a movable barrier  3088  are included in the example pneumatic system  3000 . A change in volume of the first variable volume  3082  correspondingly causes a change in volume of the second variable volume  3084 . An increase in volume of the first variable volume  3082  causes a corresponding decrease in volume of the second variable volume  3084 . A decrease in volume of the first variable volume  3082  causes an increase in volume of the second variable volume  3084 . The first variable volume  3082  may be referred to herein as a control chamber. The second variable volume  3084  may be referred to herein as a pumping chamber. 
     The first and second variable volumes  3082 ,  3094  may be configured in any suitable arrangement which would allow a change in volume in one to be tied to a change in volume of the other. In the example schematic depicted in  FIG.  36   , the first variable volume  3082  is defined by a fixed wall  3086  and a displaceable barrier  3088 . The second variable volume  3084  is adjacent the first variable volume  3082  and is defined by a second fixed wall  3089  and the displaceable barrier  3088 . As the volume of the first variable volume  3082  increases, the displaceable barrier  3088  is pushed toward the second fixed wall  3089 . As the volume of the first variable volume  3082  decreases, the displaceable barrier  3088  is pulled toward the first fixed wall  3086 . The displaceable barrier  3088  may be a membrane or diaphragm, which in some embodiments may be constructed of one or more pieces of flexible or elastic sheeting. 
     As shown, the pneumatic system  3000  includes a first positive pressure input  3075 , a second positive pressure input  3077  (which may be at a higher positive pressure than the first positive pressure source  3075 ), and a negative pressure input  3080 . The positive and negative pressure inputs  3075 ,  3077 ,  3080  are connected to the manifold assembly  3050 . By actuating the valves  3002 B in an appropriate manner, positive or negative pressure may be supplied to a first variable volume  3082  of an external fluid flow control device. Additionally, valve  3092  and valve  3094  communicating with the second variable volume  3084  may also be controlled by actuating the respective valves  3002 A. 
     When the first variable volume  3082  is connected to positive pressure and raised to a positive pressure, the first variable volume  3082  increases, displacing liquid present in the second variable volume  3084 . When the first variable volume  3082  is connected to a negative pressure and lowered to a negative pressure, the first variable volume  3082  decreases in volume, allowing the second variable volume  3084  to draw in liquid via a liquid flowpath. The first variable volume  3082  may be in communication with at least one pressure sensor  3018  so that the pressure of the first variable volume  3082  can be monitored. Optionally, the inlet valve  3092  and outlet valve  3094  connected to the second variable volume  3084  may also be in communication with one or more pressure sensors  3018  so that their pressures may also be monitored. 
     The change in volume of the second variable volume  3084  in response to the change in volume of the first variable volume  3082  may be used to pump fluid out of the second variable volume  3084  in a controlled manner. As shown, the second variable volume  3084  is connected to a first fluid reservoir  3090 . Depending on the configuration of the liquid flow paths, the second variable volume  3084  may be connected to a plurality of fluid reservoirs in some examples. For exemplary purposes, in a medical device, the first fluid reservoir  3090  may contain a liquid such as dialysate. It should be appreciated that the first fluid reservoir  3090  may contain any type of liquid or fluid. By opening valve  3092  and connecting the first variable volume  3082  to a negative pressure, fluid may be drawn into the second variable volume  3084  from the first fluid reservoir  3090 . The second variable volume  3084  is also connected to a second fluid reservoir  3095 . By closing valve  3092 , opening valve  3094  and connecting the first variable volume  3082  to positive pressure, fluid may be pumped out of the second variable volume  3084  to the second fluid reservoir  3095 . By opening and closing valves  3092  and  3094  in the opposite manner, fluid may be pumped in the opposite direction. 
     The magnitude of the pressure supplied to the first variable volume  3082  may have an effect on the rate of fluid transfer into or out of the second variable volume  3084 . Increasing the magnitude of the pressure in the first variable volume  3082  may cause the rate of fluid transfer to increase. 
     As the pressure in the first variable volume  3082  controls how fluid will be transferred through the pumping system  3000 , the first variable volume  3082  can be referred to herein as a control chamber. Since the fluid transferred is transferred into or out of the second variable volume  3084 , the second variable volume  3084  may be referred to herein as a pumping chamber. 
     A fill stroke of the pumping chamber occurs when negative pressure is supplied to the control chamber  3082  such that the volume of the pumping chamber  3084  increases from a starting volume (e.g. substantially its minimum volume) to a designated volume, or alternatively to substantially its maximum volume. A delivery stroke of the pumping chamber occurs when positive pressure is supplied to the control chamber  3082  such that the volume of the pumping chamber  3084  decreases from a starting volume (e.g. substantially its maximum volume) to a designated volume, or alternatively to substantially its minimum volume. The term “stroke” is used to generically refer to supplying pressure to the control chamber  3082  to cause fluid transfer to or from the pumping chamber  3084 . Stroke displacement refers to the amount of volume change that occurs in one of the variable volumes at any given point in a stroke. The end-of-stroke is meant to signify when a pumping stroke has completed and the pumping chamber  3084  is at substantially its maximum volume or minimum volume. In some applications, the pumping chamber may be included in a fluid handling cassette and the control chamber may be included as part of a cassette interface of a base unit to which a manifold assembly  3050  or manifold module of the manifold assembly is arranged to supply pressure. 
       FIG.  37    depicts a schematic diagram of a module  4200  which is arranged to pump liquid from a pumping chamber  4202  and make a measurement of the volume of liquid pumped. The example module  4200  shown in  FIG.  37    includes seven valves  4204 A,  4204 B,  4204 C. The valves  4204 A,  4204 B,  4204 C may be any suitable type of valves, such as any of the bi-stable valves described herein, a binary valve or a variable orifice valve. The valves  4204 A,  4204 B,  4204 C of the module  4200  are controlled by a controller  4206 . The controller  4206  commands the valves  4204 A,  4204 B,  4204 C to particular valve states. The schematic diagram also includes a pumping chamber  4202  and control chamber  4208  separated by a displaceable barrier  4205  similar to those described elsewhere in the specification (such as, e.g. a flexible diaphragm or membrane). The pumping chamber  4202  may be bounded by a flexible membrane and can be part of a removable or disposable fluid pumping cassette, and the control chamber  4208  may be part of a pneumatic pumping device (a base unit) configured to deliver pneumatic pressure to the cassette (or hydraulic pressure in some embodiments). 
     As shown, a first positive pressure input  4275 , a second positive pressure input  4277  (which may be at a higher positive pressure than the first positive pressure source  4275 ), and a negative pressure input  4280  are included. By actuating the valves  4204 B in an appropriate manner, positive or negative pressure may be supplied to the control chamber  4208 . Additionally, valve  4292  and valve  4294  to the pumping chamber  3084  may also be controlled by appropriately actuating the valves  4204 A. Thus fluid may be pumped from a source reservoir  4210  to a destination reservoir  4212 , or vice versa. 
     Pressure sensors (not shown) may be used to measure or monitor pressure associated with valves  4204 A, B as described above with reference to  FIG.  36   . Pressure sensors  4224 ,  4226  may be used to measure or monitor pressure associated with valves  4204 C. A first pressure sensor  4224  may be associated with the control chamber  4208  to monitor or measure the pressure of the control chamber  4208 . Its specific location is arbitrary as long as it can fluidly communicate with the control chamber. A second pressure sensor  4226  may be associated a with reference chamber  4228  to monitor the pressure of the reference chamber  4228 . The reference chamber  4228  is designed to be a chamber of fixed or known volume. The reference chamber  4228  optionally may be attached to or located on a manifold block  2804  ( FIG.  34 A ) of a module  4200 . 
     The controller  4206  receives and processes pressure data generated by pressure sensors  4224  and  4226 . Data from pressure sensors  4224  and  4226  may be used to determine the volume pumped or displaced over a pumping stroke. In an embodiment, before the stroke begins, a valve  4204 C is operated to isolate the control chamber  4208  from the reference chamber  4228 . The reference chamber  4228  is pressurized, preferably to a desired pressure. For example, the reference chamber  4228  may be placed in fluid communication with a vent  4230  by actuating a valve  4204 C. The pressure in the control chamber  4208  and reference chamber  4228  are measured with respective pressure sensors  4224  and  4226 . The control chamber  4208  and reference chamber  4228  are placed in fluid communication with one another by opening two valves  4204 C, and their pressures may be allowed to equalize. The equalized pressure is then measured using pressure sensors  4224  and  4226 . Since the volume and pressure of the reference chamber  4228  is known and the pressure of the control chamber  4208  is known, the change in pressure upon equalization can be used to determine using ideal gas laws the volume of the control chamber  4208 . The gas laws may be modeled, for example, to provide a reasonable approximation of the change in volume of the control chamber (and therefore also the pumping chamber). The controller  4206  records the pre-stroke volume of the control chamber  4208 . The controller  4206  then commands the stroke to be performed. The controller then determines the post-stroke volume of the control chamber  4208 . The post stroke control chamber  4208  pressure change is used to determine the pre-stroke to post-stroke control chamber volume change. This change in volume will be a measurement of the amount of liquid pumped during the stroke. The on-board controller may be programmed to compute the volume of liquid pumped, and optionally this measurement may be reported by the on-board controller via a communications bus to a master module or main controller. Alternatively, an external main or intermediate controller may be tasked with performing the volume calculations by receiving pressure data via the on-board controller. 
     Other methods of measuring a volume of fluid pumped by a pump chamber may also be used. For example, such methods may include those described in U.S. patent application Ser. No. 14/732,571, filed Jun. 5, 2015, and entitled Medical Treatment System and Methods Using a Plurality of Fluid Lines, Attorney Docket No. Q21 or U.S. patent application Ser. No. 14/723,237, filed May 27, 2015, and entitled Control System and Method for Blood or Fluid Handling Medical Device, Attorney Docket No. Q22, which are incorporated by reference herein in their entireties. 
     Referring now to  FIG.  38 A , in some embodiments, an individual valved manifold module  4302  may be dedicated to fluid volume measurement in a fluid pumping system  4300 . As shown, a single such module  4302  may be configurable to allow volume measurements of at least one fluid pump. Use of such a dedicated measurement module  4302  may be desirable when relatively precise measurements of pumped volumes are needed. A dedicated measurement module avoids having to alter the construction of the valved manifold modules  4304  dedicated to controlling a pump, for example. Alternatively, and as shown in  FIG.  37    a valved manifold module  4304  dedicated to operating a pump may include the hardware required for volume measurement, and the controller  2854  of that module may perform both pumping and volume measurement operations. 
     A measurement valved manifold module  4302  may be paired with one or more pumping modules  4304 . The measurement module  4302  may coordinate operation with each paired pumping module  4304  and provide access to a reference chamber and to a vent to measure fluid volumes pumped by the paired pumping module(s)  4304 . The pumping modules  4304  may be similar to those described above with reference to  FIG.  34 C , for example. The pumping module(s)  4304  controller  2854  can be configured to communicate with the measurement module  4304  controller  2854  over a communication bus  2864 . This communication may allow a pumping module  4304  controller  2854  to signal the measurement module controller  4304  when it is time to take a measurement (e.g. before and after a stroke). Pressure sensors  2862  of the measurement module  4302  may be in fluid communication with the control chambers  4306  under the control of the paired pumping modules  4304 . Additionally, pressure sensors  3862  of the measurement module  4302  may be in communication with at least one reference volume or chamber  4308 . The at least one reference volume or chamber  4308  is of a known volume and may, for example, be disposed within or attached to a module block  2804  ( FIG.  34 A ) of the measurement module  4302 . The at least one reference volume or chamber  4308  may also be located external to and connected with the module  4302 . 
     The pneumatic block  2856  of the measurement module  4302  may include various pneumatic components of a module  2800  such as one or more valves  2802  ( FIG.  34 A ). The pneumatic block  2856  of the measurement module  4302  may be commanded by the measurement module  4302  controller  2854  to place each of the at least one reference volumes  4308  into fluid communication with a vent  4310  or an associated control chamber  4306 . The pneumatic block  2856  of the measurement module  4302  may be also commanded by the measurement module  4302  controller  2854  to isolate each of the at least one reference volumes  4308 . Volume measurements may be made as described above. 
     In some embodiments the pneumatic block  2856  may also be controlled to connect the control chamber  4306  to the vent  4310 . This may be done to bring the pressure of a control chamber  4306  closer the pressure which will be used to perform the next stroke. For example, if a fill stroke was just performed, the control chamber  4306  may be at a negative pressure. The pressure may be vented, for example, to ambient, before a deliver stroke at a positive pressure is performed. This may help to reduce depletion of pressure reservoirs feeding the modules. 
     Referring now to  FIG.  38 B , a detailed schematic of a measurement module  4302  which is paired with a pumping module  4304  is shown. As mentioned above, the measurement module  4302  may be incorporated into a manifold and used to generate relatively precise measurements of pumped volumes moved by the pumping module  4304 . The module may include a manifold base  2804  which includes a number of inlet ports. The inlet ports may connect to both a positive pressure line or bus  4316  and a negative pressure line or bus  4314 . The positive and negative pressure lines  4316 ,  4314  may supply pressure to the modules  4304 ,  4302 , from pressurized gas reservoirs  4312 A,  4312 B. The inlet ports may also be connected to atmosphere  4310  and the control chamber  4306  of a diaphragm pump  4320  controlled by the pumping module  4304 . The module is thus arranged to charge a reference reservoir with positive or negative pressure, or to set its pressure to atmosphere, and to provide a valved connection to a control chamber of a pump whose volume is to be measured using one or more models based on the ideal gas laws. 
     The measurement module  4302  may include a first, second, third, and fourth valve assembly respectively labeled  2802 A,  2802 B,  2802 C,  2802 D. Each of the valve assemblies may be mounted to a receiving station on the manifold base  2804 . The measurement module  4302  may also include a controller  2854  which is in electrical communication with the valve assemblies  2802 A-D and configured to selectively actuate the valves  2802 A-D. The manifold base  2804  may include a fluid pathway which fluidically connects the manifold inlet port communicating with the positive pressure bus  4316  to an inlet port of valve assembly  2802 B. The manifold base  2804  may include a fluid pathway which fluidically connects the manifold inlet port communicating with the negative pressure bus  4314  to an inlet port of valve assembly  2802 C. The manifold base  2804  may include a fluid pathway which fluidically connects the manifold inlet port communicating with atmosphere to an inlet port of valve assembly  2802 D. The manifold base  2804  may also include a fluid pathway which fluidically connects the manifold inlet port in communication with the control chamber  4306  to an inlet port of valve assembly  2802 A. The manifold base  2804  may also connect the valve cavities of each valve  2802 A-D to respective sensing ports or wells in the manifold base  2804  as well as to a reference volume, chamber or reservoir  4308  of known volume. The controller  2854  may actuate the valves to selectively open or close communication between the valve cavities of each valve  2802 A-D and the inlets of each valve  2802 A-D. 
     The controller  2854  may include a number of pressure sensors  3018  ( FIG.  36   ), for example a first, second, third, and fourth pressure sensor. During assembly of the measurement module  4302 , the pressure sensors may form a reversible sealed connection with respective sensing ports in the manifold base  2804 . The controller  2854  may actuate or operate the valve assemblies  2802 A-D to charge the reference chamber  4308  to a pre-charge pressure, for example with positive of negative pressure for pressure lines  4314 ,  4316 . The controller may actuate or operate the valve assemblies  2802 A-D to open the reference chamber or reservoir  4308  to atmosphere  4310 . The controller  2854  may actuate the valve assemblies  2802 A-D to fluidically connect the reference volume  4308  to the control chamber  4306  of the diaphragm pump  4320  to equalize pressure between the control chamber  4306  and the reference chamber or reservoir  4308 . The controller  2854  may also monitor the pressure from the pressure sensors in communication with the valve cavity of one or more valve assemblies  2802 A-D. The controller  2854  may record pressures from the monitored pressure sensors before and after equalization. The pressure change may be used to determine the volume of liquid pumped by the pump via the pumping module  4304  by calculating an initial and final volume through the pressure measurements of the reference chamber and control chamber of the pump. 
     The valve assemblies  2802 A-D may be any suitable type of valve assemblies. In the example, the valve assemblies  2802 A-D are bi-stable three-way valves similar to many of those described elsewhere herein. As shown, only one inlet port for each of the valves assemblies  2802 A-D is used. The other of the inlet ports is blocked off or occluded as indicated by the encircled “B” connected to an inlet port of each of the valve assemblies  2802 A-D in  FIG.  38 B . The outlets of the valve assemblies  2802 A-D are in fluidic connection with the reference reservoir or chamber  4308 . 
     Referring now to  FIG.  39   , a portion of a manifold  4500  including a regulator module  4502  is depicted. A regulator module  4502  may regulate the pressure of a pneumatic bus to a second or regulated pressure which is different from that of the pneumatic bus. This may be accomplished by toggling a valve in the pneumatic block  2856  of the regulator module  4502  which separates the pressure bus from a separate chamber or an accumulator  4508 ,  4510 . The pressure of the accumulator  4508 ,  4510  may be sensed by a pressure sensor  3018  ( FIG.  36   ) which is monitored by the controller  2854  of the regulator module  4502 . The controller  2854  may toggle the valve using data from the pressure sensor. For example, the controller  2854  may command the valve to toggle to place an accumulator  4508 ,  4510  in communication with the pressure bus when the sensed pressure of the accumulator  4508 ,  4510  falls below a first predetermined value. The controller  2854  may command that the valve close off communication between the pressure bus and the accumulator  4508 ,  4510  when the sensed pressure of the accumulator  4508 ,  4510  is above a second predetermined value. 
     In the example embodiment, the regulator module  4502  is in communication with a positive pressure bus  4504  and a negative pressure bus  4506 . The regulator module  4502  may regulate the pressure of the positive pressure bus  4504  to a lower positive pressure. The regulator module  4502  may regulate the pressure of the negative pressure bus  4506  to a weaker negative pressure. In the example shown, ports  4502 - 1  and  4502 - 3  of the regulator module  4502  are in communication with positive pressure accumulator  4508 . Ports  4502 - 2  and  4502 - 4  of the regulator module  4502  are in communication with negative pressure accumulator  4510 . 
     The accumulators  4508 ,  4510  may be any suitable reservoir. In some embodiments, the accumulators  4508 ,  4510  may be identical. The accumulators may, for example, be rigid plastic or metal tanks and may have an interior volume between 500 ml and 2 L (e.g. 1 L). 
     Port  4502 - 3  may be an outlet port for a valve of the pneumatic block  2856  controlling fluid communication between the positive pressure bus  4504  and the positive pressure accumulator  4805 . Port  4502 - 4  may be an outlet port for a valve of the pneumatic block  2856  controlling fluid communication between the negative pressure bus  4506  and the negative pressure accumulator  4510 . The valves associated with ports  4502 - 3  and  4502 - 4  may be toggled by the regulator module  4502  controller  2854  based on the sensed pressure of their respective accumulators  4508 ,  4510  as described above. 
     In the example embodiment, ports  4502 - 1  and  4502 - 2  are not associated with valves. Instead, the pneumatic block  2856  may include pneumatic isolation members or assemblies in association with these ports  4502 - 1 ,  4502 - 2 . The pneumatic isolation members or assemblies are further described later in the specification and in the example embodiment may pneumatically isolate the pressure buses  4504 ,  4506  from ports  4502 - 1 ,  4502 - 2 . These ports  4502 - 1 ,  4502 - 2  may be connected to a fluid volume such that the pressure sensors  3018  ( FIG.  36   ) associated with the ports  4502 - 1 ,  4502 - 2  may monitor the pressure of the fluid volume. In the example embodiment, port  4502 - 1  is connected to the negative pressure accumulator  4510  to periodically measure or monitor the pressure of the negative pressure accumulator. Port  4502 - 2  is connected to the positive pressure accumulator  4508  to periodically measure or monitor the pressure of the positive pressure accumulator. 
     Additional modules  4512  of the manifold  4500  may draw from the pressure accumulators  4508 ,  4510  and operate at the regulated pressure of the accumulators  4508 ,  4510 . This may be desirable, for example, if portions of a fluid circuit controlled by a manifold  4500  operate at different pressures. In embodiments in which the fluid circuit includes at least one fluid handling cassette, the fluid valves of the cassette may be operated at greater pressures than the pump chambers of the cassette. Additionally, pump chambers of a cassette or of a number of different cassettes in a fluid circuit may be operated at different pressures. Modules  4512  controlling portions of the fluid circuit which operate at greater pressure may be disposed upstream of the regulator module  4502  and modules  4512  which operate at lesser pressures may be disposed downstream of the regulator module  4502 . Additionally, some embodiments may include a plurality of regulator modules  4502  allowing for a fluid circuit to be operated at more than two sets of pressures. 
       FIG.  40    depicts an example embodiment of a pneumatic isolation assembly  4600  which may be included in the pneumatic block  2856  of a module, for example, a regulator module  4502  ( FIG.  39   ). As mentioned above, a pneumatic isolation assembly  4600  may isolate a pressure bus or buses communicating with the module from the port with which the pneumatic isolation assembly  4600  is associated. Such a pneumatic isolation assembly  4600  may be associated with a port of any module if it is desired that that port be used, for example, for sensing purposes. In the example shown, the pneumatic isolation assembly  4600  is a modified fluid valve. The pneumatic isolation assembly  4600  includes a gasket member  4602 . The gasket member  4602  does not include pressure inlets or ports (see, e.g.  4112 ,  4114  of  FIGS.  28 A- 28 C ). As a result, the gasket member  4602  serves to block and isolate any pressure buses feeding into the pneumatic isolation assembly  4600  from the module port associated with the pneumatic isolation assembly  4600 . 
     In other embodiments, a pneumatic isolation assembly  4600  may not be a modified valve. Any suitable means of isolating the pneumatic buses from a module port may be used. For example, a block of gasketing material may be attached to a module in place of a valve. Plugs or a similar structure may be coupled into the module or a fixative or glue may be used to seal off pneumatic ports. Alternatively, although a pneumatic isolation assembly  4600  may resemble a valve, certain components of the valve may be absent. Components which are related to toggling of the valve may be removed. For example, coil assemblies  4650  may not be included in a pneumatic isolation assembly  4600 . Additionally, posts (see, e.g.  4104 ,  4106  of  FIGS.  28 A- 28 C ), a shuttle (see, e.g.  4102  of  FIGS.  28 A- 28 C ), and an interior valve cavity (see, e.g.  4116  of  FIGS.  28 A- 28 C ) may be absent. A pneumatic isolation assembly  4600  may also be constructed from different materials as magnetic flux paths within a pneumatic isolation assembly  4600  are not a concern. In some embodiments, fasteners  4644  may not be included. Instead, a pneumatic isolation assembly may be a single block of material or may include a number of pieces of material which may be snap fit, friction fit, solvent bonded, etc. together. 
       FIGS.  41 A- 41 B  depict an example embodiment of a manifold assembly  2950  including a number of valve manifold modules  2900 - 1 ,  2900 - 2 ,  2900 - 3 ,  2900 - 4  that have been installed in a cassette based fluid pumping system  3390 . Although this example employs a pneumatically driven pumping system, a similar arrangement can be applied in a hydraulically driven system. A hydraulic system may vary in its configuration to allow for pump or valve actuators that can be driven in opposite directions by appropriately directed separate positive hydraulic pressure lines acting on the actuators in opposing directions, rather than the positive and negative pressure lines acting on the same side of a membrane actuator described in the following pneumatically driven system. 
     In the example embodiment, there are four valve manifold modules  2900 - 1 ,  2900 - 2 ,  2900 - 3 ,  2900 - 4 . Each of the modules  2900 - 1 ,  2900 - 2 ,  2900 - 3 ,  2900 - 4  in the example may be substantially identical in size, location of ports, and electrical connections in order to be swappable with one another. Each module  2900 - 1 ,  2900 - 2 ,  2900 - 3 ,  2900 - 4  may include a similar electronic control board. Each module  2900 - 1 ,  2900 - 2 ,  2900 - 3 ,  2900 - 4  also includes a block of electrically actuated pneumatic valves. The pneumatic valve blocks are similar to those described above. In this example, each pneumatic valve block includes four valves and an outlet port for each valve. The outlet ports of the valves are labeled “n”av, bv, cv, dv in which “n” is the module number (i.e.  2900 -“n”). The portion of the cassette  3400  controlled by a particular port on the manifold  2950  is labeled correspondingly. For example, a fluid valve controlled by port “n”bv on the manifold  2950  would be labeled “n”bc on the cassette  3400 . Despite the valve modules  2900 - 1 ,  2900 - 2 ,  2900 - 3 ,  2900 - 4  being substantially identical, the valve modules  2900 - 1 ,  2900 - 2 ,  2900 - 3 ,  2900 - 4  perform a variety of functions and are applied in a variety of ways within the cassette based fluid pumping system  3390 . A first side  3401  of the cassette  3400  is shown in  FIG.  41 A  while a second, opposing side  3403  of the cassette  3400  is shown in  FIG.  41 B . 
     In the example embodiment shown in  FIGS.  41 A- 41 B , modules  2900 - 1  and  2900 - 2  are valve manifold modules which control fluid valves  1 AC- 1 DC and  2 AC- 2 DC on the cassette  3400 . Referring primarily to  FIG.  41 A , each of the fluid valves  1 AC- 1 DC and  2 AC- 2 DC may include a valve well  3410  defined by a valve wall  3408 . Within the valve well  3408  is a valve seat  3412 . The valve wall  3410  may be slightly proud of the valve seat  3412 . A flexible sheet covers each valve well  3408  and seals against the top of the valve wall  3410 . Application of pressure to the flexible sheet causes the sheet to displace, but the seal against the valve wall  3410  is maintained. Positive pressure causes the sheet to displace against the valve seat  3412  closing the respective fluid valve  1 AC- 1 DC and  2 AC- 2 DC. Negative pressure draws the sheeting away from the valve seat  3412 , opening the fluid valve  1 AC- 1 DC and  2 AC- 2 DC and allowing fluid to flow through. Such fluid valves are further described in U.S. Pat. No. 5,350,357 which is incorporated by reference herein in its entirety. 
     Referring again to both  FIGS.  41 A- 41 B , by commanding modules  2900 - 1  and  2900 - 2  to apply pressure so that fluid valves  1 AC- 1 DC and  2 AC- 2 DC on the cassette  3400  are opened and closed in a desired manner, various fluid pathways in the cassette may be established or blocked. Valves  2 BC and  2 CC may be opened/closed to control communication between a first fluid bus  3414  of the cassette  3400  and cassette ports  3406 A associated with each of those valves. Valve  1 AC- 1 DC,  2 AC, and  2 DC may be opened/closed to control communication between a second fluid bus  3416  of the cassette and cassette ports  3406 B associated with each of those valves. 
     Modules  2900 - 3  and  2900 - 4  are pumping or chamber modules which control fluid valves  3 AC,  3 BC,  4 AC,  4 BC of the cassette  3400 . These valves  3 AC,  3 BC,  4 AC,  4 BC act as inlet/outlet valves to or from the pump chambers  3420 A,  3420 B of the cassette  3400 . Outputs  3 CV,  3 DV,  4 CV, and  4 DV of the manifold assembly  2950  are arranged to apply pressure to flexible sheeting spanning over pump chambers  3420 A,  3420 B of the cassette  3400  as indicated by reference numbers  3 CC,  3 DC,  4 CC,  4 DC. This flexible sheeting may act as the flexible wall or barrier  3088  described above in relation to  FIG.  36   . Outputs  3 CV,  3 DV,  4 CV, and  4 DV may supply pressure to respective control chambers  3082  ( FIG.  36   ). This pressure may cause a change in volume in the associated pumping chamber  3420 A,  3420 B and thus cause fluid to be pumped by the pumping chamber  3420 A,  3420 B of the cassette  3400 . 
     The valve assembly providing output to  3 CV can be arranged to access the positive pressure line only, in which case the valve assembly providing output to  3 DV can be arranged to access the negative pressure line only, or vice versa. Outputs  3 CV and  3 DV can subsequently be merged into a single flowpath to the control port communicating with the flexible membrane overlying the pump chamber ( 3 CC,  3 DC). Access of a valve assembly to only one pressure line in a pumping module can be achieved, for example, by substituting an inlet gasket having no hole communicating with the unwanted pressure line in the manifold module. Alternatively a two way valve connected to only one of the pressure lines may be used. The valve manifold module  2900 - 4  controlling the pumping chamber designated  4 CC,  4 DC, can be arranged in a manner similar to module  2900 - 3 . 
     In some embodiments, the cassette  3400  may be used to pump fluid during a dialysis therapy such as a peritoneal dialysis therapy. In such embodiments, the cassette ports  3406 B associated with fluid valves  1 AC- 1 DC may each be connected to a reservoir (e.g. a bag) of dialysate solution. The cassette port  3406 A associated with fluid valve  2 BC of the cassette  3400  can be connected to a heated reservoir (e.g. a bag on a heating tray). The cassette port  3406 A associated with fluid valve  2 CC of the cassette can be connected to a drain or waste reservoir. The cassette port  3406 B associated with fluid valve  2 DC of the cassette  3400  can be connected to a fluid line leading to the peritoneal cavity of a patient. The modules  2900 - 1 ,  2900 - 2 ,  2900 - 3 ,  2900 - 4  may be controlled by an on-board controller or an external controller (or combination of the two) such that fluid is transferred through the cassette  3400  to administer a dialysis therapy. For example, modules  2900 - 1 ,  2900 - 2 ,  2900 - 3 ,  2900 - 4  may be controlled so that fluid is transferred from a solution reservoir to the heated reservoir. The modules  2900 - 1 ,  2900 - 2 ,  2900 - 3 ,  2900 - 4  may be controlled so that fluid is transferred from the heated reservoir to the patient. The modules  2900 - 1 ,  2900 - 2 ,  2900 - 3 ,  2900 - 4  may be controlled so that spent fluid is transferred from the patient to the drain or waste reservoir. Further description on how such a cassette may be used to transfer fluid for a dialysis therapy may be found in U.S. patent application Ser. No. 14/732,571, filed Jun. 5, 2015, and entitled Medical Treatment System and Methods Using a Plurality of Fluid Lines, Attorney Docket No. Q21 which is incorporated by reference herein in its entirety. 
     As mentioned above, the modules  2900 - 1 ,  2900 - 2 ,  2900 - 3 ,  2900 - 4  may, in some embodiments, control operation of the cassette to transfer fluid from one cassette port to another autonomously (i.e. via a suitably programmed on-board controller in the valve manifold module). Alternatively, the modules  2900 - 1 ,  2900 - 2 ,  2900 - 3 ,  2900 - 4  may receive only high level commands from a main controller of the fluid pumping system  3390 . Such commands may include, for example, a command to start pumping, stop or pause pumping, pump from a solution line to a heater bag, pump from a heater bag to a patient line, pump from a patient line to a drain line, etc. The on-board controller in turn can be programmed to coordinate the cassette valves and pumps to fulfill the high level commands. The on-board controllers of the modules  2900 - 1 ,  2900 - 2 ,  2900 - 3 ,  2900 - 4  may also communicate and coordinate operations among themselves to accomplish the high level commands with minimal or no further input from the main controller. 
       FIGS.  42 A and  42 B  depict an example embodiment of a manifold assembly  2950  including a number of valve manifold modules  2900 - 1 ,  2900 - 2 ,  2900 - 3 ,  2900 - 4  that have been installed in a cassette based fluid pumping system  3430 .  FIG.  42 A  shows the manifold assembly  2950  and the first side  3434  of a cassette  3432 .  FIG.  42 B  shows the manifold assembly  2590  and a second, opposing side  3436  of the cassette  3432 . The manifold assembly  2950  is similar to that shown in  FIGS.  41 A and  41 B , however, the cassette  3432  has a different arrangement of flow paths, valves and ports. The cassette  3430  may, however, be operated in generally the same manner as that described above in  FIGS.  41 A and  41 B . Modules  2900 - 2 ,  2900 - 3 ,  2900 - 4  are arranged as valve control modules which operate the fluid valves  2 AC- 2 DC,  3 AC- 3 DC,  4 AC, and  4 BC of the cassette  3430 . Module  2900 - 1  is arranged as a pump chamber control module. In the example embodiment, the pump chamber control module  2900 - 1  does not control inlet/outlet valves to the pump chambers  3438 A, B of the cassette  3432 . Instead, the chamber control module  2900 - 1  supplies pressure to the control chambers  3082  ( FIG.  36   ) of a base unit of the system, providing pressure to the membrane overlying the pumping chambers  3438 A,  3438 B of the cassette. Two valve assemblies on the module supply pressure to one pump chamber—one positive pressure and the other negative pressure. By coordinating operations of modules  2900 - 1 ,  2900 - 2 ,  2900 - 3 ,  2900 - 4  within the manifold  2950 , fluid may be pumped through the cassette  3432  to and from the various ports  3440  of the cassette  3432 . In some embodiments, this may be done, for example, to perform a dialysis therapy such as a peritoneal dialysis therapy. Further description on how such a cassette may be used to transfer fluid for a dialysis therapy may be found in U.S. Pat. No. 5,350,357, issued Sep. 27, 1994, and entitled Peritoneal Dialysis System Employing a Liquid Distribution and Pumping Cassette that Emulates Gravity Flow which is incorporated by reference herein in its entirety. 
       FIGS.  43 A and  43 B  depict an example embodiment of a manifold assembly including a number of valve manifold modules that have been installed or concatenated together for use in a hemodialysis system. The valve manifold modules may be concatenated in a single bank, or a smaller subset may be concatenated into a manifold bank, with a number of manifold banks stacked one above the other to optimize the space occupied by the manifold assembly. Each bank can be arranged to have ported access to positive and negative pressure lines. In the example embodiment there are 11 valve modules with the first valve module being the leftmost module and the 11 th  valve module being the rightmost module. Each of the modules in the example may be substantially identical. Each module may include substantially the same programmable electronic control board. Each module also includes a pneumatic manifold block. The pneumatic blocks are similar to those described above. In this example, each pneumatic block includes four valve assemblies and an outlet port for each valve to form a valve manifold module. Each of the outlet ports is labeled “n”a-d in which “n” is the module number. The portion of the dialysis circuit controlled by a particular port on the manifold is labeled correspondingly. For example, a valve controlled by port “n”b on the manifold would be labeled “n”b on the dialysis circuit. The pneumatic lines connecting the ports of the manifold to the dialysis circuit are not depicted for the sake of clarity of illustration. Despite the valve modules being substantially identical, the valve modules perform a variety of functions and are applied in a variety of ways within the dialysis machine, each said function being determined at least in part by the location of the module along the manifold assembly. 
     A valve manifold assembly that controls the operation of a membrane pump may comprise a valve assembly that switches between access to positive or negative pressure for an inlet flow valve of the membrane pump, a similar valve assembly for an outlet flow valve of the membrane pump, a valve assembly having access to a positive pressure line, and a valve assembly having access to a negative pressure line, the latter two valve assemblies configured to control operation of the pump membrane. Access of a valve assembly to a pressure line can be denied relative simply, for example, by replacing a gasket between the valve assembly and the pressure lines with a gasket having only one access port to either one pressure line or the other. 
     A power and a communication bus may optionally extend from module to module throughout the manifold. In an embodiment, the communications bus is configured similar to a CAN-bus, in which disruption of one module along the chain may disrupt communications to the downstream modules. However, the power bus to all modules may remain intact so that any of the downstream modules may remain operational. In certain locations along the manifold assembly, the module may be pre-programmed to enter an autonomous mode of operation for a designated period of time upon loss of communications, so that a blood pump, for example, may continue to operate when an upstream module fails or is disconnected. 
     Additionally, negative, high positive, and low positive pressure pneumatic buses extend from module to module throughout the manifold. Each module includes an on-board processor which commands the valved pneumatic block of the module and sends signals to actuate the valves of the module. Additionally, each processor receives pressure data from fluid flow paths in the pneumatic block, so that, for example, the pressure of the pumping chambers of each pump in the system can be monitored by the valve manifold module control boards. Each module also includes a generic connector which allows the module to be connected to any of a variety of peripherals. For example, any of a variety of sensors may be connected to the module via the generic connector. Data from a connected peripheral device may be conveyed to the processor of the module. In  FIGS.  43 A and  43 B , signals coming from peripheral devices in the dialysate circuit are labeled “n”s“#” where “n” is the module to which the peripheral device is connected, s is an abbreviation for the word signal, and # is an identifier for the peripheral device to distinguish between peripheral devices when more than one peripheral device is connected to an individual module. 
     As shown, module  1  is connected to the dialysate machine circuit such that only two of its outputs  1   a  and  1   b  are used. The other ports of the module are blocked off.  1   a  and  1   b  control two pneumatic or hydraulic occluders in the example diagram. The occluders may be bladders or a piston/cylinder arrangement which may be actuated with positive pressure to cause displacement of an occluder blade that contacts the fluid line to open the associated fluid line. The occluders controlled by  1   a  and  1   b  may be spring-biased and used to respectively occlude (through, e.g., release of pressure) an arterial line from a patient and a venous line to the patient. 
     As shown, in an optional arrangement, module  1  also receives a signal from two peripheral devices in the dialysis machine. The first signal,  1   s   1 , is generated by an air-in-line sensor installed on the arterial line of the dialysis machine circuit. The second signal,  1   s   2 , is generated by a second air-in-line sensor installed on the venous line of the dialysis machine circuit. The processor of module  1  may monitor signals  1   s   1 , and  1   s   2  from the air-in-line sensors. In response a determination that a signal indicates there is air in at least one of the lines, the processor of the module may issue commands to the valves to cause the pneumatic occluders to deploy. Thus based on  1   s   1  and  1   s   2 , the module may release the occluder bladders to block fluid flow and prevent air from reaching the patient. 
     Module  2  and  3 , which can be substantially the same as any other module in the manifold, are used to control fluid pumping within the system. As shown, module  2  and module  3  operate their valves to pump fluid in a two chamber fluid pump. This pump is similar to the two chamber fluid pump  2896  of  FIG.  34 F . In the example of a hemodialysis machine, it may be desirable that the two chambers be operated such that fluid is pumped in a substantially continuous fashion. This may require coordination between the on-board controllers of modules  2  and  3  as signified by the bracket grouping the two blood pump modules ( 2  and  3 ) on the manifold. The on-board controllers of modules  2  and  3  may communicate with one another over the communication bus of the manifold to synchronize pumping. Specifically, for example, the modules may coordinate pumping operations such that one blood pump is filling its fluid pumping chamber while the other module is delivering its fluid pumping chamber. 
     The blood pumps may pump blood through a dialyzer of the hemodialysis system, which is designed to extract substances such as creatinine, urea, etc. from the blood. The modules may control the two chambers of the fluid pump to pump blood at a desired rate based on coordinated commands from their respective processors. 
     Modules  4  and  5  are also used to control fluid pumping within the dialysis machine circuit. In the example in  FIG.  43 A , modules  4  and  5  are dialysate pumps which control the pumping of dialysate through the dialyzer. As above, a bracket grouping modules  4  and  5  indicates that the modules may coordinate operations with one another to ensure that dialysate is pumped in a specified manner. 
     Module  6 , also configured as a pump in  FIG.  43 B , may control an ultrafiltrate pump of the dialysis machine circuit. Module  6  may optionally control the UF pump to draw fluid out of the patient&#39;s blood as commanded by the system controller. 
     Modules  7  and  8 , which again can be substantially identical to every other module in the manifold, are used as pneumatic valve controllers which serve to operate valves of a balancing circuit of the dialysis machine circuit. Modules  7  and  8  may control the valves in the balancing circuit to ensure that the amount of fresh dialysate flowing to the dialyzer is substantially equal to the amount of spent dialysate flowing from the dialyzer. The balancing circuit valve modules are grouped together to indicate that these modules coordinate operations to ensure proper function of the dialysis machines balancing circuit. As shown, the grouped dialysate pump modules and the grouped balancing circuit valves may also coordinate operations. This may allow the dialysate pumps and balance circuit valves to work effectively together in a fully coordinated manner. 
     Modules  9  and  10 , which are configured as to operate fluid pumps are also shown as a group of modules whose on-board controllers may coordinate operations with one another. As shown in  FIG.  43 B , modules  9  and  10  control the pumping of fluid by another two chamber fluid pump. The two chamber fluid pump is a dialysate delivery pump is a pump which pumps fluid through a heater element and to the balancing circuit of the dialysis machine. As described above in relation to modules  2  and  3 , modules  9  and  10  may coordinate pumping operations to cause dialysate to pump in a substantially continuous manner. 
     Module  11 , in the example embodiment, is shown as controlling a number of routing valves. These valves may route fluid entering the depicted circuit (e.g. from a mixing circuit) to a plurality of destinations. The valve controlled by module output port  11   a  controls a venting pathway for the dialysate reservoir. The valve controlled by module output port  11   b  may be opened or closed to allow or prevent fluid flow into the dialysate reservoir or tank. The valve controlled by module output port  11   c  may be opened or closed to allow or prevent fluid flow to a drain line or drain destination. The valve controlled by  11   d  also may be opened or close to make or break a flow path to a drain line. In some embodiments, only one valve is required to coordinate flow through a single line to drain. 
     As shown, module  11  also receives a signal from two peripheral devices in the dialysis machine. The first signal,  11   s   1 , is generated by a level sensor installed on or in the dialysate tank or reservoir of the dialysis machine circuit. This level sensor may be any suitable variety of level sensors. In various embodiments, the level sensor may be, but is not limited to, a capacitive sensor, optical sensor, float sensor, rangefinder, etc. The controller of module  11  may monitor the signal  11   s   1  and open the valve controlled by output port  11   b  to allow dialysate to flow into the dialysate reservoir when the level sensor indicates the dialysate volume in the reservoir has dropped below a threshold value. The valve controlled by  11   a  may also be opened at this time to allow for air to be displaced out of the reservoir as new dialysate enters the reservoir. In some embodiments, signal  11   s   1  may also be conveyed to modules  9 - 10  such that the valve may be opened when fluid is pumped out of the dialysate reservoir to allow air to replace the fluid being removed. Alternatively, modules  9 - 10  may coordinate with module  11  to accomplish the same task. In the event that signal  11   s   1  indicates that the reservoir is has a dialysate volume above a threshold value, the valve controlled by module output port  11   b  may be commanded closed and the valve controlled by module output port  11   c  and/or d may be commanded open. Thus any excessive dialysate will be dumped to drain. 
     The second signal,  11   s   2 , is generated by a conductivity sensor installed on the fluid line coming from a mixing circuit (not shown). The processor of module  11  may monitor signal  11   s   2  from the conductivity sensor. In response a determination that the signal indicates the dialysis solution entering the depicted circuit is not suitable for use (e.g. due to a mixing problem) the controller of the module may issue commands to close the valve controlled by output port  11   b  and open at least one of the valves controlled by output port  11   c  or  d . Thus the unsuitable dialysate may be prevented from entering the dialysate reservoir and may instead by diverted to drain. 
       FIG.  44    depicts a flowchart outlining an example procedure  3100  for initiating automatic enumerating or assigning of unique identifiers to manifold modules in a manifold assembly. The assignation may be mediated by an on-board controller of the module via a connection to a common electronic communications bus. The procedure  3100  may begin with a manifold module being designated  3101  a master module. The master module may in some embodiments, be designated the master module by a hardware switch on a PCB of the manifold module. This switch may be toggled to designate a module as a master module. Alternatively, a module may be designated a master module by programming the controller of the module to designate the module as a master module. For simplicity, the master module may generally be at an end of a communications bus, for example, the first module on the communications bus. Each module may be connected to power from a power bus and defaulted to a configuration in which communication in a direction along a communications bus with any additional modules in has been disabled  3102 . For purposes of example, this direction will be referred to as a downstream direction. The master module controller may assign itself a unique identifier. For example, the master module may enumerate  3103  as module  1 . The master module may establish downstream communications  3104  to the next module of the communications bus. The master module broadcasts  3106  its module identifier on the communications bus. In an exemplary implementation, this broadcast may be performed for a predetermined period of time, for example, 20-100 ms. 
       FIG.  45    depicts a flowchart outlining an example procedure  3110  for automatically enumerating or assigning unique identifiers to manifold modules on a communications bus. A slave module first powers on  3112 . The slave module controller becomes receptive  3114  to communications on the communication bus. In some exemplary implementations, the slave module controller may be in a receiving mode  3114  to the communications bus for a predetermined period of time. This period of time may, for example, be 50-100 ms. The slave module controller may determine  3116  the value of the last claimed unique identifier. For example, the slave module controller may save the highest identifier received while receiving messages on the communications bus. The slave module controller may assign itself  3118  as the next available unique identifier. In an example, the next available unique identifier may be determined by adding one to the saved highest identifier. For example, if the highest identifier received is 1, the slave module controller would assign itself as module  2 . The slave module may establish downstream communication  3120  with the next module. The slave module can then broadcast  3122  the unique identifier it assigned itself. 
     The next slave module controller may in turn become receptive  3124  to communications on the communications bus. The controller of the next slave module determines  3126  the last claimed unique identifier while being receptive  3124  to the communications bus. This identifier should be the identifier just assigned to the previous module. The slave module controller may then assign  3128  itself the next available unique identifier. The slave module may establish downstream communication  3130  with the next downstream module. The slave module controller transmits  3132  its unique identifier on the communications bus. If  3134  there are additional modules, the procedure  3110  may return to  3124  and repeat, allowing any additional modules on the communications bus to assign themselves a unique identifier. 
       FIG.  46    depicts a flowchart outlining an example procedure  3140  for enumerating or assigning a unique identifier to a module which is installed onto a communications bus which has already been enumerated. Such a procedure  3140  may, for example, be used in the event that a bank of manifold modules of a manifold assembly needs to be expanded or when a module is swapped/replaced. The new module may be installed  3142  into the manifold assembly and connected to the communications bus. The new module controller can send a query  3144  to the master controller requesting the number of modules on the bus. The master module controller sends an appropriate response  3146  on the communications bus. The new module controller receives  3148  the response and sends  3150  a query on the communications bus requesting other modules to send their respective IDs. Each module controller can send a response  3152  on the communications bus specifying their ID. The new module controller is placed in a receiving mode on the communications bus and saves  3154  the IDs received. The new module controller can then compare  3156  the received IDs to the number of modules on the communications bus. Based on the comparison, the new module controller can determine and assign itself  3158  the appropriate identity. For example, if the new module controller receives  3148  a response that there are 10 modules on the bus and the new module controller saves  3154  identifiers for every module except module  7 , the new module can assign itself  3158  as module  7 . Alternatively, if the new module controller, for example, receives  3148  a response that there are 10 modules on the bus and the new module controller saves  3154  identifiers for modules  1 - 10 , it may assign  3158  itself as module  11 . 
     Optionally, the new identity may be transmitted on the communications bus by the new module controller. During this transmission the controllers of modules on the communications bus can check the new module unique identifier against their own and generate an error if the unique identifier matches their own. Additionally, the master module controller can save the new module unique identifier and update the total number of modules on the communications bus if necessary. 
       FIG.  47    depicts a flowchart outlining an example procedure  3160  which may be used to assign tasks to various modules in a manifold assembly. In the example procedure  3160 , the main controller may have pre-programmed tasks for a number of different manifold modules. In other embodiments, the tasks may be pre-programmed onto a master module controller and input from a main controller need not be employed. The main controller can send  3162  a query to the master module controller requesting the number of modules on the communications bus. The master module controller may send  3164  a response indicating the number of modules on the communications bus. The main controller can then compare  3166  the number of modules specified by the master controller to an expected number of modules. If  3168  the expected number of modules is greater than the number reported by the master module controller, the main controller may enter an error state and generate a notification  3170  for display on a user interface of the device in which the manifold assembly is used. In some embodiments, the main controller may enter an error state if the number of modules reported by the master module controller differs from the expected number. For example, an error state may be entered and a notification generated if the master module controller indicates that extra modules are present. 
     If  3168  the expected number of modules matches the number reported by the master module controller, the main controller can proceed to determine  3172  a task or task set for the first manifold module. The main controller can send a task command  3174  to the first module. Upon receipt, the first module controller may configure  3176  the module for the specified task or set of tasks. If  3178  there are no further modules, the task assignment process can end. If  3178  there are additional modules, the main controller determines  3180  the task set of the next module. The main controller can send a task command  3182  to the next module and upon receipt, that module controller may configure  3184  its module accordingly. If  3178  there are no further modules, the task assignment process can end. If  3178  there are additional modules,  3180 ,  3182  and  3184  may repeat until all modules have been assigned a task set. 
     The task command generated by the main controller may, in some embodiments, be a high level command. For example, in embodiments in which the modules control pneumatic pathways leading to a pumping cassette, the task command may specify that a manifold module be a pump chamber module or a fluid valve module, or a combination of the two. In an exemplary implementation, the recipient module controller may interpret this task command and automatically set its program for valve configurations, sequencing and default states accordingly. Alternatively, the task command may provide specific valve configuration information to a module. For example, a task command may include configuration settings for individual valves of the module. The task configuration command may, for example, specify a module number, valve number (e.g. 1-4), and configuration setting. Each manifold module may be configured to accept a plurality of valve assemblies. In a preferred embodiment, the number of valve assemblies per module is standardized to permit ready replacement or substitution of a valve assembly and gasket at an assigned location in the module, or ready replacement of the entire module without necessitating re-programming of the module controller. In some cases, the gasket mating a particular valve assembly to the fluidic bus (pneumatic or hydraulic) may have different communication holes or ports to the bus to permit or deny access of the valve to a particular pressure line in the bus. A non-limiting number of example configuration settings are shown in TABLE 1 as follows: 
                         TABLE 1               Valve           Configurations   Description                  Fluid   3 way valve with an input connected to positive       Valve   pressure and an input connected to negative pressure       Chamber   2 way valve with an input connected to positive pressure       Valve Pos       Chamber   2 way valve with an input connected to negative pressure       Valve Neg       Regulator   Valve which outputs to an accumulator and toggles to           regulate a source pressure to an accumulator pressure       Vent   Valve which is connected to a vent reservoir or           atmosphere       Measurement   Valve arranged to make and break fluid communication       Valve   between a reference volume and a control chamber       Blocked   Valve which is in a module but unused and has had its           ports blocked off                    
Optionally, each module may default to predetermined valve configuration settings. In such embodiments, the main controller may not generate a task command for a module if the default settings are appropriate for the task set. In some specific examples, each module may default to a pump chamber control module configuration in which two valves of the module are configured as fluid valves, one is configured as a positive chamber valve, and another is configured as a negative chamber valve.
 
     Optionally, task commands may include primary or grouped task sets addressed to a master module controller. Any of the module controllers in a manifold assembly may be assigned to be a master module controller. The master module controller can receive a primary or grouped task set assignment from a main or system controller via the communications bus. The primary or grouped task command set may assign a master module a task set to coordinate the tasks of a specific secondary module or group of secondary modules. For example, in some embodiments, the primary or grouped task command set may specify that the master module controller coordinates or synchronizes pumping performed by two or more pump chamber modules (e.g. pump chamber modules controlling two or more pump chambers of the same device or the same pump cassette). This may cause the specified secondary modules to effectively operate in tandem to provide the pumping device with greater potential throughput. Such a grouped task assignment may allow the main controller to transmit a single command set with a group identifier. The master controller of the primary module can receive this command or set of commands and transmit individual commands or tasks to secondary modules associated with the group identifier to execute the main controller command set. Although timing of inlet and outlet pump valve operations with an associated pump operation can be performed locally with the on-board controller of the individual pump control modules, synchronizing the operation of one pump/valve combination with another pump/valve combination may be a function of the group command set coordinated by the master controller. The master controller may be a program installed on any of the on-board controllers of the valved manifold modules. Optionally a master controller may not be used. Instead a controller external to the manifold assembly, such as a main or system controller may perform the functions of a master controller. 
     Another primary task command set may specify that the master module controller coordinate operations of a pump chamber module with a volume measurement module (e.g. a manifold module having a valved connection to a reference chamber and to vent for pressure/volume calculations). This may cause the master module controller to synchronize operations of the volume measurement module with the pump chamber module so that the volume measurement module performs a pressure measurement to determine the volume transferred in each pump stroke commanded by the pump chamber module. 
       FIG.  48    depicts a flowchart outlining an example procedure  3200  for commanding operation of a module. The main controller generates a command or set of commands and transmits the command  3202  to the master module controller. The master module controller receives  3204  the command. If  3206  the command is for valves on the master module, the master module controller commands execution  3208  of the command. If  3206  the command is for a slave or secondary module, the master module controller transmits  3210  the command on the communication bus with the recipient module address. The recipient module controller monitors the communication bus and receives  3212  the command. The recipient module controller then executes  3214  the command. 
     In some cases, the command may flow directly from the main controller to the recipient module depending on the type of command. For example, if the command does not require coordination between multiple modules, the command may be read directly by the recipient module and acted upon. 
       FIG.  49    depicts a flowchart outlining an example procedure  3220  for transmitting feedback data from a valve module to a main controller. A module executes a task  3222  and generates data  3224 . This data may be sensor data (e.g. pressure sensor data) generated by a sensor on the module as the task is executed. The data may also be data generated after execution of a task. For example, the data may be valve state data which specifies the current status of the valve (e.g. valve in first position or second position, valve open, valve closed, etc.). The module controller sends the data  3226  on the communications bus. In an example, data may be sent based on a predetermined schedule, for example, every 90-110 ms (e.g. every 100 ms). The main controller receives  3228  the data from the communications bus. Optionally, both the master module and any slave modules on a communications bus may provide feedback in this manner. 
     The master module may also receive data from other modules on the communications bus. This is useful in circumstances in which the master module controller coordinates operations between modules on the communications bus.  FIG.  50    depicts a flowchart outlining another example method  3230  for providing feedback from a module. A module executes a task  3232  and generates data  3234 . The module transmits the data  3236  on the communications bus. Data may be sent based on a predetermined schedule, for example, every 90-110 ms (e.g. every 100 ms). The master module controller receives  3238  the data from the communications bus, and passes  3240  the data to the main or system controller. Alternatively, both the master module controller and the main controller can receive the data when the modules transmit it. 
     The master module controller may be programmed to perform some degree of signal processing before it passes  3240  data to the main controller. For example, the master module controller may report data at a slower rate than the data it receives. It may send a summary or synopsis to the main or system controller. It may filter the data, or average a series of data points over a predetermined period of time and pass the filtered or averaged values to the main controller based on a predetermined schedule or time interval. In some exemplary implementations in a manifold system driving a fluid pumping cassette, pressure data related to the one or more pump chambers and valve state data may be transmitted to the main controller, and pumping chamber related data may be transmitted to both the main controller and the master module controller. Additionally, a master module controller or the main or system controller may generate a query requesting information (e.g. valve state data) from a specific module controller. 
       FIG.  51    depicts a flowchart outlining an example procedure  3250  of commanding operation of a valve within a valve module. The main controller sends a valve state command  3252  over the communications bus. This command may specify a valve state and be addressed to a specific valve in a specific recipient module. The controllers of the modules monitor the communications bus and the recipient module receives the command  3254 . The recipient module processor enables current flow  3256  through valve coils of the appropriate valve in a direction suitable to execute the valve state command. The recipient module sends feedback data  3258  on the communications bus. In some exemplary implementations, this data may be sent continuously or periodically on a predetermined schedule over the communications bus. For example, data may be sent every 90-110 ms. 
       FIGS.  52 A- 52 B  depicts a flowchart outlining an example procedure  3260  of a valve manifold module actuating the pumping of fluid through a pump chamber of a cassette. For sake of simplicity, the flowchart outlines pumping via a single valve manifold module, but a plurality of modules may also be employed to actuate a single pump chamber of a cassette (see, e.g.  FIG.  34 G ). In the example provided, the pumping command set is directed to one or more slave modules on a manifold assembly. A main controller transmits a pumping command  3262  over the communications bus. The pumping command may be a high level command. For example, the pumping command may be a start/resume pumping or stop/pause pumping command and may specify a pumping flow rate. The command may also specify one or more pumping targets. For example, the high level command may specify a duration of pumping, number of pumping strokes, and/or volume to be transferred. The pumping command may also specify a source and a destination for the fluid being pumped. A master module in a bank of manifold modules may be tasked to receive and process  3264  the high level pumping command set. 
     The master module controller transmits  3266  a chamber pump command with an appropriate module address. The chamber pump command specifies that a specific module toggles its valves to trigger a fill stroke or a delivery stroke of a pumping chamber, or that pumping from a pumping chamber is to be stopped or paused. In the example shown, the master module controller transmits  3266  a fill chamber command addressed to a recipient module. Slave modules monitor the communications bus and the recipient module receives the chamber fill command  3268 . The recipient module executes the chamber fill command by generating one or more valve commands. Since the chamber command is a fill chamber command in the example, the slave module controller toggles the manifold valves controlling the inlet and outlet pump chamber valves to the appropriate pressure line on the pneumatic bus, and commands the pump chamber control valves to toggle so that the positive pressure manifold valve is closed and the negative pressure control valve is opened  3270 . The inlet and outlet control valves are toggled to place the pump chamber of the cassette in communication with a fluid source. Toggling open the negative pressure manifold valve results in the application of negative pressure to the pump chamber, drawing fluid into the chamber fluid from the fluid source. The slave module controller optionally monitors pressure data  3272  sensed by a pressure sensor monitoring the pressure supplied to the pump control chamber of the pump cassette. If  3274  an end-of-stroke is detected from the pressure data, the controller of the slave module performing the pumping stroke can report the end-of-stroke condition  3276  on the communications bus. If  3274  end-of-stroke has not yet been detected the slave module controller continues monitoring pressure data  3272 . In some aspects, the slave module controller may report the end-of-stroke condition  3276  by indicating that it is in an idle state. In some aspects, the slave module controller may also be programmed to calculate or determine the flow rate during the stroke and report the result on the communications bus. This may be calculated as pump chamber volume over the time elapsed during the stroke before an end-of-stroke condition is detected. If the pumping module is paired with a measurement module or has integral volume measurement hardware (such as, e.g. a valved reference chamber, or valved communication to vent), a measurement of the volume pumped over the stroke may be taken. This measurement may be reported over the communications bus and can be used to calculate overall flow rate of the pumping cassette or of a pumping chamber. 
     The master module controller may receive the signal indicating the end-of-stroke condition and issue a command  3278  for pumping to continue, pause or stop. In the example provided, since a fill stroke was just performed, the master module controller may command for a deliver stroke to be performed, or alternatively may withhold a stop or pause command, and the on-board controller of the pump module may proceed as programmed to perform a deliver stroke. The recipient slave module controller monitors the communications bus and receives the deliver chamber command  3280 , or alternatively proceeds with its pre-programmed deliver stroke in the absence of a contrary command from the master module controller or the main or system controller. The slave module controller toggles the inlet and outlet control valves of the module to the appropriate positive or negative pressure lines to direct pumping to the appropriate fluid delivery destination, and commands the chamber valves to toggle so that positive pressure is supplied  3282  to the pump control chamber. The application of positive pressure will cause fluid to be expelled out of the pump chamber to the destination. The slave module is optionally equipped with a pressure sensor to periodically measure or monitor pressure  3284  supplied to the pumping chamber via the pump control chamber. If  3286  end-of-stroke has not yet been detected the slave module controller continues monitoring pressure data  3284 . If  3286  an end-of-stroke is detected from the pressure data, the controller of the slave module performing the pumping stroke reports the end-of-stroke condition  3288  on the communications bus. The master module controller or main controller receives the end-of-stroke signal and determines  3290  whether the pumping target (e.g. a target volume to be transferred) has been reached. 
     If  3292  the pumping target has not been reached, the master module controller or main controller can either repeat a command signal  3266  to the slave module to perform another fill stroke, or alternatively in the absence of a stop or pause command from the master module controller or main controller, the slave module controller continues its pre-programmed or pre-loaded pumping utility. The operation  3260  may repeat from that point until the pumping target has been met. If  3292  the pumping target has been reached, the master module controller may report  3294  this on the communications bus for receipt by the main or system controller. In some aspects, the master module controller may enter an idle state if  3292  the pumping target has been reached, and report  3294  the idle state on the communications bus. 
     Tracking the pumping volume or liquid flow rate can be performed in a number of ways. For example, the pumping target may be specified by the number of pumping strokes. When the number of pumping strokes is equal to the target number, the pumping target may be determined to have been met. If the pumping target is specified as pumping volume and is not a whole number multiple of a pump stroke volume, the pumping target may be deemed to have been met when the first pump stroke that causes the cumulative pumped volume to exceed the pumping target has been delivered. Alternatively, when the cumulative volume is within a pump chamber stroke volume of the target volume, the main controller, master module controller, or even the slave module controller may be programmed to determine whether another stroke (and thus an over delivery) would yield a cumulative pumped volume that is closer to the target volume than the current cumulative pumped volume. In some embodiments, if the cumulative pumped volume is within a pump chamber stroke volume of the target volume, the volume pumped during the next stroke may be tracked during the actual stroke and the pump membrane may be halted in mid-stroke when the target volume has been met. Further description of tracking a pumped volume during a stroke is provided in U.S. patent application Ser. No. 14/732,571, filed Jun. 5, 2015, entitled Medical Treatment System and Methods Using a Plurality of Fluid Lines, Attorney Docket No. Q21 which is incorporated by reference herein in its entirety. 
     In an embodiment, the controller of the slave module supplying pressure to the pumping chamber commands pumping actions (with inlet and outlet pump valve control) autonomously after receiving a high level command from the main controller. For example, the controller of the slave module supplying pressure to the pumping chamber may perform pump strokes and determine when the pumping target has been reached. If coordination with another manifold module or group of modules in not needed, a master module controller may not be needed to coordinate pumping operations. Instead, the slave module may act directly based off of commands from a main controller. Alternatively, if the pumping module is paired with a measurement module, the measurement module controller may determine when the pumping target has been reached. 
     In some embodiments, a high level pumping command from the main controller specifies a pumping source and destination. The master module controller commands modules controlling fluid valves of a pumping cassette to open or close to place the pump chamber in communication with the specified source before a fill stroke is performed. Likewise, the master module controller may command modules controlling fluid valves of the pumping cassette to open or close to place the pump chamber in fluid communication with the fluid destination before a delivery stroke is performed. 
       FIG.  53    depicts a flowchart outlining an example procedure  4700  for commanding a pump stroke from a pump chamber of a cassette via a number of valve modules. In the example shown, a first module controls pressure applied to the pump chamber and a second module controls the inlet/outlet fluid valves of the pump chamber. The procedure  4700  may, however, be readily generalized to embodiments in which the inlet/outlet fluid valves of the pump chamber are controlled by more than a single module. In general, the module controlling pressure applied to the pump chamber may receive a chamber command. This module may then coordinate operation of paired companion modules so that the proper inlet/outlet valve is opened or closed before the pump stroke begins. 
     The first module controller may receive  4702  a chamber command. The chamber command may be a fill or deliver command. This command may be generated and transmitted as described above in  FIGS.  52 A- 52 B . The first module controller transmits  4704  a chamber fluid valve command on the communications bus. The second module controller receives  4706  the chamber fluid valve command. The second module controller toggles  4708  its chamber fluid valves per the valve states specified in the chamber fluid valve command. The second module controller provides feedback data  4710  over the communications bus. This data may include an acknowledgement that the chamber fluid valve command was executed. 
     The first module controller receives this feedback and command the chamber valves of the first module to apply appropriate pressure (positive for delivery, negative for fill) to the pumping chamber  4712 . The first module controller may monitor pressure data  4714  produced by a pressure sensor periodically measuring or monitoring the pressure supplied to the pumping chamber. If  4716  end-of-stroke has not yet been detected the first module controller continues monitoring pressure data  4714 . 
     If  4716  an end-of-stroke is detected from the pressure data, the controller of the first module may report the end-of-stroke condition  4718  on the communications bus. A master module controller may receive and act on the end of stroke condition report as described above in relation  FIGS.  52 A- 52 B . 
       FIG.  54    depicts a flowchart outlining an example procedure  3300  for commanding coordinated pumping of fluid through multiple pump chambers. Pumping may be coordinated to enhance or maximize throughput of fluid in an efficient manner. For example, pumping can be coordinated to fill one chamber while delivering another, and to minimize or reduce the amount of time a pump chamber is in an idle state. 
     A main controller can send a pumping command set  3302  specifying which modules are to be used to pump the fluid. In this example, the master module controller can be programmed, for example with a primary or grouped task set (described above in relation to  FIG.  47   ), to assign a plurality of modules as constituents of a secondary group. In such embodiments, the high level command from the main controller may specify a group number or identifier. The master module controller determines  3304  which module identities are assigned to the group. The master module controller can then coordinate pumping by addressing chamber commands to those modules assigned to the group identifier. In the example provided, the master module controller synchronize  3306  pumping between modules assigned to the group by sending commands and receiving feedback from the modules over the communications bus. If  3308  the pumping target volume has not been reached, the master module controller continues synchronizing pumping operations  3306 . If  3308  the master module controller determines that the pumping target has been met, the master module controller may indicate  3310  that the pumping target volume has been met over the communications bus to the main controller. 
       FIG.  55    depicts a flowchart outlining an example procedure  3320  of commanding pumping of fluid with one pumping chamber in a filled state and a pumping command set already having been sent from a main controller. The pumping command set is for a group of two pump chambers in this case, although the procedure  3320  may be readily generalized for pumping commands to groups of more than two pump chambers. 
     The master module controller transmits  3322  a chamber command to each module of the pump group. In this example, the master module controller transmits  3322  a deliver chamber command to the pre-filled chamber module and transmits a fill chamber command to the empty chamber module. The master module controller may then monitor the communications bus and wait  3332  for an end-of-stroke indication to be issued from each chamber module. 
     The slave modules can monitor the communications bus, the full chamber module receives the deliver command  3324 , and the empty chamber module receives the fill chamber command  3326 . The full chamber module toggles the inlet and outlet control valves of the module between positive and negative pressure lines, and commands the chamber valves to toggle so that positive pressure is supplied to the pump control chamber  3328 . The inlet and outlet control valves of the full chamber module are toggled so that the pump chamber of the cassette is in communication with a designated fluid delivery destination. The empty chamber module toggles the inlet and outlet control valves of the module to connect the pump chamber with the fluid source, and commands the chamber valves to toggle so that negative pressure is supplied to the pump control chamber  3330 . The full chamber module controller may measure or monitor pressure data  3334 . The empty chamber module controller may measure or monitor pressure data  3336 . If  3338  the full chamber module controller does not detect an end-of-stroke condition or  3340  the empty chamber module does not detect an end-of-stroke condition their controllers continue to monitor pressure data  3334 ,  3336 . If  3338  the full chamber module controller detects an end-of-stroke condition, the full chamber module controller may indicate the condition over the communications bus  3342 . If  3340  the empty chamber module controller detects an end-of-stroke condition, the empty chamber module controller may indicate the condition over the communications bus  3344 . 
     In this example, the master module controller is configured to receive an end-of-stroke indication from both modules  3346 . The master module controller determines  3348  if a pumping target has been met, and if so  3350 , the master module controller transmits an indicator signal  3352  on the communications bus. If  3350  the pumping target has not been met, the procedure  3220  repeats from step  3322 . Upon each repeated operation, the full chamber module and empty chamber module will switch modes from fill to deliver and vice versa. 
     In the example provided, the master module controller waits for both chamber control module controllers to report an end-of-stroke condition before commanding additional pump strokes. In an additional configuration, the master module controller synchronizes a group of chamber control modules using one of a set of pre-programmed synchronization schemes. For example, the master module controller may synchronize pumping according to any of the pumping synchronization schemes described in U.S. patent application Ser. No. 14/732,571, filed Jun. 5, 2015, entitled Medical Treatment System and Methods Using a Plurality of Fluid Lines, Attorney Docket No. Q21 which is incorporated by reference herein in its entirety. 
       FIG.  56    shows an exemplary graph  3500  depicting pressure  3502  of a control chamber over time during a pump stroke  3504 . In the example graph  3500 , the pump stroke  3504  is a delivery stroke and positive pressure is supplied to the control chamber. When pressure  3502  is supplied to a control chamber during a pump stroke  3504 , the barrier or membrane between the control and pumping chamber is displaced toward the pumping chamber, delivering fluid and reducing its volume. A volume increase in the control chamber will drop its pressure  3502  if not communicating with the pneumatic bus at the manifold assembly. A module controller may attempt to keep the pressure  3502  supplied to an associated control chamber within a range  3506  of a target pressure  3508  during the pump stroke  3504 . This may require opening and closing a manifold valve separating the control chamber from a pressure source (i.e. pneumatic bus) multiple times over the stroke  3504  when the module controller detects that the pressure  3502  is outside the range  3506 . This may help to ensure fluid is pumped at a generally constant flow rate. As shown in the example graph  3500 , the pressure  3502  rises and falls multiple times over the stroke  3504 . Each rise in the example graph  3500  may correspond with an opening of a valve separating a control chamber from a pressure source to repressurize the control chamber. Each pressure decay may correspond to the control chamber changing in volume as fluid is pumped by the pumping chamber. 
     When a pump stroke  3504  has been completed, the control chamber volume is no longer changing. Consequently, the control chamber pressure remains substantially constant  3510 . The module controller may monitor the pressure of the control chamber to determine if the change in pressure over time is indicative of an end-of-stroke condition. In general, after a period of time with relatively little pressure change, the module controller may make a determination that an end-of-stroke condition has occurred. 
       FIG.  57    depicts a flowchart outlining an example procedure  3360  for detecting an end-of-stroke condition with a chamber control module controller. A module controller issues a valve open command  3362  at the beginning of a pumping stroke. The module controller monitors pressure data  3364  generated while the valve is open. If  3366  a minimum wait time has elapsed and if  3368  the pressure is not greater than or equal to a first threshold, the module controller continues to monitor pressure data  3364 . If  3366  a minimum wait time has elapsed and if  3368  the pressure is greater than or equal to a first threshold, the module controller issues a valve close command  3370 . The module controller continues to monitor pressure data  3372  generated while the valve is closed. 
     In an exemplary implementation, if  3374  the pressure decay over a predetermined monitoring period is not less than a threshold and if  3382  a minimum wait time has elapsed, the procedure  3360  may restart from  3362 . If  3374  the pressure decay over a predetermined monitoring period is less than a threshold, the module controller increments a counter  3376 . If  3378  the counter does not exceed a counter threshold and if  3382  a minimum wait time has elapsed the procedure  3360  may be restarted from  3362 . If  3378  the counter exceeds a counter threshold, the module controller commands valves to an idle state and indicates an end-of-stroke condition over the communications bus  3380 . The counter threshold in an exemplary implementation can be two to three counts. In the idle state, the module controller commands the inlet/outlet control valves to apply positive pressure to close the inlet and outlet fluid valves of the pumping chamber. In the idle state, the module controller commands the chamber control valves to a position in which fluid communication between pressure sources and the control chamber has been interrupted. 
       FIG.  58    depicts a flowchart outlining an example procedure  3520  for detecting an end-of-stroke condition with a chamber control module controller. A module controller issues a valve open command  3522  at the beginning of a pumping stroke. The module controller monitors pressure data  3524  generated while the valve is open. If  3526  a minimum wait time has elapsed and if  3528  the pressure is not greater than or equal to a first threshold, the module controller continues to monitor pressure data  3524 . If  3526  a minimum wait time has elapsed and if  3528  the pressure is greater than or equal to a first threshold, the module controller issues a valve close command  3530 . The module controller continues to monitor pressure data  3532  generated while the valve is closed. 
     If  3534  a minimum wait time has elapsed and if  3536  the measured pressure is below the target pressure  3508  ( FIG.  56   ), the procedure  3520  restarts at  3522 . If  3534  a minimum wait time has elapsed and if  3536  the measured pressure is below the target pressure  3508  ( FIG.  56   ), the module controller checks to if the pressure decay rate over the minimum wait time is less than a threshold. If  3538  the pressure decay rate is greater than the threshold the procedure  3520  restarts at  3522 . If  3538  the pressure decay rate is less than the threshold, the module controller commands its valves to an idle state and indicates an end-of-stroke condition over the communications bus  3540 . 
       FIG.  59    depicts a flowchart outlining an example procedure  3550  for limiting the toggle frequency of a valve within a valve module. A module controller may generate a valve pulse command  3552 , causing current to be passed through the coils of the valve to toggle the valve from a first position to a second position. The valve pulse command may be passed  3554  through a filter such as a low pass filter. The voltage value after filtering may be monitored  3556 . If  3558  the filtered value exceeds a threshold value for more than a predefined period of time, the module controller may power off voltage drivers to the valve and will generate an error message  3560 . If  3558  the filtered value does not exceed the threshold value for more than the predefined period of time, the module controller allows continued operation of the valve  3562 . The time period may differ depending on the implementation. In one example, the predefined period of time may be 3-7 seconds (e.g. 5 seconds). The low pass filter may be tuned so that it limits toggle frequency to a desired value. For example, the toggle frequency may be limited to between 20-30 hz (e.g. ˜25 hz or 40 ms). Also, the corner frequency of the low pass filter can be adjusted to obtain a filtered value consistent with the performance characteristics of the valve assembly. In one example, it can be set to about 0.1 hz. 
       FIG.  60    depicts a flowchart outlining an example procedure  4400  that may be used to control the amount of pressure delivered to a pump control chamber, which in turn can affect the instantaneous flow rate into or out of the pump chamber. in the example, the main controller generates  4402  a high level pumping command. This command may be of the type described in relation to  FIGS.  52 A- 52 B  and may also specify a flow rate. The pump control module controller or the master module controller can receive  4404  the high level pumping command or command set. The master module controller (if part of the process) determines  4406  a pressure for a stroke based on the flow rate specified in the high level pump command. In some embodiments, the pressure may be determined  4406  based on querying a look-up table stored in memory. Alternatively, a pressure may be computed based on the flow rate specified and a pre-programmed model. The master module controller transmits  4408  a chamber command to a slave module controller, which commands execution  4410  of a pumping stroke. The slave module controller provides feedback  4412  on the stroke to the master module controller after the stroke has been completed. The feedback includes a flow rate for the stroke, which is based on monitored pressure (at a suitable sampling rate) during the pump stroke. The master module controller may use the flow rate data for the stroke in a control loop  4414 . The control loop can be any suitable type of control loop such as a PI (proportional-integral) or PID (proportional-integral-derivative) control loop. The control loop outputs an estimate for the pressure value  4416  for the next stroke of that type (e.g. fill stroke, deliver stroke) to be performed. For example, the control loop may output a pressure value  4416  for the next fill stroke if the stroke just completed was a fill stroke. If  4418  pumping has not completed (e.g. a pumping target has not been reached), the procedure  4400  may repeat from step  4408  with the new pressure value from the control loop being used when commanding the subsequent stroke of that type. 
     The various embodiments described herein may be used in any of a variety of products which use fluid valves. For example, various embodiments described herein may be used in dialysis machines such as those described in U.S. Provisional Application Ser. No. 62/008,342, Attorney Docket No. M24, filed Jun. 5, 2014, and entitled Medical Treatment System Using a Plurality of Fluid Lines, U.S. Provisional Application Ser. No. 62/003,374, Attorney Docket No M41, filed May 27, 2014, and entitled Blood Treatment System and Methods, and U.S. Provisional Application Ser. No. 62/003,346, Attorney Docket No. M40, filed May 27, 2014, and entitled Hemodialysis System, as well as pneumatic pressure controllers such as those described in U.S. Provisional Application Ser. No. 62/029,813, Attorney Docket No. L27, filed Jul. 28, 2014, and entitled Dynamic Support Apparatus. 
     While the principles of the disclosure have been described herein, it is to be understood by those skilled in the art that this description is made only by way of example and not as a limitation as to the scope of the disclosure. Modifications and substitutions by one of ordinary skill in the art are considered to be within the scope of the present disclosure.