Patent Publication Number: US-RE41299-E

Title: Solenoid valve control system

Description:
The present invention is directed to solenoid-actuated fluid control valves, and more particularly to an electronic system for actuating and controlling solenoid valves. Yet more specifically, the present invention relates to improvements in the solenoid valve control system disclosed in U.S. Pat. No. 5,522,431, assigned to the assignee hereof. 
     BACKGROUND AND SUMMARY OF THE INVENTION 
     Solenoid valve systems for controlling flow of hydraulic or pneumatic fluid have been used in automated manufacturing equipment, production lines and numerous industrial applications. A plurality of solenoid valves typically are mounted on a manifold having a plurality of passages for supplying fluid to the valves and providing passages for connecting fluid couplings to various outlet ports of each valve. Each solenoid of each valve typically is separately electrically wired to an electronic system for controlling operation of the several solenoids and valves. The controller may be located at a position remote from the manifold assembly, requiring a multiplicity of extended conductor lengths for individual connection to the valve solenoids. 
     U.S. Pat. No. 5,522,431 discloses an improved solenoid valve manifold system in which each solenoid is mounted on one side face of a manifold module. The several modules are mounted end-to-end to form a manifold with interconnected through-passages for feeding fluid to and from the several valves. Each manifold module has a terminal block and valve control electronics for hard-wire connection to input/output connectors at the ends of the manifold, and for connection to the associated valve solenoid(s). Although the modular manifold system so disclosed addresses and overcomes problems theretofore extant in the art, further improvements remain desirable. In particular, the manifold system disclosed in the noted patent requires extensive interconnection by hard-wiring, greatly increasing the cost and complexity of manufacture, field installation and repair. 
     It is therefore a general object of the present invention to provide a solenoid valve control system that is constructed of interchangeable modular components, that is readily adapted for use in a variety of applications having differing input and output requirements and specifications, and that requires little or no hard-wiring within the modular manifold itself. Another and related object of the present invention is to provide a solenoid valve fluid control system of the described character that is versatile in design, and economical to assemble, install and repair. 
     A fluid control system in accordance with the present invention includes a fluid manifold having a plurality of manifold bodies fastened to each other end-to-end so as to form one or more fluid passages extending through the manifold. A solenoid valve is mounted on a side of at least one of the manifold bodies with fluid ports opening into the manifold body to the fluid passages extending therethrough. An electrical input/output connection is mounted at one end of the manifold for receiving control signals from an external source. A circuitboard arrangement extends within the manifold from the input/output connection and has conductors printed thereon for connecting the input/output connection to the solenoids of the various valves. 
     Each of the manifold bodies in the preferred embodiments of the invention includes a passage that extends in assembly through the entire manifold offset from the fluid passages and through which the circuitboard arrangement extends for connection to the various solenoid valves. Both the circuitboard passage and the fluid passages comprise through-passage segments in each of the manifold bodies that align with each other when the bodies are assembled end-to-end to form the manifold. The circuitboard arrangement preferably comprises a plurality of individual circuitboards disposed one within each of the manifold bodies, the various circuitboards being electrically interconnected in series. Each of the circuitboards includes complimentary  complementary male and female electrical connectors at opposed ends for connecting the boards in series, and a third connector along one lateral side disposed in assembly adjacent to the side of the manifold body on which the solenoid valve is mounted for making electrical connection from the circuitboard to the valve solenoid. This electrical interconnection is made through an opening in the side of the manifold body that is sealed by the electrical interconnection to the valve solenoid. The circuitboards in the preferred embodiments of the invention are provided in two forms, one providing a single output for lateral connection to a single-solenoid valve, and the other providing dual outputs for lateral connection to a dual-solenoid valve. The conductors printed on the circuitboards are arranged such that the output or outputs to the solenoid valve are always taken from the same connection terminal(s) at the upstream connector, with the remaining connector terminals being interconnected in such a way that the control signals for the remaining solenoid valves on the manifold are sequentially presented at the selected terminal (s) of the connectors. 
     The solenoid valves in the preferred embodiments of the invention comprise a valve body having a spool for selectively controlling flow of fluid through the valve body from and to the manifold, and from and to the output ports on each manifold body. A solenoid is mounted on one end of the valve body, and has an actuator operatively coupled to the valve spool. A valve control circuitboard is sandwiched between the solenoid and the valve body. The valve circuitboard has a first valve connector for interconnection with the third connector on the circuitboard in the underlying manifold body, and a second connector for connection to the coil of the solenoid in such a way that mounting of the solenoid onto the valve body automatically implements electrical connection to the valve control circuitboard. In implementations in which dual-solenoid valves are employed, with solenoids being mounted on opposed ends of the valve body, a solenoid interconnection extends through the valve body at a position offset from the valve spool for interconnecting the second solenoid with the solenoid control circuitboard. Fluid control means, such as a pressure regulator or a velocity controller, may be mounted between the solenoid valve and the corresponding manifold body side face. Electrical connection between the third connector of the circuitboard within the manifold body and the solenoid control board sandwiched between the solenoid and the control body is made by a valve interconnection circuitboard that extends through the fluid controller. 
     The manifold bodies carry screws for releasably fastening the manifold bodies end-to-end to form the manifold assembly. These screws have an externally threaded male end and an internally threaded female end for receiving the male end of a screw in the adjacent manifold body. The screws have a central portion of reduced diameter that is captured by a web within the manifold body. The manifold bodies preferably are of identical construction, and the manifold body assemblies preferably are provided in two forms, one for use in conjunction with a single-solenoid valve and the other for use in conjunction with a dual-solenoid valve. The third connectors on the circuitboards for making connection to the valve solenoids preferably are color-coded to distinguish between single-solenoid and dual-solenoid manifold bodies. 
     The electrical input/output connection at one end of the manifold preferably comprises an input/output circuitboard assembly contained within an appropriate end housing assembly. These end housing assemblies may be provided in differing forms having standardized input/output connectors and/or standardized communication protocol. The input/output circuitry may include valve drivers for supplying valve control signals to the valve solenoids by means of the series-connected circuitboards within each of the several manifold bodies. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention, together with additional objects, features and advantages thereof, will be best understood from the following description, the appended claims and the accompanying drawings in which: 
         FIG. 1  is a perspective view of a fluid control system in accordance with one presently preferred embodiment of the invention; 
         FIG. 2  is an exploded perspective view of the fluid control system illustrated in  FIG. 1 ; 
         FIG. 3  is an end elevational view of a manifold body assembly in the system of  FIG. 1 ; 
         FIG. 3A  is an exploded perspective view of the assembly illustrated in  FIG. 3 ; 
         FIG. 4  is an opposing end elevational view of the assembly illustrated in  FIG. 3 ; 
         FIG. 5  is a fragmentary sectional view taken substantially along the line  5 — 5  of  FIG. 3 ; 
         FIGS. 6A and 6B  illustrate a manifold interconnection circuitboard for a dual-solenoid valve in the system of  FIG. 1 ; 
         FIGS. 7A and 7B  illustrate a manifold interconnection circuitboard for a single-solenoid valve in the system of  FIG. 1 ; 
         FIG. 8  is a fragmentary partially sectioned view of a manifold body assembly, pressure regulator and dual-solenoid valve in the system of  FIG. 1 ; 
         FIG. 9  is an elevational view of the manifold body/pressure regulator/solenoid valve interconnection in  FIG. 8 , being taken substantially along the line  9 — 9  in  FIG. 8 ; 
         FIG. 10  is a plan view of the solenoid interconnection in  FIG. 8 ; 
         FIG. 11  is a fragmentary plan view taken substantially from the direction  11  in  FIG. 8 ; 
         FIGS. 12 and 12A  are electrical schematic diagrams that illustrate interconnection to the solenoids of a dual-solenoid valve for d.c. and a.c. control respectively; 
         FIG. 13  is a partially sectioned elevational view of a manifold body/velocity control/single-solenoid valve arrangement in the system of  FIG. 1 ; 
         FIG. 14  is an elevational view of the input/output circuitboard in the system of  FIG. 1 ; 
         FIG. 15  is a fragmentary exploded perspective view of an alternative input/output connection arrangement that can be employed in the system of  FIG. 1 ; 
         FIGS. 16 and 17  are elevation and plan views of the input/output circuitboard in the modified embodiment of  FIG. 15 ; 
         FIG. 18  is an exploded perspective view of a modified fluid control system; 
         FIG. 19  is an elevational view of the signal transfer board assembly employed in the system of  FIG. 18 ; 
         FIGS. 20 and 21  are elevational views of the input/output board assembly in the system of  FIG. 18 ; 
         FIGS. 22 and 23  are elevational views of a master input/output board assembly in the embodiment of  FIG. 18 ; and 
         FIG. 24  is an elevational view of an input/output slave board assembly in the embodiment of FIG.  18 . 
     
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
       FIGS. 1-14  illustrate a fluid control system  30  in accordance with a presently preferred embodiment of the invention as comprising a unitary manifold assembly  32 . A plurality of identical manifold bodies  34  each have machined end faces  34 a,  34 b that are disposed in spaced parallel planes. Fluid passages  36 ,  38 ,  40  extend through each manifold body  34  between the end faces and, in assembly of several manifold bodies  34  to form manifold  32 , extend longitudinally end-to-end through the manifold assembly. Ports  36 a,  38 a,  40 a ( FIGS. 2 and 3A ) on a side face  34 c of manifold body  34  open respectively into fluid passages  36 ,  38 ,  40 . Return ports on side face  34 c of manifold body  34  are internally coupled to outlet ports  41 ,  42  on the manifold body. A pair of screws  44  are captured within each manifold body  34  at positions on opposed sides of fluid passages  36 ,  38 ,  40 . Each screw  44  includes an externally threaded male end  46 , and an internally threaded female end  48  interconnected by a shank  50  of reduced diameter. End  48  contains a slot  52  for receiving the head of a screwdriver or the like. Male screw end  46  is self-tapping and threaded through a web  54  in manifold body  34 , so that following such self-tapping insertion through web  54 , screw  44  is effectively captured in assembly by web  54 . The spaced screws  44  in the several manifold bodies  34  are employed to assemble the manifold bodies end-to-end to form unitary manifold assembly  32 . A gasket  56  extends around one end face  34 b of each manifold body  34  for sealing fluid passages  36 ,  38 ,  40  from each other and from the external atmosphere. 
     A passage  60 , which is laterally offset from fluid passages  36 ,  38 ,  40  and screws  44 , extends end-to-end through each manifold body  34  so as to form a continuous passage that extends end-to-end through the manifold assembly when the manifold bodies are assembled to each other. A circuitboard assembly  62  is received within passage  60  by longitudinally sliding fit of the circuitboard side edges into opposed slots  64  that extend partway through passage  60 . Circuitboard assembly  62  preferably is provided in two forms: assembly  62 a illustrated in  FIGS. 6A and 6B , and assembly  62 b illustrated in  FIGS. 7A and 7B . The purposes of these two circuitboard forms or configurations will be explained later. Each circuitboard assembly  62  has a male connector  66  disposed at one end and a female connector  68  disposed at the opposing end, with the connectors  66 ,  68  being of complimentary  complementary mating configuration so that the circuitboard assemblies  62  disposed within the several manifold bodies  34  may be connected in series end-to-end as the manifold bodies are assembled to each other. A third connector  70  extends from one lateral side of each circuitboard assembly  62  through an opening  72  in side face  34 c of manifold body  34 . The contacts of connectors  66 ,  68  are connected to each other by conductors printed on circuitboard assembly  62 , as best seen in  FIGS. 6A and 7A . Selected contacts of connector  66  are also connected to the contacts of connector  70 , for purposes to be described. In assembly, the female duck-bill contacts  74  of connector  70  are assembled to circuitboard  62  (see  FIG. 3A ) and the circuitboard assembly is then slid into slots  64  of passage  60  with the contacts  74  not extending above the passage  60 . The body of connector  70  is then inserted through opening  72  in manifold body  34  to protect the contacts  74 , and to fasten circuitboard assembly  62  in position within the manifold body. Connector  70  preferably is color-coded in embodiments  70 a and  70 b so as to distinguish between the circuitboard assembly constructions  62 a,  62 b of  FIGS. 6A and 7A . 
       FIGS. 1 and 2  illustrate manifold assembly  32  as comprising three manifold body sub-assemblies  34  assembled to each other end-to-end between a pair of end plate assemblies  80 ,  82 . End plate assemblies  80 ,  82  close the ends of fluid passages  36 ,  38 ,  40  and provide ports  84 ,  86  for external fluid connection to the fluid passages. The end plate assemblies also have pilot supply ports  88 . A plate  89  ( FIG. 2 ) closes end plate assembly  80 . End plate assembly  80  is fastened to the adjacent manifold boy  34  by screws  44 , and end plate assembly  82  is fastened to the adjacent manifold body  34  by screws  83  received in heads  48  of screws  44  in that manifold body. An end housing assembly  90  is mounted by screws  92  to end plate assembly  82 . End housing assembly  90  includes an input/output circuitboard assembly  100  (FIG.  14 ), which may be provided in several forms, as will be described. The particular circuitboard assembly  100  illustrated in  FIG. 14  has an input/output connector  102  mounted along one side edge for exposure through an opening in the housing  104  of housing assembly  90 . The contacts of connector  102  are connected by conductors printed on circuitboard  100  to the contacts of a second connector  106  disposed on circuitboard assembly  100  for longitudinal alignment with circuitboards  62  within manifold bodies  34 . The number and configuration of contacts in connector  106  is the same as in connectors  66 ,  68  of circuitboards  62 . A transfer connector  108  ( FIG. 2 ) connects connector  106  to the connector  66  of the first circuitboard assembly  62  in the first manifold body  34 . Thus, input connector  102  is effectively connected by circuitboard  100 , connector  106  and transfer connector  108  to the several manifold body circuitboards  62  in series. Manifold  32  is shown in  FIGS. 1 and 2  as being mounted on a standard DIN mounting rail  110 . A gasket  112  is disposed between end plate assembly  82  and end housing assembly  90 . 
     In the embodiment  embodiments illustrated in  FIGS. 1-14 , three manifold bodies  34  are shown. Beginning from the right end in  FIGS. 1 and 2 , the first manifold body is coupled through a dual pressure regulator  120  to a dual-solenoid valve  122 . The second manifold body  34  is connected through a speed control module  124  to a single-solenoid valve  126 . The third manifold body  34  is unused, with the ports on the upper side face being covered by a blank station plate  128 . At each of the valved manifold bodies, the supply and return ports, to which fluid passage is controlled by the solenoid valve, are disposed at  40  ,  41 ,  42  on a side face of the manifold body, and may also open to the side face opposite to which the valve is mounted. The manifold station containing dual pressure regulator  120  and dual-solenoid valve  122  is illustrated in greater detail in  FIGS. 8-12A . Valve  122  and pressure regulator  120  are mounted to manifold body  34  by screws  121 , with gaskets  123  being disposed between each body. Dual pressure regulator  120  has a body  130  through which passages extend between the side face ports of manifold body  34  and the supply, return and controlled ports of valve  122 . A valve connector assembly  132  extends through a passage  134  in body  130  of regulator  120  from connector  70 a of manifold body  34  to provide control signals to the overlying solenoid valve  122 . Solenoid valve  122  includes a valve body  136  within which a valve spool  138  is slidably disposed for providing controlled fluid communication between input/output and exhaust ports on the valve body. A pair of solenoids  140 ,  142  are mounted on the opposed ends of valve body  136 . Each solenoid  140 ,  142  includes a coil  144  and an armature  146  in respective abutting engagement with an associated end of spool  138 . To provide electrical connection to the coils  144  of solenoids  140 ,  142 , a solenoid control circuitboard assembly  150  is sandwiched in assembly between solenoid  140  and the opposing end of valve body  136 . Solenoid control board assembly  150  has a pair of female duck-bill contacts  152  that are positioned for mating engagement with male contacts on solenoid  140  as solenoid  140  is fastened to valve body  136  with board  150  sandwiched therebetween. 
     A solenoid interconnector  154  extends through a passage  155  in valve body  136  offset from spool  138 . Interconnector  154  has a pair of spaced parallel male contacts  156  at one end that are slidably received within associated female duck-bill contacts on solenoid control board  150  as solenoid  140  is mounted to valve body  136 . The opposing end of interconnected  154  carries a pair of female duck-bill contacts  158  that slidably receive the male contacts of solenoid  142  as solenoid  142  is mounted on the opposing end of valve body  36 . Solenoid control board  150  comprises a circuitboard  160  on which contacts  152  are mounted. Conductors printed on circuitboard  160  connect contacts  152  to a three-terminal male connector  162  on one edge of circuitboard  160 . Connector  162  is removably received in a female connector  164  on circuitboard  132  as solenoid valve assembly  122  is mounted on pressure regulator  120 . Circuitboard assembly  132  has printed conductors that connect the three terminals of connector  164  to the three male contacts of connector  166 , which is received in mating engagement with connector  70 a on circuitboard  62 a as pressure regulator  120  is mounted on manifold body  34 . Circuitboard assembly  150  also carries a pair of LED&#39;s  168 ,  170  for indicating when the associated solenoids are energized. Connectors  162 ,  166  are of identical contact configuration, so that solenoid control board  150  may be plugged directly into connector  70 a (or  70 b) in applications where pressure regulator  120  (or other intervening control) is not used. 
     Valve control circuitboard  150  preferably is provided in two forms  150 a and  150 b, of which schematic diagrams are illustrated in  FIGS. 12 and 12A  respectfully.  FIG. 12  illustrates interconnection for d.c. activation of the solenoid coils in which a positive voltage is applied to each coil through a COMMon  common line (COMM). Each coil is connected to a negative line for activation of the coil when the negative line is pulled to ground. LED&#39;s  168 ,  170  are connected across respective coils through a current limiting resistor for illumination when voltage is applied to the associated coil. Are suppression diodes  172 ,  174  are connected across each coil.  FIG. 12A  illustrates solenoid control board  150 b for a.c. activation of the coils. Once again, the COMMon  common line (COMM) is connected to both coils, which have respective separate return lines. LED&#39;s  168 ,  170  are connected across the respective coils through associated sets of series current-limiting resistors. LED&#39;s  168 ,  170  are positioned adjacent to the upper edge of assembly  150  as shown in FIG.  9 . LED&#39;s  168 ,  170  are disposed in assembly beneath a clear window  180  on the outer wall of valve body  136  adjacent to indicia  182  for indicating to an operator which of the LED&#39;s is illuminated, and therefore which solenoid coil has been energized. 
       FIG. 13  is similar to  FIG. 8 , but illustrates single-coil solenoid valve  126  coupled to its associated manifold body  34  through speed control module  124 . Valve body  136  again has a passage within which spool  138  is disposed. Solenoid  140  is again mounted on one end of valve body  136 , with solenoid control assembly  150  sandwiched therebetween. The opposing end of valve body  136  is enclosed by a cover plate  184 , with a coil spring  186  being captured in compression between cover plate  184  and spool  138 . Thus, in single-solenoid valve  126 , valve  142  ( FIG. 8 ) is replaced by coil spring  186 , and solenoid interconnector  136  is deleted. Valve connector  132  is disposed within a passage  188  of speed control  124 , interconnecting solenoid control  150  with manifold card  62 b. Speed control  124  has the usual screws  124 a and  124 b for controlling air passage orifice size, and thereby controlling speed of operation of valve  126  and any equipment coupled thereto. 
     The purpose of providing manifold circuitboard  62  in two versions  62 a,  62 b will be clear. Version  62 a illustrated in  FIGS. 6A and 6B  provide two control lines to connector  70 a, thus being suitable for use in conjunction with a dual-solenoid valve  122 , while version  62 b provides a single valve control line to connector  70 b, thus being suitable for use in conjunction with a single-solenoid valve. In both assemblies, contacts “1” and “10” of connector  66  is connected to contacts “1” and “10” of connector  68  and to one contact of connector  70 a, thus providing the COMMon  common connection (COMM) for the valve solenoids. This COMMon  common connection (COMM), connected to positive (or negative) d.c. potential, or to one side of a.c. potential, is connected in series throughout the manifold, providing a single common connection to all valve solenoids. Contacts “2” and “3” of connector  66  in circuitboard  62 a are connected to the A and B contacts of connector  70 a, while the remaining contacts of connector  66  are connected to correspondingly numbered contacts of connector  68  minus two. Thus, contacts “4” and “5” of connector  66  are connected by circuitboard  62 a to contacts “2” and “3” of connector  68 , thus being positioned for connection to the A and B contacts of connector  70 a in the next manifold body. In the same way, assuming that there is a dual solenoid valve at each manifold section, contacts “6” and “7” of connector  66  in  FIG. 6B  are connected to contacts “4” and “5” of connector  68 , and will be connected to contacts “2” and “3” in connector  68  in the next manifold section preparatory to connection to the A and B terminals of connector  70 a in the third manifold section. In other words, each circuitboard has at least one first conductor printed thereon that extends from a preselected contact of said male connector to the same preselected contact of said female connector so as to extend continuously through said manifold and supply a common connection to all valves on said manifold, and a plurality of second conductors at least one of which extends to said third connector and the remainder of which extend from corresponding contacts of one of said male and female connectors to a contact on the other of said male and female connectors reduced as compared with said corresponding contacts by the number of said second conductors that connect to said third connector. 
     In contrast, within circuitboard  62 b ( FIGS. 7A and 7B ) there is a decrement of only a single contact number between connectors  66  and  68  because only one line is required for energization of the single coil in the associated single-solenoid valve. Thus, in both embodiments  62 a and  62 b, the connector contact number is decremented at each manifold station in accordance with the number of solenoids in the associated valve. It will also be noted that manifold circuitboards  62 a,  62 b automatically accommodate mixing of solenoid valves, such as single-coil valve  126  and dual-coil valve  122 . The valve control signal at contact “2” of connector  66  at the station at which single-coil valve  126  is disposed will provide the valve control signal to the valve solenoid, while contacts “3” and “4” are decremented by one in connection to contacts “2” and “3” of connector  68 . At the next station at which dual-coil valve  122  is disposed, the control signals appearing at contacts “2” and “3” of connector  66  are fed as the A and B coil control signals to connector  70 a of the manifold circuitboard  62 a employed at that section. Thus, manifold circuitboards  62  ( 62 a and  62 b) automatically accommodate differing combinations of single—and dual-solenoid valves while appropriately decrementing the conductor contact at which valve control signals are provided. In the particular embodiment illustrated in which connectors  66 ,  68  comprise eighteen-pin connectors, sixteen single-valve solenoids or eight dual-valve solenoids, or combinations thereof, may thus be accommodated in a single manifold assembly. 
     It will also be noted that the three contacts (COMM,A and B) of connector  70  ( 70 a or  70 b) are directly interconnected by valve connector circuitboard  132  with the corresponding three contacts at input connector  164  of solenoid control circuitboard  150 . In applications where no pressure regulator or speed control device is required, valve interconnection circuitboard  132  may be eliminated, and the valve mounted directly on the side face of the manifold body with connector  162  in mating engagement with connector  70  ( 70 a or  70 b). Connectors  162 ,  166  are dimensioned to seal opening  72  of manifold body  34 , and the corresponding opening of pressure regulator  132  or speed control  124  (or any other intermediate device disposed between a manifold body and a solenoid valve). 
       FIGS. 15-17  illustrate a modified end housing assembly  90 a that may be employed in place of end housing assembly  90  in  FIGS. 1 and 2 . Basically, end housing assembly  90 a comprises a shell  200  having an internally threaded gland  202  extending from one sidewall for receiving an interconnection cable connected to remote control electronics. An end plate  204  and a gasket  112  are adapted to be mounted to one end face of housing  200  by means of screws  208 . Likewise, a top plate  210  and a gasket  212  are mounted on housing  200  by screws  214 . Within housing  200 , an input/output connector board  216  ( FIGS. 15-17 ) is disposed. Connector  216  includes a terminal strip  218  having a plurality of screw-type or friction lock terminals for hardwire connection of conductors extending through gland  202 . The individual contacts of connector  218  are connected by conductors printed on circuitboard  216  to associated terminals or contacts of a connector  106  that is mounted along an edge of circuitboard  216  for alignment in assembly with manifold interconnection cards  62  ( 62 a or  62 b). Thus, end housing assembly  90 a provides for hard-wire screw terminal connection of the input/output cable, in place of connection via connector  102  ( FIGS. 1 ,  2  and  14 ) in the embodiment of  FIGS. 1-14 . 
       FIG. 18  illustrates a modified system  220 , in which components identical to those illustrated in  FIGS. 1-17  are indicated by correspondingly identical reference numerals, and components similar but not identical to those hereinabove described are indicated by identical reference numerals with a suffix. In the system of  FIG. 18 , there are four manifold bodies  34  disposed between end plate assemblies  80 ,  82 . In addition to a dual-solenoid valve  122  mounted to a manifold body  34  by a pressure regulator  120  and a single-solenoid valve  126  mounted to a manifold body  34  by a speed control  124 , the system of  FIG. 18  also includes a dual-coil solenoid valve  122  and a single-coil solenoid valve  126  mounted directly to associated manifold bodies  34  without intervening hardware. As noted above, in these mounting arrangements, connector  162  of solenoid control circuitboard  150  is in direct mating engagement with connector  70  ( 70 a or  70 b) of manifold circuitboard  62  ( 62 a or  62 b). The end housing assembly  222  of  FIG. 18  is specifically adapted for use in conjunction with bus-type electronic input/output with the external control apparatus. Specifically, housing  222  includes a first shell  224  having bus-type input/output connectors  226  and an auxiliary power connector  227  mounted thereon. An electronic bus interface assembly  228  ( FIGS. 18-21 ) is disposed within housing  224 . Interface electronics  228  includes a printed circuitboard  230  having a connector  106  along one edge for alignment and mating engagement with manifold circuitboards  62  by means of a transfer board  232  (FIGS.  18  and  19 ). Transfer board  232  comprises a circuitboard  234  having a male connector  66  and a female connector  68  at opposed ends, and conductors printed thereon directly interconnecting like or identical contacts of connectors  66 ,  68 . Thus, transfer board  232  connects the contacts of connector  106  on input/output board  228  with manifold boards  62  in sequence. Input/output board  228  also includes an electronic assembly  240  suitable for communication by means of a selected protocol, differing input/output boards  228  thus being adapted for use in conjunction with differing protocols. LED&#39;s  242  along the upper edge of assembly  228  cooperate with a window  243  in shell  224  to indicate pendency of communication, while a connector  244  on the back face of circuitboard  230  provides for connection to master and slave input/output electronic interfaces, as will be described. Input/output assembly  228  may include additional electronics, such as valve driver circuits  245  (FIG.  21 ), for converting input/output commands from a remote source into signals suitable for operating the several solenoid valves  122 ,  126  in the desired manner. 
     System  220  further includes facility for operating additional manifold assemblies in a master/slave technique. A second input/output housing shell  250  has a pair of input/output bus-type connectors  252  mounted thereon. Housing shell  250  is mounted against housing shell  224 , with a gasket  112  sandwiched therebetween. A pair of laterally opposed slots  254  within housing shell  252  received opposed side edges of a master input/output card  256  ( FIGS. 8 ,  22  and  23 ). Card  256  includes a circuitboard  258  on which a connector  260  is mounted for mating engagement with connector  244  on input/output board  228 . An input/output driver chip  262  on board  258  provides for transmission of control signals as inputs or outputs through one or both connectors  252 . Driver chip  262  is capable of up to eight input/output connections, of which two are at  252 . For up to six additional input/output connections, additional shells  250 a (only one being shown in  FIG. 18 ) are mounted to shell  250 , and the associated input/output connectors  252 a are connected to driver chip  262  by slave boards  264  (FIGS.  18  and  24 ). Slave board  264  is identical to master board  256 , except that driver chip  262  is deleted. Connector  260  on slave board  264  mates with connector  261  on master board  256 . Up to three shells  250 a, three slave boards  264  and six connectors  252 a may be connected to driver  262  on master board  256  in this manner. Further master and slave boards may be added in the same manner for additional input/output capability.