Patent Publication Number: US-2023136636-A1

Title: Solenoid valve control device

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is based upon and claims the benefit of priority from Japanese Patent Application No. 2021-179923 filed on Nov. 4, 2021, the contents of which are incorporated herein by reference. 
     BACKGROUND OF THE INVENTION 
     Field of the Invention 
     The present invention relates to a solenoid valve control device in which a plurality of solenoid valve modules are connected to a communication module (control module). 
     Description of the Related Art 
     Conventionally, there has been known a solenoid valve control device in which a plurality of solenoid valve modules are connected to a communication module (control module) that communicates with, for example, a PLC, and solenoid valves of the plurality of solenoid valve modules are controlled by one communication module. For example, JP 5641447 B2 discloses a solenoid valve control device in which a plurality of manifold solenoid valve blocks are connected in series to a solenoid valve control unit. 
     The solenoid valve control device disclosed in JP 5641447 B2 includes power supply lines, serial communication lines, and block select lines. The solenoid valve control unit of the solenoid valve control device supplies a block select signal to a solenoid valve drive circuit of a solenoid valve block to be controlled, via a predetermined block select line and a transfer wiring of the solenoid valve block. 
     SUMMARY OF THE INVENTION 
     When one communication module controls the solenoid valves of a large number of solenoid valve modules, the number of communication lines required for communication between the communication module and the solenoid valve modules may become enormous. As the number of the communication lines increases, the size of the device increases and the installation space thereby increases, and moreover, the number of processes for connecting the communication lines increases. In addition, when an operation state of the solenoid valve is diagnosed in the solenoid valve module, it is necessary for the communication module to grasp the diagnostic information, and the number of the communication lines may further increase. 
     In the solenoid valve control device disclosed in JP 5641447 B2, block select lines corresponding to the number of the solenoid valve blocks are required. Therefore, the number of the solenoid valve blocks connected to the solenoid valve control unit is limited. 
     The present invention has the object of solving the aforementioned problems. 
     According to the present invention, provided is a solenoid valve control device comprising a plurality of solenoid valve modules, and a communication module, the solenoid valve modules being connected in series to the communication module, the solenoid valve control device further comprising: a transmission line; a receiving line; and a switching line, wherein the transmission line, the receiving line, and the switching line cross the communication module and the plurality of solenoid valve modules, the solenoid valve modules each include a first communication circuit and a second communication circuit, an input terminal of the second communication circuit is connected to the transmission line, and an output terminal of the second communication circuit is connected to the receiving line, wherein a solenoid valve control signal transmitted from the communication module to the transmission line is received by the first communication circuit of each of the solenoid valve modules, and a signal related to diagnostic information is transmitted from the first communication circuit to the transmission line together with the solenoid valve control signal, and wherein the second communication circuit of each of the solenoid valve modules other than the solenoid valve module disposed at a terminal end of the plurality of solenoid valve modules receives a signal from the switching line located in the solenoid valve module disposed next thereto, and the second communication circuit of the solenoid valve module that is disposed at the terminal end and that receives no signal from the switching line transmits the solenoid valve control signal and signals related to the diagnostic information of the plurality of solenoid valve modules to the communication module via the receiving line. 
     Since the solenoid valve control device according to the present invention includes the switching line and the second communication circuit, the signals related to the diagnostic information of the plurality of solenoid valve modules are automatically transmitted from the solenoid valve module disposed at the terminal end to the communication module. As a result, the communication module can grasp the diagnostic information of the plurality of solenoid valve modules. In addition, a communication line required for feeding back the diagnostic information of the plurality of solenoid valve modules to the communication module is not particularly required. Moreover, even if the solenoid valve module disposed at the terminal end is changed by adding a solenoid valve module, the signal transmission path is automatically switched, and therefore, it is not necessary to give a special instruction to the solenoid valve module disposed at the terminal end. 
     The above and other objects, features, and advantages of the present invention will become more apparent from the following description when taken in conjunction with the accompanying drawings, in which a preferred embodiment of the present invention is shown by way of illustrative example. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    is a circuit diagram of a solenoid valve control device according to an embodiment of the present invention. 
     
    
    
     DESCRIPTION OF THE INVENTION 
     As shown in  FIG.  1   , a solenoid valve control device  10  according to an embodiment of the present invention includes a communication module  12  and a plurality of manifold solenoid valve modules  161  to  16   n.  The plurality of solenoid valve modules  161  to  16   n  have the same structure and are connected in series to the communication module  12 . One or a plurality of solenoid valves  18  are attached to each of the solenoid valve modules  161  to the  16   n.  Each of the solenoid valve modules  161  to  16   n  includes a solenoid valve control circuit  20  that outputs a drive signal to the solenoid valve  18  attached to the solenoid valve module. 
     The number of the solenoid valve modules  161  to  16   n  in the solenoid valve control device  10  is n, and for example, n=16. Further, the number of the solenoid valves  18  that can be attached to each of the solenoid valve modules  161  to  16   n  is, for example, eight at most. In this case, a maximum of 128 solenoid valves  18  can be mounted on one solenoid valve control device  10 . 
     In the following, among the plurality of solenoid valve modules  161  to  16   n,  the solenoid valve module  161  located closest to the communication module  12  is referred to as a “start-end solenoid valve module”. Further, the solenoid valve module  16   n  located farthest from the communication module  12  is referred to as a “terminal solenoid valve module”. Moreover, with respect to the two adjacent solenoid valve modules, when viewed from the solenoid valve module closer to the communication module  12 , the solenoid valve module farther from the communication module  12  is referred to as a “next-stage solenoid valve module”. Conversely, when viewed from the solenoid valve module farther from the communication module  12 , the solenoid valve module closer to the communication module  12  is referred to as a “previous-stage solenoid valve module”. 
     The communication module  12  includes a control circuit  14  that bidirectionally communicates with a PLC  52 , which is a host controller, via a bus line  54 . The communication module  12  receives signals for controlling the solenoid valves  18  of the plurality of solenoid valve modules  161  to  16   n  from the PLC 52 . A control system power supply  62  is connected to the communication module  12 . Electric power necessary for the operation of the control circuit  14  is supplied from the control system power supply  62  to the control circuit  14  via a control system power line  64 . 
     A drive system power supply  56  is connected to the communication module  12 . A drive system power line  58  extending from the drive system power supply  56  crosses the communication module  12  and the plurality of solenoid valve modules  161  to  16   n.  The drive system power line  58  includes a divided power line  600  disposed in the communication module  12 , and divided power lines  601  to  60   n  disposed in the respective solenoid valve modules  161  to  16   n.    
     By the plurality of solenoid valve modules  161  to  16   n  being connected to the communication module  12 , the divided power line  600  of the communication module  12  and the divided power lines  601  to  60   n  of the plurality of solenoid valve modules  161  to  16   n  are connected to each other. In the solenoid valve modules  161  to  16   n,  electric power necessary for driving the solenoid valves  18  is supplied to the solenoid valve control circuits  20  via the divided power lines  601  to  60   n  of the solenoid valve modules  161  to  16   n,  respectively. 
     The solenoid valve control device  10  includes a transmission line  32  extending from the control circuit  14  of the communication module  12 . The transmission line  32  is a communication line through which the communication module  12  transmits signals to the plurality of solenoid valve modules  161  to  16   n.  The transmission line  32  includes three communication lines of first to third communication lines  34 ,  36 , and  38 . The first to third communication lines  34 ,  36 , and  38  cross the communication module  12  and the plurality of solenoid valve modules  161  to  16   n.    
     The first communication line  34  includes a first divided communication line  340  disposed in the communication module  12 , and first divided communication lines  341  to  34   n  disposed in the solenoid valve modules  161  to  16   n.  Similarly, the second communication line  36  includes a second divided communication line  360  disposed in the communication module  12 , and second divided communication lines  361  to  36   n  disposed in the solenoid valve modules  161  to  16   n.  The third communication line  38  includes a third divided communication line  380  disposed in the communication module  12 , and third divided communication lines  381  to  38   n  disposed in the solenoid valve modules  161  to  16   n.    
     By the plurality of solenoid valve modules  161  to  16   n  being connected to the communication module  12 , the first divided communication line  340  of the communication module  12  and the first divided communication lines  341  to  34   n  of the plurality of solenoid valve modules  161  to  16   n  are connected to each other. Similarly, the second divided communication line  360  of the communication module  12  and the second divided communication lines  361  to  36   n  of the plurality of solenoid valve modules  161  to  16   n  are connected to each other. Further, the third divided communication line  380  of the communication module  12  and the third divided communication lines  381  to  38   n  of the plurality of solenoid valve modules  161  to  16   n  are connected to each other. 
     Based on the signals received from the PLC  52 , the control circuit  14  of the communication module  12  transmits signals for controlling the solenoid valve  18  of the solenoid valve module to be controlled, to the first to third communication lines  34 ,  36 , and  38  of the communication module  12 . The signal transmitted from the control circuit  14  to the first communication line  34  is a clock signal for synchronization. The signal transmitted from the control circuit  14  to the second communication line  36  is a signal (selection signal) for selecting the solenoid valve module to be controlled. The signal transmitted from the control circuit  14  to the third communication line  38  is a signal (solenoid valve control signal) related to control data of the solenoid valve  18 . 
     The solenoid valve control circuit  20  of each of the solenoid valve modules  161  to  16   n  includes a first communication circuit  22 . The first divided communication lines  341  to  34   n  of the respective solenoid valve modules  161  to  16   n  are branched in the middle and connected to the first communication circuits  22 . As a result, the first communication circuit  22  of each of the solenoid valve modules  161  to  16   n  can receive the clock signal via the first communication line  34 . The second divided communication lines  361  to  36   n  of the respective solenoid valve modules  161  to  16   n  are branched in the middle and connected to the first communication circuits  22 . As a result, the first communication circuit  22  of each of the solenoid valve modules  161  to  16   n  can receive the selection signal via the second communication line  36 . 
     The first communication circuit  22  is inserted in the middle of the third divided communication lines  381  to  38   n  of the respective solenoid valve modules  161  to  16   n.  As a result, the first communication circuit  22  of each of the solenoid valve modules  161  to  16   n  can receive the solenoid valve control signal via the third communication line  38 , and transfer the received solenoid valve control signal to the next-stage solenoid valve module via the third communication line  38 . The solenoid valve control circuit  20  of the solenoid valve module to be controlled among the solenoid valve modules  161  to  16   n  outputs a drive signal to the solenoid valve  18  on the basis of the received solenoid valve control signal. 
     The solenoid valve control circuit  20  of each of the solenoid valve modules  161  to  16   n  diagnoses an operation state of the solenoid valve  18  of the solenoid valve module. Specifically, the solenoid valve control circuit  20  diagnoses whether the coil of the solenoid valve  18  melts to cause a short circuit, whether the temperature in the solenoid valve module exceeds the upper limit of the allowable temperature, and the like. A signal related to the diagnostic content (diagnostic information) is transmitted from the first communication circuit  22  to the third communication line  38  together with the solenoid valve control signal, and is transmitted to the next-stage solenoid valve module. 
     The signal transmitted from the first communication circuit  22  of each of the solenoid valve modules  161  to  16   n  to the third communication line  38  also includes signals related to diagnostic information created in the solenoid valve modules from the start-end solenoid valve module  161  to the previous-stage solenoid valve module. The signal transmitted from the first communication circuit  22  of the terminal solenoid valve module  16   n  to the third communication line  38  includes signals related to diagnostic information created in all the solenoid valve modules  161  to  16   n.    
     The solenoid valve control device  10  includes a receiving line  40  extending from the control circuit  14  of the communication module  12 . The receiving line  40  is a communication line through which the communication module  12  receives a signal from the terminal solenoid valve module  16   n.  The receiving line  40  is constituted by one communication line, and crosses the communication module  12  and the plurality of solenoid valve modules  161  to  16   n.    
     The receiving line  40  includes a fourth divided communication line  400  disposed in the communication module  12 , and fourth divided communication lines  401  to  40   n  disposed in the solenoid valve modules  161  to  16   n.  By the plurality of solenoid valve modules  161  to  16   n  being connected to the communication module  12 , the fourth divided communication line  400  of the communication module  12  and the fourth divided communication lines  401  to  40   n  of the plurality of solenoid valve modules  161  to  16   n  are connected to each other. 
     The solenoid valve control circuit  20  of each of the solenoid valve modules  161  to  16   n  includes a second communication circuit  24  constituted by a general-purpose logic IC. The second communication circuit  24  includes an input terminal  26 , an output terminal  28 , and an output enable terminal  30 . In each of the solenoid valve modules  161  to  16   n,  the input terminal  26  of the second communication circuit  24  is connected, via a first connection line  48 , to corresponding one of the third divided communication lines  381  to  38   n  each extending from the first communication circuit  22  toward the next-stage solenoid valve module. Further, in each of the solenoid valve modules  161  to  16   n,  the output terminal  28  of the second communication circuit  24  is connected, via a second connection line  50 , to corresponding one of the fourth divided communication lines  401  to  40   n  constituting the receiving line  40 . 
     The solenoid valve control device  10  includes a switching line  42  extending from the control circuit  14  of the communication module  12 . A constant voltage (High signal) is always supplied to the switching line  42 . The switching line  42  crosses the communication module  12  and the plurality of solenoid valve modules  161  to  16   n.    
     The switching line  42  includes a divided switching line  420  disposed in the communication module  12 , and divided switching lines  421  to  42   n  disposed in the solenoid valve modules  161  to  16   n.  By the plurality of solenoid valve modules  161  to  16   n  being connected to the communication module  12 , the divided switching line  420  of the communication module  12  and the divided switching lines  421  to  42   n  of the plurality of solenoid valve modules  161  to  16   n  are connected to each other. 
     Each of the solenoid valve modules  161  to  16   n  includes a first branch switching line  44  branching from corresponding one of the divided switching lines  421  to  42   n,  and a second branch switching line  46  extending from the output enable terminal  30  of the second communication circuit  24 . By the plurality of solenoid valve modules  161  to  16   n  being connected to the communication module  12 , the end portion of the second branch switching line  46  of each of the solenoid valve modules  161  to  16   n  is connected to the end portion of the first branch switching line  44  of the next-stage solenoid valve module. However, in the terminal solenoid valve module  16   n,  since there is no solenoid valve module of the next stage, the end portion of the second branch switching line  46  is open. 
     Accordingly, the output enable terminals  30  of the second communication circuits  24  of the solenoid valve modules other than the terminal solenoid valve module  16   n  are connected to the switching line  42 . Specifically, the output enable terminal  30  of each of the solenoid valve modules is connected, via the second branch switching line  46  of that solenoid valve module and the first branch switching line  44  of the next-stage solenoid valve module, to the divided switching line of the next-stage solenoid valve module. 
     On the other hand, the output enable terminal  30  of the second communication circuit  24  of the terminal solenoid valve module  16   n  is separated from the switching line  42 . A High signal is input to the output enable terminal  30  connected to the switching line  42 , and a Low signal is input to the output enable terminal  30  separated from the switching line  42 . 
     When a High signal is input to the output enable terminal  30 , the second communication circuit  24  sets the output terminal  28  to high impedance regardless of the signal input to the input terminal  26 . On the other hand, when a Low signal is input to the output enable terminal  30 , the second communication circuit  24  outputs the same signal as the signal input to the input terminal  26 , from the output terminal  28 . That is, the second communication circuit  24  outputs a Low signal from the output terminal  28  when a Low signal is input to the input terminal  26 , and outputs a High signal from the output terminal  28  when a High signal is input to the input terminal  26 . 
     Therefore, in the solenoid valve modules other than the terminal solenoid valve module  16   n,  the output terminals  28  of the second communication circuits  24  are in a high impedance state. Therefore, the second communication circuits  24  are disconnected from the fourth divided communication lines, and no signal is transmitted to the receiving line  40 . 
     On the other hand, in the terminal solenoid valve module  16   n,  the signal transmitted from the first communication circuit  22  to the third divided communication line  38   n  is transmitted to the fourth divided communication line  40   n  constituting the receiving line  40 , via the first connection line  48 , the second communication circuit  24 , and the second connection line  50 . That is, the terminal solenoid valve module  16   n  transmits the signal, which is transmitted through the third communication line  38 , to the communication module  12  through the receiving line  40 . 
     As a result, the solenoid valve control signal and the signals related to the diagnostic information of all the solenoid valve modules  161  to  16   n  are fed back to the communication module  12 , and the communication module  12  can grasp the diagnostic information of the respective solenoid valve modules  161  to  16   n.  In  FIG.  1   , the flow of the solenoid valve control signal and the signals related to the diagnostic information are indicated by arrows. 
     Each of the solenoid valve modules  161  to  16   n  includes a solenoid valve control circuit power line  47  that branches from corresponding one of the divided switching lines  421  to  42   n  and reaches the solenoid valve control circuit  20 . Electric power necessary for the operation of the solenoid valve control circuit  20  of each of the solenoid valve modules  161  to  16   n  is supplied from the control system power supply  62  via the control circuit  14  of the communication module  12 , the switching line  42 , and the solenoid valve control circuit power line  47 . 
     A signal transmission system between the communication module  12  and the plurality of solenoid valve modules  161  to  16   n  through the transmission line  32  and the receiving line  40  is a system in which serial peripheral interface (SPI) communication is performed in a daisy chain mode. The first communication circuit  22  of each of the solenoid valve modules  161  to  16   n  is constituted by a communication IC in which SPI communication can be connected in a daisy chain mode. 
     According to the present embodiment, since the switching line  42  and the second communication circuit  24  are provided, the signals related to the diagnostic information of the plurality of solenoid valve modules  161  to  16   n  are automatically transmitted from the terminal solenoid valve module  16   n  to the communication module  12 . As a result, the communication module  12  can grasp the diagnostic information of the plurality of solenoid valve modules  161  to the  16   n.  Further, a communication line for feeding back the diagnostic information of the plurality of solenoid valve modules  161  to the  16   n  to the communication module  12  is not particularly required. In addition, even if the terminal solenoid valve module is changed by adding a solenoid valve module, the signal transmission path is automatically switched, and therefore, it is not necessary to give a special instruction to the terminal solenoid valve module. 
     Moreover, transmission of signals between the communication module  12  and the plurality of solenoid valve modules  161  to  16   n  is performed through the transmission line  32  and the receiving line  40  that cross these modules. As a result, the number of communication lines required to transmit signals between the communication module  12  and the plurality of solenoid valve modules  161  to  16   n  can be reduced as much as possible. In the present embodiment, the solenoid valve control signal and the signals related to the diagnostic information can be transmitted through a total of four communication lines including the communication lines constituting the transmission line  32  and the communication line constituting the receiving line  40 . 
     The present invention is not limited to the embodiment described above, and various configurations may be adopted therein without deviating from the essence and gist of the present invention.