JP2013040653A - Solenoid valve drive circuit, and solenoid valve unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a solenoid valve drive circuit whose circuit board can be miniaturized while suppressing the deterioration of precision in controlling a drive current.SOLUTION: A microcomputer 46 is provided in a solenoid valve circuit 40A, and a voltage divider circuit 48 connected to a power source terminal 41 is connected to the microcomputer 46. The microcomputer 46 sets a value of a current made to flow through a solenoid coil 32 and understands an input voltage value Vin of the power source terminal 41 from a split voltage value Vad of the voltage divider circuit 48. Then, the microcomputer 46 performs the duty control of turning ON/OFF of a MOSFET 45 on the basis of the input voltage value Vin so that the current of the set value may flow through the solenoid coil 32.

Description

  The present invention relates to a solenoid valve drive circuit that drives a solenoid valve, and a solenoid valve unit that includes the solenoid valve drive circuit.

  2. Description of the Related Art Conventionally, as an electromagnetic valve driving circuit that drives an electromagnetic valve provided in the middle of a flow path, there is one that performs feedback control of a current flowing through a solenoid coil included in the electromagnetic valve (see, for example, Patent Document 1). In this electromagnetic valve drive circuit, the current flowing through the solenoid coil is detected by the current detection unit, and the detected current value is fed back to the switch control unit. Then, the switch control unit generates a pulse signal based on the comparison between the feedback current detection value and the optimum current value, and applies a voltage to the solenoid coil for a time corresponding to the pulse width.

Japanese Patent No. 4359855

  However, the solenoid valve drive circuit described in Patent Document 1 requires a current detection circuit and a comparison circuit as long as feedback control is executed. A detection resistor provided for current detection is connected in series with the solenoid coil. For this reason, it is necessary to reduce the resistance value of the detection resistor in order to ensure the drive current of the solenoid coil. In this case, however, the potential difference between both ends of the resistor is also reduced, so that an additional amplifier circuit is also required. Then, it is inevitable that the substrate on which the solenoid valve driving circuit is formed is increased in size by providing a current detection circuit, an amplification circuit, a comparison circuit, and the like. As a result, the miniaturization of the solenoid valve provided with the solenoid valve drive circuit is hindered.

  The present invention has been made in view of such circumstances, and a main object of the present invention is to provide an electromagnetic valve driving circuit capable of downsizing a circuit board while suppressing a decrease in accuracy of controlling a driving current. There is to do. Moreover, the electromagnetic valve unit provided with the electromagnetic valve drive circuit is provided as a subordinate object.

  The present invention employs the following means in order to solve the above problems.

  The first means is an electromagnetic valve drive circuit for driving an electromagnetic valve having a solenoid coil based on a voltage applied from a DC power supply, and a detection terminal connected to the DC power supply, and the solenoid coil in series. A switching element connected to the DC power source for turning on and off the application of a voltage from the DC power source to the solenoid coil, a terminal voltage detecting means for detecting a terminal voltage value of the detection terminal, and a preset current setting Switch control means for duty-controlling on / off of the switching element based on the terminal voltage value so as to cause a current of a value to flow through the solenoid coil.

  According to the above configuration, the solenoid valve having the solenoid coil is driven by the solenoid valve drive circuit based on the voltage applied from the DC power supply. A solenoid coil and a switching element are connected in series to the DC power supply, and the switching element turns on and off the application of voltage from the DC power supply to the solenoid coil.

  Here, a detection terminal is connected to the DC power source, and a terminal voltage value which is a voltage value of the detection terminal is detected. Then, on / off of the switching element is duty-controlled based on this terminal voltage value so that a current having a preset current set value flows through the solenoid coil.

  For this reason, when the voltage applied from the DC power supply changes, the detected terminal voltage value changes, and on / off of the switching element is duty-controlled based on this terminal voltage value. Therefore, even if the voltage applied from the DC power supply changes, the current of the current set value can be passed through the solenoid coil. As a result, the DC power supply is not limited to a specific voltage value, and can cope with a wide range of voltages, and can suppress a reduction in the accuracy of controlling the current flowing through the solenoid coil.

  And, as a result of performing open loop control with such a solenoid valve drive circuit having a free power supply, the circuits (current detection circuit, amplifier circuit, comparison circuit, etc.) necessary for feedback control become unnecessary. As a result, the configuration of the solenoid valve drive circuit is simplified, and the substrate on which the circuit is provided can be downsized.

  In the second means, the terminal voltage detection means includes a plurality of voltage dividing resistors connected in series to each other, and the voltage dividing resistors are connected to the DC power source in parallel with the solenoid coil, and the detection The terminal is connected between the plurality of voltage dividing resistors.

  According to the above configuration, since the voltage dividing resistor is connected to the DC power supply in parallel with the solenoid coil, the coil voltage does not decrease due to the voltage dividing resistor, and the resistance value of the voltage dividing resistor can be increased. Thereby, the current flowing through the voltage dividing resistor can be reduced, and the current flowing through the solenoid coil can be increased. For this reason, the power consumption in the voltage dividing resistor can be reduced, and the power loss of the solenoid valve drive circuit by the terminal voltage detecting means can be reduced. Furthermore, since the detection terminal is connected between the plurality of voltage dividing resistors, the terminal voltage value of the detection terminal is determined by the ratio of the plurality of voltage dividing resistors, and the amplifier circuit can be omitted.

  In the third means, when the voltage applied from the DC power source becomes a preset maximum voltage, the plurality of voltage divisions so that the terminal voltage value becomes the maximum allowable voltage of the terminal voltage detection means. The resistance ratio is set.

  According to the above configuration, the amplifier circuit for amplifying the terminal voltage value can be omitted, and the fluctuation range (dynamic range) of the terminal voltage value can be maximized. As a result, the accuracy of duty control based on the terminal voltage value can be improved.

  In the fourth means, the switch control means controls the on / off duty ratio of the switching element to be inversely proportional to the terminal voltage value.

  If the power when the current of the current set value is flowing through the solenoid coil is constant, the voltage and the current are in an inversely proportional relationship. The magnitude of the current is proportional to the on / off duty ratio. Therefore, according to the above configuration, since the ON / OFF duty ratio is controlled to be inversely proportional to the terminal voltage value, even if the voltage applied from the DC power supply changes, the current of the preset current set value is changed to the solenoid. Can flow through the coil.

  The fifth means includes a current value setting means for setting the current setting value assuming a temperature rise of the solenoid coil.

  According to the above configuration, the current set value to be passed through the solenoid coil is set on the assumption that the coil temperature rises in advance. For this reason, even if the resistance value of the solenoid coil increases due to an increase in coil temperature and the current value flowing through the solenoid coil decreases, it is possible to suppress a decrease in the driving force of the solenoid valve. In particular, in the configuration in which the switch control means controls the current value flowing through the solenoid coil by open loop control, unlike the feedback control, the current value flowing through the solenoid coil cannot be reflected in the control. For this reason, if the current value is set on the assumption of a rise in coil temperature as in the case of this means, the effect of suppressing a decrease in accuracy of controlling the drive current is great.

  In the sixth means, the current value setting means includes a reference temperature that is a reference temperature before energizing the solenoid coil, and the solenoid coil is heated to a temperature that is higher than the reference temperature as the solenoid coil is energized. A coil saturation temperature, which is a temperature that is increased and saturated, and a minimum required current value that is a minimum current value required for the solenoid coil even when the solenoid coil is heated to the coil saturation temperature; The current setting value is set based on

  According to the above configuration, since the current set value is set in consideration of the temperature rise of the solenoid coil accompanying energization, even if the solenoid coil temperature rises from the reference temperature to the coil saturation temperature, the solenoid coil The minimum required current value that is the minimum required current value can be secured. For this reason, the magnetic attractive force by a solenoid coil and by extension, the drive force of a solenoid valve can be hold | maintained reliably.

  In the seventh means, the highest ambient temperature, which is the highest value assumed as the ambient temperature of the solenoid coil, is used as a parameter, and the current value setting means sets the maximum ambient temperature to a coil temperature due to energization of the solenoid coil. The coil saturation temperature is calculated by adding the increased value.

  Since the temperature around the solenoid coil may vary depending on where the solenoid valve is installed, the coil saturation temperature may be excessively estimated when the maximum ambient temperature is determined uniformly.

  In this regard, according to the above configuration, the maximum ambient temperature is used as a parameter, and the coil saturation temperature is calculated by adding the coil temperature increase value due to energization of the solenoid coil to the maximum ambient temperature. For this reason, coil saturation temperature can be grasped | ascertained correctly and by extension, an electric current setting value can be set appropriately.

  In an eighth means, an energization coefficient indicating a ratio of energization time compared to continuous energization in the solenoid coil, and an operation frequency which is the number of on / off times per predetermined time of a voltage applied from the DC power source to the solenoid coil. First temperature rise value correcting means for correcting the coil temperature rise value based on the energization coefficient and the operation frequency as parameters is provided.

  As a drive mode of the solenoid valve, there is a case where the solenoid coil is switched on and off instead of being continuously energized to be always on. In such a case, since the temperature of the solenoid coil does not rise as in the case of continuous energization, the coil saturation temperature also becomes lower, the current value set by the current value setting means can be reduced, and power saving is achieved. Even when the voltage applied to the solenoid coil is turned on / off, the temperature rise of the solenoid coil changes according to the operation frequency, which is the number of on / off times per predetermined time. For example, even with the same duty ratio and the same energization coefficient, when the operation frequency is low, the continuous energization time becomes longer than when it is high, and the temperature rise of the solenoid coil is promoted.

  In this regard, according to the above configuration, the coil temperature increase value is corrected based on the energization coefficient indicating the ratio of energization time compared to continuous energization in the solenoid coil and the operation frequency. Therefore, power saving can be realized by reducing the current set value.

  Specifically, as in the ninth means, the first temperature increase value correcting means increases the coil temperature increase value as the energization coefficient increases, and increases the coil temperature increase value as the operation frequency increases. A configuration of reducing the size can be employed.

  In the tenth means, when the current set value set by the current value setting means is changed, it is calculated based on the changed current set value and the resistance value of the solenoid coil at the reference temperature. And a second temperature increase value correcting means for correcting the coil temperature increase value by multiplying the power consumption of the solenoid coil by a heat dissipation coefficient specific to the solenoid coil.

  Since the coil temperature rise value fluctuates according to the power consumption of the solenoid coil, when the current set value is changed, the numerical value of the power consumption also changes and the coil temperature rise value also changes. Here, the coil temperature increase value can be calculated by multiplying the power consumption of the coil by the heat dissipation coefficient unique to the solenoid coil.

  In this regard, according to the above configuration, the power consumption of the solenoid coil calculated based on the current set value after change and the resistance value of the solenoid coil at the reference temperature is multiplied by the heat dissipation coefficient unique to the solenoid coil. The temperature rise value is corrected. Then, the coil saturation temperature is calculated using the corrected coil temperature increase value, and the current setting value can be reset based on the coil saturation temperature. Therefore, the current set value can be set smaller, and power can be saved without causing unnecessary current to flow through the solenoid coil.

  According to an eleventh means, in an electromagnetic valve unit having a plurality of electromagnetic valves, the electromagnetic valve driving circuit described in any one of the first to tenth means is provided, and each electromagnetic valve is driven by the electromagnetic valve driving circuit. The

  According to the above configuration, in each solenoid valve included in the solenoid valve unit, the substrate of the solenoid valve drive circuit is miniaturized while suppressing a decrease in accuracy of controlling the drive current, and thus the whole solenoid valve unit can be miniaturized. .

  The twelfth means includes a plurality of solenoid valves provided with the solenoid valve drive circuit described in any one of the first to tenth means, and a wiring connection portion to which wiring connected to an external device is connected, A wiring block having a wiring block circuit for supplying a voltage applied from a DC power source to each solenoid valve, wherein the switching element and the switch control means in the solenoid valve drive circuit are respectively first. The wiring block circuit is connected to the DC power supply in series with the first switching element to turn on and off the application of voltage from the DC power supply to the first switching element. A second switching element; a plurality of steps representing driving stages of the plurality of solenoid valves; and a solenoid included in each solenoid valve in each step. When detecting at least one of the rise and fall of the pulse signal output from the external device to the wiring connection unit, the operation pattern setting means for setting the relationship with the on / off state of the id coil as the operation pattern information, Second switch control means for controlling on / off of the second switching element so that the on / off state of each solenoid coil becomes the on / off state after switching the step of the operation pattern information.

  According to the above configuration, the solenoid valve unit includes the plurality of solenoid valves including the solenoid valve drive circuit described above, and a voltage is supplied to each solenoid valve from the DC power supply through the wiring block circuit. Whenever the second switch control means detects at least one of the rising edge and the falling edge of the pulse signal output from the external device to the wiring connection section, the second switch control means sequentially switches the set operation pattern information steps. Along with this step switching, the solenoid coil of each solenoid valve is turned on and off corresponding to the step after the switching. Then, the solenoid coil that is turned on by this control is controlled by the solenoid valve drive circuit to flow a current having a current set value.

  As described above, in the centralized wiring system in which the power supply to each solenoid coil is controlled to be turned on / off by the wiring block circuit, the on / off switching is performed by a pulse signal from an external device. In this case, among the wirings connecting the external device and the wiring block, one wiring for transmitting the pulse signal is sufficient for the signal line for controlling the electromagnetic valve. Even if the solenoid valve (solenoid coil) increases or decreases, this point does not change. For this reason, the number of signal lines can be reduced and wiring can be saved without using a special control device or peripheral equipment. By reducing the wiring, it is possible to realize a reduction in manufacturing cost, a reduction in man-hours for wiring, and downsizing of the apparatus due to a reduction in wiring space.

  The thirteenth means includes a plurality of solenoid valves, and a wiring block having a wiring connection portion to which wiring connected to an external device is connected, and supplying a voltage applied from the DC power source to each solenoid valve. The electromagnetic valve drive circuit described in any one of the first to tenth means is formed on the wiring block substrate of the wiring block, which is an electromagnetic valve unit, and the plurality of electromagnetic valves are driven. And an operation pattern setting means for setting, as operation pattern information, a relationship between a plurality of steps representing the ON / OFF state of the solenoid coil included in each solenoid valve in each step, and the switch control means is provided from the external device. When at least one of the rising edge and falling edge of the pulse signal output to the wiring connection portion is detected, the solenoid coils are turned on. As off state is off state after switching the steps of the operation pattern information, and controls on and off of the switching element.

  According to the above configuration, similarly to the twelfth means, the signal line for controlling the electromagnetic valve is sufficient for one wiring for transmitting the pulse signal, and wiring saving can be realized. In addition, the solenoid valve driving circuit described above is provided on the wiring block board, and the switch control means not only controls the current value flowing through each solenoid coil, but also performs on / off control of each solenoid coil in accordance with step switching. ing. As described above, when one circuit executes the on / off control of the power supply and the current value control, duplication of elements and means constituting the circuit can be avoided as compared with the case where each is performed by another circuit. Thereby, the number of parts can be reduced and the manufacturing cost can be reduced.

  In the fourteenth means, the wiring connection portion is provided with a parameter input terminal that is connected to the switch control means, and when the switch control means uses the parameter to control the switching element, the parameter is input. It has been.

  According to the above configuration, in the seventh means and the eighth means, when the parameter is input to set the current setting value assuming the temperature rise of the solenoid coil, further wiring saving is achieved. It becomes possible. That is, in the configuration in which each solenoid valve is provided with a solenoid valve drive circuit, parameter input wiring is required in each solenoid valve, whereas in the above configuration, the parameter input terminal provided in the wiring connection portion of the wiring block Thus, the parameter input can be unified. As a result, in a configuration that requires parameter input, wiring can be further reduced.

The perspective view which shows a solenoid valve manifold. The exploded perspective view of a solenoid valve manifold. The disassembled perspective view which shows a single solenoid type solenoid valve block. The circuit diagram which shows a solenoid valve circuit (single solenoid type). The graph which shows the relationship between input voltage value Vin and duty ratio. The circuit diagram which shows the solenoid valve circuit (single solenoid type) of 2nd Embodiment. The functional block diagram which shows the arithmetic processing by a microcomputer. The disassembled perspective view which shows a part of solenoid valve manifold of 3rd Embodiment. The exploded perspective view of a wiring block. The circuit diagram which shows the electric constitution of a solenoid valve manifold. The functional block diagram which shows the control system of a solenoid valve manifold. The table | surface which shows an example of operation | movement pattern information. The time chart which shows the electricity supply control based on the operation pattern information of FIG. The circuit diagram which shows the electric constitution of the modification of a solenoid valve manifold. The time chart which shows the modification of the process which resets a step number in the middle.

[First Embodiment]
Hereinafter, a first embodiment will be described with reference to the drawings. Before describing the solenoid valve drive circuit, first, a solenoid valve driven by the solenoid valve drive circuit and a solenoid valve manifold as a solenoid valve unit formed by connecting a plurality of solenoid valves will be described.

  FIG. 1 is a perspective view showing a solenoid valve manifold, and FIG. 2 is an exploded perspective view of the solenoid valve manifold shown in FIG. As shown in FIGS. 1 and 2, the solenoid valve manifold 10 includes a supply / exhaust block 11, a plurality of solenoid valve blocks 12, and a pair of end blocks 13, and the blocks 11 to 13 are connected on a connecting rail 14. Has been. An air supply / exhaust block 11 is disposed on one side of the connection direction (direction in which the connection rail 14 extends) X of the electromagnetic valve blocks 12 connected in plurality. Then, both ends in the connecting direction X of the block structure composed of the air supply / exhaust block 11 and the plurality of solenoid valve blocks 12 are sandwiched between the end blocks 13. By fixing the end blocks 13 on both sides to the connecting rail 14, all the blocks 11 to 13 are held in an integrated state as the electromagnetic valve manifold 10.

  The solenoid valve manifold 10 has first and second common supply passages 15 and 16 and first and second common exhaust passages 17 and 18. High-pressure air is collectively supplied to each electromagnetic valve block 12 via the common air supply passages 15 and 16, and high-pressure air from each electromagnetic valve block 12 is exhausted collectively via the common exhaust passages 17 and 18. The Inner ports 15a to 18a are formed in each electromagnetic valve block 12 for each flow path, and the internal ports 15a to 18a communicate with each other by connecting the electromagnetic valve blocks 12 to form respective common flow paths 15 to 18. Is done. Openings at both ends of the common flow paths 15 to 18 are closed by the end block 13.

  The air supply / exhaust block 11 has an air supply port 21 and an exhaust port 22. Both ports 21 and 22 are provided on the side surface when the connecting direction X is the front-rear direction, and open toward a direction Y orthogonal to the side surface. The air supply port 21 communicates with the common air supply passages 15 and 16, and high pressure air is supplied from the external supply source to the common air supply passages 15 and 16 through the air supply port 21. The exhaust port 22 communicates with the common exhaust passages 17 and 18, and high-pressure air is exhausted to the outside through the exhaust port 22.

  Each solenoid valve block 12 includes two types, a single solenoid type solenoid valve block 12A having one pilot valve 23 and a double solenoid type solenoid valve block 12B having two pilot valves 23. Each type of solenoid valve block 12A, 12B has the same outer shape. FIGS. 1 and 2 show a combination of both types of solenoid valve blocks 12A and 12B, but only a single solenoid type solenoid valve block 12A or a double solenoid type solenoid valve block 12B can be used. The manifold 10 may be configured. The number of solenoid valve blocks 12 to be connected is also arbitrary.

  FIG. 3 is an exploded perspective view showing a single solenoid type solenoid valve block 12A. As shown in FIG. 3, the electromagnetic valve block 12 </ b> A includes a base portion 24, the pilot valve 23, an electrical cover 25, a main valve portion 26, and an output port portion 27. The solenoid valve block 12A assembled with these is formed in a thin rectangular parallelepiped shape as a whole (see FIG. 2).

  A valve attachment portion 31 is formed on the base portion 24 so as to be partially removed, and the pilot valve 23 is attached to the valve attachment portion 31. The pilot valve 23 incorporates a pilot valve body, a solenoid coil 32 (see FIG. 4 described later), and a plunger (movable iron core). In the pilot valve 23, the plunger is moved by energization control to the solenoid coil 32, and the pilot valve body is driven to open and close accordingly. That is, when the solenoid coil 32 is energized, the plunger is attracted from its reference position, and when deenergized, the plunger returns to the reference position. With this operation, the pilot valve body is driven to open and close. The first common air supply flow path 15 and the first common exhaust flow path 17 are flow paths for supplying and exhausting operating air to and from the pilot valve 23, and are provided in the base portion 24. Then, the opening and closing of the pilot valve body is driven to control the supply and discharge of operating air to the main valve portion 26.

  In order to control energization of the solenoid coil 32, the pilot valve 23 is electrically connected to the electromagnetic valve substrate 34 via the connection terminal 33. By attaching the electrical cover 25, the electromagnetic valve substrate 34 is covered, and the assembled state of the pilot valve 23 is also maintained. The electrical cover 25 is provided with a connector connection portion 36 having external connection terminals (a power supply terminal 41 and a ground terminal 42 described later) of the electromagnetic valve substrate 34. The connector K of the lead wire L is connected to the connector connecting portion 36 (see FIG. 2).

  The main valve portion 26 has a built-in spool valve. The position of the spool valve is switched by operating air that is supplied and discharged by the pilot valve 23. The output port portion 27 is provided with an output port 37. When the position of the spool valve is controlled to be switched by the main valve portion 26, the output port 37 is connected to the second common supply passage 16 or the second common exhaust passage. It communicates with the flow path 18. If the output port 37 communicates with the second common air supply channel 16, the working air is output from the output port 37. When the output port 37 communicates with the second common exhaust flow path 18, the output of the working air from the output port 37 is stopped. Each output port 37 of each solenoid valve block 12 is connected to an external device (for example, a pneumatic cylinder or the like) through a pipe, and driving of the external device is controlled by output control of working air.

  In the double solenoid type solenoid valve block 12B, as shown in FIG. 2, a pair of pilot valves 23 is attached to the base portion 24, a pair of spool valves are provided in the main valve portion 26, and an output port portion 27 is provided. Then, a pair of output ports 37 are provided. In this electromagnetic valve block 12B, the position of one spool valve is switched by one pilot valve, and the position of the other spool valve is switched by the other pilot valve. Thereby, the working air output from each output port 37 is controlled.

  As described above, the solenoid valve manifold 10 is configured. Next, an electromagnetic valve circuit as an electromagnetic valve driving circuit formed on the electromagnetic valve substrate 34 in each of the electromagnetic valve blocks 12A and 12B will be described. First, a single solenoid type configuration will be described.

  FIG. 4 is a circuit diagram showing a solenoid valve circuit in the single solenoid type solenoid valve block 12A. As shown in the figure, the electromagnetic valve circuit 40A has a power terminal 41 connected to a DC power source and a ground terminal 42 connected to ground. The electromagnetic valve circuit 40A is connected to the solenoid coil 32 through the connection terminal 33 (see FIG. 3) of the pilot valve 23. Then, one end of the solenoid coil 32 is connected to the power supply terminal 41 and the other end of the solenoid coil 32 is connected to the ground terminal 42 via the electromagnetic valve circuit 40A. Between the power supply terminal 41 and one end of the solenoid coil 32, a backflow prevention diode 43 is provided with the direction from the power supply terminal 41 to the solenoid coil 32 as a forward direction.

  The electromagnetic valve circuit 40 </ b> A includes a reflux diode 44, a MOSFET 45, a microcomputer 46 for PWM control, a constant voltage circuit 47, and a voltage dividing circuit 48. The reflux diode 44 is a flywheel diode and is connected in parallel with the solenoid coil 32. The return diode 44 absorbs a surge voltage (back electromotive force) generated when the energization of the solenoid coil 32 is stopped. That is, the surge current is attenuated by the closed circuit formed by the solenoid coil 32 and the return diode 44, thereby suppressing the influence of the surge voltage.

  The MOSFET 45 is a current control switching element (first switching element). The MOSFET 45 is an n-channel type and is connected between the solenoid coil 32 and the ground terminal 42. Specifically, the drain of the MOSFET 45 is connected to the solenoid coil 32 and the source is connected to the ground terminal 42. The gate of the MOSFET 45 is connected to the PWM output terminal of the microcomputer 46 and is connected to the ground terminal 42 via a pull-down resistor 49.

  Here, the microcomputer 46 outputs a PWM control signal to switch the MOSFET 45, and the switching operation mode of the MOSFET 45 is variably set by adjusting the duty ratio of the PWM control signal. Therefore, the microcomputer 46 corresponds to switch control means (first switch control means). A predetermined current flows through the solenoid coil 32 by the switching operation of the MOSFET 45. Note that the MOSFET 45 is completely turned off by the pull-down resistor 49 in a state where the PWM control signal is not output from the microcomputer 46 due to the power supply to the electromagnetic valve circuit 40 being turned off.

  The constant voltage circuit 47 is a circuit that generates a constant voltage as a driving power source for the microcomputer 46, and includes an NPN bipolar transistor (transistor) 51, a Zener diode 52, a resistor 53, and a capacitor 54. The collector of the transistor 51 is connected to the power supply terminal 41 through a diode 55 for preventing backflow, and the emitter is connected to the power supply input port (Vcc input port) of the microcomputer 46 and the capacitor 54. The collector and base of the transistor 51 are connected via a resistor 53. The base of the transistor 51 is connected to the cathode side of the Zener diode 52. The anode side of the Zener diode 52 is connected to the ground terminal 42. Note that the breakdown voltage of the Zener diode 52 is set to the drive voltage Vcc of the microcomputer 46, and the resistor 53 is set to a value that can suppress the current consumption of the Zener diode 52.

  According to such a constant voltage circuit 47, when a predetermined voltage is applied to the power supply terminal 41, the drive voltage Vcc is supplied to the microcomputer 46 through the transistor 51. At that time, the drive voltage Vcc stabilized by the capacitor 54 is supplied to the microcomputer 46. The ground port (GND port) of the microcomputer 46 is connected to the ground terminal 42.

  The duty ratio of the PWM control signal output from the microcomputer 46 is adjusted based on the input voltage value Vin applied to the power supply terminal 41. In this case, the microcomputer 46 performs a calculation using the input voltage value Vin applied to the power supply terminal 41 and a current setting value I0 set in advance as a current value for energizing the solenoid coil 32 as arguments. The calculation is performed by the following equation (1).

Duty ratio (%) = (I0 × R0) / Vin × 100 (1)
Here, R0 is the reference resistance value of the solenoid coil 32 at the reference temperature T0 (for example, 20 ° C.), and is calculated from the current value Icmax flowing through the solenoid coil 32 when the input voltage value Vin is the maximum value Vinmax. The reference temperature T0 is a reference temperature before energization of the solenoid coil 32.

  The voltage dividing circuit 48 is a circuit that generates a divided voltage Vad taken into the microcomputer 46. That is, the microcomputer 46 grasps the input voltage value Vin by the divided voltage Vad (terminal voltage value). One end of the voltage dividing circuit 48 is connected to the power supply terminal 41 via the diode 43 for preventing backflow, and the other end of the voltage dividing circuit 48 is connected to the ground terminal 42. The voltage dividing circuit 48 is connected to a DC power supply in parallel with the solenoid coil 32. The voltage dividing circuit 48 includes two voltage dividing resistors 56 and 57 connected in series with each other, and a voltage dividing point 58 between the first voltage dividing resistor 56 and the second voltage dividing resistor 57 is a microcomputer. It is connected to 46 analog input ports (AD ports). Therefore, the divided voltage Vad of the voltage dividing circuit 48 is input to the microcomputer 46, and the microcomputer 46 grasps the input voltage value Vin based on the divided voltage Vad. For this reason, the microcomputer 46 corresponds to a terminal voltage detection means, and the voltage dividing point 58 corresponds to a detection terminal.

  The ratio (R1: R2) between the first voltage dividing resistor 56 (R1) and the second voltage dividing resistor 57 (R2) is obtained by previously calculating the maximum input voltage value Vinmax and the maximum allowable voltage Vadmax input to the microcomputer 46. It is set and calculated from the following voltage (2) from both voltages.

R1: R2 = (Vinmax−Vadmax): Vadmax (2)
Therefore, for example, if the maximum input voltage value Vinmax is 30 V and the maximum allowable voltage Vadmax is 5 V, the ratio of the voltage dividing resistance value is 5: 1. Since current always flows through the voltage dividing circuit 48, it is desirable to increase the combined resistance of the voltage dividing resistors 56 and 57 in order to minimize the power loss caused thereby. For example, the resistance value of the voltage dividing resistor 56 is 500 kΩ, and the resistance value of the voltage dividing resistor 57 is 100 kΩ.

  FIG. 5 is a graph showing the relationship between the input voltage value Vin and the duty ratio. When the reference resistance value R0 of the solenoid coil 32 is 300Ω and the current setting value I0 (25 mA) is adjusted to flow, the measured value of the duty ratio for each input voltage is shown. According to the equation (1) described above, if the current setting value I0 and the reference resistance value R0 of the solenoid coil 32 are constant, the duty ratio is inversely proportional to the input voltage value Vin. Such a relationship is also shown in the graph of FIG. In the specific example shown in the graph of FIG. 5, when the input voltage value Vin is lower than 7.5V, the current setting value I0 of 25 mA cannot be obtained. For this reason, the region where the input voltage value Vin is lower than 7.5V is a non-settable region.

  As described above, in the electromagnetic valve circuit 40A, the PWM control according to the input voltage value Vin is performed in an open loop. That is, the duty ratio is adjusted based on the input voltage value Vin, and the driving of the MOSFET 45 is controlled so that the current of the current set value I0 flows through the solenoid coil 32. Thereby, the driving force of the plunger in the pilot valve 23 is ensured.

  Note that the double solenoid type solenoid valve circuit has two single solenoid type solenoid valve circuits 40A described above. Here, the microcomputer 46, the constant voltage circuit 47 serving as a power supply path to the microcomputer 46, and the ground terminal 42 are shared. Since the power supply path to the other solenoid coil 32 is increased, as shown in FIG. 2, in the case of the double solenoid type solenoid valve block 12B, the lead wire L is increased by one to three. Since the other configuration is the same as that of the single solenoid type solenoid valve circuit 40A, further detailed description is omitted.

  According to the electromagnetic valve circuit 40 in the first embodiment described in detail above, the following advantageous effects can be obtained.

  (1a) In order to cause the current of the current set value I0 to flow through the solenoid coil 32, the microcomputer 46 determines the MOSFET 45 based on the input voltage value Vin, in other words, based on the divided voltage Vad reflecting the input voltage value Vin. ON / OFF duty control. If the divided voltage value Vad changes with the change of the input voltage value Vin, the microcomputer 46 performs duty control on and off of the MOSFET 45 based on the changed divided voltage Vad. Therefore, even if the voltage applied from the DC power source changes, the current of the current set value I 0 can be passed through the solenoid coil 32. As a result, the DC power supply is not limited to a specific voltage value, and can cope with a wide range of input voltages, and it can be suppressed that the accuracy of controlling the current flowing through the solenoid coil 32 is lowered.

  (1b) Since open-loop control is performed by such a solenoid valve circuit 40 having a free power supply, circuits (current detection circuit, amplification circuit, comparison circuit, etc.) necessary for feedback control are not necessary. Thereby, the structure of the solenoid valve circuit 40 is simplified, and the solenoid valve substrate 34 provided with the circuit can be downsized. Further, since the current detection circuit is unnecessary, it is not necessary to connect the current detection resistor constituting the circuit to the solenoid coil 32 in series. For this reason, a voltage drop due to the current detection resistor can be avoided.

  (1c) The solenoid valve circuit 40 includes a voltage dividing circuit 48 connected to a DC power supply in parallel with the solenoid coil 32, and the microcomputer 46 grasps the input voltage value Vin based on the divided voltage Vad. In this configuration, since the solenoid coil 32 and the voltage dividing resistors 56 and 57 are connected in parallel to the DC power supply, the resistance values of the voltage dividing resistors 56 and 57 can be increased. Thereby, the current flowing through the voltage dividing resistors 56 and 57 can be reduced, and the current flowing through the solenoid coil 32 can be increased. For this reason, the power consumption in the voltage dividing resistors 56 and 57 can be reduced, and the power loss of the solenoid valve circuit 40 can be reduced. Further, the divided voltage Vad is determined by the ratio of the plurality of voltage dividing resistors 56 and 57, and the amplifier circuit can be omitted.

  (1d) In the voltage dividing circuit 48, when the voltage applied from the DC power source becomes a preset maximum voltage, the voltage dividing resistor 56 is set so that the divided voltage Vad becomes the maximum allowable voltage Vadmax of the microcomputer 46. , 57 is set. For this reason, the amplifier circuit for amplifying the divided voltage Vad can be omitted, and the fluctuation range (dynamic range) of the divided voltage Vad can be maximized. As a result, the accuracy of duty control based on the divided voltage Vad can be improved.

  (1e) In performing the control of the MOSFET 45, the microcomputer 46 controls the on / off duty ratio of the MOSFET 45 to be inversely proportional to the input voltage value Vin (in other words, the divided voltage value Vad). Here, assuming that the electric power when the current of the current set value I0 flows through the solenoid coil 32 is constant, the voltage and the current are in an inversely proportional relationship. The magnitude of the current is proportional to the on / off duty ratio. Therefore, if the ON / OFF duty ratio is controlled to be inversely proportional to the input voltage value Vin (divided voltage Vad), even if the voltage applied from the DC power supply changes, the current of the preset current setting value I0 is changed. It can flow through the solenoid coil 32.

  (1f) In feedback control, even if the resistance value rises due to heat generation of the solenoid coil 32, control is performed so that more current flows so that the current of the current set value flows to the solenoid coil 32. For this reason, “coil heat generation → current increase” is repeated, and there is a problem that heat generation and power consumption of the solenoid coil 32 are excessively increased. On the other hand, according to the solenoid valve circuit 40, since the open loop control is performed, such a problem can be solved.

  In addition, you may implement the said 1st Embodiment with the form shown as a modification below.

  In the first embodiment, the microcomputer 46 calculates the duty ratio by substituting the input voltage value Vin and the current setting value I0 into the above equation (1). However, the microcomputer 46 calculates the duty ratio based on the map data. It may be. In this case, the relationship between the input voltage value Vin and the current set value I0 and the duty ratio is obtained in advance by experiment, and is converted into map data and stored in advance in the internal memory of the microcomputer 46. Then, the microcomputer 46 calculates the optimum value of the duty ratio from the map data based on the detected input voltage value Vin and the current set value I0.

  In the first embodiment, the PWM control signal is output to the MOSFET 45 by the duty ratio calculation of the microcomputer 46. In addition to this, a signal output terminal is provided separately, and the signal output terminal is connected to the output port of the microcomputer 46. It may be connected to output the PWM control signal to the outside of the circuit. Thereby, the output status of the PWM control signal can be grasped by an external device, and the control status can be monitored.

  In the first embodiment, the constant voltage circuit 47 includes the transistor 51, the Zener diode 52, the resistor 53, and the capacitor 54. However, the constant voltage circuit 47 may include other elements. For example, a constant voltage circuit using a constant current diode can be considered. In addition, a bipolar transistor or the like may be used instead of the MOSFET 45 for the switching element (first switching element).

  In the first embodiment, the working air is exhausted from the exhaust port 22 of the air supply / exhaust block 11 to the outside. However, the exhaust port 22 may be connected to a vacuum suction device to be evacuated. In this case, the output port 37 of the electromagnetic valve block 12 plays a role as a suction port by being connected to the exhaust port 22 via the second common exhaust passage 18. Thereby, not only the output of working air but also air suction can be performed, and the application can be expanded.

  In the first embodiment, the voltage dividing circuit 48 includes the two voltage dividing resistors 56 and 57. However, a configuration including three or more voltage dividing resistors may be employed. In this case, a voltage dividing point corresponding to the detection terminal may be provided between any voltage dividing resistors, but the voltage dividing ratio is input to the analog input port of the microcomputer 46 when the input voltage value Vin is the maximum value Vinmax. It is desirable to set the divided voltage Vad to be the maximum allowable voltage Vadmax. A configuration in which the divided voltage Vad is smaller than the maximum allowable voltage Vadmax when the input voltage value Vin is the maximum value Vinmax may be employed.

  In the first embodiment, the pull-down resistor 49 is provided so that the MOSFET 45 is turned off when the microcomputer output is off. Instead, the gate of the MOSFET 45 is connected to the power source of the microcomputer 46 via the pull-up resistor. A pull-up configuration connected to the input port (emitter of the transistor 51) may be employed. According to this configuration, the solenoid coil 32 can be kept on (energized) at a minimum while the input voltage is being input when the microcomputer output is other than off.

[Second Embodiment]
By the way, in the solenoid valve circuit 40 of the said 1st Embodiment, when calculating a duty ratio from the input voltage value Vin, it does not consider that the temperature of solenoid coil 32 itself rises. Actually, the temperature of the solenoid coil 32 (coil temperature) rises depending on the ambient temperature at the place where the solenoid valve manifold 10 is installed and the use situation such as continuing energization of the solenoid coil 32. Since the increase in coil temperature is accompanied by an increase in the resistance value (coil resistance value) of the solenoid coil 32, the current value (coil current value) flowing through the solenoid coil 32 decreases.

  With respect to this point, with the conventional technique in which the coil current value is detected and feedback controlled, it is possible to perform control such that the duty ratio is increased as the coil current value decreases. On the other hand, in the open loop control such as the solenoid valve circuit 40, even if the actual coil current value decreases due to the increase in coil temperature, it cannot be reflected in the energization control to the solenoid coil 32. On the one hand, this leads to the effects described in the above (1c) and (1f), but on the other hand, there arises a problem that only a current smaller than the current set value I0 can flow.

  As a second embodiment that addresses such a problem, an electromagnetic valve circuit in which the microcomputer 46 sets the current set value I0 in consideration of an increase in coil temperature will be described. Here, the microcomputer 46 also has a function as current value setting means.

  FIG. 6 is a circuit diagram showing the solenoid valve circuit (single solenoid type) of the second embodiment. As shown in FIG. 6, the solenoid valve circuit 60 has substantially the same configuration as the solenoid valve circuit 40 in the first embodiment. Therefore, the same components are denoted by the same reference numerals, description thereof is omitted, and differences between them will be described.

  Various parameters are required for the microcomputer 46 to calculate a current value assuming an increase in coil temperature. Among the necessary parameters, given values such as numerical values and experimental values unique to the solenoid coil 32 are stored in advance in the internal memory 46a of the microcomputer 46. On the other hand, regarding a numerical value that can be changed according to the usage status of the user, it is necessary to input the numerical value to the microcomputer 46. For this reason, the solenoid valve circuit 60 is provided with a parameter input terminal 61, and the parameter input terminal 61 is connected to a parameter input port (PM port) of the microcomputer 46. An external input device is connected to the parameter input terminal 61, and necessary parameters are input to the microcomputer 46 using the external input device. The input parameters are stored in the internal memory 46a of the microcomputer 46.

  Arithmetic processing performed by the microcomputer 46 is as follows.

<1> Calculation of Current Set Value Assuming Coil Temperature Increase As described above, the coil resistance value increases as the coil temperature increases due to energization of the solenoid coil 32. For this reason, the current setting value I0 at the reference temperature T0 is calculated assuming that the coil resistance value increases. Specifically, based on external factors such as vibration and impact on the solenoid coil 32, the usage status of the solenoid valve manifold 10, etc., the current value (minimum necessary for maintaining the driving force in the solenoid valve block 12 ( Obtain the minimum required current value. This is determined as the coil current value Is at the time when the coil temperature rises to the saturation temperature (coil saturation temperature) Ts, and the current setting value I0 is calculated based on the coil current value Is. Thereby, even if the coil temperature rises and the value of the current flowing through the solenoid coil 32 decreases, it is possible to suppress a decrease in driving force in the solenoid valve block 12.

  Here, when the coil temperature rises from the reference temperature T0 to the coil saturation temperature Ts and the coil resistance value rises from the reference resistance value R0 to the saturation resistance value Rs, the coil temperature and the coil resistance value are between There is a relationship of the following formula (3).

R0 / Rs = (234.5 + T0) / (234.5 + Ts) "(3)
In the above, the numerical value “234.5” is a temperature coefficient for calculating the conductor resistance of copper, which is the material of the solenoid coil 32. The coil saturation temperature Ts is a value (Ta + Tb) obtained by adding the temperature rise value (coil temperature rise value) Tb of the solenoid coil 32 to the maximum value (maximum ambient temperature) Ta of the ambient temperature at the place where the solenoid valve manifold 10 is installed. It is. This is because the temperature rise of the solenoid coil 32 depends not only on the temperature rise of the coil itself but also on the ambient temperature. The coil temperature increase value Tb is a temperature increase value when a predetermined current is continuously supplied to the solenoid coil 32.

  When this equation (3) is replaced with the relationship between the current setting value I0 at the reference temperature T0 and the coil current value Is at the coil saturation temperature Ts, the following equation (4) is derived.

Is / I0 = (234.5 + T0) / (234.5 + Ts)
I0 = {(234.5 + Ts) / (234.5 + T0)} × Is (4)
The current set value I0 is calculated by substituting the reference temperature T0, the coil saturation temperature Ts, and the coil current value Is into this equation (4).

  In this case, the reference temperature T0 is set to normal temperature (for example, 20 ° C.), and the coil current value Is is set as a given constant as described above, and is stored in the internal memory 46a of the microcomputer 46. Stored in advance. Among the numerical values necessary for calculating the coil saturation temperature Ts, the coil temperature increase value Tb is preliminarily stored in the internal memory 46a as a provisional value Tbz obtained experimentally on the premise of continuous energization for the solenoid coil 32 to be used. Yes. On the other hand, since the maximum ambient temperature Ta is a numerical value depending on actual user use conditions, it is a parameter input by the user.

<2> Correction of Temporary Coil Temperature Increase Value Tbz Based on Energization Rate and Operation Frequency As described above, the provisional value Tbz on the premise of continuous energization is set in advance as the coil temperature increase value Tb. However, some users may use the solenoid valve manifold 10 while switching between energization and non-energization instead of continuous energization. The coil temperature increase value Tb changes according to the energization rate for the solenoid coil 32. For this reason, it is necessary to correct the coil temperature increase value Tb based on the energization rate. The energization rate is a percentage of the energization time compared to continuous energization.

  In this correction, the energization coefficient B and the operation frequency H are used. The energization coefficient B indicates the ratio of energization time compared to continuous energization, and the operation frequency H is the number of on / off times per predetermined time (for example, 1 minute) of the voltage applied from the DC power source to the solenoid coil 32. Since the energization coefficient B and the operation frequency H are numerical values depending on actual user use conditions, they are parameters input by the user.

  The coil temperature increase value Tb is proportional to the energization coefficient B. If the coil temperature increase value Tb in the case of continuous energization is multiplied by the energization coefficient B, the coil temperature increase value Tb at this energization coefficient B is obtained. .

  However, the coil temperature increase value Tb is also affected by the operation frequency H. For example, even with the same duty ratio and the same energization coefficient B, when the operation frequency H is low, the continuous energization time becomes longer than when it is high, and the temperature rise of the solenoid coil 32 is promoted. For this reason, when calculating the coil temperature increase value Tb in consideration of the energization rate (energization coefficient B), the corrected energization coefficient calculated in consideration of the operation frequency H, not the numerical value of the energization coefficient B input by the user itself. Bh is used. This corrected energization coefficient Bh is calculated by the following equation (5).

Bh = [{− (1-B) / α} × log ₁₀ H] +1 (5)
Α is a coefficient specific to the solenoid coil 32, and is determined by the use situation and the like. This coefficient α is stored in the internal memory 46 a of the microcomputer 46. If the input energization coefficient B and the operation frequency H are substituted into the above equation (5), the corrected energization coefficient Bh is obtained.

  Therefore, by multiplying the corrected energization coefficient Bh by the provisional value Tbz of the coil temperature increase value Tb, a corrected coil temperature increase value Tbh1 corrected in consideration of the energization rate (energization coefficient B) and the operation frequency H is obtained ( Tbh1 = Bh × Tbz). The correction coil temperature increase value Tbh1 calculated in this way is temporarily stored in the internal memory 46a of the microcomputer 46.

<3> Correction of Temperature Rise Value Tb Based on Temporary Current Setting Value I0z In the correction of <2> described above, the provisional value Tbz of the coil temperature rise value Tb is corrected in consideration of the energization rate and the operation frequency H, and the correction coil temperature is corrected. An increase value Tbh1 is obtained. Here, the provisional current set value I0z is calculated using the correction coil temperature increase value Tbh1, and the correction based on the provisional current set value I0z will be described.

  Such correction is necessary for the following reason. That is, according to the above equation (4), when the coil temperature increase value Tb is changed by correction, the current set value I0 is also changed. Since the coil temperature increase value Tb varies according to the power consumption W of the solenoid coil 32, when the current set value I0 is changed, the numerical value of the power consumption W also changes and the coil temperature increase value Tb also changes. For this reason, it is necessary to reflect the fluctuations in the current setting value I0 and the power consumption W caused by the change from the provisional value Tbz to the correction coil temperature rise value Tbh1 in the change in the coil temperature rise value Tb accompanying the fluctuation.

  In this case, the provisional coil saturation temperature Tsz is calculated by adding the correction coil temperature increase value Tbh1 to the maximum ambient temperature Ta input by the user, and this is substituted into the above equation (4) to obtain the provisional current setting value. Obtain I0z. Then, the recorrected coil temperature rise value Tbh2 is calculated using the relationship between the coil temperature rise value Tb and the power consumption W of the solenoid coil 32.

  That is, the relationship of the following equation (6) exists between the coil temperature increase value Tb and the power consumption W of the solenoid coil 32.

Tb = A × W (6)
In this equation (6), A is a heat dissipation coefficient specific to the solenoid coil 32. The current value I, the temperature rise value Tb due to continuous energization at this current value I, and the reference resistance value R0 of the solenoid coil 32 are Is used to calculate. W is power, and W = I × I × R0. By substituting these values into “A = Tb / W”, the heat dissipation coefficient A is calculated. For example, when the reference resistance value R0 of the solenoid coil 32 is 300Ω, the coil temperature increase value Tb when the current value I is continuously energized at 25 mA is 30 ° C., so the heat dissipation coefficient A can be calculated as 158. The heat dissipation coefficient A obtained in this way is stored in advance in the internal memory 46a of the microcomputer 46.

  If the heat dissipation coefficient A and the power consumption W (I0z × I0z × R0) of the solenoid coil 32 at the provisional current set value I0z are substituted into the above equation (6), the recorrected coil temperature increase value Tbh2 can be calculated. . The recorrected coil temperature rise value Tbh2 is temporarily stored in the internal memory 46a of the microcomputer 46.

<4> Calculation of current set value I0 based on recorrected coil temperature rise value Tbh2 The provisional value Tbz of the coil temperature rise value Tb is subjected to the above-described two corrections to obtain the recorrected coil temperature rise value Tbh2. Using this re-correction coil temperature rise value Tbh2, a current set value I0 at the reference temperature T0 is calculated. In this case, the re-correction coil temperature increase value Tbh2 is added to the maximum ambient temperature Ta input by the user to calculate the coil saturation temperature Ts, and this is substituted into the above equation (4). This current set value I0 is also temporarily stored in the internal memory 46a of the microcomputer 46.

<5> Overall Flow of Calculation Processing Next, the flow of the entire temperature correction calculation processing performed by the microcomputer 46 will be described based on the above <1> to <4>. FIG. 7 is a functional block diagram showing such calculation processing.

  As shown in FIG. 7, in the first temperature increase value calculation unit 62 in this calculation process, the provisional value Tbz of the coil temperature increase value Tb is corrected based on the energization coefficient B and the operating frequency H, and the corrected coil temperature increase value Tbh1. Is calculated. Specifically, the coefficient α stored in the internal memory 46a of the microcomputer 46, the energization coefficient B and the operation frequency H input as parameters by the user are substituted into the above-described equation (5), and the corrected energization coefficient Bh is obtained. calculate. Then, the corrected energization coefficient Bh is multiplied by the provisional value Tbz stored in the internal memory 46a (Bh × Tbz) to obtain a corrected coil temperature increase value Tbh1. Therefore, the first temperature rise value calculation unit 62 corresponds to first temperature rise value correction means.

  The subsequent provisional current set value calculation unit 63 calculates a provisional current set value I0z based on the correction coil temperature increase value Tbh1 so as to perform correction in consideration of the increase in coil temperature in accordance with the magnitude of the current value. . In this case, first, the correction coil temperature increase value Tbh1 is added to the maximum ambient temperature Ta input as a parameter by the user to calculate a temporary coil saturation temperature Tsz (Tsz = Ta + Tbh1). The provisional current set value I0z is obtained by substituting the provisional coil saturation temperature Tsz, the reference temperature T0, and the coil current value Is, which is the minimum necessary current value, into the aforementioned equation (4).

  Further, the second temperature increase value calculation unit 64 continues to calculate the coil temperature increase value Tb of the solenoid coil 32 at the temporary current set value I0z, that is, the recorrected coil temperature increase value Tbh2, and correct the coil temperature increase value Tb again. To do. In this case, the re-corrected coil temperature increase value Tbh2 is obtained by substituting the provisional current set value I0z, the heat radiation coefficient A, and the reference resistance value R0 into the above-described equation (6). Therefore, the second temperature rise value calculation unit 64 corresponds to a second temperature rise value correction unit.

  Thereafter, the current set value calculation unit 65 calculates the current set value I0 based on the recorrected coil temperature rise value Tbh2 obtained through the two corrections as described above. In this case, first, the re-correction coil temperature increase value Tbh2 is added to the maximum ambient temperature Ta, thereby obtaining the coil saturation temperature Ts (Ts = Ta + Tbh2). The coil saturation temperature Ts, the reference temperature T0, and the coil current value Is are substituted into the aforementioned equation (4) to obtain a current set value I0.

  The duty ratio calculation unit 66 calculates the duty ratio based on the current setting value I0. In this case, the duty ratio is calculated by substituting the current set value I0 and the input voltage value Vin applied to the power supply terminal 41 into the aforementioned equation (1). Then, the microcomputer 46 performs PWM control of switching of the MOSFET 45 based on the calculated duty ratio.

  In the electromagnetic valve circuit 60 of the second embodiment described in detail above, the following advantageous effects are obtained in addition to the effects (1a) to (1d) and (1f).

  (2a) In the electromagnetic valve circuit 60 that performs open-loop control of the current flowing through the solenoid coil 32, the microcomputer 46 sets the current set value I0 assuming that the temperature of the solenoid coil 32 rises. For this reason, even if the current value decreases due to an increase in coil temperature, it is possible to suppress a decrease in driving force in the electromagnetic valve block 12. In addition, the current set value I0 is set based on the relational expression (the above formula (4)) that represents the coil temperature rise and the current change accompanying the temperature rise. For this reason, when the current set value I0 is set, a change in the current accompanying an increase in the coil temperature is accurately reflected, so that the accuracy of controlling the current flowing through the solenoid coil 32 can be improved and the power can be saved.

  (2b) The current set value I0 is set based on the reference temperature T0, the coil saturation temperature Ts, and the coil current value Is that defines the minimum required current value. Thus, the current set value I0 is set in consideration of the temperature rise of the solenoid coil 32 due to energization. Therefore, even when the coil temperature rises from the reference temperature T0 to the coil saturation temperature Ts, the solenoid coil 32 is set. Then, the minimum required current value is secured. For this reason, the magnetic attraction force by the solenoid coil 32 and the driving force of the electromagnetic valve block 12 can be reliably held.

  (2c) Since the ambient temperature around the solenoid coil 32 may vary depending on the location where the solenoid valve manifold 10 is installed by the user, when the maximum ambient temperature Ta is determined uniformly, the coil saturation temperature Ts is excessively increased. There is a risk of estimating. In this regard, in the second embodiment, the maximum ambient temperature Ta is input by the user as a parameter, and the coil saturation temperature Ts is calculated by adding the coil temperature increase value Tb to the maximum ambient temperature Ta. For this reason, the coil saturation temperature Ts can be accurately grasped, and the current set value I0 can be appropriately set.

  (2d) The first temperature rise value calculation unit 62 corrects the provisional value Tbz of the coil temperature rise value Tb determined on the basis of the energization coefficient B and the operation frequency H, assuming continuous energization. Specifically, the provisional coil temperature increase value Tbz is increased as the energization coefficient B is increased, and the provisional coil temperature increase value Tbz is decreased as the operation frequency H is increased. Since the current set value I0 is calculated based on the correction coil temperature increase value Tbh1, the current set value I0 can be reduced to realize power saving.

  (2e) Since the coil temperature increase value Tb varies according to the power consumption W of the solenoid coil 32, when the current set value I0 is changed, the value of the power consumption W also changes and the coil temperature increase value Tb also changes. . Therefore, the provisional current set value I0z is calculated based on the correction coil temperature increase value Tbh1, and then the coil temperature is determined by the second temperature increase value calculation unit 64 according to the power consumption W at the provisional current set value I0z. The increase value Tb is corrected to the re-correction coil temperature increase value Tbh2. Since the current set value I0 is set based on the re-correction coil temperature increase value Tbh2, the current set value I0 can be set smaller, and power can be saved without causing unnecessary current to flow through the solenoid coil 32.

  In addition, you may implement the said 2nd Embodiment with the form shown as a modification below.

  In the second embodiment, the provisional coil temperature increase value Tbz is corrected by the first temperature increase value calculation unit 62. However, such correction is not necessary when continuous energization of the solenoid coil 32 is performed. In this case, the provisional current set value calculation unit 63 of the microcomputer 46 calculates the provisional current set value I0z using the provisional coil temperature increase value Tbz.

  In the second embodiment, the coil temperature increase value Tb is corrected to a numerical value corresponding to the power consumption W by the second temperature increase value calculation unit 64, but such correction is not essential. The current setting value I0 may be calculated using the correction coil temperature increase value Tbh1 corrected by the first temperature increase value calculation unit 62.

  In the second embodiment, the maximum ambient temperature Ta is input by the user. However, the ambient temperature at the place where the solenoid valve manifold 10 is installed may be the maximum ambient temperature Ta. In this case, a temperature sensor or the like may be connected to the parameter input terminal 61 so that the detected ambient temperature data is input as the maximum ambient temperature Ta.

  In the second embodiment, the energization coefficient B and the operation frequency H, which are parameters, are input by the user. However, parameters obtained by automatic self-measurement of the electromagnetic valve circuit 40 may be used. For example, the parameter can be obtained by measuring the energization state using an internal counter and an internal timer of the microcomputer 46 and converting the measured value by an internal program.

  As a modification of the first embodiment, the configuration in which the signal output terminal is provided has been described. However, when such a configuration is adopted, a numerical value or the like in which the provisional coil temperature increase value Tbz is corrected is output through the signal output terminal. The calculation status may be monitored.

  In the second embodiment, the solenoid valve circuit 60 sets the current set value I0 assuming an increase in coil temperature on the premise of the solenoid valve circuit 40 of the first embodiment. In other words, a free power supply is provided, and the current flowing through the solenoid coil 32 is controlled in an open loop assuming that the coil temperature rises.

  Instead of this, a current set value I0 that assumes an increase in coil temperature may be set in an electromagnetic valve circuit in which the input voltage value Vin is fixed to a predetermined value without being a free power supply. Specifically, the following configuration can be omitted. That is, a voltage dividing point 58 as a detection terminal connected to the DC power supply, a configuration for inputting the divided voltage Vad of the voltage dividing circuit 48 to grasp the input voltage value Vin, and a switching element based on the input voltage value Vin The configuration for duty-controlling on / off of the MOSFET 45 can be omitted.

  Moreover, even if it is the structure which performs feedback control instead of open loop control, you may make it set the electric current setting value I0 assumed coil temperature rise. Even in such a configuration, even if the resistance value of the solenoid coil 32 increases due to an increase in coil temperature and the current value flowing through the solenoid coil 32 decreases, it is possible to suppress a decrease in the driving force of the solenoid valve. .

[Third Embodiment]
In the first embodiment, as shown in FIG. 2, each solenoid valve block 12 is provided with a connector connecting portion 36 to which a connector K of a lead wire L is connected. Also in the second embodiment, each electromagnetic valve block 12 has a configuration in which the parameter input lead wire L is further increased by one. In such an individual wiring system, when the number of solenoid valve blocks 12 to be connected is increased, the wiring is increased by that amount, and the wiring connecting portion is also extended in the connecting direction, resulting in inconvenient wiring. .

  In this regard, a configuration of a concentrated wiring system in which a wiring block is provided instead of one end block 13 (see FIG. 2) and wiring is concentrated on the wiring block is known. In this case, the wiring block is provided with a flat cable connector type or a D-sub connector type concentrated wiring connection portion. According to such a configuration, wiring routing is improved to some extent by centralized wiring.

  However, even with this configuration, the number of wires does not change in proportion to the increase in the number of solenoid valve blocks 12 to be connected. This is because each solenoid valve block 12 needs to be controlled by being energized through an individual energization path. In addition to the increase in the number of solenoid valve blocks 12, if a plurality of solenoid valve manifolds 10 are installed, the wiring increases accordingly. For this reason, the above-described conventional centralized wiring configuration is not sufficient as a configuration that eliminates the inconvenience of wiring. Moreover, in the control system of the apparatus in which the solenoid valve manifold 10 is incorporated, the memory capacity and the scale of the control program increase in proportion to the number of wires. Furthermore, it is conceivable to control each solenoid valve block 12 using serial communication in order to reduce the number of wires, but there is a problem that the processing contents become complicated and the product cost increases.

  As a third embodiment that addresses such a problem, a solenoid valve manifold that reduces wiring is described. FIG. 8 is an exploded perspective view showing a part of the solenoid valve manifold of the third embodiment. In addition, about the same structure as 1st Embodiment, the same code | symbol is attached | subjected and description is abbreviate | omitted and it demonstrates centering on a different structure.

  As shown in FIG. 8, the solenoid valve manifold 70 differs from the solenoid valve manifold 10 shown in the first embodiment in that a wiring block 71 is provided instead of one end block 13 (see FIG. 2). The wiring block 71 is provided with a power connector connecting portion 72 and a signal connector connecting portion 73 as a wiring connecting portion.

  The power connector connecting portion 72 is disposed at the upper part of the side surface of the wiring block 71, and the power connector Kv provided at one end of the power wiring M1 is connected from the direction Y orthogonal to the side surface. The power supply wiring M1 has a power supply lead Lv and a ground lead Lg.

  On the other hand, the signal connector connection portion 73 is disposed on the opposite side of the wiring block 71 from the block holding surface 71 a and at a substantially central portion between the side surfaces. The signal connector Ks provided at one end of the signal wiring M2 is connected to the signal connector connection portion 73 along the connecting direction X. The other end of the signal wiring M2 is connected to an external control device of the solenoid valve manifold 70. The signal wiring M2 has a power supply lead Lv, a signal lead Ls, and a ground lead Lg.

  The wiring block 71 will be described in more detail.

  FIG. 9 is an exploded perspective view of the wiring block 71. As shown in FIG. 9, the wiring block 71 is configured such that a block body 74, a wiring block substrate 75, and an electrical cover 76 are integrated, and the wiring block substrate 75 is built in the wiring block 71. ing. The block main body 74 is provided with a board mounting portion 77 as a base for mounting the wiring block board 75. A wiring block substrate 75 is attached to the substrate attachment portion 77 so that the circuit forming surface 75a faces the opposite side of the block holding surface 71a. In the substrate mounting state, the electrical cover 76 is mounted from the side facing the circuit forming surface 75 a, and the wiring block substrate 75 is covered with the electrical cover 76.

  The wiring block substrate 75 is provided with the power connector connecting portion 72 and the signal connector connecting portion 73. Terminals of the connector connecting portions 72 and 73 are electrically connected to an electric circuit formed on the wiring block substrate 75. In addition, a connection connector connecting portion 78 is provided on the surface of the wiring block substrate 75 opposite to the circuit forming surface 75a. The connecting connector connecting portion 78 is electrically connected to an electric circuit formed on the wiring block substrate 75. As shown in FIG. 8, in the solenoid valve manifold 70, the connecting connector connecting portion 78 is connected to the connecting connector 38 of the solenoid valve block 12 adjacent to the wiring block 71, and the connecting connectors 38 of the solenoid valve blocks 12 are connected to each other. Connected. Then, electric power is supplied from the connecting connector connecting portion 78 toward each electromagnetic valve block 12.

  The power connector connecting portion 72, the signal connector connecting portion 73, and the connecting connector connecting portion 78 are provided so as to protrude from the front and back surfaces of the wiring block substrate 75, respectively. As shown in FIG. 9, through holes 74 a and 76 a and a notch groove 74 b are formed in the block main body 74 and the electrical cover 76, and when integrated as the wiring block 71, each connector connecting portion 72 is utilized using these. 73 and the connecting connector connecting portion 78 are exposed to the outside.

  Next, the electrical configuration of the solenoid valve manifold 70 will be described. FIG. 10 is a circuit diagram showing the electrical configuration. The electrical configuration shown in FIG. 10 assumes a solenoid valve manifold 70 having six solenoid coils 32 in which six single solenoid type solenoid valve blocks 12A are connected.

  As shown in FIG. 10, the electrical configuration of the solenoid valve manifold 70 includes the solenoid valve substrate 34 provided in each solenoid valve block 12 and the wiring block substrate 75 provided in the wiring block 71. Both the boards 34 and 75 are connected. Among these, the electromagnetic valve circuit 40 of the first embodiment or the electromagnetic valve circuit 60 of the second embodiment is formed on the electromagnetic valve substrate 34. Each of the solenoid valve circuits 40 and 60 is connected to the solenoid coil 32 and controls the value of the current flowing through the solenoid coil 32. This point is as described in the first embodiment or the second embodiment.

  On the other hand, a wiring block circuit 80 is formed on the wiring block substrate 75. The wiring block circuit 80 has power terminals 81a and 81b to which a DC power is input, ground terminals 82a and 82b, and a signal input terminal 83 on the external connection side. The power terminals 81a and 81b and the ground terminals 82a and 82b include a power terminal 81a and a ground terminal 82a provided in the power connector connection part 72, and a power terminal 81b and a ground terminal 82b provided in the signal connector connection part 73. . The signal input terminal 83 is provided in the signal connector connection portion 73.

  On the other hand, on the connection side with the electromagnetic valve block 12, the wiring block circuit 80 is provided with a plurality of electromagnetic valve connection terminals 84. The solenoid valve connection terminals 84 are provided in the connection connector connection portion 78 and have at least “number of solenoid coils 32 n + 1”. It should be noted that the number of solenoid valve connection terminals 84 exceeding “n + 1” may be provided in order to widely support even when the number of coils is different, and in that case, the number of solenoid valve connection terminals 84 exceeding “n + 1” is not yet present. Used terminal. In this embodiment, seven solenoid valve connection terminals 84 are provided.

  Of the solenoid valve connection terminals 84, one solenoid valve connection terminal 84a is an output terminal for supplying power, and the power supply terminals 81a and 81b are connected to the solenoid valve connection terminal 84a. A backflow preventing diode 85 is provided between the power supply terminal 81a and the solenoid valve connection terminal 84a. On the other hand, the other solenoid valve connection terminals 84 are for grounding, and the ground terminals 82a and 82b are connected to the respective solenoid valve connection terminals 84.

  The solenoid valve connection terminal 84a for supplying power is connected to the power terminal 41 in each solenoid valve substrate 34. The other electromagnetic valve connection terminals 84 are connected to the ground terminals 42 of the electromagnetic valve boards 34 in a one-to-one correspondence relationship. For this reason, power is supplied to each solenoid valve block 12 from the DC power supply connected to the power supply terminal 81 through the wiring block circuit 80. In each solenoid valve block 12, power is supplied to the solenoid coil 32 through each solenoid valve circuit 40.

  More specifically, the wiring block circuit 80 includes a MOSFET 86, a microcomputer 87, a constant voltage circuit 88, and a voltage dividing circuit 89.

  MOSFET 86 is an n-channel type and corresponds to a second switching element for on / off control of solenoid coil 32. The MOSFET 86 has at least the same number as the number of solenoid coils 32. It should be noted that the number of MOSFETs 86 exceeding the number of solenoid coils 32 may be provided in order to deal with a wide range of cases when the number of coils is different. In that case, the MOSFTE 86 exceeding the number of coils is unused. In this embodiment, six MOSFETs 86 having the same number of coils are provided.

  Each MOSFET 86 is connected between one of the solenoid valve connection terminals 84 excluding the solenoid valve connection terminal 84a for supplying power and the ground terminals 82a and 82b. In this case, the drain of the MOSFET 86 is connected to the electromagnetic valve connection terminal 84, and the source is connected to the ground terminals 82a and 82b. The gate of each MOSFET 86 is connected to the output port of the microcomputer 87 corresponding one-to-one with each other, and is connected to the ground terminals 82 a and 82 b via the pull-down resistor 91. For this reason, each MOSFET 86 is connected to a DC power supply in series with the MOSFET 45 of the corresponding electromagnetic valve circuit 40, and turns on and off the application of voltage from the DC power supply to the MOSFET 45, respectively.

  The microcomputer 87 outputs the switch control signal to each MOSFET 86 or stops the output, thereby switching each MOSFET 86 individually. The power supply to the solenoid coil 32 is turned on / off by the switching operation of the MOSFET 86. Therefore, the microcomputer 87 corresponds to second switch control means for on / off control. When the switch control signal is not output from the microcomputer 87 and the power supply to the solenoid coil 32 is turned off, the MOSFET 86 is completely turned off by the pull-down resistor 91. Incidentally, it is possible to adopt a pull-up configuration in place of the pull-down resistor 91 here.

  The constant voltage circuit 88 is a circuit that generates a constant voltage as a driving power source for the microcomputer 87, and the configuration thereof is the same as the constant voltage circuit 47 in the electromagnetic valve circuits 40 and 60. That is, the transistor 92, the Zener diode 93, the resistor 94, and the capacitor 95 are provided, and the collector of the transistor 92 is connected to the power supply terminals 81a and 81b through the backflow preventing diode 96. When a predetermined voltage is applied to the power supply terminals 81a and 81b by the constant voltage circuit 88, a drive voltage Vcc is generated and supplied to the VCC port of the microcomputer 87. The ground port (GND port) of the microcomputer 87 is connected to the ground terminals 82a and 82b.

  The voltage dividing circuit 89 is a circuit that generates a signal voltage Vs input to the microcomputer 87. One end of the voltage dividing circuit 89 is connected to the signal input terminal 83 via a backflow preventing diode 97, and the other end of the voltage dividing circuit 89 is connected to the ground terminals 82a and 82b. The voltage dividing circuit 89 includes two voltage dividing resistors 98 and 99 connected in series with each other, and a voltage dividing point between the first voltage dividing resistor 98 and the second voltage dividing resistor 99 is the microcomputer 87. It is connected to a signal input port (IN port). The signal voltage input to the signal input terminal 83 is divided by these voltage dividing resistors 98 and 99, and the divided signal voltage Vs is input to the microcomputer 87. The voltage dividing ratio between the two voltage dividing resistors 98 and 99 is set to a value that generates a voltage having the same potential as the drive voltage Vcc of the microcomputer 87.

  Next, control of the solenoid valve manifold 70 having the above configuration will be described. For this control, an external control device such as an operation device by the user or a control unit of a device in which the electromagnetic valve manifold 70 is incorporated is required. FIG. 11 is a functional block diagram showing, in a simplified manner, each configuration necessary for explaining the control processing of a control system including an external control device. Each of the six solenoid coils 32 is abbreviated as SOL1 to SOL6, and the individual solenoid coils 32 are distinguished.

  As shown in FIG. 11, the external control device GK outputs a control signal SIG that is a pulse signal in order to control energization of the solenoid coils SOL1 to SOL6. The control signal SIG is input to the wiring block substrate 75 through the signal lead line Ls, further divided by the voltage dividing circuit 89, and input to the microcomputer 87 as the signal voltage Vs.

  When the microcomputer 87 detects the rise of the control signal SIG output from the external control device GK, the microcomputer 87 outputs a switch control signal to the MOSFET 86 corresponding to the solenoid coil 32 that needs to be switched on and off, and outputs the switch control signal. Or stop. When the MOSFET 86 is turned on by the output of the switch control signal, power is supplied from the DC power source D to the solenoid coil 32. On the other hand, when the output of the switch control signal is stopped and the MOSFET 86 is turned off, the power supply to the solenoid coil 32 is stopped. When the energization of the solenoid coil 32 is controlled to be turned on / off in this manner, the output state of the working air is switched at the output port 37 of each solenoid valve block 12 as described in the first embodiment.

  Here, when the rising edge of the control signal SIG is detected, which of all the solenoid coils SOL1 to SOL6 is to be switched on / off is the operation pattern information stored in advance in the internal memory 87a of the microcomputer 87. Select based on. In the operation pattern information, a plurality of steps representing driving stages of the plurality of solenoid coils 32 are associated with the on / off states of the solenoid coils 32 for each step. That is, in which step, which solenoid coil 32 is turned on or off is patterned. Therefore, the microcomputer 87 corresponds to an operation pattern setting unit.

  FIG. 12 is a table showing an example of the operation pattern. According to the pattern example shown in FIG. 12, for example, in step 1 to step 12, only solenoid coil SOL <b> 1 is turned off, and the remaining solenoid coils SOL <b> 2 to SOL <b> 6 are all turned on. Note that the operation pattern information in FIG. 12 is merely an example. The number of steps and the on / off mode are arbitrary, and are set as desired by the user. Even after the predetermined operation pattern information is set and stored in the internal memory 87a, it can be changed to another operation pattern information by using the writing device.

  FIG. 13 is a time chart illustrating energization control based on the operation pattern information illustrated in FIG. As shown in the figure, the external control device GK outputs a pulse signal having a uniform high level section as the control signal SIG1. The interval between the pulse signals is determined by the duration of the on / off state in each step, and the duration is set in advance in the external control device GK.

  When the microcomputer 87 detects the first rise t1-1, the solenoid coils SOL1 to SOL6 are switched to the state of step 1 in the operation pattern information. That is, the solenoid coils SOL5 and SOL6 are switched from the initial state where all the solenoid coils SOL1 to SOL6 are not energized (off) to the energized (on) state. In this case, by outputting a switch control signal to the MOSFET 86 corresponding to the solenoid coils SOL5 and SOL6 and turning it on, the solenoid coils SOL5 and SOL6 are switched to the energized state. The state of step 1 is continued until the next step 2 is switched.

  In the energized state, the solenoid valve circuits 40 and 60 perform PWM control by an open loop corresponding to the input voltage value Vin, and control is performed so that a current having a current set value I0 flows. This point is as described in the first embodiment and the second embodiment.

  Thereafter, when the microcomputer 87 detects the next rise t2-1, the solenoid coils SOL1 to SOL6 are switched to the state of step 2 in the operation pattern information. That is, the solenoid coils SOL1 and SOL3 that were in the non-energized state in the state of step 1 are switched to the energized state. Then, the state of step 2 is continued until switching to the next step 3.

  Thus, whenever the microcomputer 87 newly detects the rising edge of the control signal SIG1 until the state of step 12 which is the final step is reached, the microcomputer 87 switches to the state of the subsequent step in the operation pattern information. Then, when the rising edge t1-2 of the new control signal SIG1 is detected after the state of step 12, the carry of the number of steps is reset and the state is switched to the state of step 1 again. In this way, as long as the control signal SIG1 is input, the switching from the step 1 to the step 12 is repeatedly executed.

  According to the third embodiment described in detail above, the following advantageous effects can be obtained.

  (3a) In the centralized wiring system in which the power supply to each solenoid valve block 12 is controlled to be turned on / off by the wiring block circuit 80, the on / off switching is performed by detecting the rising edge of the control signal SIG from the external control device GK. In this case, the signal lead wire Ls for controlling the electromagnetic valve is sufficient for one wiring for transmitting the control signal SIG to one electromagnetic valve manifold 70. Even if the number of the solenoid valve blocks 12 is increased or decreased, one signal lead wire Ls is still sufficient. As a result, the number of signal lead wires Ls can be reduced and wiring can be saved without using a special control device or peripheral equipment. By reducing the wiring, it is possible to realize a reduction in manufacturing cost, a reduction in man-hours for wiring, and downsizing of the apparatus due to a reduction in wiring space.

  (3b) When the rising edge of the control signal SIG, which is a pulse signal, is detected, all the solenoid coils 32 included in the solenoid valve manifold 70 are simultaneously switched to the next step ON / OFF state based on the operation pattern information. Since the on / off states of the solenoid coils 32 are switched synchronously in this way, for example, when the operating air output state is switched at the same timing for a plurality of solenoid valve blocks 12 as in a semiconductor mounting device or the like, Preferred.

  (3c) In the configuration in which the control signal is individually output for each solenoid valve block 12 from each external control device GK through the individual signal lines as in the past, even if the on / off of energization is controlled at the same timing, the control signal is There is an inconvenience that output deviation occurs. On the other hand, in the third embodiment, as one control signal SIG rises, the microcomputer 87 transmits a switch control signal all at once in order to switch to the on / off state in the subsequent step. For this reason, synchronization is easily obtained.

  In addition, you may implement the said 3rd Embodiment with the form shown as a modification below.

  In the said 3rd Embodiment, the solenoid valve circuit 40,60 used as the free power source is formed in the solenoid valve board | substrate 34 of the solenoid valve block 12 using the structure of the said 1st Embodiment and 2nd Embodiment. . Instead, a configuration in which the wiring block circuit 80 is provided with a function as a solenoid valve circuit that is configured as a free power source may be employed. In this case, the wiring block circuit 80 becomes an electromagnetic valve drive circuit.

  FIG. 14 is a circuit diagram showing an electrical configuration of a solenoid valve manifold having such a wiring block circuit. The following description will be focused on differences from the electrical configuration of the solenoid valve manifold 70 in the third embodiment.

  As shown in the figure, since the wiring block circuit 101 has a free power supply circuit function and functions as an electromagnetic valve circuit, unlike the third embodiment, the electromagnetic valve circuit 40, 60 need not be formed. For this reason, the solenoid valve substrate 34 is only formed with an energization path that electrically connects the terminals on the power input side and the coil side. In addition, you may form the circuit which consists of elements, such as LED, in order to alert | report an electricity supply state in the solenoid valve board | substrate 34. FIG.

  Next, the wiring block circuit 101 includes a parameter input terminal 102 in the power connector Kv. This is provided in the electromagnetic valve circuit 60 in the second embodiment and the third embodiment. The parameter input terminal 102 is connected to a parameter input port (PM port) of the microcomputer 87. An external control device GK is connected to the parameter input terminal 102, and necessary parameters (such as the energization coefficient B described above) are input to the microcomputer 87 using the external control device GK.

  The wiring block circuit 101 is also provided with a voltage dividing circuit 103 for the microcomputer 87 to grasp the input voltage value Vin. The voltage dividing circuit 103 corresponds to the voltage dividing circuit 48 in the electromagnetic valve circuits 40 and 60, and includes two voltage dividing resistors 104 and 105 connected in series with each other. The voltage of the DC power supply connected to the power supply terminal 81a is divided, and the divided voltage Vad is input to the AD port, whereby the microcomputer 87 grasps the input voltage value Vin.

  In the wiring block circuit 101, the microcomputer 87 first has an energization switching function for controlling on / off of energization by a switching operation of the MOSFET 86. This is a function that the microcomputer 87 originally has. In addition to this, the microcomputer 87 also has a current control function for controlling the value of the current flowing through the solenoid coil 32 by the switching operation of the MOSFET 86 when the energization switching function is used. This current control function is a function of the microcomputer 46 included in the solenoid valve circuits 40 and 60 of the first and second embodiments.

  Therefore, when the microcomputer 87 outputs a switch control signal to turn on the MOSFET 86, the switch control signal is output as a PWM control signal for PWM control of the MOSFET 86. That is, the microcomputer 87 outputs a switch control signal with the duty ratio adjusted based on the input voltage value Vin, and controls the switching operation of the MOSFET 86 so that the current having the current setting value I0 flows through the solenoid coil 32.

  According to the configuration using the wiring block circuit 101, the circuit configuration formed on the electromagnetic valve substrate 34 can be further simplified than the electromagnetic valve circuits 40 and 60. Thereby, the circuit mounting area can be further reduced in the electromagnetic valve substrate 34, and the electromagnetic valve substrate 34 can be downsized. Further, the electromagnetic valve circuits 40 and 60 of the electromagnetic valve substrate 34 and the wiring block circuit 80 of the wiring block substrate 75 are provided with redundant elements such as MOSFETs 45 and 86 and microcomputers 46 and 87. One is enough. Thereby, the number of parts can be reduced and the manufacturing cost can be reduced.

  Further, in the third embodiment, when the electromagnetic valve circuit 60 that enables temperature correction of the current set value I0 is used, the parameter input terminal 61 provided for each electromagnetic valve substrate 34 of each electromagnetic valve block 12 causes the parameter to be changed. Must be entered. With this, it is not possible to reduce the wiring for parameter input. On the other hand, in the configuration of the modified example, since the parameter input can be unified, in the configuration that enables the temperature correction of the current set value I0, the wiring can be further reduced.

  In this modification, the MOSFET 86 corresponds to a switching element having both on / off control and current control functions, and the microcomputer 87 corresponds to switch control means having both on / off control and current control functions. . The microcomputer 87 also corresponds to input voltage detection means.

  In the third embodiment, the microcomputer 87 switches to the next step when the rising edge of the control signal SIG is detected. However, when the microcomputer 87 detects at least one of the rising edge and the falling edge of the control signal SIG, the microcomputer 87 performs it. This is enough. An example of the case where both rising and falling are detected is shown in the time chart shown in FIG.

  As shown in the figure, the control signal SIG2 in this case is different from the control signal SIG1 for detecting the rising edge, and the length of the high level section for each pulse is different. The length of the high level section and the interval between the pulse signal and the pulse signal are determined by the duration of the on / off state in each step. Then, when the microcomputer 87 detects the rising edge, the step is switched, and when it detects the subsequent falling edge, the microcomputer 87 switches to the next step. Further, either the operation mode for detecting the rising edge or the operation mode for detecting the rising or falling edge may be selectable by the user depending on the usage state of the solenoid valve manifold 70.

  In the third embodiment, the step number is sequentially incremented up to the final step 12 and then returned to the first step 1. However, the step number may be reset before reaching the final step 12. As a condition for resetting the step number, for example, as shown in FIG. 15A, it can be adopted that the power input to the microcomputer 87 is turned off. Further, as shown in FIG. 15B, it can be adopted that the pulse output stop of the control signal SIG2 has continued for a predetermined time S. The latter condition may be reset when the pulse output of the control signal SIG2 continues for a predetermined time.

  In the third embodiment, as the solenoid valve circuit formed on the solenoid valve substrate 34, the solenoid valve circuits 40 and 60 of the first and second embodiments, that is, a free power source and the solenoid coil 32 are used. It is assumed that the flowing current is controlled by open loop. Instead of this, an electromagnetic valve circuit that is not a free power source and that has the input voltage value Vin fixed at a predetermined value and that switches to the next step in the operation pattern information upon detection of the control signal SIG may be employed. Moreover, even if it is the structure which performs feedback control instead of open loop control, the structure switched to the next step in operation | movement pattern information by the detection of the control signal SIG is employable.

  In the third embodiment, the MOSFET 86 is used as the second switching element, but a bipolar transistor or the like may be used instead.

  DESCRIPTION OF SYMBOLS 10,70 ... Solenoid valve manifold (solenoid valve unit), 12 ... Solenoid valve block, 32 ... Solenoid coil, 40, 60 ... Solenoid valve circuit (solenoid valve drive circuit), 41 ... Power supply terminal, 45 ... MOSFET (switching element, First switching element), 46... Microcomputer (input voltage detecting means, switch control means, first switch control means, current value setting means), 56, 57... Voltage dividing resistor, 58. ... 1st temperature rise value calculation part (1st temperature rise value correction means), 64 ... 2nd temperature rise value calculation part (2nd temperature rise value correction means), 71 ... Wiring block, 73 ... Signal connector connection part (wiring) Connection unit), 80 ... wiring block circuit, 86 ... MOSFET (switching element, second switching element), 87 ... microcomputer (input voltage detection means, switch control means, second Switch control means, operation pattern setting means).

Claims (14)

An electromagnetic valve drive circuit for driving an electromagnetic valve having a solenoid coil based on a voltage applied from a DC power source,
A detection terminal connected to the DC power supply;
A switching element that is connected to the DC power source in series with the solenoid coil and that turns on and off the application of voltage from the DC power source to the solenoid coil;
Terminal voltage detection means for detecting a terminal voltage value of the detection terminal;
Switch control means for duty-controlling on / off of the switching element based on the terminal voltage value in order to flow a current of a preset current setting value to the solenoid coil;
An electromagnetic valve drive circuit comprising: The terminal voltage detection means includes a plurality of voltage dividing resistors connected in series with each other,
The voltage dividing resistor is connected to the DC power source in parallel with the solenoid coil,
The electromagnetic valve driving circuit according to claim 1, wherein the detection terminal is connected between the plurality of voltage dividing resistors.   The ratio of the plurality of voltage dividing resistors is set so that the terminal voltage value becomes the maximum allowable voltage of the terminal voltage detection means when the voltage applied from the DC power supply is a preset maximum voltage. The electromagnetic valve drive circuit according to claim 2, wherein:   4. The solenoid valve drive circuit according to claim 1, wherein the switch control unit controls an ON / OFF duty ratio of the switching element so as to be inversely proportional to the terminal voltage value. 5.   5. The solenoid valve drive circuit according to claim 1, further comprising a current value setting unit configured to set the current set value in consideration of a temperature rise of the solenoid coil. The current value setting means includes
A reference temperature that is a reference temperature before energization of the solenoid coil;
A coil saturation temperature, which is a temperature at which the solenoid coil rises and becomes saturated with respect to the reference temperature in response to energization of the solenoid coil;
Even when the solenoid coil rises to the coil saturation temperature, the minimum required current value that is the minimum current value required for the solenoid coil,
The electromagnetic valve drive circuit according to claim 5, wherein the current set value is set based on the current value. The maximum ambient temperature, which is the maximum value assumed as the ambient temperature of the solenoid coil, is used as a parameter.
The solenoid valve drive circuit according to claim 6, wherein the current value setting means calculates the coil saturation temperature by adding a coil temperature increase value due to energization of the solenoid coil to the maximum ambient temperature. . The energization coefficient indicating the ratio of energization time compared to continuous energization in the solenoid coil and the operation frequency that is the number of on / off times per predetermined time of the voltage applied from the DC power source to the solenoid coil are parameters.
8. The solenoid valve drive circuit according to claim 7, further comprising first temperature increase value correcting means for correcting the coil temperature increase value based on the energization coefficient and the operation frequency.   The said 1st temperature rise value correction | amendment means enlarges the said coil temperature rise value, so that the said electricity supply coefficient is large, and makes the said coil temperature rise value small, so that the said operation frequency is high. Solenoid valve drive circuit.   When the current set value set by the current value setting means is changed, consumption of the solenoid coil calculated based on the changed current set value and the resistance value of the solenoid coil at the reference temperature The second temperature rise value correcting means for correcting the coil temperature rise value by multiplying electric power by a heat dissipation coefficient specific to the solenoid coil, according to any one of claims 7 to 9. The solenoid valve drive circuit described. In a solenoid valve unit having a plurality of solenoid valves,
An electromagnetic valve unit comprising the electromagnetic valve driving circuit according to any one of claims 1 to 10, wherein each electromagnetic valve is driven by the electromagnetic valve driving circuit. A plurality of solenoid valves comprising the solenoid valve drive circuit according to any one of claims 1 to 10,
A wiring block having a wiring connecting portion to which wiring connected to an external device is connected, and having a wiring block circuit for supplying a voltage applied from the DC power supply to each solenoid valve;
A solenoid valve unit comprising:
The switching element and the switch control means in the solenoid valve drive circuit are respectively a first switching element and a first switch control means,
The wiring block circuit is
A second switching element connected to the DC power supply in series with the first switching element and configured to turn on and off the application of a voltage from the DC power supply to the first switching element;
An operation pattern setting means for setting, as operation pattern information, a relationship between a plurality of steps representing a driving stage of the plurality of solenoid valves and an on / off state of a solenoid coil included in each solenoid valve in each step;
When at least one of the rising edge and the falling edge of the pulse signal output from the external device to the wiring connection portion is detected, the ON / OFF state of each solenoid coil is an ON / OFF state after switching the operation pattern information step. Second switch control means for controlling on / off of the second switching element,
Solenoid valve unit equipped with. A plurality of solenoid valves;
A wiring block to which wiring connected to an external device is connected, and a wiring block for supplying a voltage applied from the DC power supply to each solenoid valve;
A solenoid valve unit comprising:
The electromagnetic valve drive circuit according to any one of claims 1 to 10 is formed on a wiring block substrate included in the wiring block.
The operation pattern setting means for setting, as operation pattern information, a relationship between a plurality of steps representing driving stages of the plurality of solenoid valves and an on / off state of a solenoid coil included in each solenoid valve in each step,
When the switch control unit detects at least one of a rising edge and a falling edge of a pulse signal output from the external device to the wiring connection portion, the on / off state of each solenoid coil switches the step of the operation pattern information. An on-off state of the switching element is controlled so as to be in an on / off state after the operation.   The wiring connection portion is provided with a parameter input terminal that is connected to the switch control means and to which parameters are input when the switch control means controls the switching element using parameters. The electromagnetic valve unit according to claim 13.

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