JP2011141019A - Solenoid valve driving device, solenoid valve, solenoid valve driving method, and drive control program of solenoid valve driving device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a solenoid valve driving device, having high detection precision of a plunger holding state. <P>SOLUTION: The solenoid valve driving device 1 maintains a valve open state of a solenoid valve 4 by supplying holding current which is smaller than starting current to the solenoid valve 4 after the valve open state is made by supply of starting current. It includes a detection resistance R3 serially arranged with the solenoid valve 4 to detect energization current to the solenoid valve 4, a monitoring means 3 to monitor detection voltage generating at the detection resistance R3 in a case where current is supplied to the solenoid valve 4, an abnormality detection means 6 to detect whether the solenoid valve 4 is normally opened or the solenoid valve 4 is abnormally closed based on variation of detection voltage monitored by the monitoring means 3 in a case where the holding current is being supplied to the solenoid valve 4, and an automatic restoration means 6 to automatically restore the solenoid valve 4 to the valve open state by increasing current to be supplied to the solenoid valve 4 in a case where abnormality is detected by the abnormality detection means 6. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention provides an electromagnetic valve driving device that maintains a valve open state of the solenoid valve by supplying a holding current smaller than the start current to an electromagnetic valve that is in a valve open state by supplying a startup current, The present invention relates to an electromagnetic valve driving method and a drive control program for an electromagnetic valve driving device.

  The operation of the solenoid valve used for fluid control is controlled by controlling the amount of current supplied by the solenoid valve driving device. When a starting current is supplied to the solenoid, the solenoid valve is attracted to a fixed iron core fixed to the solenoid, and the valve is opened. Thereafter, the solenoid valve is supplied with a holding current (for example, 58 to 70% of the rated current), and maintains the valve open state.

  By the way, when the supply current supplied to the solenoid valve from the power source is controlled to be constant, the current value of the current flowing through the solenoid valve increases after the start of current supply and decreases as the valve starts to open. When the plunger hits the fixed iron core and is attracted, the current value of the current flowing through the solenoid valve rises again and stabilizes to a predetermined current value. When the power supply to the solenoid valve is stopped, the current value of the current flowing through the solenoid valve increases after decreasing until the plunger leaves the fixed iron core, and starts decreasing again when the plunger contacts the valve seat. Therefore, the solenoid valve starts the valve opening operation when supplying the starting current (the valve body starts to open the valve away from the valve seat) or less, and starts the valve closing operation when the starting current supply is stopped (plunger). If the holding current is set in a range equal to or greater than the current value), the open state can be maintained.

  However, if the holding current is reduced, the plunger is likely to move away from the fixed iron core and return to the valve seat position due to vibration / impact from the device, vibration / impact from the fluid flow, and the like. On the other hand, for example, by setting the holding current to a value smaller than the starting current value and larger than the current value at the start of the valve opening operation (for example, 58 to 70% of the rated current), the abnormal return of the plunger is prevented. Attempting to do so results in energy loss. Therefore, the conventional solenoid valve driving device is provided with, for example, a vibration sensor that detects vibration to reduce the holding current. According to this, it is determined whether there is a possibility that the plunger may return to the valve closed position due to vibration detected by the vibration sensor, and when there is a possibility that the plunger returns, by increasing the current value supplied to the solenoid, Abnormal return of the plunger can be prevented (see, for example, Patent Document 1).

JP 2009-14185 A

  However, in the conventional solenoid valve driving device, when the solenoid valve is used to control a highly viscous liquid, the plunger moving speed is slow even when the plunger moves in the valve seat direction due to an external impact or the like. Since the impact when closing is small, there is a possibility that an abnormality cannot be detected. There is also a problem that it is difficult to distinguish between the impact from the apparatus and the vibration of the fluid pressure. Therefore, the conventional solenoid valve driving device has a low degree of detection of the plunger holding state. Further, a vibration sensor or the like is required for detecting the plunger holding state, which is expensive.

  The present invention has been made to solve the above-described problems, and includes an inexpensive solenoid valve drive device, solenoid valve, solenoid valve drive method, and drive control program for the solenoid valve drive device with high detection accuracy of the plunger holding state. The purpose is to provide.

The solenoid valve drive device, the solenoid valve, the solenoid valve drive method, and the drive control program for the solenoid valve drive device according to the present invention have the following configuration.
In a solenoid valve driving device that maintains a valve open state of the solenoid valve by supplying a holding current smaller than the start current to a solenoid valve that is in a valve open state by supplying a startup current, in series with the solenoid valve A detection resistor arranged to detect the energization current to the solenoid valve; a monitoring means for monitoring a detection voltage generated in the detection resistor when supplying a current to the solenoid valve; and the holding current to the solenoid valve An abnormality detecting means for detecting whether the electromagnetic valve is normally opened or the electromagnetic valve is abnormally closed due to a change in the detection voltage monitored by the monitoring means. And an automatic return means for automatically returning the solenoid valve to a valve open state by increasing a current supplied to the solenoid valve when the abnormality detection means detects an abnormality.

  The monitoring means compares a detection voltage generated in the detection resistor with a reference voltage adjusted to a target current value. When the detection voltage is equal to or lower than the reference voltage, a current is supplied to the solenoid valve. When the detection voltage exceeds the reference voltage, the driving means that stops driving and does not supply current to the solenoid valve, and the driving state of the driving means is detected by an electric signal. Drive waveform acquisition means for acquiring a drive waveform, and the abnormality detection means is a valve-open-state drive waveform acquired by the drive waveform acquisition means when the electromagnetic valve is supplied with the holding current; When the holding current is supplied, when the electromagnetic valve is in a valve closed state, the driving waveform is acquired by the drive waveform acquisition unit, and the holding current is supplied to the electromagnetic valve. Later the drive waveform acquisition It is determined whether or not the drive waveform acquired by the stage matches the drive waveform in the valve open state. If the drive waveform matches the drive waveform in the valve open state, it is determined that the drive waveform is normal. It is preferable that an abnormality is determined when the drive waveform does not coincide with the valve open state.

  Further, when the solenoid valve to which the holding current is supplied performs the valve closing operation from the valve open state, the OFF time during the valve closing operation acquired by the drive waveform acquisition unit is the OFF of the drive waveform during the valve open state. The abnormality detection means measures an OFF time of the drive waveform acquired by the drive waveform acquisition means after supplying the holding current to the solenoid valve, and the OFF time of the drive waveform It is preferable to detect an abnormality even when the drive waveform is longer than the OFF time in the valve open state.

  In addition, a decrease value is obtained by equally dividing a predetermined value from a value that can reliably start the solenoid valve into an open state to a current value of 0, and the current value supplied to the solenoid valve is decreased according to the decrease value. Storage means for storing the driving waveform at the time of lowering obtained by the driving waveform obtaining means in association with the current value at the time of current lowering, and the current value supplied to the solenoid valve from zero to the same value as the lowering value If the drive waveform acquired by the drive waveform acquisition means coincides with the drive waveform at the time of descent when it is increased, the current value currently measured is It is preferable to have holding current value learning means for adding a margin value and determining a holding current value.

  In addition, after the holding current value learning unit determines the holding current value, when the current value supplied to the solenoid valve is further increased by the same value as the lowering value, it is acquired by the drive waveform acquiring unit. Starting current value to determine the starting current value by adding a margin value to the current measured current value It is preferable to have learning means.

  The monitoring means opens and closes a circuit that supplies current to the solenoid valve by PWM output at a constant cycle, and controls the current value of the current supplied to the solenoid valve to be constant, and the drive means keeps the current constant. And a ripple value measuring means for measuring a ripple value of a detection voltage generated in the detection resistor in a state where the electromagnetic valve is supplied with the holding current constant. The ripple value of the detection voltage generated in the detection resistor is different between when the valve is open and when the solenoid valve is abnormally closed with the holding current being supplied constantly, and the ripple Whether or not the ripple measurement value measured by the value measuring means coincides with the holding determination ripple value of the detection voltage generated in the detection resistor when the solenoid valve is supplied with the holding current at a constant value and is opened. Judge Wherein it is determined to be normal if the ripple measurement value matches the holding determination ripple value, it is preferable if the ripple measurement value does not match the held determination ripple value is for determining that abnormal.

  In addition, a decrease value is obtained by equally dividing a predetermined value from a value that can reliably start the solenoid valve into an open state to a current value of 0, and the current value supplied to the solenoid valve is decreased according to the decrease value. A first storage means for storing the ripple value at the time of falling measured by the ripple value measuring means in association with the current value at the time of the current drop, and the current value supplied to the solenoid valve from zero to the falling value. A second storage means for storing the rising ripple value measured by the ripple value measuring means in association with the current value at the time of current rise when the same value is increased; and the second storage means stored in the first storage means A lower limit current value in a hysteresis region having a different ripple value is obtained from the falling ripple value and the rising ripple value stored in the second storage means, and the holding current value is obtained by adding a margin value to the lower limit current value. A holding current value learning means determining, it is preferable to have a.

  Further, an upper limit current value in a hysteresis region having different ripple values is obtained from the falling ripple value stored in the first storage means and the rising ripple value stored in the second storage means, and the upper limit current value is obtained. It is preferable to have a starting current value learning means for determining a starting current value by adding a margin value to the learning current value one larger than

  Moreover, it is preferable to have a notifying means for notifying that the abnormality detecting means has detected an abnormality.

  It is preferable that it is a solenoid valve which has any one said solenoid valve drive device.

  In a solenoid valve driving method for maintaining a valve open state of the solenoid valve by supplying a holding current smaller than the start current to a solenoid valve that is in a valve open state by supplying a startup current, a current is supplied to the solenoid valve. When supplying, a monitoring step of monitoring a detection voltage generated in a detection resistor that is arranged in series with the electromagnetic valve and detects an energization current to the electromagnetic valve, and the holding current is supplied to the electromagnetic valve An abnormality detection step for detecting whether the solenoid valve is normally opened or the solenoid valve is abnormally closed due to a change in the detection voltage monitored in the monitoring step; An automatic return step of automatically returning the solenoid valve to the valve open state by increasing the current supplied to the solenoid valve when an abnormality is detected in the step.

  In a drive control program for a solenoid valve driving device that maintains a valve open state of the solenoid valve by supplying a holding current smaller than the start current to a solenoid valve that is in a valve open state by supplying a startup current. Monitoring means for monitoring a detection voltage generated in a detection resistor that is arranged in series with the electromagnetic valve and detects a current flowing to the electromagnetic valve when supplying current to the electromagnetic valve; and Abnormality detection for detecting whether the electromagnetic valve is normally opened or abnormally closed due to a change in the detection voltage monitored by the monitoring means when a holding current is supplied And an automatic return means for automatically returning the electromagnetic valve to the valve open state by increasing the current supplied to the electromagnetic valve when the abnormality detection means detects an abnormality.

  In the electromagnetic valve driving device, the electromagnetic valve, the electromagnetic valve driving method, and the drive control program for the electromagnetic valve driving device configured as described above, the electromagnetic valve to which the holding current is supplied may be abnormally closed due to an external impact or the like. Normally, an electromagnetic valve has a different inductance that is generated when the valve is open and when the valve is closed. In a specific circuit, the detection voltage generated by a detection resistor in series with the solenoid valve is affected by the inductance. Changes. Focusing on this point, in the above configuration, when a holding current is supplied to the solenoid valve, the detection voltage generated in the detection resistor is monitored, and the change of the detection voltage causes the solenoid valve to open normally or abnormally. Detect if closed. For this reason, unlike the detection method (current waveform, plunger impact vibration, etc.) that uses a transient phenomenon associated with the movement of the plunger, the operation state of the solenoid valve is statically and constantly changed by the change in the detection voltage generated in the detection resistor. Since it detects, it is not necessary to provide a vibration sensor etc. in a solenoid valve, and abnormality can be detected rapidly at low cost. Moreover, for example, even when the solenoid valve controls a highly viscous liquid and the impact when the valve is closed is small, the abnormal valve closing operation and the normal valve closing operation of the solenoid valve are clearly discriminated by the change in the detection voltage. High detection accuracy. When abnormality of the solenoid valve is confirmed, the current supplied to the solenoid valve is increased from the holding current, and the solenoid valve is automatically automatically returned to the valve open state instantly.

  Therefore, according to the electromagnetic valve driving device, the electromagnetic valve, the electromagnetic valve driving method, and the drive control program for the electromagnetic valve driving device configured as described above, the detection accuracy of the plunger holding state can be increased. In addition, paying attention to the fact that the detection voltage generated in the detection resistor changes depending on whether the solenoid valve opens normally when the holding current is supplied or abnormally closes the valve, the operating state of the solenoid valve changes depending on the detection resistor change. Since it detects, it is not necessary to provide a vibration sensor etc. in a solenoid valve, and it is cheap.

  In the solenoid valve driving device having the above-described configuration, in a specific circuit, the supply and shut-off of current to the solenoid valve are controlled by the influence of the inductance generated in the solenoid valve when the valve is open and when the valve is closed. The drive state of the drive means is different between when the solenoid valve is open and when the valve is closed. Focusing on this, in the above configuration, the drive waveform acquisition means detects the drive state of the drive means from the electrical signal to acquire the drive waveform (eg, ON time, OFF time), and detects the operation state of the solenoid valve from the drive waveform. is doing. That is, the drive waveform acquired by the drive waveform acquisition means after supplying the holding current to the solenoid valve is the valve open state acquired by the drive waveform acquisition means when the solenoid valve supplied with the hold current is in the valve open state. If the drive waveform matches the drive waveform when the valve is open, it is determined that the solenoid valve is in a normal state with the valve open, and the drive waveform is If the drive waveform does not coincide with the open-state drive waveform, it is determined that the valve is not in an open state even though the holding current is supplied to the solenoid valve. For this reason, unlike the detection method using a transient phenomenon associated with the movement of the plunger (current waveform, impact vibration of the plunger, etc.), the operation state of the solenoid valve is statically detected by the drive waveform of the drive means. It is not necessary to provide a vibration sensor or the like in the solenoid valve, and an abnormality can be detected quickly at a low cost. In addition, for example, even when the solenoid valve controls a highly viscous liquid and the impact when the valve is closed is small, the abnormal valve closing operation and the normal valve closing operation of the solenoid valve are clearly distinguished by the drive waveform, so the detection accuracy Is expensive.

  The electromagnetic valve driving device having the above configuration is driven when the valve is in the open state, when the solenoid valve to which the holding current is supplied operates to close the valve from the valve open state. Paying attention to the difference from the OFF time of the waveform, measure the OFF time of the drive waveform acquired by the drive waveform acquisition means after supplying the holding current to the solenoid valve, and the OFF time of the drive waveform of the drive waveform when the valve is open Even when it is longer than the OFF time, an abnormality is detected and the solenoid valve is automatically returned to the valve open state. Therefore, according to the said structure, abnormality can be detected during the valve closing operation | movement of a solenoid valve, and a solenoid valve can be automatically returned to a normal valve open state earlier than other methods, such as impact detection.

  The solenoid valve drive device having the above configuration equally divides the current value from 0 to a current value of 0 that can reliably start the solenoid valve in the valve open state, obtains the fall value, and lowers the current value supplied to the solenoid valve. When it is lowered according to the value, the drive waveform acquired by the drive waveform acquisition means is stored in the storage means as a sample drive waveform in association with the current value at the time of current drop. Then, the current value supplied to the solenoid valve is increased from zero by the same value as the decrease value, and the current value that the drive waveform acquired by the drive waveform acquisition means does not match the sample drive waveform is searched and searched. The holding current value is determined by adding a margin value to the flow value. Therefore, according to the said structure, the holding current value which considered the individual difference can be supplied to a solenoid valve, a valve open state can be maintained, and an energy-saving effect can be improved further.

  After determining the holding current value, the electromagnetic valve driving device having the above configuration further increases the current value supplied to the electromagnetic valve by the same value as the decrease value, and the driving waveform acquired by the driving waveform acquisition means is sampled. A current value that matches the drive waveform is searched, and a starting current value is determined by adding a margin value to the searched current value. Therefore, according to the solenoid valve driving device having the above-described configuration, the starting current for opening the solenoid valve at the time of starting can be made smaller than the rated current in consideration of individual differences, and the energy saving effect can be further enhanced.

  The electromagnetic valve driving device having the above-described configuration includes a case where the electromagnetic valve is opened by being supplied with a constant holding current under the influence of a change in inductance caused by a valve opening / closing operation of the electromagnetic valve, However, the ripple value of the detection voltage generated in the detection resistor arranged on the downstream side of the electromagnetic valve is different from that in the case where the valve is abnormally closed while the holding current is supplied constantly. Focusing on this point, the solenoid valve drive device measures the ripple value of the detected voltage after switching the current supplied to the solenoid valve from the starting current to the holding current, and the measured ripple value is supplied to the solenoid valve. It is compared with the holding discrimination ripple value of the detection voltage generated in the detection resistor when it is supplied constantly. When the measured ripple value matches the hold determination ripple value, it is determined to be normal, and when the measured ripple measurement value does not match the hold determination ripple value, it is determined to be abnormal. For this reason, unlike the detection method that uses the transient phenomenon associated with the movement of the plunger (current waveform, impact vibration of the plunger, etc.), the operation state of the solenoid valve is statically steady due to the ripple value of the detection voltage generated in the detection resistor. Therefore, it is not necessary to provide a vibration sensor or the like on the solenoid valve, and an abnormality can be detected quickly at a low cost. Moreover, for example, even when the solenoid valve controls a highly viscous liquid and the impact when the valve is closed is small, the abnormal valve closing operation and normal valve closing operation of the solenoid valve are clearly discriminated by the ripple value of the detection voltage. , Detection accuracy is high.

  The electromagnetic valve driving device having the above-described configuration obtains a descending value by equally dividing a predetermined value from a predetermined value that can activate the electromagnetic valve into the valve open state to a current value of 0, and a current value supplied to the electromagnetic valve, When it is lowered according to the obtained fall value, the ripple value at the time of fall measured by the ripple value measuring means is stored in the first storage means in association with the current value at the time of current fall. Then, when the current value supplied to the solenoid valve is increased from zero by the same value as the decrease value, the rising ripple value measured by the ripple value measuring means is associated with the current value at the time of the current increase in the second memory. Store in the means. Then, a lower limit current value in a hysteresis region having different ripple values is obtained from the falling ripple value stored in the first storage means and the rising ripple value stored in the second storage means, and a margin value is added to the obtained lower limit current value. Is added to determine the holding current value to learn the holding current value suitable for the solenoid valve. Therefore, according to the electromagnetic valve driving device having the above-described configuration, the holding current value in consideration of individual differences can be supplied to the electromagnetic valve to maintain the valve open state, and the energy saving effect can be further enhanced.

  The electromagnetic valve driving device having the above configuration obtains an upper limit current value in a hysteresis region having different ripple values from the falling ripple value stored in the first storage means and the rising ripple value stored in the second storage means. The starting current value suitable for the solenoid valve is learned by adding a margin value to the learning current value that is one larger of the upper limit current value and determining the starting current value. Therefore, according to the solenoid valve driving device having the above-described configuration, the starting current for opening the solenoid valve at the time of starting can be made smaller than the rated current in consideration of individual differences, and the energy saving effect can be further enhanced.

  Since the electromagnetic valve drive device having the above configuration notifies the abnormality by the notification means, it is possible to notify the user of the abnormality of the electromagnetic valve and to take an appropriate measure.

It is a circuit diagram of the solenoid valve drive device concerning a 1st embodiment of the present invention. It is a figure which shows an example of the timing chart which applies a detection voltage waveform and a drive voltage to a solenoid valve. It is a figure which shows an example of a drive waveform and a detection voltage waveform. It is a flow of the drive control program of a solenoid valve drive device. It is a flow of the drive control program of the solenoid valve drive device concerning a 2nd embodiment of the present invention. It is a figure which shows an example of the detection voltage waveform and drive waveform of a solenoid valve drive device. It is a circuit diagram of the solenoid valve drive device concerning a 3rd embodiment of the present invention. It is a flow of a learning program. It is a circuit diagram of the solenoid valve drive device concerning a 4th embodiment of the present invention. It is a flow of the learning program which concerns on 4th Embodiment of this invention. It is a circuit diagram of the solenoid valve drive device concerning a 5th embodiment of the present invention. It is a flow of the drive control program of a solenoid valve drive device. It is a circuit diagram of the solenoid valve drive device concerning a 6th embodiment of the present invention. It is a figure which shows the plunger adsorption state current waveform at the time of starting in PWM system control. It is a figure which shows the plunger non-adsorption state current waveform in PWM system control. It is a figure which shows the plunger adsorption state current waveform in PWM system control. It is a figure which shows the electric current waveform at the time of abnormal reset in PWM system control. It is a flow of the drive control program of a solenoid valve drive device. It is a flow of the learning program memorize | stored in the solenoid valve drive device concerning 7th Embodiment of this invention. It is a circuit diagram of the solenoid valve drive device concerning an 8th embodiment of the present invention.

  Hereinafter, an embodiment of a solenoid valve drive device, a solenoid valve, a solenoid valve drive method, and a drive control program for a solenoid valve drive device according to the present invention will be described with reference to the drawings.

(First embodiment)
<Configuration of electromagnetic valve drive device>
FIG. 1 is a circuit diagram of an electromagnetic valve drive device (hereinafter referred to as “drive device”) 1 according to a first embodiment of the present invention.
The driving device 1 is connected to the power source E1 and the solenoid valve 4, and supplies the starting current to the solenoid valve 4 that is in the valve open state to supply a holding current smaller than the starting current to thereby open the solenoid valve 4. To maintain. The driving device 1 includes a control unit 2 that controls the value of voltage and current supplied from the power source E1 to the electromagnetic valve 4, and a value that is controlled by the control unit 2 by opening and closing a circuit that connects the power source E1 and the electromagnetic valve 4. Drive means 3 for driving the solenoid valve 4 by supplying the voltage / current to the solenoid valve 4.

  In the control means 2, the power supply terminal CN1 is connected to the power supply E1. The power supply terminal CN1 is connected to a microcomputer power supply E2 in parallel, and power is supplied to a microcomputer 6 (an example of drive waveform acquisition means, abnormality detection means, holding current value control means, hereinafter referred to as “microcomputer”). The microcomputer power supply E <b> 2 is connected to the capacitor C in parallel and supplies stable power to the microcomputer 6. The microcomputer 6 is connected to a host device (not shown) via the input terminal CN3 and inputs / outputs electrical signals to / from the host device (not shown). The microcomputer 6 stores various programs and data in a nonvolatile read / write EEPROM (an example of a storage unit) 7. Then, the microcomputer 6 outputs a command from the D / A converter 8 to the driving means 3 via the signal output terminal 9, and the driving state of the driving means 3 is a first signal input terminal by an electric signal (ON / OFF signal). Input from 10.

  On the other hand, in the driving means 3, the solenoid valve connection terminal CN <b> 2 is connected in parallel with the solenoid 5 of the solenoid valve 4. A bidirectional breakdown diode D2 is connected in parallel to the solenoid valve connection terminal CN2 to constitute a surge circuit that protects the drive device 1 from an abnormally high voltage. The drive means 3 has a detection resistor R3 arranged in series with the solenoid valve 4 on the downstream side of the solenoid valve 4, and can detect the energization current to the solenoid valve 4 by the detection voltage generated in the detection resistor R3. The driving means 3 compares the command (reference voltage) output from the microcomputer 6 with the detection voltage generated in the detection resistor R3 by the comparator OP, switches between high output and low output, and opens and closes the transistors TR1 and TR2. Thus, the circuit connecting the power source E1 and the solenoid valve 4 is opened and closed.

  Specifically, the contact M1 between the solenoid valve 4 and the detection resistor R3 is connected to the negative input terminal of the comparator OP so that the detection voltage generated in the detection resistor R3 is input to the comparator OP as an input voltage. It has become. The comparator OP has a positive input terminal connected to the signal output terminal 9 of the microcomputer 6 and inputs a reference voltage. The output terminal of the comparator OP is connected to a contact M2 provided on a wiring connecting the transistor TR2 and the first signal input terminal 10, and the output voltage is applied to the base of the transistor TR2. The collector of the transistor TR2 is connected to the base of the transistor TR1 provided on the wiring connecting the power source E1 and the upstream side of the solenoid 5, and the emitter is connected to the wiring connecting the power source E1 and the downstream side of the solenoid 5. ing. The transistor TR1 has a collector connected to the power supply E1 and an emitter connected to the solenoid 5.

  Therefore, the driving means 3 outputs a high output from the comparator OP when the detection voltage (input voltage) generated at the detection resistor R3 is lower than the reference voltage, that is, when the current flowing to the solenoid valve 4 is lower than the reference current value. Thus, the transistors TR1 and TR2 are closed so that power can be supplied to the solenoid 5. On the other hand, when the detection voltage generated in the detection resistor R3 is larger than the reference voltage, that is, when the energization current to the solenoid valve 4 is larger than the reference current value, the comparator OP outputs low to open the transistors TR1 and TR2, and the solenoid Shut off the power supply to 5.

  The driving means 3 has diodes (or shots) on the downstream side of the transistor TR1 and the upstream side of the transistor TR2 so that the current stored in the solenoid 5 can be driven to drive the solenoid valve 4 even when the transistors TR1 and TR2 are opened. (Key barrier diode) D1 is connected in parallel with the solenoid valve connection terminal CN2. Therefore, the drive means 3 opens and closes the transistors TR1 and TR2 as appropriate, thereby setting the current supplied to the solenoid 5 in the hysteresis range set in the comparison circuit 11 (resistors R1, R2, comparator OP) according to the command of the control means 2. It is possible to stabilize within.

  In the microcomputer 6, the first signal input terminal 10 is connected to the base of the transistor TR2 through the contact M2, and the driving means 3 opens and closes the transistors TR1 and TR2 according to the output of the comparator OP to supply power to the solenoid 5. The operation to be detected is detected by an electrical signal.

Incidentally, the degree of change in the current value of the solenoid valve 4 changes due to the inductance change of the solenoid 5 during the valve opening / closing operation. Therefore, the comparator OP constitutes a hysteresis type self-excited converter in which the period corresponding to the hysteresis by the resistors R1 and R2 changes.
In the present embodiment, the microcomputer 6 and the comparison circuit 11 constitute “monitoring means” for monitoring the detection voltage generated in the detection resistor R3.

<Drive current waveform characteristics of solenoid valve drive device>
When the drive device 1 supplied the rated current to the solenoid 5 for a predetermined time to open and close the solenoid valve 4, an experiment was conducted to examine the change in the detection voltage generated in the detection resistor R3 due to the current flowing through the solenoid 5. FIG. 2 shows a timing chart showing the relationship between the detection voltage and time obtained in this experiment (detection voltage waveform characteristics) and the timing at which the drive voltage is applied to the electromagnetic valve 4.
As shown at T0 in FIG. 2, when a drive voltage is applied to the solenoid valve 4, a current starts to flow through the solenoid 5, and a fixed iron core (not shown) starts to be excited, so that the detection voltage generated at the detection resistor R3 starts to rise. As shown at T1 in FIG. 2, when the detection voltage rises to the voltage value a1, a plunger (not shown) begins to be attracted to a fixed iron core (not shown). Normally, the solenoid valve 4 is designed to start the valve opening operation at a value a1 smaller than the rated voltage value a2 (for example, 60% of the rated voltage value) in order to reliably open the valve. The electromagnetic valve 4 starts to decrease in voltage value from the voltage value a1 at T1 when the valve opening operation starts. When the unillustrated plunger hits a fixed iron core (not illustrated) and ends the valve opening operation, the detected voltage starts to increase from the voltage value a4 at the end of the valve opening operation T2 shown in FIG. It becomes stable at the voltage value a2 as a value.

  As indicated by T3 in FIG. 2, when the application of the drive voltage to the solenoid 5 is stopped, the current flowing through the solenoid 5 decreases while consuming energy by the coil resistance of the solenoid 5, so that the detection voltage generated at the detection resistor R3 is a voltage. It starts to decrease from the value a2. As shown at T4 in the figure, when a plunger (not shown) leaves a fixed iron core (not shown) and starts the valve closing operation, a current flows to the solenoid 5 due to electromagnetic induction accompanying the lowering of the plunger (not shown), and the voltage value of the detected voltage is a3. Increase again from. Then, as shown at T5 in the figure, when a plunger (not shown) brings a valve body (not shown) into contact with a valve seat (not shown) and the valve is closed, the detected voltage is returned from the voltage value a5 according to the inductance in the return state of the plunger. It decreases and eventually becomes zero.

  As shown in the detected voltage waveform of FIG. 2, the voltage value slope P1 when the plunger is not attracted between (T0-T1) at the voltage value a4 and the slope P2 of the voltage value when the plunger is attracted after T2 are Different. This difference indicates that the inductance changes due to the non-adsorption / adsorption of the plunger, and the gradient P2 of the voltage value from T2 after the plunger adsorption, where the inductance increases, is the gradient P1 of the current value when the plunger is not adsorbed. It has become more gradual.

  Here, the voltage value a3 at the start of the valve closing operation T4 is smaller than the voltage value a1 at the start of the valve opening operation T1. In other words, the solenoid valve 4 can maintain the valve open state even at a voltage value smaller than the voltage value a1 at the start of the valve opening operation. In order to obtain an energy saving effect, it is desirable to make the holding current value for holding the valve open state of the electromagnetic valve 4 smaller than the current value a1 at the time T1 when the valve opening operation starts. However, if the holding current value is reduced, the electromagnetic valve 4 can easily perform an abnormal valve closing operation due to an external impact or the like. Measures for detecting an abnormal valve closing operation of the solenoid valve 4 with a vibration sensor or the like increase the number of parts, leading to an increase in cost, or when the solenoid valve 4 controls a highly viscous fluid, the vibration when the valve is closed is small. Therefore, there is a problem that the abnormality cannot be detected. Therefore, in the present embodiment, a static and stable electric signal indicates a driving state in which the driving unit 3 is driven to supply a current to the electromagnetic valve 4 instead of a dynamic index such as plunger movement or current change (not shown). (ON / OFF signal) is acquired, and the operation state of the solenoid valve 4 is detected by the drive waveform of the electric signal. Hereinafter, the reason why the operation state of the electromagnetic valve 4 can be confirmed based on the drive waveform acquired from the drive unit 3 will be specifically described.

  The inventor applies a holding current to the solenoid valve 4 to open the solenoid valve 4 and then applies an external shock to the solenoid valve 4 to cause the solenoid valve 4 to close abnormally. An experiment was conducted to measure the detection voltage generated at the same time and to measure the driving waveform of the ON / OFF signal acquired from the contact M2. FIG. 3 shows the detected voltage waveform acquired from the contact M1 until the electromagnetic valve 4 performs the abnormal valve closing operation from the valve open state and becomes the valve closed state, and the drive waveform of the ON / OFF signal acquired from the contact M2. .

Comparing the detected voltage waveforms in the valve open state and the valve closed state shown in FIG. 3, the detection voltage cycle X1 in the valve open state is longer than the detection voltage cycle X2 in the valve close state. As shown by P1 and P2 in FIG. 2, the electromagnetic valve 4 has two inductance components in a valve open state (plunger adsorption state) and a valve closed state (plunger non-adsorption state). When the current value of the current supplied to the solenoid 5 is controlled to be constant, the coil resistance generated by the solenoid 5 and the hysteresis voltage width are constant. Therefore, in the valve open state and the valve closed state, the inductance component and the coil component And a current change slope (T = L / R (T: time constant, L: hysteresis value, R: coil resistance value)), and a current change according to an exponential function occurs within the hysteresis width. The hysteresis value acts as the same inductance for both the valve opening and valve closing slopes. Therefore, the detection voltage cycle in the valve open state and in the valve closed state varies depending on both the ON time and the OFF time.
On the other hand, the drive waveform (ON / OFF signal of the contact M2) in FIG. 3 shows the normal duty ratio (ON time t1 / 1 period) when the valve is opened in the holding current supply state even if the detection voltage periods X1 and X2 change. Y1) is the same as the duty ratio (ON time t2 / 1 cycle Y2) at the time of abnormality in which the valve is closed in the holding current supply state. This means that the power consumption consumed by the solenoid 5 is constant. However, the period of the drive waveform is longer in the normal period Y1 than in the abnormal period Y2. In other words, the OFF time (or ON time t1) detected at normal time is longer than the OFF time (ON time t2) detected at abnormal time.

  As described above, when the holding current is supplied to the solenoid valve 4 and the period of the ON / OFF signal drive waveform (ON time / OFF time) acquired from the contact M2 is viewed, the valve open state and the valve close state of the solenoid valve 4 The state can be detected by being electrically and statically distinguished.

In addition, as shown in FIG. 3, when the solenoid valve 4 to which a holding current is supplied is applied with an external impact and starts an abnormal valve closing operation, the voltage value of the detection voltage increases, and the detection during the abnormal valve closing operation is performed. The voltage waveform period X3 exhibits a transient phenomenon that is longer than the detection voltage period X1 when the valve is open. This is because the magnetic energy stored in the plunger attracted state is released as the plunger returns and flows transiently as current while being consumed as thermal energy by the diode D1 and the coil resistance.
On the other hand, when the driving waveform of the contact M2 in FIG. 3 is seen, when the solenoid valve 4 is supplied with a holding current and an external impact is applied to start the valve closing operation, the solenoid valve 4 is turned off until the solenoid valve 4 is closed. The signal continues to be input, and the OFF time becomes longer than the normal OFF time.
Therefore, the normal opening state of the electromagnetic valve 4 and the transient phenomenon of the abnormal valve closing operation can be electrically distinguished from each other by the OFF time of the driving waveform of the contact M2.

  Here, the valve opening / closing operation of the solenoid valve 4 has been described using the voltage value of the detection voltage generated in the detection resistor R3, but the current value flowing through the solenoid 5 can be used in the same manner as the above detection voltage waveform. Needless to say, the current waveform fluctuates and the opening / closing operation of the solenoid valve 4 can be explained in the same manner as the detected voltage waveform.

<Solenoid valve drive method>
An electromagnetic valve driving method will be described.
When the microcomputer 6 shown in FIG. 1 does not input a drive command from a host device (not shown), the microcomputer 6 does not output a voltage to the comparator OP. Therefore, the transistors TR1 and TR2 are turned off and opened, and no current is supplied from the power source E1 to the solenoid 5.

  When the drive command is input to the microcomputer 6 from the host device (not shown) via the input terminal CN3 when the solenoid valve 4 is not energized, the drive device 1 executes the drive control program for the solenoid valve drive device shown in FIG. Read from the EEPROM 7 and execute. The microcomputer 6 that executes the drive control program of the electromagnetic valve driving device supplies the solenoid 5 with a rated current to start the electromagnetic valve 4 and then supplies the holding current stored in the EEPROM 7 in advance to the solenoid 5. While the valve open state is maintained and this holding current is supplied, an ON / OFF signal is input from the driving means 3 to monitor the operation state of the solenoid valve 4, and the solenoid valve 4 performs an abnormal valve closing operation or the valve When the valve is in the closed state, the solenoid valve 4 is automatically returned to the valve open state. Hereinafter, this will be specifically described with reference to FIG.

  The microcomputer 6 first outputs a 100% rated current drive command (start-up voltage) from the D / A converter 8 to the comparator OP of the drive means 3 in Step 1 (hereinafter abbreviated as “S1”) in FIG. In S2, a 100% rated current command (starting reference voltage Vc) is output for 0.3 seconds, and the solenoid valve 4 is opened.

  The operation of the driving means 3 at the time of starting will be described in detail. A voltage that is sufficiently higher than the voltage that the rated current is generated in the detection resistor R3 is output from the terminal of the microcomputer 6 so that the comparator OP maintains a high output. Let The transistors TR1 and TR2 continue to be turned on, and a rated current defined by the detection voltage generated in the detection resistor R3 and the voltage of the power source E1 flows through the solenoid valve 4.

  Then, in S3 of FIG. 4, the current supplied to the solenoid 5 is switched from the starting current to the holding current by outputting a holding current value command (holding reference voltage Vc) to the comparator OP. Here, the holding current value command indicates that the detection voltage generated in the detection resistor R3 by the current supplied to the solenoid 5 is equal to or lower than the voltage value a1 (see FIG. 2) at the time T1 when the valve opening operation starts and the valve closing operation starts. It is defined to be equal to or greater than the voltage value a3 at time T3, and is stored in the EEPROM 7 in advance.

When the holding current value command is output, the driving unit 3 operates as follows.
When the detection voltage (input voltage) Vb generated in the detection resistor R3 is equal to or lower than the holding reference voltage Vc, the comparator OP outputs a high voltage to close the transistors TR1 and TR2 and supply current from the power supply E1 to the solenoid 5. When the detection voltage Vb exceeds the holding reference voltage Vc, the comparator OP outputs a low level to open the transistors TR1 and 2 and cut off the current supplied to the solenoid 5. At this time, the current stored in the solenoid 5 continues to flow in one direction between the diode (or Schottky barrier diode) D1 and the solenoid 5, but the current consumes energy by the resistance component of the detection resistor R3, The current value decreases. When the detection voltage Vb becomes equal to or lower than the holding reference voltage Vc, the comparator OP outputs again to close the transistors TR1 and TR2 and supply current to the solenoid 5. By repeating this series of operations, a constant holding current is supplied to the solenoid 5, and the solenoid valve 4 is opened.

  In S <b> 4 of FIG. 4, the microcomputer 6 starts monitoring the drive waveform based on the ON / OFF signal input to the first signal input terminal 10. The monitoring of the operation state of the solenoid valve 4 is started. Then, in S5, it is determined whether or not the driving means 3 has opened / closed the transistors TR1 and TR2 and started holding current oscillation depending on whether or not the ON / OFF signal is input in a pulse form. When the ON / OFF signal is not inputted in a pulse form and the start of the holding current oscillation cannot be confirmed (S5: NO), the process waits as it is.

  On the other hand, when the ON / OFF signal is input in a pulse form and the start of holding current oscillation is confirmed (S5: YES), a timer (not shown) built in the microcomputer 6 is cleared in S6, and the ON signal Measurement of input time (ON time) is started. In S7, it is determined whether or not the driving of the driving means 3 is stopped by closing the transistors TR1 and TR2 depending on whether or not an OFF signal is input to the first signal input terminal 10. If the transistors TR1 and TR2 are opened and the driving means 3 is not stopped (S7: NO), the ON signal continues to be input to the first signal input terminal 10, so that the process waits. On the other hand, when the transistors TR1 and TR2 are closed and the driving means 3 is stopped (S7: YES), since the ON time in one cycle has been measured, the ON time measurement value is stored in the EEPROM 7 in S8. It is determined whether or not it is within the stored determination ON time range for holding the drive waveform when the valve is open.

  When the ON time measurement value is within the range of the holding discrimination ON time (S8: YES), it is considered that the solenoid valve 4 is in a closed state and is abnormal (Y1, t1, Y2, FIG. 3). t2), the process returns to S1. By repeating the processing after S1, the starting current larger than the holding current is supplied to the solenoid valve 4 to automatically return the solenoid valve 4 to the valve open state, the starting current is switched to the holding current, and the solenoid valve 4 is opened again. Maintain state.

  On the other hand, if the ON time measurement value is not within the holding discrimination ON time range (S8: NO in FIG. 4), the timer built in the microcomputer 6 is cleared and input to the first signal input terminal 10 in S9. Measurement of the input time (OFF time) of the OFF signal to be started is started. In S <b> 10, it is determined whether or not the current OFF time measurement value is equal to or longer than the determination OFF time for holding the drive waveform in the valve open state stored in the EEPROM 7. If the current OFF time measurement value is not equal to or greater than the holding determination OFF time (S10: NO), it is determined in S11 whether the driving unit 3 has started driving. When the ON signal is input to the first signal input terminal 10, the transistors TR1 and TR2 are closed and the current is supplied to the solenoid 5, so that the driving means 3 starts driving when the ON signal is input again to the microcomputer 6. In this case, the determination is made when the OFF signal has been input. If the driving means 3 has not started driving during the input of the OFF signal (S11: NO), the process returns to S10 and the OFF time is monitored.

  When the current OFF time measurement value is longer than the holding determination OFF time (S10: YES), the solenoid valve 4 is abnormally closed (transient state) even though the holding current is supplied. Therefore, the process returns to S1. Then, by repeating the processing after S1, a starting current larger than the holding current is supplied to the solenoid valve 4, the solenoid valve 4 is automatically returned to the valve open state, the starting current is switched to the holding current, and the solenoid valve 4 is turned on again. Maintain valve open. Thereby, it is possible to detect the abnormal return of the plunger at an early stage and to open the solenoid valve 4.

  On the other hand, if the current OFF time measurement value is not longer than the holding determination OFF time (S10: NO) and the driving means 3 starts driving (S11: YES), the OFF time measurement value is determined in S12. Is within the range of the holding discrimination OFF time.

When the OFF time measurement value is within the holding determination OFF time range (S12: YES), the drive waveform matches the drive waveform when the valve is open, and the solenoid valve 4 is normally maintained in the valve open state. Since it is thought that there is, it returns to S6. And the process after S6 is repeated and the holding operation of the solenoid valve 4 is continuously monitored.
On the other hand, when the OFF time measurement value is not within the holding discrimination OFF time range (S12: NO), it is considered that the solenoid valve 4 supplied with the holding current is in a closed state and is abnormal. Therefore, it returns to S1. Then, by repeating the processing after S1, a starting current larger than the holding current is supplied to the solenoid valve 4 to bring the solenoid valve 4 into the valve open state, and then the starting current is switched to the holding current to open the solenoid valve 4. Maintain state.

  By repeating the above processing, the electromagnetic valve driving device 1 monitors the holding operation of the electromagnetic valve 4 by detecting the operation state of the driving means 3 with an electric signal (ON / OFF signal) while operating the electromagnetic valve 4. When the abnormality of the electromagnetic valve 4 is detected, the electromagnetic valve 4 can be automatically returned to the valve open state.

<Effect>
As described above, the solenoid valve drive device 1, the solenoid valve 4, the solenoid valve drive method, and the drive control program for the solenoid valve drive device according to the present embodiment have the solenoid valve 4 to which a holding current is supplied by an external impact or the like. The valve may close abnormally. Normally, the solenoid valve 4 has different inductances in the valve open state and in the valve closed state. In a specific circuit, the inductance is affected by the inductance and is generated in the detection resistor R3 arranged in series with the solenoid valve 4. The detected voltage changes. Focusing on this point, in the above configuration, when the holding current is supplied to the solenoid valve 4, the detection voltage generated at the detection resistor R3 is monitored, and the change in the detection voltage R3 causes the solenoid valve 4 to open normally. Detect whether the valve is closed abnormally. For this reason, the solenoid valve drive device 1, the solenoid valve 4, the solenoid valve drive method, and the drive control program for the solenoid valve drive device of the present embodiment are based on the detection method (current waveform, plunger Unlike the shock vibration), the operation state of the solenoid valve 4 is detected statically and constantly by the change of the detection voltage generated in the detection resistor R3, so there is no need to provide a vibration sensor etc. in the solenoid valve 4 at low cost. Abnormalities can be detected quickly. Moreover, for example, even when the solenoid valve 4 controls a highly viscous liquid and the impact when the valve is closed is small, the abnormal valve closing operation and the normal valve closing operation of the solenoid valve 4 are clearly discriminated by the change in the detection voltage. So detection accuracy is high. When abnormality of the solenoid valve 4 is confirmed, the current supplied to the solenoid valve 4 is increased from the holding current, and the solenoid valve is automatically returned to the valve open state instantly.

  Therefore, according to the solenoid valve drive device 1, the solenoid valve 4, the solenoid valve drive method, and the drive control program for the solenoid valve drive device, the detection accuracy of the plunger holding state can be increased. Further, paying attention to the fact that the detection voltage generated in the detection resistor R3 changes depending on whether the solenoid valve 4 is normally opened or not when the holding current is supplied, the solenoid valve 4 is changed by the change of the detection resistor R3. Therefore, it is not necessary to provide a vibration sensor or the like in the solenoid valve, and it is inexpensive.

  In the solenoid valve drive device 1 having the above-described configuration, in a specific circuit, the current is supplied to and shut off from the solenoid valve 4 under the influence of inductance generated in the solenoid valve when the valve is open and when the valve is closed. The driving state of the driving means 3 to be controlled is different between when the solenoid valve 4 is in the valve open state and when the valve is in the closed state. Focusing on this, in the electromagnetic valve drive device 1, the microcomputer 6 detects the drive state of the drive means 3 by an ON / OFF electric signal to acquire a drive waveform, and detects the operation state of the solenoid valve 4 from the drive waveform. is doing. That is, the drive waveform (ON time / OFF time) acquired by the microcomputer 6 after supplying the holding current to the solenoid valve 4 is acquired by the microcomputer 6 when the solenoid valve 4 to which the holding current is supplied is in the valve open state. If the drive waveform matches the drive waveform in the valve open state, it is determined whether the drive waveform matches the drive waveform in the valve open state (holding determination ON time / holding determination OFF time). If the drive waveform does not match the drive waveform when the valve is open, the valve is kept open despite the solenoid valve being supplied with holding current. It is judged as abnormal. Therefore, unlike the detection method (current waveform, plunger impact vibration, etc.) using a transient phenomenon associated with the movement of the plunger, the operation state of the electromagnetic valve is statically and constantly detected by the drive waveform of the drive means 3. In addition, it is not necessary to provide a vibration sensor or the like in the solenoid valve, and an abnormality can be detected quickly at a low cost. In addition, for example, even when the solenoid valve controls a highly viscous liquid and the impact when the valve is closed is small, the abnormal valve closing operation and the normal valve closing operation of the solenoid valve are clearly distinguished by the drive waveform, so the detection accuracy Is expensive.

  When the solenoid valve 4 to which the holding current is supplied performs the valve closing operation from the valve open state, the electromagnetic valve driving device 1 according to the present embodiment shows the valve closing operation when one cycle of the drive waveform acquired by the microcomputer 6 is viewed. OFF time is different from the transient OFF time of the drive waveform when the valve is open. Paying attention to this, the solenoid valve driving device 1 measures the OFF time of the drive waveform acquired by the microcomputer 6 after supplying the holding current to the solenoid valve 4, and the drive waveform when the OFF time of the drive waveform is in the valve open state. Even when it is longer than the OFF time, an abnormality is detected, and the solenoid valve 4 is automatically returned to the valve open state. Therefore, the solenoid valve drive device 1 of the present embodiment can detect an abnormality before the solenoid valve 4 to which the holding current is supplied is completely closed, and is faster than other methods such as shock detection. Can be automatically returned to a normal valve open state.

  The electromagnetic valve drive device 1 of the present embodiment supplies the holding current to the electromagnetic valve 4 because the holding current value is equal to or less than the current value at the start of valve opening and equal to or greater than the current value at the start of valve closing. After that, the solenoid valve 4 can be used with a holding current that is closer to the current value at the start of valve closing, so that power can be reduced and heat generation can be prevented. In addition, unlike the timer operation that allows an excessive margin, when the open state of the solenoid valve 4 is confirmed after the start-up current is supplied, the start-up current is immediately switched to the hold current and the operation shifts to the valve-open state hold operation of the solenoid valve 4. And there is little wasted energy loss. In addition, since the solenoid valve 4 is confirmed to be open by the starting current and then the holding operation is performed, the holding operation of the solenoid valve 4 can be reliably performed.

  Since the solenoid valve drive device 1 of the present embodiment is detachably attached to the existing solenoid valve 4 by connecting the solenoid valve connection terminal CN2 to the solenoid 5, the integral construction of the solenoid valve 4 and the vibration sensor or the sensor There is no need to make a major design change from current devices such as wiring or to replace the solenoid valve 4, and the existing solenoid valve 4 can be used as it is to reduce power consumption and cost.

  In addition, if the electromagnetic valve drive device 1 of this embodiment provides alerting means, such as a lamp and an audio output device, in the microcomputer 6 or a host device, and the microcomputer 6 detects an abnormality, the abnormality is notified. It is possible to notify the user of the abnormality of the electromagnetic valve 4 and perform appropriate measures.

(Second Embodiment)
Next, a second embodiment of the present invention will be described. FIG. 5 is a flow of a drive control program of the solenoid valve drive device according to the second embodiment of the present invention. FIG. 6 is a diagram showing an example of the detection voltage generated in the detection resistor R3 acquired from the contact M1 and the drive waveform of the ON / OFF signal acquired from the contact M2, and in particular, the starting current for the solenoid valve 4 is shown. The detected voltage waveform and the drive waveform from the start of supplying the current until the holding current is supplied are shown.
The second embodiment is different from the first embodiment in that the drive control program of the solenoid valve driving device starts the solenoid valve 4 without supplying 100% rated current to save energy (S15 to S20 in FIG. 5). To do. Therefore, only the starting operation of the solenoid valve 4 will be described here, and the same points as in the first embodiment will be used in the drawings and the description with the same reference numerals as in the first embodiment, and the description will be omitted as appropriate.

<Detection voltage waveform and drive waveform>
In the detection voltage waveform shown in FIG. 6, the voltage value of the detection voltage generated in the detection resistor R3 increases from the start current supply start time T10 at which the start current starts to be supplied to the start valve opening operation start time T11 at which the valve starts to open, Thereafter, the plunger (not shown) of the solenoid valve 4 moves down to T12 when the start valve opening operation ends in contact with a fixed iron core (not shown). Thereafter, the voltage value of the detection voltage rises again and stabilizes at a voltage value a11 slightly higher than the start valve opening operation start time T11 as indicated by P11 in the figure (starting current stabilization time T13, T14). The voltage value of the detection voltage increases or decreases in small increments until the starting current is switched to the holding current by the opening / closing operation of the transistors TR1 and TR2. When a holding current smaller than the starting current is started to be supplied to the solenoid valve 4 (at the start of holding current supply T14), the voltage value of the detection voltage decreases and becomes stable at the holding voltage value a12 (at the holding current stabilization time T15). When the voltage value is stabilized at the holding voltage value, the detection voltage cycle is stabilized at X1.
In this case, the drive waveform maintains the ON state from the start-up current supply start time T10 to the start-up current stabilization time T13, and is turned ON / OFF in a short cycle Y4 from the start-up current stabilization time T13. Then, it is turned OFF from the holding current supply start time T14 to the holding current stabilization time T15, and after the holding current stabilization time T15, it is turned ON / OFF in a cycle Y1 longer than the cycle Y4.
Therefore, whether or not the electromagnetic valve 4 is opened by supplying the starting current can be determined by whether or not the drive waveform oscillates and the ON / OFF time of the oscillated cycle.

<Electromagnetic valve drive method>
Next, the electromagnetic valve driving method will be described.
When the microcomputer 6 receives a drive command from a host device (not shown), the microcomputer 6 starts a drive control program for the electromagnetic valve drive device shown in FIG. Then, in S15 of FIG. 5, an activation current drive command is given to the drive unit 3 so that the activation current value stored in advance in the EEPROM 7 is output to the drive unit 3. The starting current value is equal to or greater than the voltage value a1 (see FIG. 6) of the starting valve opening operation T11 at which the fixed iron core (not shown) begins to attract the plunger (not shown) in order to reduce the power consumption at the time of starting and is 100% rated. It is set in a range less than the current value.

  In S16, the starting current value is maintained for 0.3 seconds, and in S17, the drive waveform is monitored by the ON / OFF signal input from the contact M2 to the first signal input terminal 10. Then, in S18, the ON time and OFF time of the drive waveform are the start determination ON time and start determination included in the period Y4 from the start current stabilization time T13 to the holding current supply start time T14 stored in advance in the EEPROM 7. It is determined whether or not it coincides with the OFF time (see Y4 in FIG. 6). If the ON time and OFF time of the drive waveform coincide with the start determination ON time and OFF time (S18: YES), it is considered that the solenoid valve 4 has been opened due to the start current, and the process proceeds to S3. Since the process after S3 is the same as that of the first embodiment, the description thereof is omitted.

  On the other hand, when the ON time and OFF time of the drive waveform do not coincide with the start determination ON time and OFF time (S18: NO), the solenoid valve 4 has not yet been opened, so in S19. The 100% rated current drive command is output to the drive means 3, and the current value of the current supplied to the solenoid 5 is increased to the rated current value. In S20, the supply of 100% rated current is maintained for 0.2 seconds to open the solenoid valve 4, and then the process returns to S15 to supply the current to the solenoid 5 again with the starting current value stored in the EEPROM 7. To do. In this way, since the 100% rated current value is supplied to the solenoid 5 so that the solenoid valve 4 is in the valve open state, the startup current corresponding to the current required for the start valve opening operation start time T11 is supplied to the solenoid 5. When the start-up current is supplied again, the ON / OFF time of the drive waveform becomes equal to the ON / OFF time of the start discrimination value (S15, S16, S17, S18: YES). Therefore, the process proceeds to S3.

<Effect>
Therefore, according to the drive control program for the drive device 1 and the solenoid valve drive device of the present embodiment, the solenoid valve 4 is activated by supplying the solenoid 5 with a startup current smaller than the 100% rated current. The power consumption can be reduced and the energy saving effect can be enhanced.

(Third embodiment)
Next, a third embodiment of the present invention will be described. FIG. 7 is a circuit diagram of an electromagnetic valve driving device 31 according to the third embodiment of the present invention. FIG. 8 is a flow of the learning program.
7 of the third embodiment is a learning program (an example of a holding current value learning unit and a starting current value learning unit, in which a microcomputer 32 learns a starting current value and a holding current value. See FIG. 8. ) Is different from the second embodiment. Therefore, here, the learning function will be mainly described, and the same points as in the second embodiment will be used in the drawings and the description with the same reference numerals as those in the second embodiment, and the description will be omitted as appropriate.

<Circuit configuration of solenoid valve drive device>
As shown in FIG. 7, in the electromagnetic valve driving device 31, a switch SW for starting a learning function is connected to the microcomputer 32. The microcomputer 32 includes light emitting diodes LD1 to LD5 that emit light when the switch SW is turned on, so that the user can be notified that the learning function is being executed. The electromagnetic valve driving device 31 is connected to the contact M1 between the electromagnetic valve connection terminal CN2 and the detection resistor R3 and the second signal input terminal 34 of the microcomputer 32, and the voltage / current of the contact M1 is A / D. Measurement can be performed by inputting to the converter 33.

<Learning method of holding current value and starting current value>
Next, a learning method of the holding current value and the starting current value will be described with reference to FIG.
The learning program shown in FIG. 8 is stored in the EEPROM 7 and is executed by the microcomputer 32 when the switch SW is pressed. As shown in FIG. 6, the learning program obtains a starting voltage value a11 for starting the solenoid valve 4 in the valve open state and a holding voltage value a12 for holding the valve open state of the solenoid valve 4. The microcomputer 32 is determined according to the characteristics.

  Specifically, the microcomputer 32 first outputs a rated voltage drive command (overcurrent value command) from the D / A converter 8 to the comparator OP in S21 of FIG. The driving means 3 opens and closes the solenoid valve 4 by applying a rated voltage to the solenoid 5 by the comparator OP opening and closing the transistors TR1 and TR2. In S22, the microcomputer 32 converts the voltage signal input from the contact M1 by the A / D converter 33, measures the rated current value based on the detected voltage generated in the detection resistor R3, and stores it in the EEPROM 7.

  In S23, the microcomputer 32 switches the 100% drive command to the 80% rated current value command and outputs the command to the comparator OP to reduce the current supplied to the solenoid 5 to 80% of the rated current. Since the normal solenoid valve 4 has a current set at 58 to 70% rated current, the solenoid valve 4 can maintain the valve open state even if the current supplied to the solenoid 5 is reduced to 80% of the rated current. Then, in S24, the current value from 0 to the rated current value of 80% is equally divided (for example, 40 divisions), and the 80% rated current value is divided by a certain amount (for example, 2% of the rated 80% current value) by the current value. In step S25, it is determined whether the current value has become zero. If the current value is not 0 (S25: NO), in S26, the ON / OFF time is stored in association with the current current value (current value during descent). By repeating the processes of S24, S25, and S26, the current value is gradually decreased to zero by a certain amount (decreasing value), and the ON time and OFF time in one cycle of each decreasing current value are acquired. The The “constant amount” is obtained by equally dividing a range from a predetermined value set to a value larger than the holding current to a current value of 0, and does not necessarily have to be 2% of the rated current value. The ON / OFF cycle acquired by this processing is hereinafter referred to as “current falling time cycle characteristic”.

  When the current supplied to the solenoid 5 is reduced to zero (S25: YES), the solenoid valve 4 is reliably closed. In S27, the microcomputer 32 outputs a command for setting the current value supplied to the solenoid 5 to 0 to the comparator OP. In S28, the current value supplied to the solenoid 5 is increased by the same value as the decrease value (2% of the rated current) used when the current decrease period characteristic is acquired. In S29, based on the ON / OFF signal inputted from the contact M2 to the first signal input terminal 10, the driving state of the driving means 3 is detected by the ON / OFF signal, and the driving waveform (ON time / OFF time) is measured. Then, the measured drive waveform is stored in the temporary storage area (an example of a storage unit) 35 in association with the current value (current value at the time of increase).

  Then, in S30, the current value at the time of falling corresponding to the current value at the time of rising is searched from the temporary storage area 35, and the driving waveform (ON time / OFF time) of the searched current value at the falling time and the current driving waveform (ON) are searched. It is determined whether or not (time / OFF time) matches. Here, “match” includes an error range. If the current drive waveform (ON time / OFF time) matches the ON time / OFF time of the current drop value searched (S30: YES), it is considered that the solenoid valve 4 is closed, so S28. Then, the current value is further increased, and it is determined whether or not the drive waveform at the time of the current decrease matches the measured drive waveform.

  When the current drive waveform (ON time / OFF time) does not coincide with the searched drive waveform ON time / OFF time of the current value at the time of searching (S30: NO), the solenoid valve 4 is in the holding state when it is lowered, Since it is considered that hysteresis has occurred, in S31, the current value is determined as the current value at the start of the valve closing operation, and the current drive waveform (ON time / OFF time) is determined as the current current value (valve closing operation start). The current value is stored in the EEPROM 7. In S32, a current value larger than the current value at the start of the valve closing operation stored in the EEPROM 7 is determined as the holding current value, and a drive waveform (ON time, OFF time) corresponding to the holding current value is determined at the start of the valve closing operation. Drive waveforms (holding discrimination ON time, holding discrimination OFF time) are stored in the EEPROM 7 respectively. In the present embodiment, for example, a larger current value is set as the holding current value, which is a current value that is twice the hysteresis generation lower limit current value or a current value that is 22% of the rated current (twice of twentieth of the power consumption). To do. In addition, for example, an allowable value given the hysteresis lower limit current value taking into account a margin value (coil temperature range, variation in the number of coil turns, variation in magnetic characteristics of the core plunger, etc., for example, current corresponding to 5% of the rated current Value)) may be added and set as the holding current value. Then, a value within 10% of the current value centered on the period when the current drops is used for the holding drive waveform (holding determination ON time, holding determination OFF time). In an environment with a lot of vibration and impact, a margin value may be selectable, for example, by giving a sufficient margin as an added value.

  In S33, the current value of the current supplied to the solenoid 5 is further increased by the same value (2% of the rated current) as the decrease value used when the current decrease period characteristic is acquired. Then, the current value at the time of rising and the drive waveform (ON time / OFF time) input to the first signal input terminal 10 are stored in the temporary storage area 35. Then, in S35, the current value at the time of falling corresponding to the current value at the time of rising is searched from the temporary storage area 35, the driving waveform (ON time, OFF time) of the searched current value at the falling time and the measured driving waveform ( It is determined whether or not the ON time and OFF time match. When the drive waveform of the searched current value at the time of searching does not match the measured drive waveform, hysteresis is still generated by the valve closing operation, and the plunger (not shown) does not hit the fixed iron core (not shown). Therefore, the process returns to S33, the rising current value is increased by the same value as the decreasing value, and the same processing as described above is performed.

  When the measured drive waveform (ON time, OFF time) matches the searched drive waveform (ON time, OFF time) at the time of the current drop (S35: YES), the solenoid valve 4 is in the valve open state and hysteresis. Therefore, the current value is determined as the current value when the valve is open and stored in the EEPROM 7. In S37, a value equal to or greater than the current value in the valve open state is determined as a starting current value, and a driving waveform (ON time, OFF time) corresponding to the starting current value is set as a driving waveform (starting determination ON time). , OFF time) in the EEPROM 7. For example, a starting value is obtained by adding a margin value (a current value corresponding to 5% to 10% of the rated current) to the current value when the valve is open. For example, a value within 5% of the driving cycle corresponding to this starting current value is used for the starting driving waveform.

  When the microcomputer 32 finishes learning as described above, the microcomputer 32 turns off the switch SW and turns off the light emitting diodes LD1 to LD5. By this turn-off operation, the user can confirm that the learning function has ended and the drive device 1 can be normally operated. Since the normal operation is the same as the operation described in the second embodiment (see FIG. 5), the description is omitted.

<Effect>
The electromagnetic valve drive device 31 of the present embodiment equally divides the predetermined value from the current value 0 that can activate the electromagnetic valve 4 into the valve open state to obtain a descending value and supplies it to the electromagnetic valve 4. When the current value is decreased according to the decrease value, the drive waveform acquired by the microcomputer 32 is stored in the temporary storage area 35 as a sample drive waveform in association with the current value at the time of current decrease. Then, the current value supplied to the solenoid valve 4 is increased from zero by the same value as the decrease value, and the current value in which the drive waveform acquired by the microcomputer 32 does not coincide with the sample drive waveform is searched for. A holding current value is determined by adding a margin value to the value and stored in the EEPROM 7. Therefore, according to the electromagnetic valve drive device 31 of the present embodiment, the holding current value considering individual differences can be supplied to the electromagnetic valve 4 to maintain the valve open state, and the energy saving effect can be further enhanced. . Specifically, for example, in the solenoid valve 4 in which the current at the start of valve closing is 5% of the rated current, for example, a margin value corresponding to 5% of the rated current value is added to the current value at the start of valve closing. If the open state of the solenoid valve is maintained at 10% of the rated current, the holding power can be reduced to 1/100 of the rated power, and the solenoid valve 4 having a long energization time can provide a great energy saving effect.

  After determining the holding current value, the electromagnetic valve drive device 31 of the present embodiment further increases the current value supplied to the electromagnetic valve 4 by the same value as the above-mentioned decrease value, and the drive waveform acquired by the microcomputer 32 Is searched for a current value that matches the sample driving waveform, and a starting current value is determined by adding a margin value to the searched current value, and stored in the EEPROM 7. Therefore, according to the electromagnetic valve drive device 31 of the present embodiment, the starting current for opening the electromagnetic valve 4 at the time of starting is made smaller than the rated current in consideration of individual differences, and the electromagnetic valve 4 is opened with the minimum power. Since it can be activated to the state, the energy saving effect of the solenoid valve can be further enhanced. In particular, the solenoid valve driving device 31 has a current value at the time of starting and holding smaller than that of the conventional product, so that the operation of the solenoid valve 4 is not easily affected by the temperature of the solenoid 5, and the response of the solenoid valve 4 has a rated voltage. This is the same as when applied to the solenoid valve 4.

  Since the solenoid valve drive device 31 according to the present embodiment determines the holding current and the starting current by learning, an appropriate holding current value and starting current value can be set even with the solenoid valve 4 having a low rated current / rated voltage. The solenoid valve 4 with a small rated current / rated voltage has a large current rising slope (speed) and can respond faster than a solenoid valve with a high rated current / rated voltage.

  Since the solenoid valve drive device 1 of the present embodiment informs the user that the holding current value and the starting current value are learned by the light emission of the light emitting diodes LD1 to LD5, the normal operation is performed before the learning operation is completed. The trouble can be avoided.

(Fourth embodiment)
Next, a fourth embodiment of the present invention will be described. FIG. 9 is a circuit diagram of a solenoid valve driving device 36 according to the fourth embodiment of the present invention. FIG. 10 is a flow of a learning program according to the fourth embodiment of the present invention.
The electromagnetic valve driving device 36 shown in FIG. 9 has an A / D converter 33 and wiring for connecting the A / D converter 33 and the contact M1 from the circuit diagram of the electromagnetic valve driving device 31 shown in FIG. The contact M1 is removed and connected only to the negative input terminal of the comparator OP. The learning program shown in FIG. 10 of the fourth embodiment is different from the third embodiment in that the rated current value is learned (S41 to S43). Therefore, here, the method for learning the rated current value will be mainly described, and the same points as those in the third embodiment are denoted by the same reference numerals as those in the third embodiment in the drawings and description, and description thereof will be omitted as appropriate.

  When the switch SW is pressed, the microcomputer 37 executes the learning program shown in FIG. The microcomputer 37 outputs a 100% drive command in S40, and then in S41, the comparator OP opens and closes the transistors TR1 and TR2, so that the signal input from the contact M2 via the first signal input terminal 10 oscillates. Check if it has stopped. When the drive command is temporarily reduced and the signal from the contact M2 starts oscillating, the command value (output voltage of the D / A converter 9) at that time is multiplied by the detection voltage of the detection resistor R3. The value is slightly smaller than the rated current value. The command value at this time is stored in the EEPROM 7. Therefore, the microcomputer 37 can measure the rated current without A / D conversion. As a result, the electromagnetic valve drive device 36 of the present embodiment does not require the A / D converter 33 required in the third embodiment, and can use a low-cost microcomputer 37.

(Fifth embodiment)
Next, a fifth embodiment of the present invention will be described. FIG. 11 is a circuit diagram of an electromagnetic valve drive device 41 according to the fifth embodiment. FIG. 12 is a flowchart of the drive control program for the solenoid valve drive device according to the fifth embodiment of the present invention.
In the fifth embodiment, after the drive control program of the solenoid valve drive device learns the drive waveform during the valve open state during holding using the PWM control, the electromagnetic control is performed based on the learned drive waveform during the valve open state during hold. The point which makes the valve 4 perform normal operation | movement differs from 1st Embodiment. Therefore, here, it demonstrates centering on a different point from 1st Embodiment, the point which is common in 1st Embodiment uses the same code | symbol as 1st Embodiment for drawing and description, and abbreviate | omits description suitably.

<Configuration of electromagnetic valve drive device>
In the electromagnetic valve drive device 41 shown in FIG. 11, the microcomputer 42 is connected to the contact M1 between the electromagnetic valve connection terminal CN2 and the detection resistor R3 via the A / D converter 33 via the second signal input terminal 34. The voltage and current of the contact M1 can be measured. The PWM controller 43 of the microcomputer 42 is connected to the base of the transistor TR3 via the PWM command output terminal 44. The transistor TR3 has a collector connected to a contact M3 provided on a wiring connecting the base of the transistor TR1 and a collector of the transistor TR2, and a contact M4 provided on a wiring connecting the detection resistor R3 and the power source E1. An emitter is connected to control opening and closing of the transistor TR1. Further, the microcomputer 42 is connected so that the light emitting diodes LD1 and LD2 (an example of a notification unit) can blink. The microcomputer 42 turns on the light emitting diode LD1 when the electromagnetic valve 4 performs normal operation, and turns on the light emitting diode LD2 when an abnormality occurs in the electromagnetic valve 4.

<Electromagnetic valve drive method>
When the microcomputer 42 inputs a drive command from a host device (not shown), the drive control program for the electromagnetic valve drive device shown in FIG. 12 is read from the EEPROM 7 and executed. In S50, the microcomputer 42 outputs a command for setting the current value to 0 from the D / A converter 8, and turns off the transistor TR2. In S51, when the microcomputer 42 outputs a PWM drive command having a duty ratio of 22% from the PWM controller 43 to the transistor TR3, the transistors TR1 and TR3 are opened and closed, and the current supplied to the solenoid 5 is set to the 22% rated current value. Stabilize. In this case, the power consumption of the microcomputer 42 is suppressed to about 1/20 of the power consumption when a 100% drive command is output to the comparator OP. Since the solenoid valve 4 is energized from a current value of zero, even if a 22% rated current is supplied to the solenoid 5, the plunger (not shown) is not attracted to the fixed iron core (not shown). Note that the duty ratio of the PWM drive command can be arbitrarily set depending on how much power consumption of the microcomputer 42 is suppressed, and the power consumption is suppressed to about 1/10 when 100% drive command is output to the comparator OP. If desired, a PWM drive command with a duty ratio of 31% may be output to the transistor TR3.

  In S52, the voltage change of the detection resistor R3 is input to the A / D converter 33, the average current value of the current flowing through the solenoid 5 is measured, and the obtained current value is used as the holding current AD value (rated current 22%). Current value) is stored in the EEPROM 7.

  In S53, the holding current value command is output to the comparison circuit 11, and the hysteresis detection type self-excited switching operation is started. That is, the PWM output is stopped and the energization to the solenoid 5 is turned off, and a command is supplied from the D / A converter 8 to the comparator OP to supply current to the solenoid 5 at the rated current of 22% obtained in S52. To do. As a result, in the driving means 3, the comparator OP compares the reference voltage from the microcomputer 42 and the input voltage from the contact M1 (detection voltage generated at the detection resistor R3), switches the output, and opens and closes the transistors TR1 and TR2. Start. At this time, the solenoid valve 4 is in a closed state, and the voltage of the contact M1 changes due to the inductance of the solenoid 5 when the plunger is not attracted. Therefore, in S54, an ON / OFF signal is input from the contact M2 to the microcomputer 42, and the abnormal return ON time and the abnormal return OFF time when the holding current is supplied in the abnormal recovery state are measured and stored in the EEPROM 7. Thereby, the ON time and OFF time when the solenoid valve 4 is not in the valve open state when the holding current is supplied are acquired.

  In S55, a 100% current value based on the current value of the rated current of 22% is calculated, and the calculated 100% current value command or MAX command (starting current value command) is output to the comparator OP. In S55, the starting current value command is maintained for 0.3 seconds, and the solenoid valve 4 is opened to start.

  In S56, a holding current value command for supplying a 22% rated current to the solenoid 5 is output to the comparator OP, and the current value of the current supplied to the solenoid 5 is decreased to the holding current value and the operation proceeds to the holding operation. . In S57, the drive waveform is monitored based on the ON / OFF signal input to the first signal input terminal 10. In S58, it is determined whether or not the oscillation due to the supply of the holding current has been started. When the ON signal is not input and the oscillation due to the supply of the holding current is not started (S58: NO), the process waits while monitoring the drive waveform.

  When the ON signal is input and oscillation by supplying the holding current is started (S58: YES), in S59, the timer in the microcomputer 42 is cleared and the ON time measurement for inputting the ON signal is started. Then, in S60, it is determined whether or not the driving unit 3 has stopped driving depending on whether or not the ON signal is switched to the OFF signal. If the drive has not been stopped (S60: NO), the system waits as it is.

  When the drive stop is confirmed (S60: YES), in S61, it is determined whether or not the measured ON time is the same as the abnormal recovery ON time measured in S54. If the measured ON time is the same as the abnormal return ON time (S61: YES), it is considered that the solenoid valve 4 is not normally maintained in the valve open state, and the process returns to S55. Then, starting and holding operations are performed again by the solenoid valve 4 by executing the processing after S55.

  On the other hand, if the measured ON time is not the same as the abnormal recovery ON time (S61: NO), whether or not the driving means 3 has stopped driving is determined in S62 depending on whether or not the ON signal is switched to the OFF signal. to decide. If the drive is not stopped (S62: NO), the process waits as it is. When the driving is stopped (S62: YES), in S63, the timer in the microcomputer 42 is cleared and measurement of the OFF time for inputting the OFF signal is started. Then, in S64, it is determined whether or not driving is started based on whether or not the OFF signal is switched to the ON signal. If the OFF signal is not switched to the ON signal and it is determined that the drive has not started (S64: NO), the process waits as it is. If the OFF signal is switched to the ON signal and it is determined that the driving is started (S64: YES), it is determined in S65 whether or not the measured OFF time coincides with the abnormal return OFF time measured in S54. If the measured OFF time does not coincide with the abnormal recovery OFF time (S65: NO), it is considered that the solenoid valve 4 is normally maintained in the valve open state, so the process returns to S59 and continues based on the drive waveform. The operation state of the solenoid valve 4 is monitored. On the other hand, when the measured OFF time coincides with the abnormal return OFF time (S65: YES), it is considered that the solenoid valve 4 is not normally maintained in the valve open state, and the process returns to S55. Then, starting and holding operations are performed again by the solenoid valve 4 by executing the processing after S55.

<Effect>
As described above, the electromagnetic valve drive device 41 of the present embodiment always performs the valve-opening drive waveform at the time of holding (determination of the abnormal return ON time and the abnormal return OFF time) before performing the normal operation and acquires the acquired holding time. Since the operating state of the solenoid valve 4 is monitored based on the valve opening driving waveform, it is not necessary to learn the holding current and the starting current in advance. Therefore, the operation state of the electromagnetic valve 4 can be detected using the abnormal return ON time and the abnormal return OFF time suitable for use, and the operability of the apparatus can be further enhanced.

(Sixth embodiment)
Next, a sixth embodiment of the present invention will be described. FIG. 13 is a circuit diagram of an electromagnetic valve driving device 61 according to the sixth embodiment.
In the electromagnetic valve driving device 61 of the sixth embodiment, a PWM converter circuit is used instead of the hysteresis converter circuit. Specifically, the PWM controller 70 is used instead of the comparison circuit 11. In the constant current control at the time of starting and holding, a voltage command of a designated current is output from the microcomputer 62 to the PWM controller 70. The PWM controller 70 compares the voltage command with the detected voltage generated in the detection resistor R3 by detecting the current flowing through the solenoid 5 of the solenoid valve 4, and if the detected voltage is less than the voltage command, the PWM waveform If the detected voltage is larger than the voltage command, the current supplied to the solenoid valve 4 is controlled to the specified constant current by controlling the PWM waveform to reduce the ON duty. To do.
In the present embodiment, the microcomputer 62, the PWM controller 70, the peak hold circuit 71, and the bottom hold circuit 72b constitute “monitoring means”.

14 to 17 show a detection voltage (voltage inputted from the contact M1) generated in the detection resistor R3 shown in FIG. 13 and a PWM output (measured by CP in the figure) outputted from the PWM controller 70 shown in FIG. Is an output). In particular, FIG. 14 is a diagram showing a plunger adsorption state current waveform at start-up in PWM system control. FIG. 15 is a diagram showing a plunger non-adsorption state current waveform in PWM control. FIG. 16 is a diagram illustrating a plunger adsorption state current waveform in PWM control. FIG. 17 is a diagram illustrating a current waveform at the time of abnormal recovery in PWM control.
As shown in FIG. 14 to FIG. 16, the PWM output that the PWM controller 70 outputs so that the current is controlled to the starting current value or the holding current value is a period of Tp1 when the starting current is supplied and when the holding current is supplied. The same. However, the ON time Tdon during one cycle Tp1 when the starting current is supplied is longer than the ON time Td1 during one cycle Td1 when the holding current is supplied. As shown in FIGS. 15 and 16, the PWM output in the plunger non-adsorption state and the PWM output in the plunger adsorption state when holding current is supplied have the same period Tp1 and the ON time Tp1 in the period Tp1.

  As shown in FIGS. 14 to 16, when the PWM controller 70 is controlling the current to a constant current, detection is performed in accordance with the impedance of the solenoid 5 and the current value at that time in the ON state of the fixed frequency PWM waveform. When the detection voltage generated in the resistor R3 increases and the PWM waveform is OFF, the detection voltage generated in the detection resistor R3 decreases according to the impedance of the solenoid 5 and the current value at that time. Therefore, the detection voltage generated in the detection resistor R3 fluctuates between a certain width (ripple value r) with the target voltage value z interposed therebetween. That is, when the plunger is in an attracted state as shown in FIG. 16 and the coil inductance is large, and when the plunger is in a non-adsorbed state and the coil inductance is small as shown in FIG. In other words, the ripple value r of the detection voltage is smaller when the attracting state has a larger inductance. By monitoring the ripple value r of the detection voltage, the adsorption / non-adsorption of the plunger can be determined.

Next, the operation of the electromagnetic valve driving device 61 will be described. FIG. 18 is a flow of a drive control program of the solenoid valve drive device.
When the ON signal or the power source that means it is energized, the microcomputer 62 of the control means 2 outputs a command voltage value corresponding to the starting current value to the PWM controller 70 (S71). The PWM controller 70 starts driving the transistor TR1 according to the command value.

  The driving control method for the transistor TR1 is performed by the microcomputer 62 outputting an ON pulse to the PWM controller 70 at a constant frequency. At this time, the microcomputer 62 reads the detection voltage generated in the detection resistor R3 due to the current flowing through the electromagnetic valve 4 into the A / D converter 63, so that the current of the current flowing through the electromagnetic valve 4 is reached until the starting current is reached. Monitor the value. This is determined by obtaining an average value of measured values for a certain time by inputting a current detection voltage to the terminal 65. The microcomputer 62 widens the pulse width of the ON pulse output to the PWM controller 70 if the current value is smaller than the command value, and narrows the pulse width of the ON pulse if the current value is larger than the command value. Thus, the driving unit 3 is driven so that the current value becomes the target current value.

  As described above, the microcomputer 62 expects that the driving means 3 has entered constant current driving (for example, after 0.3 seconds), and resets commands from the terminals 68 and 69 to the peak hold circuit 71 and the bottom hold circuit 72. (S72, S73), and the current value monitoring hold operation is started. The current value monitoring and holding operation is performed for at least one PWM cycle or more, and the peak value (maximum current value) and the bottom value (minimum current value) are respectively connected to the A / D converter 63 via terminals 66 and 67. Load with. Then, the current fluctuation range (= ripple value at start-up), which is the difference between the peak value and the bottom value, is measured (S74).

  In the case of an A / D converter that can perform A / D conversion without leaving a PWM-driven current waveform, it is not necessary to use the peak hold circuit 71 and the bottom hold circuit 72, and the PWM current waveform is set to one cycle or more. It is possible to convert continuously, select the maximum value / minimum value from these, and obtain the ripple value from the difference.

  A comparison is made as to whether or not the ripple value at the time of start-up matches a preset ripple value indicating start-up adsorption within a permissible range (S75). When the ripple value at the time of startup matches the specified ripple value (S75: YES), it can be determined that the plunger is in the suction state, and the operation proceeds to the holding operation after S76. On the other hand, when the ripple value at the start does not coincide with the specified ripple value (S75: NO), 100% rated voltage is applied for 0.2 seconds, and after secure suction (S82, S83), the process goes to S71. Returning, the above starting current command is issued again, and the adsorption confirmation sequence is performed.

  When shifting to the holding operation after S76, the holding current command voltage is output to the PWM controller 70 to decrease the current value (S76). The average current value is monitored based on the detection voltage generated in the detection resistor R3 (S77). If the holding current value is reached (S78: YES), the ripple value of the detection voltage generated in the detection resistor R3 is measured here. I do. That is, a reset command is issued to the peak hold circuit 71 and the bottom hold circuit 72 (S79), and a monitoring hold operation for the current value (detected voltage value) is started. Monitor and hold the current value (detected voltage value) for at least one PWM cycle, and each peak value (maximum current value or maximum voltage value) and bottom value (minimum current value or minimum voltage value) are connected The data is read by the A / D converter 63 via 66 and 67. Then, the fluctuation range of the detected voltage (= the ripple value of the detected voltage at the time of holding), which is the difference between the peak value and the bottom value, is measured (S80). If the measured ripple measurement value is smaller than the preset holding determination ripple value (S81: YES), the holding operation is maintained (the plunger is in the suction state), and the process returns to S79, and again the ripple value Repeat monitoring. On the other hand, if the measured ripple value is equal to or greater than the preset holding determination ripple value (S81: NO), it is determined that an abnormal return has occurred (the plunger is not in the attracted state), and the 100% rated voltage is 0.2. After a certain amount of time, a reliable suction is expected (S82, S83), the process returns to S71, and an activation current command is issued again to perform the suction confirmation sequence. Then, after confirming the suction, the operation moves to a holding operation.

  The microcomputer 62 repeats the above processing while the ON signal is input from the host device or while the power source that means it is energized. Since the holding operation is performed with a smaller current than that at the time of activation, a great effect is achieved in reducing power consumption. Further, since the abnormal return operation is statically performed based on the ripple value of the detection voltage generated in the detection resistor R3 during PWM control, for example, even if the fluid controlled by the solenoid valve 4 has high viscosity, The return can be detected, and the operation detection accuracy of the solenoid valve 4 can be improved. In other words, the operational reliability of the electromagnetic valve 4 can be guaranteed. Furthermore, since it is not necessary to provide a vibration sensor or the like, the apparatus cost can be reduced.

  As described above, the solenoid valve drive device 61, the solenoid valve 4, the solenoid valve drive method, and the drive control program for the solenoid valve drive device according to the present embodiment include the solenoid valve 4 to which a holding current is supplied due to an external impact or the like. The valve may close abnormally. Normally, the solenoid valve 4 has different inductances in the valve open state and in the valve closed state. In a specific circuit, the inductance is affected by the inductance and is generated in the detection resistor R3 arranged in series with the solenoid valve 4. The detected voltage changes. Focusing on this point, in the above configuration, when the holding current is supplied to the solenoid valve 4, the detection voltage generated at the detection resistor R3 is monitored, and the change in the detection voltage R3 causes the solenoid valve 4 to open normally. Detect whether the valve is closed abnormally. For this reason, the solenoid valve drive device 61, the solenoid valve 4, the solenoid valve drive method, and the drive control program for the solenoid valve drive device according to the present embodiment are based on the detection method (current waveform, plunger Unlike the shock vibration), the operation state of the solenoid valve 4 is detected statically and constantly by the change of the detection voltage generated in the detection resistor R3, so there is no need to provide a vibration sensor etc. in the solenoid valve 4 at low cost. Abnormalities can be detected quickly. Moreover, for example, even when the solenoid valve 4 controls a highly viscous liquid and the impact when the valve is closed is small, the abnormal valve closing operation and the normal valve closing operation of the solenoid valve 4 are clearly discriminated by the change in the detection voltage. So detection accuracy is high. When abnormality of the solenoid valve 4 is confirmed, the current supplied to the solenoid valve 4 is increased from the holding current, and the solenoid valve is automatically returned to the valve open state instantly.

  Therefore, according to the solenoid valve drive device 61, the solenoid valve 4, the solenoid valve drive method, and the drive control program for the solenoid valve drive device, the detection accuracy of the plunger holding state can be increased. Further, paying attention to the fact that the detection voltage generated in the detection resistor R3 changes depending on whether the solenoid valve 4 is normally opened or not when the holding current is supplied, the solenoid valve 4 is changed by the change of the detection resistor R3. Therefore, it is not necessary to provide a vibration sensor or the like in the solenoid valve, and it is inexpensive.

  The electromagnetic valve driving device 61 configured as described above is affected by the change in inductance generated by the opening / closing operation of the electromagnetic valve 4, and the electromagnetic valve 4 is supplied with a constant holding current and opened. The ripple value of the detection voltage generated in the detection resistor R3 arranged on the downstream side of the electromagnetic valve 4 differs depending on whether the electromagnetic valve is abnormally closed with the holding current supplied constantly. Focusing on this point, the solenoid valve drive device 61 measures the ripple value of the detected voltage after switching the current supplied to the solenoid valve 4 from the starting current to the holding current, and the measured ripple measurement value is sent to the solenoid valve 4. A comparison is made with the holding determination ripple value of the detection voltage generated in the detection resistor R3 when the holding current is supplied constant. When the measured ripple value matches the hold determination ripple value, it is determined to be normal, and when the measured ripple measurement value does not match the hold determination ripple value, it is determined to be abnormal. Therefore, unlike the detection method (current waveform, plunger impact vibration, etc.) using a transient phenomenon associated with the movement of the plunger, the operation state of the electromagnetic valve 4 is statically determined by the ripple value of the detection voltage generated in the detection resistor R3. Since it detects constantly, it is not necessary to provide a vibration sensor etc. in a solenoid valve, and abnormality can be detected rapidly at low cost. Moreover, for example, even when the solenoid valve 4 controls a highly viscous liquid and the impact when the valve is closed is small, the abnormal valve closing operation and the normal valve closing operation of the solenoid valve 4 are clearly discriminated by the ripple value of the detection voltage. Therefore, the detection accuracy is high.

(Seventh embodiment)
Next, a seventh embodiment of the present invention will be described. FIG. 19 is a flowchart of a learning program stored in the solenoid valve driving device 61 according to the seventh embodiment of the present invention.
In the seventh embodiment, when an electromagnetic valve 4 without control data is connected, a program for causing the control means 2 to learn the operating conditions of the electromagnetic valve 4 is the electromagnetic valve driving device 61 described in the sixth embodiment. Are stored in the microcomputer 62 (see FIG. 13).

  When the solenoid valve 4 is set in the connected state and the learning mode activation input is input, the microcomputer 62 of the control means 2 executes the learning program shown in FIG. 19 stored in the EEPROM 7. First, the microcomputer 62 outputs a current command equal to or higher than the rated current to the PWM controller 70, and sets the driving means 3 to the rated voltage driving state (driving transistor 100% ON state) (S91). At this time, the detection voltage generated in the detection resistor R3 is read by the A / D converter 63 and recorded as the rated current value of the solenoid valve 4 (S92).

  The microcomputer 62 equally divides the current value from 0 to the rated current value recorded in S92 (for example, 50 divisions). Then, until the current value becomes 0, a current value command is sequentially issued from the D / A converter 64 to the PWM controller 70 so as to decrease the current value from the high current value at a constant rate (for example, 2%) (S93, S94). Then, at the time of each descending current value command output, the microcomputer 62 resets the peak hold circuit 71 and the bottom hold circuit 72 in anticipation of the steady control operation state (excluding transient phenomena) at each descending current value. (S95), the monitoring hold operation of the detection voltage generated in the detection resistor R3 is started. That is, at least one PWM cycle, the peak hold circuit 71 and the bottom hold circuit 72 perform a monitoring hold operation of the detected voltage, the respective peak value and bottom value are read into the A / D converter 63, and the peak value ( The difference (ripple value) between the maximum voltage value) and the bottom value (minimum voltage value) is measured, and the descent current value command and the ripple value are associated and temporarily recorded (S95, S96, S97).

  While the operations of S93 to S97 are repeated, the plunger opens at some current value. If the current value command 0 is further continued, the plunger is surely returned (S94: YES, S98).

  Next, current value commands having the same current value as the current value at the time of descending are issued in order from the lowest (S99), and the ripple value r at each current value is measured by the same method (S95 to S97). Then, temporary recording is performed (S100 to S102). This is continued until the current immediately before the rated current (S103). Then, at some current value, adsorption of the plunger occurs.

  Depending on whether the plunger is attracted or not, the magnetic resistance of the solenoid 5 of the electromagnetic valve 4 changes and the inductance changes greatly. For example, in a certain DC24V solenoid valve, the inductance changes to about 1.4H at the time of adsorption, compared to about 0.6H at the time of non-adsorption. Due to the change, the ripple value r of the detection voltage (current flowing through the electromagnetic valve 4) also changes as shown in FIGS. A current region (ripple value hysteresis region) in which the ripple value r greatly changes between when the current is increased and when the current is decreased represents a plunger operation hysteresis region that can take two states, an adsorption state and a return state. If the current value (detection voltage) is below this hysteresis region, it will always be in the recovery state. If the current value (detection voltage) is above this hysteresis region, it will always be in the adsorption region. Under operating conditions, it varies slightly depending on factors such as vibration, pressure, and flow rate. Therefore, in actuality, it is used with a margin under more safe conditions. Within this plunger operation hysteresis region, if the driving means 3 is driven to have a constant current value in both states, the duty cycle is the same, but the ripple value r is different. Therefore, even during the holding operation, it can be easily determined based on the ripple value r of the detection voltage whether the suction state or the abnormal recovery state.

  Therefore, based on the ripple value stored in the temporary recording area 35 in S97 and S102, upper and lower limit current values of hysteresis areas having different ripple values are obtained (S104). Then, the lowest current value in the ripple value hysteresis region is set as the return current value (S105). Then, a margin value (for example, 5% of the rated current) is added to the return current value, and the current value used for learning close to that value is recorded and used as the holding current (S106). If the recorded holding current value is in the hysteresis region, it has two ripple values, and therefore, for example, an intermediate value (average value) of the two ripple current values is recorded and used as a holding determination value (S107). .

  Thus, during normal operation, if the measured ripple value measured when holding the plunger is larger than the hold determination ripple value acquired by the learning program, it can be determined that the plunger has returned to an abnormal state and the inductance is in a decreasing state. Further, if the measured ripple value at the time of holding the plunger is equal to or less than the holding determination ripple value acquired by the learning program, it can be determined that the plunger is maintained and the inductance is in a large state. In an environment where there is a lot of vibration shock, a margin value may be selectable, for example, a sufficient margin according to that is given to the holding current as an added value. If the minimum current required for holding the plunger is obtained from another request such as a guaranteed impact value, this is given as data.

  Then, the lowest current value in which the driving cycle does not change due to current rise and fall in the high current region, that is, the learning current value that is one level above the ripple value hysteresis region is recorded as the adsorption current (S108). The current value used for learning, which is close to a value obtained by adding a margin value (for example, 10% of the rated current) to this adsorption current, is recorded and used as the starting current value (S109). Then, for example, within 5% of the ripple value of the starting current value is recorded as an adsorption determination ripple value, and is used for determination of normal adsorption (S110). As described above, the microcomputer 62 ends the execution of the learning program.

  The magnitude of the ripple value exists in the same manner at the time of start-up adsorption and at the time of start-up non-adsorption. Therefore, the suction confirmation at the time of starting can be performed using the suction discrimination ripple value. In addition, in the plunger adsorption / non-adsorption determination method based on the current (voltage) ripple value, as in the second embodiment, the activation current value smaller than the rated current can be learned to reduce the power consumption during activation. .

  If power consumption is not reduced at the time of startup, since the purpose of suction operation and suction confirmation is at startup, it may be determined such as 80% of the rated current, or the rated current that is energized for 100% for a short time. It may be adsorbed by the method, and the adsorption may be confirmed from the cycle by dropping to an appropriate starting current.

  As described above, the solenoid valve driving device 61 of the seventh embodiment equally calculates the fall value by dividing the current value 0 from the predetermined value that can reliably start the solenoid valve 4 into the valve open state. When the current value supplied to the electromagnetic valve 4 is lowered according to the obtained fall value, the drop ripple value measured by the microcomputer 62 is stored in the primary storage means 35 in association with the current value at the time of current drop. Then, when the current value supplied to the solenoid valve 4 is increased from zero by the same value as the decrease value, the rising ripple value measured by the microcomputer 62 is associated with the current value at the time of current increase, and the primary storage means 35. To remember. Then, a lower limit current value in a hysteresis region having a different ripple value is obtained from the falling ripple value and the rising ripple value stored in the primary storage means 35, and a holding current value is determined by adding a margin value to the obtained lower limit current value. Thus, the holding current value suitable for the electromagnetic valve 4 is learned. Therefore, according to the electromagnetic valve driving device 61 of the present embodiment, the holding current value considering individual differences can be supplied to the electromagnetic valve to maintain the valve open state, and the energy saving effect can be further enhanced.

  The solenoid valve driving device 61 of the present embodiment obtains the upper limit current value of the hysteresis region having different ripple values from the falling ripple value and the rising ripple value stored in the primary storage area 35, and obtains one of the obtained upper limit current values. The starting current value suitable for the solenoid valve 4 is learned by adding the margin value to the larger learning current value and determining the starting current value. Therefore, according to the solenoid valve drive device 61 of the present embodiment, the starting current for opening the solenoid valve at the time of starting can be made smaller than the rated current in consideration of individual differences, and the energy saving effect can be further enhanced.

(Eighth embodiment)
Next, an eighth embodiment of the present invention will be described. FIG. 20 is a circuit diagram of an electromagnetic valve driving device 81 according to the eighth embodiment.
The electromagnetic valve driving device 81 shown in FIG. 20 is different from the first embodiment in that a circuit is configured so as to omit the D / A converter 8 included in the electromagnetic valve driving device 1 of the first embodiment. To do. Here, differences from the first embodiment will be mainly described, and common points will be denoted by the same reference numerals as those in the first embodiment, and description thereof will be omitted as appropriate.

In the solenoid valve driving device 81, the wiring in which the resistors R21, R22, and R23 are provided in series is connected between the microcomputer power supply E2 and the microcomputer 82 and the downstream side of the transistor TR3. A resistor R1 constituting the comparison circuit 11 is connected between the resistors R21 and R22. The transistor TR3 has a base connected to the microcomputer 82, an emitter connected between the resistors R22 and R23, and a collector connected to a wiring connecting the detection resistor R3 and the power source E1.
In this embodiment, the microcomputer 82, the comparison circuit 11, the resistors R21 to R25, and the transistor TR3 constitute “monitoring means”.

  In such a solenoid valve drive device 81, when the microcomputer 82 turns off the transistor TR3, the voltage applied to the contact M11 is defined by the resistors R21, R22, and R23. On the other hand, when the microcomputer 82 turns on the transistor TR3, the voltage applied to the contact M11 is defined by the resistors R21 and R22. Therefore, the electromagnetic valve drive device 81 changes the voltage applied to M11 by the microcomputer 82 turning ON / OFF the transistor TR3 and changes the reference voltage of the comparator OP. Therefore, the D / A converter 8 of the first embodiment. Even if is omitted, the starting current value and the holding current value can be controlled. Since the microcomputer 82 does not include the D / A converter 8, the solenoid valve driving device 81 cannot learn the starting current value and the holding current value, but can be made low-cost by using an inexpensive microcomputer 82.

In addition, this invention is not limited to the said embodiment, Various application is possible.
(1) For example, in the above embodiment, the drive control program and learning program for the electromagnetic valve driving device are stored in the EEPROM 7, but the host device stores the drive control program and learning program for the electromagnetic valve driving device, and the electromagnetic valve driving device. The drive control program of the solenoid valve drive device may be downloaded when 1, 31, 41 inputs a drive command from the host device. Further, the solenoid valve driving device 1, 31, 41 is input to the host device by causing the solenoid valve driving device to execute a drive control program or a learning program, and to input a command created by executing the solenoid valve driving device drive control program. The control means 2 and the drive means 3 may be controlled.
(2) For example, in the above embodiment, when the current detection AD conversion circuit is in the solenoid valve drive device 1, 31, 41, 100% drive is performed at the time of ON activation periodically or always, and the current value is measured. Thus, the coil resistance of the solenoid 5 is obtained, the current solenoid valve temperature is estimated based on a change from the resistance value of the known temperature, and temperature correction may be applied to various set values.
(3) For example, in the above embodiment, the rated current value 100% is supplied to the solenoid valve 4 and driven, the current value falling time from the rated current value 100% to the holding current value is measured, and the inductance measurement is performed individually. You may carry out about the solenoid valve 4.
(4) In the first and second embodiments, when the minimum current required for holding the plunger is obtained from another request such as a guaranteed anti-impact value, it is given as data and obtained by the microcomputer 6. You may make it detect the operation state of the solenoid valve 4 compared with a drive waveform.
(5) If the performance characteristics of the solenoid valve can be limited, the binary value of the start / hold current can be set with the resistance voltage divider and the switching transistor instead of the D / A converter 8 shown in FIG.
(6) In the sixth embodiment, if the current value waveform is monitored by the high-speed A / D converter 63, the peak hold circuit 71 and the bottom hold circuit 72 are not essential.
(7) In the first embodiment, the solenoid valve 4 is activated by outputting a rated current drive command. However, the activation current may be smaller than the rated current.

1, 31, 36, 41, 51, 61, 81 Electromagnetic valve driving device 3 Driving means 4 Electromagnetic valve 6, 32, 37, 42, 52, 62, 82 Microcomputer (monitoring means, driving waveform acquisition means, abnormality detection means, An example of notification means, holding current value control means, holding current value learning means, starting current value learning means, ripple value measuring means)
R3 detection resistors LD1 to LD3 Light-emitting diode (an example of notification means)

Claims (12)

In the solenoid valve driving device that maintains the valve open state of the solenoid valve by supplying a holding current smaller than the start current to the solenoid valve that is in the valve open state by supplying the start current,
A detection resistor that is arranged in series with the solenoid valve and detects an energization current to the solenoid valve;
Monitoring means for monitoring a detection voltage generated in the detection resistor when supplying a current to the solenoid valve;
Whether the solenoid valve is opened normally or the solenoid valve is closed abnormally due to a change in the detection voltage monitored by the monitoring means when the holding current is supplied to the solenoid valve An anomaly detection means for detecting
An electromagnetic valve driving device comprising: automatic return means for automatically returning the electromagnetic valve to a valve open state by increasing a current supplied to the electromagnetic valve when the abnormality detection means detects an abnormality. In the electromagnetic valve drive device according to claim 1,
The monitoring means includes
The detection voltage generated in the detection resistor is compared with a reference voltage adjusted to a target current value, and when the detection voltage is equal to or lower than the reference voltage, the current is supplied to the solenoid valve. When the detected voltage exceeds the reference voltage, driving means that stops driving and does not supply current to the solenoid valve;
Drive waveform acquisition means for detecting a drive state of the drive means by an electric signal and acquiring a drive waveform,
The abnormality detection means includes a valve-open-time drive waveform acquired by the drive waveform acquisition means when the solenoid valve is supplied with the holding current, and a valve when the solenoid valve is supplied with the holding current. When the valve is in a closed state, the drive waveform acquired by the drive waveform acquisition unit is different from the drive waveform in the valve closed state, and the drive waveform acquired by the drive waveform acquisition unit after the holding current is supplied to the solenoid valve It is determined whether or not the drive waveform coincides with the open-state drive waveform. When the drive waveform matches the drive waveform during the valve-open state, it is determined to be normal, and the drive waveform matches the drive waveform during the valve-open state. An electromagnetic valve driving device characterized in that if it is not, it is judged as abnormal. In the electromagnetic valve drive device according to claim 2,
When the solenoid valve supplied with the holding current performs the valve closing operation from the valve open state, the OFF time during the valve closing operation acquired by the drive waveform acquisition means is the OFF time of the drive waveform during the valve open state. Is different,
The abnormality detection means measures an OFF time of the drive waveform acquired by the drive waveform acquisition means after supplying the holding current to the solenoid valve, and the OFF time of the drive waveform is the drive waveform when the valve is open. An electromagnetic valve driving device that detects an abnormality even when the time is longer than an OFF time. In the solenoid valve drive device according to claim 2 or claim 3,
When the fall value is obtained by equally dividing the predetermined value from the predetermined value that can start the solenoid valve into the valve open state to the current value 0, and the current value supplied to the solenoid valve is lowered according to the fall value Storage means for storing the driving waveform at the time of descent acquired by the driving waveform acquisition means in association with the current value at the time of descent of current;
When the current value supplied to the solenoid valve is increased from zero by the same value as the decrease value, it is determined whether or not the drive waveform acquired by the drive waveform acquisition means matches the drive waveform at the time of decrease And a holding current value learning means for determining a holding current value by adding a margin value to a currently measured current value when it is determined that they do not coincide with each other. In the electromagnetic valve drive device according to claim 4,
After the holding current value learning means determines the holding current value, the drive waveform acquisition means obtains the drive when the current value supplied to the solenoid valve is further increased by the same value as the fall value. Starting current value learning means for determining whether or not the waveform matches the driving waveform at the time of lowering, and determining a starting current value by adding a margin value to the current value currently measured when it is determined that they match An electromagnetic valve driving device comprising: In the electromagnetic valve drive device according to claim 1,
The monitoring means includes
A driving means for opening and closing a circuit for supplying current to the solenoid valve by a PWM output at a constant period, and controlling the current value of the current to be supplied to the solenoid valve to be constant;
A ripple value measuring means for measuring a ripple value of a detection voltage generated in the detection resistor in a state where the driving means controls the current to be constant,
The abnormality detection means includes a case where the electromagnetic valve is supplied with the holding current constant and the valve is opened, and a case where the electromagnetic valve is abnormally closed with the holding current supplied constant. The ripple value of the detection voltage generated in the detection resistor is different, and the ripple measurement value measured by the ripple value measuring means is when the solenoid valve is supplied with the holding current constant and the valve is opened. It is determined whether or not the holding determination ripple value of the detection voltage generated in the detection resistor matches, and when the ripple measurement value matches the holding determination ripple value, it is determined as normal, and the ripple measurement value is An electromagnetic valve driving device characterized in that an abnormality is determined when the holding determination ripple value does not match. In the electromagnetic valve drive device according to claim 6,
When the fall value is obtained by equally dividing the predetermined value from the predetermined value that can start the solenoid valve into the valve open state to the current value 0, and the current value supplied to the solenoid valve is lowered according to the fall value First storage means for storing the ripple value at the time of falling measured by the ripple value measuring means in association with the current value at the time of current drop;
When the current value supplied to the solenoid valve is increased from zero by the same value as the decreasing value, the rising ripple value measured by the ripple value measuring means is stored in association with the current value when the current increases. A second storage means;
A lower limit current value of a hysteresis region having a different ripple value is obtained from the falling ripple value stored in the first storage means and the rising ripple value stored in the second storage means, and a margin is provided for the lower limit current value. And a holding current value learning means for determining the holding current value by adding a value. In the electromagnetic valve drive device according to claim 7,
An upper limit current value in a hysteresis region having different ripple values is obtained from the falling ripple value stored in the first storage means and the rising ripple value stored in the second storage means, and one of the upper limit current values is obtained. An electromagnetic valve driving device comprising a starting current value learning means for determining a starting current value by adding a margin value to a larger learning current value. In the electromagnetic valve drive device according to any one of claims 1 to 8,
An electromagnetic valve driving device comprising: a notifying means for notifying that the abnormality detecting means has detected an abnormality.   An electromagnetic valve comprising the electromagnetic valve driving device according to any one of claims 1 to 9. In the solenoid valve driving method of maintaining the valve open state of the solenoid valve by supplying a holding current smaller than the start current to the solenoid valve that is in the valve open state by supplying the startup current,
A monitoring step of monitoring a detection voltage generated in a detection resistor that is arranged in series with the electromagnetic valve and detects an energization current to the electromagnetic valve when supplying a current to the electromagnetic valve;
When the holding current is supplied to the solenoid valve, the solenoid valve is normally opened due to a change in the detection voltage monitored in the monitoring step, or the solenoid valve is abnormally closed. An anomaly detection step for detecting
An electromagnetic valve drive method comprising: an automatic return step for automatically returning the electromagnetic valve to a valve open state by increasing a current supplied to the electromagnetic valve when an abnormality is detected in the abnormality detection step. . In the drive control program of the solenoid valve driving device that maintains the valve open state of the solenoid valve by supplying a holding current smaller than the start current to the solenoid valve that is in the valve open state by supplying the start current,
Computer
Monitoring means for monitoring a detection voltage generated in a detection resistor that is arranged in series with the electromagnetic valve and detects a current flowing to the electromagnetic valve when supplying current to the electromagnetic valve;
Whether the solenoid valve is opened normally or the solenoid valve is closed abnormally due to a change in the detection voltage monitored by the monitoring means when the holding current is supplied to the solenoid valve An anomaly detection means for detecting
An electromagnetic valve drive device that functions as an automatic return means for automatically returning the electromagnetic valve to a valve open state by increasing a current supplied to the electromagnetic valve when the abnormality detection means detects an abnormality. Drive control program.

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