JP2018054585A - Disconnection detector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To rapidly detect a disconnection of a wire connected to a solenoid coil of a solenoid valve without error.SOLUTION: A disconnection detector 1 includes: a first switching element 2 for switch-controlling whether current is made to flow to a solenoid coil of the solenoid valve; a first disconnection detection circuit 3 for detecting a disconnection of a wire connected to the solenoid coil when the first switching element is in on; and a second disconnection detection circuit 4 for detecting the disconnection of the wire when the first switching element is in off.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a disconnection detection device that detects disconnection of wiring connected to a solenoid coil of a solenoid valve.

  Solenoid valves are widely used for the purpose of switching control of the flow rate of oil supplied to an engine and the steering of a ship. The opening and closing of the solenoid valve is controlled depending on whether or not a current is passed through the solenoid coil. The circuit that controls whether or not current flows through the solenoid coil of a marine solenoid valve is placed at a location far from the solenoid valve for the purpose of avoiding noise and the need to secure a location for the solenoid valve. Sometimes. In this case, wiring for electrically connecting the solenoid coil of the solenoid valve and a circuit for controlling the solenoid coil must be routed in the ship.

  The longer the total length of the wiring, the higher the possibility of disconnection. In large vehicles such as ships, it is often not easy to notice even if the wiring is disconnected, and the controlled object will not operate normally, so it will be understood that the disconnection has occurred for the first time. Can cause problems.

  The current in the circuit for controlling whether or not to pass a current through the solenoid coil varies due to various factors during the period when the current is passed through the solenoid coil. Therefore, it is not easy to detect the disconnection of the wiring connected to the solenoid coil during the period in which the current flows through the solenoid coil. In view of this, there has been proposed a method for detecting the disconnection of wiring within a period in which no current is passed through the solenoid coil (see Patent Document 1).

Japanese Patent No. 5233760

  Patent Document 1 discloses a technique for detecting disconnection when no current is flowing through the solenoid coil, but does not disclose performing disconnection detection while a current is flowing through the solenoid coil. Since it is not possible to know in advance at what timing the disconnection will occur, it is desirable to be able to detect the disconnection quickly regardless of whether or not current is flowing through the solenoid coil.

  Since the solenoid coil of the solenoid valve is an inductive load, the current flowing through the solenoid coil gradually increases to a steady current with a constant slope after starting to flow. Therefore, the current flowing through the solenoid coil is less than the steady current within a predetermined period after the current starts to flow through the solenoid coil, and there is a possibility that it is erroneously determined to be disconnected within this period.

  The present invention has been made in order to solve the above-described problems, and provides a disconnection detection device capable of detecting a disconnection of a wiring connected to a solenoid coil of a solenoid valve quickly and without error.

In order to solve the above-described problem, in one aspect of the present invention, a first switching element that performs switching control as to whether or not to pass a current through a solenoid coil of a solenoid valve;
A first disconnection detection circuit for detecting disconnection of wiring connected to the solenoid coil when the first switching element is on;
A disconnection detection device is provided, comprising: a second disconnection detection circuit that detects disconnection of the wiring when the first switching element is off.

  Disconnection signal generation for outputting a first signal for notifying that the wiring is disconnected when a disconnection is detected continuously for a predetermined time in at least one of the first disconnection detection circuit and the second disconnection detection circuit May be provided.

  The disconnection signal generation unit may prohibit the output of the first signal for the predetermined time after the open / close state of the electromagnetic valve is switched.

A disconnection detection combining unit that generates a second signal indicating that the disconnection has been detected when a disconnection of the wiring is detected in at least one of the first disconnection detection circuit and the second disconnection detection circuit;
The disconnection signal generation unit may output the first signal when the second signal is continuously detected for the predetermined time.

The disconnection signal generation unit includes a resistor and a capacitor,
The predetermined time may be a time according to a time constant between the resistor and the capacitor.

The disconnection signal generation unit starts a count operation when a disconnection is detected in at least one of the first disconnection detection circuit and the second disconnection detection circuit, and counts up while the disconnection is continuously detected. Have a counter to
The predetermined time may be a time when the count value of the counter becomes a predetermined value.

The first disconnection detection circuit includes:
A first current detector for detecting a current flowing through the solenoid coil when the first switching element is on;
A current determination unit that determines whether or not the current detected by the first current detection unit is equal to or less than a predetermined threshold, and determines that the current is disconnected when the current is equal to or less than the threshold;

The second disconnection detection circuit includes:
A second current detection unit that detects a current flowing through a path connected in parallel to the first switching element when the first switching element is off;
And a second switching element that is turned on or off by a current detected by the second current detection unit.

A light emitting element that operates as the second current detection unit and emits light when a current flows through a path connected in parallel to the first switching element;
A photocoupler that operates as the second switching element and that is turned on when the light emitting element emits light and that is electrically insulated from each other may be provided.

A plurality of disconnection detectors for detecting disconnection of a plurality of wires connected to a plurality of solenoid valves, and
A wiring group disconnection detection unit that generates a third signal for notifying that a disconnection has occurred in at least one of the plurality of wirings when a disconnection is detected in at least one of the plurality of disconnection detectors; ,
Each of the plurality of disconnection detectors may include the first switching element, the first disconnection detection circuit, and the second disconnection detection circuit.

  The electromagnetic valve may be used for switching ship equipment.

  According to the present invention, the disconnection of the wiring connected to the solenoid coil of the solenoid valve can be detected quickly and without error.

The circuit diagram of the disconnection detection apparatus by the 1st Embodiment of this invention. The figure which shows the specific structural example of a disconnection signal production | generation part. The figure which shows the specific structural example of a disconnection signal production | generation part. The figure which shows the specific structural example of a disconnection signal production | generation part. The figure which shows the specific structural example of a disconnection signal production | generation part. The timing diagram of the disconnection detection apparatus of FIG. The timing diagram of the disconnection detection apparatus by one comparative example. The circuit diagram of the disconnection detection apparatus by 2nd Embodiment. The timing diagram of the disconnection detection apparatus of FIG.

  Hereinafter, embodiments of the present invention will be described in detail. Below, the disconnection detection apparatus which detects the disconnection of the wiring mainly connected with the solenoid coil of the solenoid valve mounted in a ship is demonstrated. However, the disconnection detection apparatus according to the present embodiment can also be applied to the purpose of detecting disconnection of the wiring connected to the solenoid coil of the solenoid valve mounted on various apparatuses other than the ship.

(First embodiment)
FIG. 1 is a circuit diagram of a disconnection detection apparatus 1 according to a first embodiment of the present invention. The disconnection detecting device 1 of FIG. 1 includes a drive transistor (first switching element) 2, a first disconnection detection circuit 3, and a second disconnection detection circuit 4.

  The drive transistor 2 performs switching control as to whether or not current flows through the solenoid coil L of the solenoid valve. The drive transistor 2 in FIG. 1 shows an example of an NPN bipolar transistor, but it may be composed of a PNP bipolar transistor or FET (Field Effect Transistor). The drive transistor 2 in FIG. 1 is turned on when the base voltage is high, and causes a current to flow through the solenoid coil L. The opening and closing of the solenoid valve is controlled by switching whether or not a current is passed through the solenoid coil L.

  The first disconnection detection circuit 3 detects the disconnection of the wiring connected to the solenoid coil L when the drive transistor 2 is turned on, that is, when the current flows through the solenoid coil L. The electromagnetic valve mounted on the ship may be installed at a location far away from the disconnection detection device of FIG. 1, and the wiring connected to the solenoid coil L becomes long and is easily disconnected. For this reason, the 1st disconnection detection circuit 3 detects a disconnection in the state in which the electric current is flowing through the solenoid coil L.

  The first disconnection detection circuit 3 includes a current sensor 5 and a current determination unit 6. The current sensor 5 is connected in series to the solenoid coil L. More specifically, the solenoid coil L, the current sensor 5 and the drive transistor 2 are connected in series between the power supply voltage node Vcc and the ground node. The current flowing through the solenoid coil L flows through the current sensor 5, then flows between the collector and emitter of the drive transistor 2, and is guided to the ground node. The current sensor 5 detects the current flowing through the solenoid coil L by electrically insulating it. Thereby, the noise of the wiring connected to the solenoid coil L is not transmitted to the subsequent circuit on the current sensor 5.

  The current determination unit 6 detects a current flowing through the current sensor 5 and determines whether or not the detected current is equal to or less than a threshold value. If the detected current is equal to or smaller than the threshold value, the current determination unit 6 outputs a first disconnection detection signal V1 indicating that a disconnection has been detected. The first disconnection detection signal V1 is, for example, a signal that becomes a high potential when a disconnection is detected.

  The second disconnection detection circuit 4 detects disconnection of the wiring connected to the solenoid coil L when the drive transistor 2 is off. The second disconnection detection circuit 4 includes resistors R1 and R2 and a photocoupler 7. More specifically, a series circuit in which the resistor R1 and the light emitting element 7a in the photocoupler 7 are connected in series is connected in parallel between the collector and the emitter of the drive transistor 2. A resistor R2 and a light receiving element 7b in the photocoupler 7 are connected in series between the power supply voltage node Vcc2 and the ground node. The light receiving element 7b is a second switching element and is turned on when a current flows through the resistor R1 and the light emitting element 7a in the photocoupler 7. Since the light emitting element 7a and the light receiving element 7b are electrically insulated, the use of the photocoupler 7 prevents the influence of noise and the like of the wiring connected to the solenoid coil L from being transmitted to the circuit on the rear stage side of the photocoupler 7.

  When the drive transistor 2 is off, no current flows between the collector and the emitter of the drive transistor 2, but a slight current is present in the resistor R 1 and the light emitting element 7 a in the photocoupler 7 as long as the wiring is not disconnected. Flows. Due to this current, the light receiving element 7b in the photocoupler 7 is turned on, and accordingly the light receiving element 7b is also turned on, and the connection path between the resistor R2 that is the output of the second disconnection detection circuit 4 and the photocoupler 7 is set to the low potential. Become. On the other hand, when the wiring is disconnected, no current flows through the resistor R1 and the light emitting element 7a in the photocoupler 7. Therefore, the light receiving element 7b in the photocoupler 7 is turned off, and the output of the second disconnection detection circuit 4 becomes a high potential. In this way, the second disconnection detection circuit 4 outputs the second disconnection detection signal V2 that becomes a high potential when the disconnection is detected.

  As described above, the disconnection detection device 1 in FIG. 1 performs the disconnection detection when the drive transistor 2 is on in the first disconnection detection circuit 3, and detects the disconnection when the drive transistor 2 is off in the second disconnection detection circuit 4. Do it.

  In addition, the disconnection detection apparatus 1 in FIG. 1 is not an essential component, but may include a disconnection detection synthesis unit 8 and a disconnection signal generation unit 9. The disconnection detection combining unit 8 generates a second signal V3 indicating that a disconnection is detected when a disconnection of the wiring is detected in at least one of the first disconnection detection circuit 3 and the second disconnection detection circuit 4. More specifically, the disconnection detection synthesis unit 8 outputs a first disconnection detection signal V1 that outputs a high potential when the first disconnection detection circuit 3 detects a disconnection, and a high potential when the second disconnection detection circuit 4 detects a disconnection. A second signal V3 which is a logical sum with the second disconnection detection signal V2 is generated and output. The second signal V3 is a signal that goes high when a disconnection is detected in at least one of the first disconnection detection circuit 3 and the second disconnection detection circuit 4.

  The disconnection signal generation unit 9 indicates that the wiring connected to the solenoid coil L is disconnected when a disconnection is detected continuously for at least one of the first disconnection detection circuit 3 and the second disconnection detection circuit 4 for a predetermined time. The 1st signal Vout to alert | report is output. The first signal Vout is a final output signal of the disconnection detection device 1 in FIG. When the first signal Vout is, for example, a high potential, it is notified that the wiring is disconnected. The first signal Vout may be received by a warning circuit (not shown), for example, and arbitrary warning processing may be performed.

  The reason for providing the disconnection signal generation unit 9 is that, in particular, the ship is equipped with various devices that perform electromagnetic radiation, and the total length of the wiring connected to the solenoid coil L is long. This is because the disconnection detection circuit 3 and the second disconnection detection circuit 4 may temporarily erroneously detect disconnection. Since the disconnection signal generation unit 9 does not output the first signal Vout unless a disconnection is detected for a predetermined time, even if a disconnection is temporarily detected by noise superimposed on the wiring, the influence thereof Not receive. In addition, immediately after switching the opening / closing direction of the solenoid valve, the current flowing through the solenoid coil L may be lower than the steady-state current. However, by providing the disconnection signal generator 9, the opening / closing direction of the solenoid valve is switched. Since disconnection detection is not performed for a predetermined time, there is no problem of erroneously detecting disconnection immediately after switching the opening / closing direction of the solenoid valve.

  2A, 2B, 2C, and 2D are diagrams illustrating specific configuration examples of the disconnection signal generation unit 9. FIG. The disconnection signal generation unit 9 in FIG. 2A includes resistors R3 and R4, a capacitor C, a switch 11, a comparator 12, and a reference voltage generation circuit 13. A resistor R4 and a capacitor C are connected in series between the power supply voltage node Vcc and the ground node. A connection node between the resistor R4 and the capacitor C is connected to the first input terminal of the comparator 12, and the resistor R3 and the switch 11 are connected in series between the connection node and the ground terminal. The reference voltage generated by the reference voltage generation circuit 13 is input to the second input terminal of the comparator 12.

  The switch 11 is switched on or off by the logic of the second signal V3 output from the disconnection detection synthesis unit 8. More specifically, the switch 11 is turned off when a disconnection is detected by the disconnection detection combining unit 8, and the switch 11 is turned on when no disconnection is detected.

  In both the first disconnection detection circuit 3 and the second disconnection detection circuit 4, when the disconnection is not detected, the switch 11 is on, and the charge charged in the capacitor C is discharged via the resistor R3. Therefore, the voltage at the first input terminal of the comparator 12 is lower than the reference voltage at the second input terminal, and the comparator 12 outputs, for example, a low potential.

  When a disconnection is detected in at least one of the first disconnection detection circuit 3 and the second disconnection detection circuit 4, the switch 11 is turned off, and charge is accumulated in the capacitor C via the resistor R4. The time required for the charge to be accumulated in the capacitor C depends on a time constant that is a multiplication of the capacitance of the capacitor C and the resistance value of the resistor R4. If the switch 11 continues to be off, the accumulated charge in the capacitor C gradually increases, and the voltage at the first input terminal of the comparator 12 also increases. When the disconnection is detected continuously for a predetermined time, the voltage of the first input terminal exceeds the reference voltage of the second input terminal, and the output of the comparator 12 (first signal Vout) changes to, for example, a high potential.

  The disconnection signal generation unit 9 in FIG. 2B is obtained by partially changing the circuit in FIG. 2A. 2B has a resistor R4, a switch 11, and a capacitor C connected in series between the power supply voltage node Vcc and the ground node. A resistor R3 is connected to the capacitor C in parallel. A connection node of the switch 11, the capacitor C, and the resistor R3 is connected to the first input terminal of the comparator 12.

  The switch 11 is turned on when a disconnection is detected by the disconnection detection combining unit 8 and turned off when a disconnection is not detected. As described above, the switch 11 in FIG. 2B is turned on or off at a timing opposite to that of the switch 11 in FIG. 2A.

  When no disconnection is detected in either the first disconnection detection circuit 3 or the second disconnection detection circuit 4, the switch 11 is turned off, and the electric charge accumulated in the capacitor C is discharged through the resistor R3. When a disconnection is detected in at least one of the first disconnection detection circuit 3 and the second disconnection detection circuit 4, the switch 11 is turned on and the capacitor C is charged via the resistor R4. When the disconnection continues and is detected for a predetermined time, the voltage across the capacitor C increases, and the first signal Vout, which is the output of the comparator 12, becomes a high potential.

  The disconnection signal generator 9 in FIG. 2C includes a counter 14 instead of the capacitor C in FIGS. 2A and 2B. Resistors R4 and R3 and a switch 11 are connected in series between the power supply voltage node Vcc and the ground node. A connection node between the resistors R3 and R4 is connected to an enable terminal of the counter 14. The counter 14 performs a count-up operation at a predetermined clock cycle when the enable terminal is at a high potential. Similarly to the switch 11 in FIG. 2A, the switch 11 is turned on when the disconnection detection combining unit 8 does not detect a disconnection, and is turned off when the disconnection is detected. While the switch 11 is off, the enable terminal is at a low potential, and the counter 14 does not perform a count-up operation. When the switch 11 is turned off, the enable terminal becomes a high potential, and the counter 14 performs a count-up operation.

  When a disconnection is detected in at least one of the first disconnection detection circuit 3 and the second disconnection detection circuit 4, the counter 14 performs a count-up operation while the disconnection continues. The output value of the counter 14 is input to the first input terminal of the comparator 12. The reference voltage is input to the second input terminal of the comparator 12 as in FIGS. 2A and 2B. When the output value of the counter 14 becomes equal to or higher than the reference voltage, the first signal Vout that is the output of the comparator 12 becomes a high potential. When the disconnection continues for a predetermined time, the first signal Vout that is the output of the counter 14 changes to a high potential.

  FIG. 2D is a flowchart when the processing operation of the disconnection signal generation unit 9 is performed by software. The flowchart of FIG. 2D can be executed by a computer, for example. The computer repeats the process of FIG. 2D at short intervals.

  First, it is determined whether or not a disconnection is detected by the disconnection detection / synthesis unit 8 (step S1). If no disconnection is detected, the count value is initialized to zero (step S2), the first signal Vout is set to a low potential (step S3), and the process ends.

  If it is determined in step S1 that a disconnection has been detected, it is determined whether the count value is greater than or equal to a threshold value (step S4). If the count value is less than the threshold value, the count value is counted up (step S5), the first signal Vout is set to a low potential (step S6), and the process is terminated.

  If it is determined in step S4 that the count value is greater than or equal to the threshold value, the first signal Vout is set to a high potential (step S7), and the process ends.

  3A is a timing chart of the disconnection detecting device 1 of FIG. 1, and FIG. 3B is a timing chart of the disconnection detecting device 1 according to a comparative example. The disconnection detection device 1 according to a comparative example is a device in which the disconnection signal generation unit 9 is omitted from the disconnection detection device 1 of FIG.

  3A and 3B show the gate voltage Vg of the drive transistor 2, the collector-emitter voltage Vce of the drive transistor 2, the current Iin flowing through the light emitting element 7a in the photocoupler 7, and the output current of the light receiving element 7b in the photocoupler 7. The waveforms of Iout, current Icoil flowing through the solenoid coil L, current Isensor detected by the current sensor 5, and final output signal Vout are shown. FIG. 3A also shows a voltage waveform Vo at the first input terminal of the comparator 12 in the disconnection signal generation unit 9.

  Since the disconnection detection device 1 in FIG. 3B does not have the disconnection signal generation unit 9, when a disconnection is detected in at least one of the first disconnection detection circuit 3 and the second disconnection detection circuit 4, it is used as a final output signal as it is. Reflected. Immediately after the opening / closing of the solenoid valve (time t1), the current flowing through the solenoid coil L becomes lower than the steady-state current, and the disconnection is temporarily detected erroneously due to the influence of noise, etc., and this is the final output as it is. Output as signal Vout. Therefore, as shown in FIG. 3B, an erroneous disconnection is detected immediately after the opening / closing of the solenoid valve is switched. On the other hand, the disconnection signal generation unit 9 in the disconnection detection apparatus 1 according to the present embodiment does not continue disconnection for a predetermined time even if disconnection is detected in at least one of the first disconnection detection circuit 3 and the second disconnection detection circuit 4. This is not reflected in the first signal Vout which is the final output signal. Therefore, as shown in FIG. 3A, the disconnection detection is not performed within a predetermined time after the opening / closing of the solenoid valve is switched, and the erroneous detection of the disconnection can be prevented.

  As described above, in the first embodiment, whether or not a current flows through the solenoid coil L of the solenoid valve, the disconnection of the wiring connected to the solenoid coil L is detected, so that the disconnection is quickly detected. it can. In the present embodiment, the first disconnection detection circuit 3 that detects disconnection when the drive transistor 2 that controls whether or not the current flows through the solenoid coil L is on, and the second that detects disconnection when the drive transistor 2 is off. As long as the first signal Vout notifying that the disconnection has occurred is not output unless the disconnection is detected continuously for at least one of the predetermined time with the disconnection detection circuit 4, as just after switching of the opening / closing of the solenoid valve. Even if the current flowing through the solenoid coil L is lower than the steady-state current, or if a disconnection is detected temporarily due to noise or the like, the first signal Vout is not output, and disconnection detection prevents erroneous detection. It can be performed.

(Second Embodiment)
Ships and the like are equipped with a plurality of solenoid valves, and the number of wires connected to the solenoid coil L of each solenoid valve increases, which may make the detection of disconnection complicated. In the second embodiment described below, disconnection detection of a plurality of wirings is efficiently performed.

  FIG. 4 is a circuit diagram of the disconnection detecting device 1 according to the second embodiment. FIG. 4 shows an example of detecting the disconnection of the wiring connected to the solenoid coil L of the two solenoid valves. However, the number of solenoid valves may be three or more, and the circuit of FIG. Applicable to detection.

  The disconnection detecting device 1 of FIG. 4 detects the disconnection of the wiring connected to the solenoid coil L of the first electromagnetic valve and the first wiring disconnection detection unit 21 that detects the disconnection of the wiring connected to the solenoid coil L of the first electromagnetic valve. A second wiring disconnection detection unit 22 and a wiring group disconnection detection unit 23 are provided.

  Each of the first wiring disconnection detection unit 21 and the second wiring disconnection detection unit 22 has the same circuit configuration as that of the disconnection detection device 1 in FIG. 1, and includes a drive transistor 2, a first disconnection detection circuit 3, and a second disconnection detection circuit. 4, a disconnection detection synthesis unit 8, and a disconnection signal generation unit 9.

  The wiring group disconnection detector 23 generates and outputs a logical sum signal (third signal) Vout of the output signal V4 of the first disconnection detection circuit 3 and the output signal V5 of the second disconnection detection circuit 4. The third signal Vout is a signal for informing the final disconnection.

  The third signal Vout notifies that a disconnection has occurred when a disconnection is detected in at least one of the plurality of wires connected to the solenoid coils L of the plurality of solenoid valves. Since each of the first disconnection detection circuit 3 and the second disconnection detection circuit 4 includes the disconnection signal generation unit 9, only when the disconnection is detected continuously for a predetermined time, the third signal is also determined. The disconnection is notified only when the disconnection is detected continuously for a predetermined time.

  FIG. 5 is a timing chart of the disconnection detection device 1 of FIG. FIG. 5 shows waveforms of signals similar to those in FIG. 3A for each of the first wiring disconnection detection unit 21 and the second wiring disconnection detection unit 22. Times t <b> 1 to t <b> 2 indicate timings when current flows through the solenoid coil L corresponding to the first wiring disconnection detection unit 21. Times t <b> 3 to t <b> 6 indicate timing when current flows through the solenoid coil L corresponding to the second wiring disconnection detection unit 22. Times t3 to t6 are periods in which the drive transistor 2 of the second wiring disconnection detection unit 22 is on. It shows that the disconnection of the wiring has occurred at time t4. When disconnection occurs, no current flows through the solenoid coil L, and no current is detected by the current sensor 5. However, at time t5 after the disconnection continues for a predetermined time, the first signal V5 of the second wiring disconnection detection unit 22 becomes high, and the disconnection is notified. The third signal Vout goes high as soon as the first signal V5 goes high.

  On the other hand, after time t3, no current flows through the solenoid coil L corresponding to the first wiring disconnection detection unit 21, but it indicates that a disconnection was detected at time t8. At a time t9 when a predetermined time has elapsed since the detection of the disconnection, the first signal Vout of the first wiring disconnection detection unit 21 becomes high, and accordingly, the third signal also becomes high, and the disconnection is notified.

  As described above, in the second embodiment, by providing the wiring group disconnection detection unit 23, it is possible to collectively detect disconnection of a plurality of wirings connected to the solenoid coils L of the plurality of solenoid valves. Even if a break occurs in any of the wirings, the break can be detected quickly and accurately.

  The aspect of the present invention is not limited to the individual embodiments described above, and includes various modifications that can be conceived by those skilled in the art, and the effects of the present invention are not limited to the contents described above. That is, various additions, modifications, and partial deletions can be made without departing from the concept and spirit of the present invention derived from the contents defined in the claims and equivalents thereof.

  DESCRIPTION OF SYMBOLS 1 Disconnection detection apparatus, 2 Drive transistor, 3 1st disconnection detection circuit, 4 2nd disconnection detection circuit, 5 Current sensor, 6 Current determination part, 7 Photocoupler, 7a Light emitting element, 7b Light receiving element, 8 Disconnection detection synthetic | combination part, 9 disconnection signal generation unit, 11 switch, 12 comparator, 13 reference voltage generation circuit, 14 counter, 21 first wiring disconnection detection unit, 22 second wiring disconnection detection unit, 23 wiring group disconnection detection unit

Claims (11)

A first switching element that switches and controls whether or not a current flows through a solenoid coil of a solenoid valve;
A first disconnection detection circuit for detecting disconnection of wiring connected to the solenoid coil when the first switching element is on;
A disconnection detection device comprising: a second disconnection detection circuit that detects disconnection of the wiring when the first switching element is off.   Disconnection signal generation for outputting a first signal for notifying that the wiring is disconnected when a disconnection is detected continuously for a predetermined time in at least one of the first disconnection detection circuit and the second disconnection detection circuit The disconnection detection device according to claim 1, further comprising: a unit.   The disconnection detection device according to claim 2, wherein the disconnection signal generation unit prohibits the output of the first signal for the predetermined time after the open / close state of the electromagnetic valve is switched. A disconnection detection combining unit that generates a second signal indicating that the disconnection has been detected when a disconnection of the wiring is detected in at least one of the first disconnection detection circuit and the second disconnection detection circuit;
The disconnection detection device according to claim 2 or 3, wherein the disconnection signal generation unit outputs the first signal when the second signal is continuously detected over the predetermined time. The disconnection signal generation unit includes a resistor and a capacitor,
The disconnection detecting device according to any one of claims 2 to 4, wherein the predetermined time is a time corresponding to a time constant between the resistor and the capacitor. The disconnection signal generation unit starts a count operation when a disconnection is detected in at least one of the first disconnection detection circuit and the second disconnection detection circuit, and counts up while the disconnection is continuously detected. Have a counter to
The disconnection detecting device according to any one of claims 2 to 4, wherein the predetermined time is a time at which a count value of the counter becomes a predetermined value. The first disconnection detection circuit includes:
A first current detector for detecting a current flowing through the solenoid coil when the first switching element is on;
A current determination unit that determines whether or not the current detected by the first current detection unit is equal to or less than a predetermined threshold, and determines that the current is disconnected when the current is equal to or less than the threshold. Disconnection detection apparatus as described in any one of Claims. The second disconnection detection circuit includes:
A second current detection unit that detects a current flowing through a path connected in parallel to the first switching element when the first switching element is off;
The disconnection detection apparatus according to claim 1, further comprising: a second switching element that is turned on or off by a current detected by the second current detection unit. A light emitting element that operates as the second current detection unit and emits light when a current flows through a path connected in parallel to the first switching element;
The disconnection detection apparatus according to claim 8, further comprising a photocoupler that operates as the second switching element and is disposed in proximity to each other so that a light receiving element that is turned on when the light emitting element emits light is electrically insulated from each other. A plurality of disconnection detectors for detecting disconnection of a plurality of wires connected to a plurality of solenoid valves, and
A wiring group disconnection detection unit that generates a third signal for notifying that a disconnection has occurred in at least one of the plurality of wirings when a disconnection is detected in at least one of the plurality of disconnection detectors; ,
10. The disconnection detection device according to claim 1, wherein each of the plurality of disconnection detectors includes the first switching element, the first disconnection detection circuit, and the second disconnection detection circuit.   The disconnection detecting device according to any one of claims 1 to 10, wherein the electromagnetic valve is used for switching ship equipment.

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