JP6476835B2 - Signal converter - Google Patents

Description

  The present invention relates to a signal conversion device that receives a contact signal instructing valve operation, converts it into a control signal that drives an electromagnetic valve that controls the valve operation, and outputs the control signal to a control signal line connected to the electromagnetic valve. The present invention relates to a signal conversion device installed in a dangerous place.

  FIG. 11 shows a configuration example of a system for remotely operating a valve installed in a dangerous place using a solenoid type electromagnetic valve 300. Here, “hazardous location” means a hazardous location classified as a special hazardous location, type 1 hazardous location, or type 2 hazardous location in the factory electrical equipment explosion proof guidelines, but other guidelines, standards, etc. It may be a “dangerous place” defined by

  In this figure, a solenoid type electromagnetic valve 300, a pneumatic switch 301, and a valve 302 are arranged in a dangerous place, and a contact information control unit 310, a contact switch 320, a power source 330, an explosion-proof barrier 340, and a current measuring device 360 are installed in a safe place. Has been. The explosion-proof barrier 340 and the solenoid type electromagnetic valve 300 are connected by a control signal line 350.

  When the operator instructs the contact information control unit 310 to operate the valve, the contact switch 320 is turned on, power is supplied from the power source 330 to the solenoid type solenoid valve 300 via the explosion-proof barrier 340 and the control signal line 350, and the solenoid type electromagnetic The valve 300 is driven. When the solenoid type electromagnetic valve 300 is driven, the valve 302 is operated by the pneumatic switch 301. The explosion-proof barrier 340 is used to limit the voltage and current output via the control signal line 350 to the solenoid type electromagnetic valve 300 installed in the hazardous area.

  Since the control signal line 350 is wired, an open circuit failure such as disconnection may occur. In order to detect this open circuit failure, a current measuring device 360 is arranged between the power supply 330 and the contact switch 320, and the measurement result of the current measuring device 360 is input to the diagnosis unit 311 of the contact information control unit 310. ing.

  When an open circuit failure has not occurred in the control signal line 350, a current flows from the power source 330 to the control signal line 350 when the contact switch 320 is turned on. On the other hand, when an open circuit failure has occurred in the control signal line 350, no current flows through the control signal line 350 even when the contact switch 320 is turned on.

  For this reason, the diagnosis unit 311 diagnoses an open circuit failure based on the measurement result of the current measuring device 360 when the contact switch 320 is switched on. Specifically, if the current measuring device 360 detects a current when the contact switch 320 is turned on, it is diagnosed that an open circuit failure has not occurred, and the current measurement is performed when the contact switch 320 is turned on. If the device 360 does not detect current, it is diagnosed that an open circuit fault has occurred.

Special table 2003-528269

  In the remote valve operation by wire using the control signal line 350, it is necessary to lay the control signal line 350 from a safe place to a dangerous place. Recently, it has been proposed to perform the remote valve operation wirelessly. If the valve remote operation is performed wirelessly, it is not necessary to lay the control signal line 350 from the safe place to the dangerous place.

  FIG. 12 is a diagram illustrating a configuration example of a system for performing remote valve operation wirelessly. In this figure, a terminal device 410 and a terminal-side wireless communication device 420 are installed in a safe place, and a valve-side wireless communication device 430, a signal converter 440, a solenoid type electromagnetic valve 300, and a pneumatic switch are opened and closed in a dangerous place. A container 301 and a valve 302 are installed.

  When the operator instructs the valve operation with the terminal device 410, the operation instruction is wirelessly transmitted from the terminal side wireless communication device 420 connected to the terminal device 410 to the valve side wireless communication device 430. The valve-side wireless communication device 430 outputs this operation instruction as a contact signal to the signal conversion device 440.

  A signal conversion device 440 that is an intrinsically safe explosion-proof device includes a contact information control unit 441, a battery 442, an explosion-proof barrier 443, and a contact switch 444. The contact switch 444 and the solenoid type electromagnetic valve 300 are connected by a control signal line 450. The contact information control unit 441 switches on / off of the contact switch 444 in accordance with a contact signal from the valve-side wireless communication device 430.

  When the contact switch 444 is turned on, a control signal flows through the control signal line 450 and the solenoid type electromagnetic valve 300 is driven by electric power supplied from the battery 442. When the solenoid type electromagnetic valve 300 is operated, the valve 302 is operated by the pneumatic switch 301.

  The explosion-proof barrier 443 is used to limit the voltage and current of the control signal output to the solenoid type electromagnetic valve 300 via the control signal line 450. FIG. 13 is a diagram illustrating a configuration example of the explosion-proof barrier 443. As shown in the figure, the explosion-proof barrier 443 includes a current limiting unit that limits the current and a voltage limiting unit that limits the voltage. Here, the current limiting unit is configured by a resistor R11, and the voltage limiting unit is configured by Zener diodes ZD11 and ZD12.

  In a system that performs valve remote control wirelessly, it is not necessary to lay a wired line from a safe place to a dangerous place, but to lay a control signal line 450 wired from the signal conversion device 440 to the solenoid type electromagnetic valve 300 in the dangerous place. Become.

  For this reason, there is a case where it is desired to detect an open circuit fault of the control signal line 450. In order to detect an open circuit failure of the control signal line 450, for example, as shown in FIG. 14, a current measuring device 460 is connected between the signal converter 440 and the solenoid type solenoid valve 300, and the contact signal is turned on. It is conceivable to detect the current that sometimes flows.

However, in order to connect the current measuring device 460 to the outside of the signal converter 440 that is an intrinsically safe explosion-proof device, the current measuring device 460 needs to satisfy the following three conditions.
1) Equipment that has received intrinsically safe explosion-proof certification 2) Equipment that can electrically receive the voltage and current applied to the control signal line 450 3) Solenoid type electromagnetic with limited current and voltage Although the device can supply the valve 300, the current measuring device 460 that satisfies these conditions is not common. In addition, as an operation method of intrinsically safe explosion-proof equipment, parallel connection of intrinsically safe explosion-proof equipment is not permitted, and such connection cannot be realized in a hazardous area. For this reason, it is not easy to detect an open circuit failure of the control signal line laid in the dangerous place.

  Accordingly, an object of the present invention is to enable detection of an open circuit failure of a control signal line through which a control signal for driving an electromagnetic valve flows in a system that performs remote valve operation wirelessly.

In order to solve the above problem, the signal conversion device according to the first aspect of the present invention receives a contact signal instructing valve operation, converts it into a control signal for driving an electromagnetic valve for controlling the valve operation, A signal conversion device that outputs to a control signal line connected to the solenoid valve, the battery supplying power to the solenoid valve, an explosion-proof barrier that limits the voltage and current output to the control signal line, and the explosion-proof A contact switch provided between the barrier and the control signal line; a second contact switch provided between the battery and the explosion-proof barrier; and the contact switch and the second based on the contact signal. A contact information control unit for controlling the contact switch, a current detection unit for detecting a current output from the explosion-proof barrier, and a current detection unit when the contact switch and the second contact switch are on. Based on the output results, characterized by comprising a diagnosis unit, a detecting open circuit failure of the control signal line.
Here, a pull-up resistor may be connected in parallel with the second contact switch.
In order to solve the above problems, a signal conversion device according to a second aspect of the present invention receives a contact signal instructing valve operation, converts it into a control signal for driving an electromagnetic valve for controlling the valve operation, A signal conversion device that outputs to a control signal line connected to the solenoid valve, the battery supplying power to the solenoid valve, an explosion-proof barrier that limits the voltage and current output to the control signal line, and the explosion-proof A contact switch provided between the barrier and the control signal line; a second contact switch provided between the battery and the explosion-proof barrier; and a pull-up resistor connected in parallel with the second contact switch. And a voltage detection unit for detecting the voltage on the battery side of the pull-up resistor, and contact information for turning on the contact switch after turning on the second contact switch based on the contact signal Based on the difference between the detection voltage of the control unit and the voltage detection unit when only the second contact switch is on, and the detection voltage of the voltage detection unit when the second contact switch and the contact switch are on. And a diagnostic unit for detecting an open circuit fault of the control signal line.
In order to solve the above problem, a signal conversion device according to a third aspect of the present invention receives a contact signal instructing valve operation, converts it into a control signal for driving an electromagnetic valve for controlling the valve operation, A signal conversion device that outputs to a control signal line connected to the solenoid valve, the battery supplying power to the solenoid valve, an explosion-proof barrier that limits the voltage and current output to the control signal line, and the explosion-proof A contact switch provided between the barrier and the control signal line; a short-circuit current limiting resistor connected to the battery; and a second contact provided between the short-circuit current limiting resistor and the explosion-proof barrier. A switch, a pull-up resistor connected in parallel with the second contact switch, a current detection unit for detecting a current flowing through the short-circuit current limiting resistor, and the second contact switch based on the contact signal. After that, the contact information control unit that turns on the contact switch, the detection current of the current detection unit when only the second contact switch is on, and the second contact switch and the contact switch are on And a diagnostic unit for detecting an open circuit failure of the control signal line based on a difference from a detected current of the current detecting unit.

  According to the present invention, in a system that performs remote valve operation wirelessly, it becomes possible to detect an open circuit failure of a control signal line through which a control signal for driving an electromagnetic valve flows.

It is a figure which shows the structural example of the system which performs valve | bulb remote operation by radio | wireless in this embodiment. It is a figure which shows 1st Example of a current detection part. It is a figure which shows the modification of 1st Example of an electric current detection part. It is a figure which shows 2nd Example of a current detection part. It is a figure which shows 3rd Example of an electric current detection part. It is a figure which shows another example of the signal converter for suppressing consumption of a battery. It is a figure which shows another example of the signal converter for preventing the malfunctioning of a solenoid type solenoid valve. It is a figure which shows the further another example of the signal converter for preventing the malfunctioning of a solenoid type solenoid valve, and suppressing consumption of a battery. It is a figure which shows the example at the time of using a current detection part instead of a voltage detection part. It is a figure which shows the structural example using the reference | standard load for short circuit determination. It is a figure which shows the structural example of the system which operates the valve installed in the dangerous place remotely using a solenoid type solenoid valve. It is a figure which shows the structural example of the system which performs valve | bulb remote operation by radio | wireless. It is a figure which shows the structural example of an explosion-proof barrier. It is a figure which shows the structural example which detects the open circuit failure of a control signal line in the system which performs valve | bulb remote operation by radio | wireless.

  Embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a diagram illustrating a configuration example of a system for performing a valve remote operation wirelessly according to the present embodiment. In this system, a terminal device 210 and a terminal-side wireless communication device 220 are installed in a safe place, and a valve-side wireless communication device 230, a signal conversion device 100, a solenoid type electromagnetic valve 200, and a pneumatic switch are opened and closed in a dangerous place. A vessel 201 and a valve 202 are installed. A plurality of solenoid type solenoid valves 200 and the like may be installed.

  When the operator instructs the valve operation with the terminal device 210, the operation instruction is wirelessly transmitted from the terminal side wireless communication device 220 connected to the terminal device 210 to the valve side wireless communication device 230. The valve-side wireless communication device 230 outputs this operation instruction to the signal conversion device 100 as a contact signal.

  The signal conversion device 100 that is an intrinsically safe explosion-proof device includes a contact information control unit 110, a contact switch 120, a battery 130, an explosion-proof barrier 140, and a current detection unit 150, and is housed in a pressure-proof explosion-proof housing. The contact switch 120 and the solenoid type electromagnetic valve 200 are connected by a control signal line 240. The contact information control unit 110 switches the contact switch 120 on and off in accordance with a contact signal from the valve-side wireless communication device 230.

  When the contact switch 120 is turned on, a control signal flows through the control signal line 240, and the solenoid type electromagnetic valve 200 is driven by the power supplied from the battery 130. When the solenoid type electromagnetic valve 200 is operated, the valve 202 is operated by the pneumatic switch 201.

  The explosion-proof barrier 140 is used to limit the voltage and current of the control signal output to the solenoid type electromagnetic valve 200 via the control signal line 240. As shown in the figure, the explosion-proof barrier 140 includes a current limiting unit 141 that limits current and a voltage limiting unit 142 that limits voltage.

  Since the control signal line 240 laid in the hazardous area is wired, an open circuit failure such as disconnection may occur. In order to detect this open circuit failure, a current detector 150 is provided. The current detection unit 150 detects the current output from the explosion-proof barrier 140, and the detection result of the current detection unit 150 is input to the diagnosis unit 111 of the contact information control unit 110.

  When an open circuit failure has not occurred in the control signal line 240, a current flows from the battery 130 to the control signal line 240 when the contact switch 120 is turned on. On the other hand, when an open circuit fault has occurred in the control signal line 240, no current flows through the control signal line 240 even when the contact switch 120 is turned on.

  Therefore, the diagnosis unit 111 diagnoses an open circuit failure based on the detection result of the current detection unit 150 when the contact switch 120 is switched on. Specifically, when the contact switch 120 is turned on, if the current detection unit 150 detects a current, it is diagnosed that no open circuit fault has occurred, and when the contact switch 120 is turned on, the current detection is performed. When the unit 150 does not detect the current, it is diagnosed that an open circuit fault has occurred.

  When the diagnosis unit 111 diagnoses that an open circuit failure has occurred, for example, the diagnosis unit 111 outputs an alarm to the terminal device 210 via the valve-side wireless communication device 230 and the terminal-side wireless communication device 220.

  Since the signal conversion device 100 of the present embodiment detects the current in the intrinsically safe explosion-proof device, it is not necessary to connect a current measuring device to the outside, and the solenoid type electromagnetic valve 200 can be directly connected. For this reason, use in a dangerous place is permitted, and an open circuit failure of the control signal line 240 installed in the dangerous place can be detected.

  A specific configuration example of the current detection unit 150 of the signal conversion device 100 will be described. FIG. 2 is a diagram illustrating a first embodiment of the current detection unit 150. In the explosion-proof barrier 140, the resistor R1 constitutes a current limiting part 141, and the Zener diodes ZD1 and ZD2 connected in parallel constitute a voltage limiting part 142. The current limiter 141 is arranged closer to the contact switch 120 than the voltage limiter so that no current flows through the current limiter 141 when the contact switch 120 is off. Of course, the explosion-proof barrier 140 may be constituted by other parts. For example, the current limiting unit 141 may be configured with a plurality of resistors, or Zener diodes may be combined in another combination.

  In the first embodiment, the current detection unit 150 includes a voltage divider 151a, a voltage divider 151b, an AD converter 152a, and an AD converter 152b, and obtains a value proportional to the voltage across the resistor R1 that is the current limiting unit 141. And input to the diagnosis unit 111. In addition to the current limiting resistor R1, a current detecting resistor may be separately connected in series. In this case, what is necessary is just to connect to the back | latter stage of the voltage limiting part 142 in the signal converter 100, and you may be outside the explosion-proof barrier 140.

  Here, the voltage divider 151a and the voltage divider 151b are provided for limiting the voltage input to the AD converter 152a and the AD converter 152b to be smaller than the withstand voltage of the AD converter 152a and the AD converter 152b. The partial pressure ratio is known.

  The output value of the voltage divider 151a is digitally converted by the AD converter 152a, and the output value of the voltage divider 151b is digitally converted by the AD converter 152b, and each becomes a value proportional to the voltage across the resistor R1.

  The diagnosis unit 111 can calculate the value of the current output from the explosion-proof barrier 140 based on the voltage dividing ratio of the voltage divider 151a and the voltage divider 151b and the value of the resistance R1. That is, the value of the current output by the explosion-proof barrier 140 is obtained by dividing the voltage drop value at the resistor R1 by the value of the resistor R1. The diagnosis unit 111 diagnoses that an open circuit failure has not occurred when the explosion-proof barrier 140 outputs a current when the contact switch 120 is turned on, and the explosion-proof barrier 140 does not output a current. In this case, it is diagnosed that an open circuit fault has occurred.

  In this embodiment, since the value of the current flowing through the resistor R1 can be acquired based on the outputs of the AD converter 152a and the AD converter 152b, the control signal can be used if the acquired current is equal to or greater than a predetermined value. You may make it diagnose that the short circuit fault generate | occur | produced on the line 240. FIG. Here, the predetermined value can be determined based on the operating current of the solenoid type electromagnetic valve 200.

  The diagnosis unit 111 may record the value of the current flowing through the resistor R1 at a predetermined interval. In this case, since the change tendency of the current value can be acquired, it becomes possible to diagnose the degree of wear of the battery 130, the deterioration with time of the control signal line 240, and the like. For example, if the current value tends to gradually decrease, it is possible to grasp the situation where the battery 130 is gradually depleted, and if the current value changes rapidly, it is assumed that some abnormality has occurred in the control signal line 240. Can be diagnosed.

  FIG. 3 is a diagram illustrating a modification of the first embodiment of the current detection unit 150. In the first embodiment described above, two AD converters 152a and 152b are used. However, in the modified example, one AD converter 152 is used. The outputs of the voltage divider 151a and the voltage divider 151b are switched by a changeover switch 153 and guided to the AD converter 152 in order. The diagnosis unit 111 controls switching of the changeover switch 153.

  The diagnosis unit 111 can sequentially acquire values proportional to the voltage across the resistor R1 by sequentially switching the changeover switch 153 while the contact switch 120 is on.

  Also in the modification of the first embodiment, since the current value output by the explosion-proof barrier 140 can be acquired, the diagnostic unit 111 outputs the current when the contact switch 120 is turned on. If there is an open circuit fault, it is diagnosed that no open circuit fault has occurred, and if the explosion-proof barrier 140 is not outputting current, it is diagnosed that an open circuit fault has occurred. Further, if the acquired current is equal to or greater than a predetermined value, it may be diagnosed that a short circuit failure has occurred in the control signal line 240.

  FIG. 4 is a diagram illustrating a second embodiment of the current detection unit 150. In the second embodiment, the current detection unit 150 is configured by the difference detection device 154, and the detection result of the presence or absence of a voltage difference at both ends of the resistor R1 that is the current limiting unit 141 is input to the diagnosis unit 111. Here, when a voltage difference occurs between both ends of the resistor R1, it indicates that the explosion-proof barrier 140 outputs a current. When no voltage difference occurs between both ends of the resistor R1, the explosion-proof barrier 140 outputs a current. Indicates that it has not.

  The diagnosis unit 111 diagnoses that an open circuit failure has not occurred when the explosion-proof barrier 140 outputs a current when the contact switch 120 is turned on, and the explosion-proof barrier 140 does not output a current. In this case, it is diagnosed that an open circuit fault has occurred.

  When the difference detection device 154 is configured to output an analog value having a magnitude corresponding to the voltage difference between both ends of the resistor R1, the value of the current flowing through the resistor R1 itself can be acquired. In this case, if the acquired current is equal to or greater than a predetermined value, it may be diagnosed that a short circuit failure has occurred in the control signal line 240.

  FIG. 5 is a diagram illustrating a third embodiment of the current detection unit 150. In the third embodiment, the current detection unit 150 includes a light emitting element and a light detection element, and the detection result of the light detection element is input to the diagnosis unit 111. Here, a light-emitting diode or the like can be used as the light-emitting element, and the light-emitting element is connected in series to the resistor R1 at the subsequent stage of the voltage limiting unit 142 in the signal conversion device 100. As the light detection element, a photodiode, a phototransistor, or the like can be used, and the light detection element is disposed so as to detect light of the light emitting element.

  When the light detection element detects light, it indicates that the explosion-proof barrier 140 outputs current, and when the light detection element does not detect light, it indicates that the explosion-proof barrier 140 does not output current. Yes.

  The diagnosis unit 111 diagnoses that an open circuit failure has not occurred when the explosion-proof barrier 140 outputs a current when the contact switch 120 is turned on, and the explosion-proof barrier 140 does not output a current. In this case, it is diagnosed that an open circuit fault has occurred.

  When the light emitting element emits light with a luminance corresponding to the current value and outputs a signal corresponding to the luminance of the light detected by the light detecting element, the value of the current flowing through the resistor R1 itself is acquired. Will be able to. In this case, if the acquired current is equal to or greater than a predetermined value, it may be diagnosed that a short circuit failure has occurred in the control signal line 240.

  Next, another example of the signal conversion apparatus 100 will be described. In the signal conversion device 100 shown in FIG. 2, current flows from the battery 130 to the voltage limiting unit 142 regardless of whether the contact switch 120 is on or off, and the battery 130 is consumed. That is, the battery 130 is consumed even when the solenoid type solenoid valve 200 is not driven. Another example of the signal conversion device 100 is configured to suppress the consumption of the battery 130 when the contact switch 120 is turned off, paying attention to this point. In addition, the diagnostic criteria for the open circuit fault and the diagnostic criteria for the short-circuit fault of the diagnosis unit 111 can be the same for other examples shown below. In addition, the above-described modifications can be applied as appropriate.

  A signal conversion device 100 shown in FIG. 6 is another basic type, and a second contact switch 160 is provided between the battery 130 and the voltage limiting unit 142. Similarly to the contact switch 120, the second contact switch 160 is turned on and off by the contact information control unit 110 in accordance with a contact signal from the valve-side wireless communication device 230. In this example, the contact information control part 110 shall switch the contact switch 120 and the 2nd contact switch 160 simultaneously.

  A resistor R2 is connected between the second contact switch 160 and the battery 130. Although the resistor R2 is omitted in the above-described embodiment, the resistor R2 is a resistor that limits a short-circuit current when the wiring from the battery 130 is short-circuited or absorbs a potential difference between the battery 130 and the voltage limiting unit 142. is there. The second contact switch 160 may be provided in the explosion-proof barrier 140. The resistor R2 is arranged in front of the wiring from the battery 130 so that the short-circuit current when the wiring from the battery 130 is short-circuited can be limited.

  In the signal conversion device 100 shown in FIG. 6, no current flows from the battery 130 to the voltage limiting unit 142 when the second contact switch 160 is off. Since the second contact switch 160 is turned on and off in the same manner as the setting switch 120 is turned on and off, the second contact switch 160 is turned off except when the solenoid type electromagnetic valve 200 is driven. For this reason, consumption of the battery 130 when the contact switch 120 is turned off can be suppressed.

  Incidentally, in general, FETs are used for the contact switch 120 and the second contact switch 160 as shown in FIG. In addition, the voltage divider 151 connects the resistor Ra and the resistor Rb in series, grounds one end, and generates a divided voltage by taking out the voltage at the connection point between the resistor Ra and the resistor Rb. In the figure, only the voltage divider 151b is shown, but the same applies to the voltage divider 151a.

  In this configuration, when the contact switch 120 and the second contact switch 160 are off, no voltage is applied to the voltage limiting unit 142. When the second contact switch 160 is turned on, the voltage limiter 142 increases from 0V to the limit voltage in an instant. At this time, a charging current flows through a parasitic capacitance existing between the source and drain of the FET constituting the contact switch 120. Since this current flows through the control signal line 240, the solenoid type electromagnetic valve 200 may malfunction.

  Therefore, as shown in FIG. 7, a pull-up resistor R <b> 3 is connected in parallel with the second contact switch 160. Since the voltage of the voltage limiting unit 142 is pulled up by the pull-up resistor R3 when the second contact switch 160 is off, the voltage of the voltage limiting unit 142 suddenly increases when the second contact switch 160 is turned on. Can be suppressed. For this reason, the charging current does not flow through the parasitic capacitance of the FET constituting the contact switch 120, and malfunction of the solenoid type electromagnetic valve 200 can be prevented.

  In this figure, since the resistors R1 and R2 are generally selected to be small values, the voltage applied to the voltage limiting unit 142 when the second contact switch 160 is off is the voltage of the battery 130, the pull-up resistor R3, The voltage is divided by the combined resistance of the voltage divider 151a and the voltage divider 152b. That is, a value obtained by subtracting the voltage drop of the resistor R 3 from the voltage of the battery 130 is applied to the voltage limiting unit 142.

  In order to suppress a change in the applied voltage of the voltage limiting unit 142 so that the charging current does not flow when the second contact switch 160 is switched on, the applied voltage of the voltage limiting unit 142 is limited even when the second contact switch 160 is turned off. The voltage needs to be almost reached. For this reason, the pull-up resistor R3 cannot be increased.

  However, if the pull-up resistor R3 is too small, the current flowing through the pull-up resistor R3 increases when the second contact switch 160 is turned off, and the consumption of the battery 130 cannot be sufficiently suppressed. For this reason, it is necessary to set the pull-up resistor R3 to an appropriate value. However, since the combined resistance of the voltage divider 151 varies depending on the components used, adjustment of the pull-up resistor R3 becomes complicated. In addition, by providing a contact switch in the voltage divider 151a and the voltage divider 151b and interlocking with the on / off of the second contact switch 160, a change in the applied voltage of the voltage limiting unit 142 when the second contact switch 160 is on is suppressed. Is possible, but the structure is a little complicated.

  A further example of the signal conversion apparatus 100 will be described with reference to FIG. The signal converter 100 shown in FIG. 8 includes a contact information control unit 110, a contact switch 120, a battery 130, an explosion-proof barrier 140, a voltage detection unit 155, a second contact switch, a resistor R2, and a pull-up resistor R3.

  A second contact switch 160 and a pull-up resistor R3 are connected in parallel to the battery 130 via a resistor R2, and an explosion-proof barrier 140 and a contact switch 120 are further connected. The explosion-proof barrier 140 includes a current limiting unit 141 and a voltage limiting unit 142 as in the above example. The resistor R2 and the pull-up resistor R3 may be included in the explosion-proof barrier 140.

  In this example, the voltage detection unit 155 includes a set of voltage divider 151 and ADC 152, and is disposed closer to the battery 130 than the pull-up resistor R3. Then, the contact information control unit 110 switches on / off of the contact switch 120 with a signal S1, and switches on / off of the second contact switch 160 with a signal S2.

  At this time, when the contact signal from the valve-side wireless communication device 230 is turned on, first, the signal S2 is turned on and then the signal S1 is turned on. That is, the second contact switch 160 is turned on first. Simultaneously when turning off.

  When the contact switch 120 and the second contact switch 160 are off, the voltage applied to the voltage limiting unit 142 is not divided by the voltage divider 151 or the pull-up resistor R3, so that even if the pull-up resistor R3 is set to a large value, the voltage is limited. Can rise to voltage.

  For this reason, even when the second contact switch 160 is turned on, the voltage does not increase, and the charging current can be prevented from flowing. For this reason, there is no possibility of malfunction of the solenoid type solenoid valve 200. Further, by setting the pull-up resistor R3 to a large value, it is possible to suppress the consumption of the battery 130 when the second contact switch 160 is turned off.

  The diagnosis unit 111 of the contact information control unit 110 diagnoses an open circuit failure in the following configuration in the following procedure. That is, when the signal S2 is turned on at time t1 and the second contact switch 160 is turned on by the contact signal from the valve-side wireless communication device 230, the measured value of the voltage detector 155 is acquired and set to the voltage V1. Then, when the signal S1 is turned on at time t2 and the contact switch 120 is turned on, the measurement value of the voltage detection unit 155 is obtained again to be the voltage V2.

  The diagnosis unit 111 diagnoses an open circuit failure based on the difference between the voltage V1 and the voltage V2. When no open circuit failure has occurred, when the contact switch 120 is turned on, a current is output to the solenoid type electromagnetic valve 200, so that the voltage V2 is lower than the voltage V1. Therefore, if the difference between the voltage V1 and the voltage V2 is equal to or greater than the predetermined reference value dV, it is diagnosed that no open circuit fault has occurred, and if the difference between the voltage V1 and the voltage V2 is less than the predetermined reference value dV. Diagnose that an open circuit fault has occurred.

  In addition, when a short circuit failure occurs in the control signal line 240, the voltage V2 greatly decreases when the contact switch 120 is turned on. For this reason, if the difference between the voltage V1 and the voltage V2 is greater than or equal to a predetermined value dS (> dV), it may be diagnosed that a short-circuit failure has occurred in the control signal line 240.

  As shown in FIG. 9, the current flowing through the short-circuit current limiting resistor R <b> 2 connected between the battery 130 and the second contact switch 160 is changed using the current detection unit 150 instead of the voltage detection unit 155. It may be detected to detect an open circuit fault. At this time, the short-circuit current limiting resistor R4 is also connected at the connection point between the battery 130 and the current detector 150.

  In this case, the diagnosis unit 111 diagnoses an open circuit fault in the following procedure. That is, when the signal S2 is turned on at time t1 and the second contact switch 160 is turned on by the contact signal from the valve side wireless communication device 230, the current flowing through the resistor R2 is calculated as I1. Then, when the signal S1 is turned on at time t2 and the contact switch 120 is turned on, the current flowing through the resistor R2 is calculated again to be the current I2. The method for calculating the current is as described above.

  Diagnosis unit 111 diagnoses an open circuit failure based on the difference between current I1 and current I2. When the open circuit failure has not occurred, when the contact switch 120 is turned on, a current is output to the solenoid type electromagnetic valve 200, so that the current I2 becomes larger than the current I1. Therefore, if the difference between the current I1 and the current I2 is equal to or greater than the predetermined reference value dI, it is diagnosed that no open circuit fault has occurred, and if the difference between the current I1 and the current I2 is less than the predetermined reference value dI. Diagnose that an open circuit fault has occurred.

  Further, when a short-circuit failure occurs in the control signal line 240, the current I2 greatly increases when the contact switch 120 is turned on. For this reason, if the difference between the current I1 and the current I2 is equal to or greater than a predetermined value dT (> dI), it may be diagnosed that a short circuit fault has occurred in the control signal line 240.

  For example, the values dS and dT used for the short-circuit failure determination can determine values corresponding to the use environment in which the short-circuit state is gradually caused by the influence of humidity or the like, for example, by the configuration shown in FIG. In addition, although this figure is an example in the case of determining dS using the voltage detection part 155, you may make it determine dT using the electric current detection part 150. FIG. In this configuration, the output of the explosion-proof barrier 140 is also connected to the reference load 180 via the third contact switch 170. For example, the reference load 180 is set to be slightly smaller than the impedance of the solenoid type solenoid valve 200 to be used.

  Then, while the contact switch 120 is kept off, the second contact switch 160 is turned on to measure the voltage V1, and then the third contact switch 170 is turned on to measure the voltage V2. By determining the difference between the voltage V1 and the voltage V2 at this time as a value dS for determining a short-circuit fault, a value dS corresponding to the use environment can be determined. In normal use, the third contact switch 170 is kept off. When dT is determined using the current detector 150, the current I1 and the current I2 are measured by turning on and off the third contact switch 170, and the difference between the current I1 and the current I2 is determined as a value dT for determining a short-circuit fault. Just do it.

DESCRIPTION OF SYMBOLS 100 ... Signal converter 110 ... Contact information control part, 111 ... Diagnosis part, 120 ... Contact switch, 130 ... Battery, 140 ... Explosion-proof barrier, 141 ... Current restriction part, 142 ... Voltage restriction part, 150 ... Current detection part, 151 ... Voltage divider, 152 ... AD converter, 153 ... Changeover switch, 154 ... Difference detection device, 155 ... Voltage detection unit, 160 ... Second contact switch, 170 ... Third contact switch, 180 ... Reference load, 200 ... Solenoid Type solenoid valve, 201 ... pneumatic switch, 202 ... valve, 210 ... terminal device, 220 ... terminal side wireless communication device, 230 ... valve side wireless communication device, 240 ... control signal line

Claims (4)

A signal conversion device that receives a contact signal instructing valve operation, converts the contact signal into a control signal that drives an electromagnetic valve that controls the valve operation, and outputs the control signal to a control signal line connected to the electromagnetic valve;
A battery for supplying power to the solenoid valve;
An explosion-proof barrier that limits the voltage and current output to the control signal line;
A contact switch provided between the explosion-proof barrier and the control signal line;
A second contact switch provided between the battery and the explosion-proof barrier;
A contact information control unit for controlling the contact switch and the second contact switch based on the contact signal;
A current detector for detecting a current output from the explosion-proof barrier;
A diagnostic unit that detects an open circuit failure of the control signal line based on a detection result of the current detection unit when the contact switch and the second contact switch are on;
A signal conversion device comprising: 2. The signal converter according to claim 1 , wherein a pull-up resistor is connected in parallel with the second contact switch. A signal conversion device that receives a contact signal instructing valve operation, converts the contact signal into a control signal that drives an electromagnetic valve that controls the valve operation, and outputs the control signal to a control signal line connected to the electromagnetic valve;
A battery for supplying power to the solenoid valve;
An explosion-proof barrier that limits the voltage and current output to the control signal line;
A contact switch provided between the explosion-proof barrier and the control signal line;
A second contact switch provided between the battery and the explosion-proof barrier;
A pull-up resistor connected in parallel with the second contact switch;
A voltage detector for detecting a voltage on the battery side of the pull-up resistor;
A contact information control unit that turns on the contact switch after turning on the second contact switch based on the contact signal;
The control signal is based on a difference between a detection voltage of the voltage detection unit when only the second contact switch is on and a detection voltage of the voltage detection unit when the second contact switch and the contact switch are on. A diagnostic unit for detecting line open circuit faults;
A signal conversion device comprising: A signal conversion device that receives a contact signal instructing valve operation, converts the contact signal into a control signal that drives an electromagnetic valve that controls the valve operation, and outputs the control signal to a control signal line connected to the electromagnetic valve;
A battery for supplying power to the solenoid valve;
An explosion-proof barrier that limits the voltage and current output to the control signal line;
A contact switch provided between the explosion-proof barrier and the control signal line;
A short-circuit current limiting resistor connected to the battery;
A second contact switch provided between the short-circuit current limiting resistor and the explosion-proof barrier;
A pull-up resistor connected in parallel with the second contact switch;
A current detector for detecting a current flowing through the short-circuit current limiting resistor;
A contact information control unit that turns on the contact switch after turning on the second contact switch based on the contact signal;
The control signal is based on a difference between a detection current of the current detection unit when only the second contact switch is on and a detection current of the current detection unit when the second contact switch and the contact switch are on. A diagnostic unit for detecting line open circuit faults;
A signal conversion device comprising: