JP5202582B2 - Electrical device and diagnostic method for electrical device - Google Patents

Description

  The present invention relates to a circuit configuration for diagnosing the operation of a voltage monitoring device that monitors a power supply voltage supplied to an electronic device.

  When the power supply voltage required for the operation of electronic devices such as computers and digital circuits becomes abnormal, there is a possibility that an unexpected malfunction will occur in the CPU, memory, etc. mounted on the electronic device. Therefore, a power supply voltage monitoring device for diagnosing whether the voltage supplied from the power supply is normal is required.

  By adding a voltage monitoring device to an electronic device, if the power supply voltage becomes abnormal, the voltage monitoring device detects the abnormality, and the voltage monitoring device sends a reset signal to the electronic device to safely stop the electronic device. The power supply and the load can be shut off by operating a shut-off circuit that shuts off the power supply path. However, if the voltage monitoring device fails and no longer transmits a reset signal or cut-off signal, the electronic device will not be stopped by the reset signal when the voltage abnormality occurs, or the power supply and load cannot be cut off by the cut-off signal. There is a risk that an abnormal voltage is supplied to the electronic device and the electronic device operates abnormally.

  Patent Document 1 discloses a circuit configuration for performing failure diagnosis of a power supply shielding circuit. In the circuit configuration described in the patent document, a capacitor and a voltage monitoring device are provided between the power shielding device and the load. The input voltage at the time of shielding is stabilized by the capacitor, and the voltage monitoring device monitors that the voltage drops within a certain time determined by the discharge time constant of the capacitor. If the voltage does not drop within a certain time, it is diagnosed that the shielding circuit is broken.

JP 2007-141469 A

  In the above prior art, the power supplied to the load is directly shielded during failure diagnosis, and therefore, when a capacitor included in the circuit fails and is short-circuited, fluctuations in the power supply voltage supplied to the load are not affected. There is a risk of stabilizing and affecting the operation of the load. In view of the above problems, an object of the present invention is to provide a circuit configuration capable of diagnosing a failure of a voltage monitoring apparatus without destabilizing a power supply voltage supplied to a load even at the time of diagnosis.

  In order to achieve the above object, the first feature of the present invention is a load having a power supply voltage input terminal and a reset input terminal, a voltage monitoring device for monitoring a power supply voltage supplied to the load, and an input to the voltage monitoring device. Fault diagnosis of a power supply monitoring device having a voltage adjustment device for changing a voltage value to be detected, a failure diagnosis device for diagnosing the presence or absence of a failure of the voltage monitoring device, and a capacitor for maintaining a voltage that serves as an input signal to the reset input during diagnosis The gist of the present invention is that the circuit configuration enables the above. When the voltage applied to the reset input terminal decreases, the load is reset.

  Moreover, the voltage supplied to the voltage monitoring device is lowered while the circuit connecting the voltage monitoring device and the reset input terminal of the load is opened by the switch, and the failure diagnosis is performed by confirming that the voltage monitoring device transmits a reset signal. It is characterized by that.

  According to the present invention, it is possible to detect a failure of the voltage monitoring device without affecting the operation of the electronic device. In addition, when the present invention is applied to a device that requires high safety such as a signal device of a railway system, a highly reliable and safe system configuration is possible.

It is a figure which shows an example of a structure of the failure diagnosis apparatus of the voltage monitoring apparatus by Example 1 of this invention. It is a figure which shows an example of a structure of the failure diagnosis apparatus of the voltage monitoring apparatus by Example 2 of this invention. It is a flowchart which shows the failure diagnosis procedure in Example 1 of this invention. It is a flowchart which shows the failure diagnosis procedure in Example 1 of this invention. It is a sequence diagram which shows the operation | movement at the time of power supply abnormality in the failure diagnosis apparatus of Example 1 and 2 of this invention. It is a sequence diagram which shows the operation | movement at the time of the failure diagnosis in the failure diagnosis apparatus of Example 1 and 2 of this invention. It is a sequence diagram which shows the operation | movement at the time of the diagnosis at the time of the voltage monitoring apparatus failure in the failure diagnosis apparatus of Example 1 and 2 of this invention. It is a figure which shows the relationship between the voltage fluctuation | variation at the time of power supply abnormality, and operation | movement of each apparatus in the failure diagnosis apparatus of Example 1 and 2 of this invention. It is a figure which shows the relationship of the voltage fluctuation at the time of a diagnosis, and operation | movement of each apparatus when each apparatus is normal in the failure diagnosis apparatus of Example 1 and 2 of this invention. It is a figure which shows the relationship between the voltage fluctuation | variation at the time of a diagnosis, and operation | movement of each apparatus when the voltage monitoring apparatus has failed in the failure diagnosis apparatus of Example 1 and 2 of this invention. It is a figure which shows the relationship between the voltage fluctuation | variation at the time of a diagnosis, and operation | movement of each apparatus when the voltage adjustment apparatus has failed in the failure diagnosis apparatus of Example 1 and 2 of this invention. It is a figure which shows the relationship between the voltage fluctuation | variation at the time of a diagnosis, and operation | movement of each apparatus when the switch has an open failure in the failure diagnosis apparatus of Example 1 and 2 of this invention. It is a figure which shows the relationship between the voltage fluctuation | variation at the time of a diagnosis, and operation | movement of each apparatus when the switch has closed failure in the failure diagnosis apparatus of Example 1 and 2 of this invention.

  Hereinafter, specific embodiments of the present invention will be described in each example.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings. However, it should be noted that the drawings are schematic.

  FIG. 1 shows the configuration of this embodiment. In this embodiment, a load 1 having a power input terminal 11 and a reset input terminal 12, a power supply 2, a voltage monitoring device 3 for monitoring a power supply voltage 21 supplied to the load 1, and whether or not the voltage monitoring device 3 has failed. A fault diagnosis device 4 for diagnosis, a voltage adjustment device 5 for changing a voltage value input to the voltage monitoring device 3, a switch 6 for dividing a circuit connecting the voltage monitoring device 3 and the reset input terminal 12 of the load 1 at the time of diagnosis, and diagnosis It is comprised by the capacitor | condenser 7 which maintains the voltage used as the input signal to the reset input terminal 12 during.

  The function and configuration of each device will be described below. The load 1 includes a power input terminal 11 and a reset input terminal 12. When the power supply voltage 21 applied to the reset input terminal 12 is equal to or higher than a certain value, the load 1 is not reset, and when it is equal to or lower than the certain value, the reset is applied. Normally, a voltage of a certain value or more is applied to the reset input terminal 12, and when the voltage monitoring device 3 or the failure diagnosis device 4 transmits a reset signal, the voltage is lowered to a certain value or less to be reset. . When the load 1 is reset, the load 1 stops its operation, stops the output from the load 1, or stops the operation of the electronic device equipped with the load 1.

  The power source 2 is a device used to supply the power source voltage 21 to the load 1 and is, for example, a DC power source that outputs DC 5V. The positive terminal of the power source 2 is connected to the power source input terminal 11 of the load 1. Further, the voltage monitoring device 3 is connected via the voltage adjusting device 5.

  The voltage monitoring device 3 determines whether the monitoring voltage 22 supplied via the voltage adjusting device 5 is within the range of the monitoring threshold value, and transmits a reset signal 23 if it is out of the range. For example, when the operable range of the load 1 is 4.9 V to 5.1 V, the lower limit threshold of the monitor threshold is set to 4.85 V, and the upper limit threshold is set to 5.05 V, the monitor voltage 22 is 4.85 V or less or 5 A reset signal 23 is transmitted when the voltage becomes 0.05 V or higher. The reset signal 23 is connected to the reset input terminal 12 and the capacitor 7 of the load 1 through the failure diagnosis device 4 and the switch 6.

  The failure diagnosis device 4 is connected to the voltage adjustment device 5 and the switch 6 and diagnoses a failure of the voltage monitoring device 3. FIG. 3 shows a flowchart of the failure diagnosis procedure of the voltage monitoring device 3 by the failure diagnosis device 4. At the start of diagnosis, a voltage adjustment instruction 25 (instruction to set the monitoring voltage 22 to be equal to or higher than the threshold value) is transmitted to the voltage adjustment device 5 and the switch 6 is opened (9000). When the reset signal 23 is received from the voltage monitoring device 3 (9001), it is determined that the voltage monitoring device 3 is normal (9002). When it is determined that the voltage monitoring device 3 is normal, the switch 6 is closed, a voltage restoration instruction (instruction for making the monitoring voltage 22 the same as the power supply voltage 21) is transmitted to the voltage adjusting device 5 (9003), and the diagnosis is finished. . Failure diagnosis device 4 stands by until it receives reset signal 23 from voltage monitoring device 3 (9004).

  When the voltage adjustment device 5 receives the voltage adjustment instruction 25 from the failure diagnosis device 4, the value of the monitoring voltage 22 applied to the voltage monitoring device 3 based on the instruction is equal to or higher than the upper threshold value of the monitoring threshold value of the voltage monitoring device 3. Change to the following: When a voltage recovery instruction is received from the failure diagnosis device 4, the power supply voltage 21 and the monitoring voltage 22 have the same value. As a configuration of the voltage adjusting device 5, for example, a transformer or a voltage divider is connected between the power source 2 and the voltage monitoring device 3, and when the voltage adjusting instruction 25 is received from the failure diagnosis device 4, the voltage is adjusted using these devices. When the monitoring voltage 22 applied to the monitoring device 3 is stepped up or down and a voltage restoration instruction is received, the monitoring voltage 22 is returned to the normal voltage. In addition, a switch is provided between the power source 2 and the voltage monitoring device 3 and is normally closed. When the voltage adjustment instruction 25 is received, the switch is opened and the monitoring voltage 22 is lowered (even if the power voltage is opened, the power source voltage 21 is a state in which the voltage is maintained), and when a voltage restoration instruction is received, the switch may be closed to return the monitoring voltage 22 to the normal voltage.

  The switch 6 is provided to prevent the load 1 from receiving the reset signal 23 transmitted from the voltage monitoring device 3 at the time of diagnosis of the voltage monitoring device 3, and between the voltage monitoring device 3 and the reset input terminal 12. Arranged and connected to the fault diagnosis device 4. Based on the switch opening / closing instruction 24 from the failure diagnosis device 4, opening / closing of the switch 6 is selected.

  The capacitor 7 is provided to stabilize the voltage applied to the reset input terminal 12 even when the switch 6 is opened at the time of diagnosis of the voltage monitoring device 3. When the switch 6 is opened, the capacitor 7 is set according to a set time constant. Is discharged and the voltage drops after a certain time. During normal operation, the switch 6 is closed and the capacitor 7 is charged. The time constant of the capacitor 7 is maintained at a voltage higher than a certain value so as not to be reset for a certain time (hereinafter referred to as a diagnosis upper limit time) required for performing the diagnosis, and within a short time after the diagnosis upper limit time has elapsed. The voltage is adjusted to fall below a certain value so as to be reset. In addition, it is not always necessary to use a capacitor, maintain a voltage above a certain value so that resetting does not occur for a certain period of time, and after the diagnosis upper limit time elapses, the voltage drops below a certain value so that it can be reset within a short time Such a device may be replaced with a capacitor.

  If the load 1 is not reset when each device fails, there is a risk that the load 1 will be unstable due to fluctuations in the power supply voltage 21. Therefore, it is necessary that the load 1 is reset when the diagnosis is performed when each device fails. In the configuration shown in FIG. 1, it will be described that the load 1 is reset when the voltage monitoring device 3 diagnoses even when each device fails.

  First, the operation when each device is normal will be described. FIG. 6 is a sequence diagram of the failure diagnosis procedure, and FIG. The failure diagnosis device 4 opens the switch 6 at the start of diagnosis, and instructs the voltage adjustment device 5 to change the voltage to a voltage that is greater than or equal to the upper threshold value or less than the lower threshold value of the voltage monitoring device 3 (in FIG. 9). This shows a case where the monitoring voltage 22 is changed to a value below the lower threshold of the monitoring threshold). The voltage adjustment device 5 changes the monitoring voltage 22 based on an instruction from the failure diagnosis device 4. When the voltage monitoring device 3 detects that the monitored voltage 22 is outside the threshold range, the voltage monitoring device 3 transmits a reset signal 23. When the failure diagnosis device 4 receives the reset signal 23 from the voltage monitoring device 3 within the diagnosis upper limit time, it diagnoses that the voltage monitoring device 3 and the voltage adjustment device 5 are normal, and ends the diagnosis.

  The sequence diagram of the operation of each device when the power supply 2 is broken will be described with reference to FIG. 5, and the relationship between the voltage fluctuation and the operation of the voltage monitoring device 3 will be described with reference to FIG. When a power failure occurs during normal operation, the monitoring voltage 22 exceeds the monitoring voltage threshold, the voltage monitoring device 3 transmits a reset signal 23 to the load 1, and the load 1 is reset.

  FIG. 7 shows a sequence diagram of failure diagnosis when the voltage monitoring device 3 is broken down, and FIG. 10 explains the relationship between the voltage fluctuation and the operation of each device. The failure diagnosis device 4 opens the switch 6 at the start of diagnosis and instructs the voltage adjustment device 5 to change the voltage to a voltage equal to or higher than the monitoring threshold value of the voltage monitoring device 3. If the voltage monitoring device 3 is out of order and the reset signal 23 is not transmitted, the failure diagnosis device 4 continues to wait. In this case, since the switch 6 is in an open state, the capacitor 7 continues to be discharged, thereby causing a reset input. The voltage applied to the terminal 12 decreases, and the load 1 is reset due to the voltage decrease after the diagnosis upper limit time has elapsed.

  When the failure diagnosis device 4 is out of order, an erroneous operation of the voltage regulator 5 and an erroneous operation of the switch 6 are assumed. An erroneous operation of the voltage regulator 5 and the switch 6 results in an event equivalent to a failure of the erroneously operated device alone, and the load 1 is reset.

  The relationship between the voltage fluctuation at the time of failure diagnosis and the operation of each device when the voltage adjusting device 5 has failed will be described with reference to FIG. The failure diagnosis device 4 opens the switch 6 at the start of diagnosis, and instructs the voltage adjustment device 5 to change the voltage to a voltage equal to or higher than the upper threshold value or lower than the lower threshold value of the voltage monitoring device 3. If the voltage regulator 5 fails and the voltage does not fluctuate, the monitoring device does not transmit the reset signal 23, so the failure diagnostic device 4 continues to wait. In this case, the switch 6 is open, so the capacitor 7 is discharged. By continuing to do so, the voltage applied to the reset input terminal 12 decreases, and after the diagnosis upper limit time has elapsed, the load 1 is reset due to the voltage decrease.

  There are two types of failure of the switch 6: an open failure that remains open and a close failure that remains closed. The relationship between the voltage fluctuation at the time of failure diagnosis and the operation of each device when there is an open failure will be described with reference to FIG. When the switch 6 has an open failure at the end of the diagnosis, the capacitor 7 continues to discharge, the voltage applied to the reset input terminal 12 decreases, and the load 1 is reset due to the voltage decrease after the diagnosis upper limit time has elapsed. Next, the relationship between the voltage fluctuation at the time of failure diagnosis and the operation of each device in the case of a closed failure will be described with reference to FIG. When the switch 6 has a closed failure at the start of diagnosis, the load 1 receives the reset signal 23 transmitted from the voltage monitoring device 3 at the time of diagnosis, and the load 1 is reset.

  The diagnosis procedure described above enables failure diagnosis of the voltage monitoring device 3. In the above description, the fault diagnosis of the voltage monitoring device 3 has been described. However, since the load 1 is also reset when the fault diagnosis device 4, the voltage adjustment device 5, the switch 6, or the capacitor 7 fails, the fault diagnosis of these devices is performed. Is also possible.

  In the above description, it is assumed that the load 1 is stopped when a reset is applied, but external output by the load 1 may be stopped. When the external output is stopped, the load 1 does not include the reset input terminal 12, and when the reset is applied, a switch is provided between the external output of the load 1 and the external device. It is good also as a structure which disconnects an external apparatus and stops the external output by the load 1. FIG.

  In the first embodiment, the capacitor 7 maintains a voltage of a certain value or more so that the reset is not applied within the diagnosis upper limit time, and the voltage is reduced to a certain value or less so that the reset is performed within a short time after the diagnosis upper limit time has elapsed. It is assumed that the adjustment is made to decrease, and the failure of the capacitor 7 is not considered. However, when it is assumed that the capacitor 7 has failed, if the time to decrease to the reset voltage threshold is very short or very long than the diagnosis upper limit time, the configuration of FIG. Reliability or safety may be affected.

  First, the case where the discharge time of the capacitor 7 in the configuration of FIG. 1 is much shorter than the diagnosis upper limit time will be described. In this case, after the diagnosis is started and the switch 6 is opened, the voltage applied to the reset input terminal 12 is lowered before the diagnosis is completed. Therefore, the load 1 is reset at the time of diagnosis. As a result, the operating rate of the electronic device is lowered, which affects the reliability. However, since the load 1 is reset when the capacitor 7 fails, the load 1 operates on the safe side.

  Next, the case where the discharge time of the capacitor 7 in the configuration of FIG. 1 is much longer than the diagnosis upper limit time will be described. After the diagnosis is started and the switch 6 is opened, when the voltage monitoring device 3, the voltage regulator 5, or the switch 6 fails and the switch 6 does not close, the capacitor 7 is discharged to the load 1 by the extended discharge time. The time of the dangerous state that does not require resetting increases. This is an event that occurs due to multiple failures of the capacitor 7 and other devices. However, since there is no method for detecting the failure of the capacitor 7 in the configuration of FIG. You may add measures against

  A configuration for solving the above problem is shown in FIG. In this configuration, a voltage monitoring device 3b that monitors the voltage applied to the reset input terminal 12 is added. The fault diagnosis device 4 is connected to the reset input terminal of the load 1. The voltage monitoring device 3b constantly monitors the voltage value applied to the reset input terminal 12 as the reset input terminal voltage value 26 and transmits the voltage value to the failure diagnosis device 4 at regular intervals, or the voltage applied to the reset input terminal 12 When the value falls outside the range of the monitoring threshold, the failure diagnosis device 4 is notified of a change in voltage value. The fault diagnosis procedure of the voltage monitoring circuit is the same as the procedure shown in the first embodiment. The failure diagnosis procedure of the capacitor 7 and the voltage monitoring device 3b by the failure diagnosis device 4 will be described below.

  FIG. 4 shows a flowchart of the failure diagnosis procedure in the circuit configuration of FIG. At the start of diagnosis, a voltage adjustment instruction 25 (instruction for setting the monitoring voltage 22 to be equal to or higher than the upper limit threshold of the monitoring threshold or lower than the lower limit threshold) is transmitted to the voltage adjusting device 5, and the switch 6 is opened (9100). After opening the switch 6, the failure diagnosis device 4 confirms that the voltage decreases from the reset input voltage value 26 received from the voltage monitoring device 3 b according to the set time constant of the capacitor 7 (9101). If it does not decrease according to the time constant, the failure diagnosis device 4 diagnoses that the capacitor 7 has failed (9106), and transmits a reset signal 23b to the load 1 for resetting (9107). When the voltage decreases according to the set time constant of the capacitor 7 and the reset signal 23 is received from the voltage monitoring device 3 (9102), the voltage monitoring device 3 determines that it is normal (9104). When the voltage monitoring device 3 determines that it is normal, the switch 6 is closed, a voltage restoration instruction is transmitted to the voltage adjustment device 5 (9105), and the diagnosis is terminated. Failure diagnosis device 4 stands by until reset signal 23 is received from voltage monitoring device 3 (9103).

  In the failure diagnosis of the voltage monitoring device 3b, the failure of the voltage monitoring device 3b is detected by checking whether the voltage monitoring device 3b can monitor that the reset input terminal voltage value 26 decreases in synchronization with the start of diagnosis.

  In the circuit configurations shown in the first and second embodiments described above, the reset input terminal 12 is provided in the load 1, but may be provided in another device. For example, a device that operates the operation of the entire electronic device may be provided, and when the reset is applied, the entire electronic device may be stopped.

  In order to improve the reliability of the system, it is necessary to diagnose the operation of the voltage monitoring device and detect the failure of the voltage monitoring device at an early stage, but in order to diagnose the operation of the voltage monitoring device, It is effective to reduce the power supply voltage monitored by the voltage monitoring device and confirm that the voltage monitoring device correctly transmits the reset signal. In the embodiment described above, the voltage to the load can be stabilized even when diagnosing the voltage monitoring device by connecting the voltage regulator in parallel with the power source. Further, by connecting the output of the voltage monitoring device to the load reset input terminal 12, when the voltage monitoring device detects an abnormality in the power supply voltage, the load can be quickly stopped and the safety of the system can be maintained. .

  Here, when the diagnosis of the voltage monitoring device is performed, the voltage monitoring device transmits a reset signal, which causes a problem that the electronic device is stopped due to the signal and the operating rate is lowered, but there is a problem between the reset input terminal and the voltage monitoring device. By providing a switch and opening the switch at the time of diagnosis, it is not necessary to stop the load at the time of diagnosis of the voltage monitoring device, so that the operating rate of the system can be improved.

  Furthermore, by connecting a capacitor between the switch and the reset input terminal as shown in FIGS. 1 and 2, the load can be stopped reliably when an abnormality occurs in the voltage monitoring device or the like. It becomes possible to improve safety.

  An embodiment in which a fail-safe CPU is used as the load of each of the above-described embodiments will be described. When the voltage supplied to the fail-safe CPU is about several volts, the fail-safe CPU is designed to maintain a high fail-safe that does not cause a malfunction, for example, when the fluctuation is about 10% or less of the applied voltage. There are many cases. Therefore, it is necessary for the power supply device to maintain a voltage within a range in which the fail safe CPU ensures high fail safety. The present invention is particularly effective when applied to an electrical device having such a failsafe CPU as a load, and a highly reliable and safe system configuration is possible.

  Diagnose failure of power supply voltage monitoring devices used in electronic equipment without reducing system availability in train control systems, electronic interlocking devices in the railway field, and control systems where safety is important, such as car control and elevator control Thus, the system can be safely stopped even when a power supply abnormality or failure occurs.

Claims (12)

A load that receives power from the power source;
In an electrical device comprising a voltage monitoring device connected in parallel with a power supply and monitoring a power supply voltage,
A voltage regulator connected in series to a parallel line to which the voltage monitoring device is connected and capable of adjusting a voltage input to the voltage monitoring device;
A diagnostic device that transmits a voltage adjustment instruction to the voltage regulator when performing a diagnosis, receives a signal related to a voltage monitoring result from the voltage monitoring device, and diagnoses the state of the voltage monitoring device; Electrical equipment. The electric device according to claim 1,
The signal related to the voltage monitoring result is a reset signal output from the voltage monitoring device when a voltage detection value detected by the voltage monitoring device is out of a predetermined range.
The load includes a reset input terminal that receives the reset signal;
An electrical device comprising: reset means for stopping operation of a load when receiving the reset signal, or stopping output to the outside of the load when receiving the reset signal. The electrical device according to claim 2,
A switch disposed between the voltage monitoring device and the reset input terminal and capable of interrupting the reset signal;
The diagnostic apparatus transmits an switch opening command to the switch when performing diagnosis. The electrical device according to claim 3,
The diagnostic device transmits a switch closing command to the switch when receiving the reset signal at the time of diagnosis. The electric device according to claim 4,
The reset signal is a voltage signal whose voltage value is smaller than a predetermined voltage value,
Arranged between the switch and the reset input terminal, the voltage applied to the reset input terminal is maintained above the predetermined voltage value, and is applied to the reset input terminal after a predetermined time has elapsed with the switch open. An electrical apparatus comprising voltage maintaining means for making a voltage smaller than the predetermined voltage value. The electric device according to claim 5,
The voltage maintaining means is a capacitor,
A terminal voltage monitoring device for monitoring the voltage of the reset input terminal;
The diagnostic apparatus outputs the reset signal to the reset signal input terminal based on a detection result of a voltage of the reset input terminal. A load that receives power from the power source;
In a method for diagnosing an electrical device comprising a voltage monitoring device connected in parallel with a power supply and monitoring a power supply voltage,
A voltage regulator capable of adjusting a voltage input to the voltage monitoring device, connected in parallel with the power supply and in series with the voltage monitoring device,
During diagnosis, a voltage adjustment command is transmitted from the diagnosis device to the voltage adjustment device,
The voltage adjustment device that has received the voltage adjustment command adjusts the voltage input to the voltage monitoring device to a voltage value outside a predetermined range;
The voltage monitoring apparatus detects a voltage value adjusted by the voltage adjustment apparatus, and outputs a signal related to a voltage monitoring result to the diagnosis apparatus based on the detected voltage value. The diagnostic method for an electrical device according to claim 7,
The signal related to the voltage monitoring result is a reset signal output from the voltage monitoring device when a voltage detection value detected by the voltage monitoring device is out of a predetermined range.
The load having a reset input terminal that receives the reset signal stops operation of the load when the reset signal is received, or stops output to the outside of the load when the reset signal is received. A diagnostic method for electrical equipment. The diagnostic method for an electrical device according to claim 7,
A method for diagnosing an electrical device, wherein a switch disposed between the voltage monitoring device and the reset input terminal and capable of interrupting the reset signal is opened when performing diagnosis. In the diagnostic method of the electric equipment according to claim 9,
A diagnostic method for an electrical device, wherein the diagnostic device transmits a switch close command to the switch when receiving the reset signal at the time of diagnosis. The method for diagnosing an electric device according to claim 10,
The reset signal is a voltage signal whose voltage value is smaller than a predetermined voltage value,
The voltage maintaining means disposed between the switch and the reset input terminal maintains a voltage applied to the reset input terminal at the predetermined voltage value or more, and the reset input is performed after a predetermined time has elapsed while the switch is open. A method for diagnosing an electric device, wherein a voltage applied to a terminal is made smaller than the predetermined voltage value. In the diagnostic method of the electric equipment of Claim 11,
The voltage maintaining means is a capacitor,
The diagnostic apparatus outputs the reset signal to the reset signal input terminal based on a detection result of a voltage at the reset input terminal.

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