Electronic control unit

Abstract

Electronic control unit including: a driver circuit comprising: a measuring unit for measuring a voltage at one end of an electromagnetic load connected to a power supply or to ground, or a current of the electromagnetic load, and for determining whether a disturbance occurs; and a storage unit for storing disturbance occurrence information and information for distinguishing between a state in which the disturbance is not generated and a state in which the disturbance cannot be diagnosed, based on a measurement output of the measuring unit therein, wherein the driver circuit drives the electromagnetic load; and an operational processing section that sends an ON / OFF command signal to drive the electromagnetic load to the driver circuit, the information to distinguish between the state in which the disturbance is not generated and the state in which the disturbance cannot be diagnosed is captured by the memory unit of the driver circuit, and the occurrence or non-occurrence of the disturbance is identified by it in order to perform a fault diagnosis.

Description

Technical area

[0001] The present invention relates to an electronic control unit that drives an electromagnetic load through a switching element and detects a disconnection, a power interruption, and a ground fault between the electromagnetic load and a driving circuit. Current state of the art

[0002] In an electronic control unit, a FET (Field Effect Transistor) has been widely used as a driving element that performs a switching operation based on a drive signal from an operation processing device to thereby drive and control electromagnetic loads such as a relay, a solenoid, and a heater.

[0003] Generally, the prior art, as a driver circuit using an FET, includes a low-voltage driver circuit in which a power supply, a load, an FET, and a power ground are connected in this order, and a high-voltage driver circuit in which a power supply, an FET, a load, and a power ground are connected in this order. The FETs of these driver circuits are switch-controlled to thereby control the activation and deactivation of an electromagnetic load, thus enabling the driving and control of the electromagnetic load.

[0004] Where appropriate, these electronic control units must include a diagnostic function to specify the driver circuit fault detection and its fault mode to improve safety or maintainability. The fault mode indicates an electrical open path between the electromagnetic load and the driver circuit (disconnection), a short circuit of a line connecting the load and the driver circuit to ground (ground fault), and a short circuit of the line connecting the load and the driver circuit to the power supply (power interruption).

[0005] Patent Literature 1 describes a technology for providing a driving circuit that compares a voltage value when an FET signal is turned off and a predetermined threshold, thereby enabling to accurately distinguish a disconnection, a power interruption, and a ground fault from each other and to distinguish them both when the driving circuit is configured as the low-voltage driving circuit and when the driving circuit is configured as the high-voltage driving circuit.

[0006] Furthermore, Patent Literature 2 describes a technology for masking detection processing of a failure as a technology for avoiding the erroneous detection of a failure mode diagnosis.

[0007] EP 2 323 258 A1 relates to a fault diagnosis device for an electromagnetic load circuit, comprising fault diagnosis means that detect a layer short circuit in which a high-side switching element, a low-side switching element or the electromagnetic load itself is short-circuited to the supply voltage terminal or ground at a certain impedance, and performs a fault diagnosis.

[0008] EP 3 035 523 A1 relates to an engine control unit comprising a plurality of hardware units which output motor current for an electric motor, a control unit and a misdiagnosis unit, wherein when a faulty hardware unit is detected by the misdiagnosis unit, the misdiagnosis unit stops the operation of the faulty hardware unit and continues the drive of the electric motor with another hardware unit.

[0009] EP 3 103 686 A1 relates to a load drive circuit comprising a load drive element that controls a load, a measuring unit that measures a physical quantity and outputs it as a signal for diagnosing a malfunction of the load, and a diagnostic circuit that checks whether a malfunction exists based on this signal. The diagnosis is performed when the load drive element is switched on or off.

[0010] EP 3 159 220 A1 relates to a vehicle control unit that controls the power supply of another control unit via a power control circuit that controls a second switch in its current path. Proper disconnection of the switch is verified by detecting changes in the communication data of the other control unit when its power supply is interrupted.

[0011] US 2011 / 0 188 163 A1 relates to an anomaly detection circuit comprising a first circuit that monitors the sink current flowing through an H-bridge circuit, and a second circuit that detects an anomalous condition when the sink current is not detected by the first circuit for a predetermined time.

[0012] US 2011 / 0 298 276 A1 concerns a starter drive circuit with semiconductor switches that activates a starter according to external commands via a series circuit between a battery and the starter. All switches must be conductive to activate the starter. A voltage or current is monitored to determine whether the starter can be started and whether the switches are faulty. List of citationsPatent literature Patent literature 1: JP 2008 - 92 277 A Patent literature 2: JP 2014 - 225 780 A Summary of the inventionTechnical problem

[0013] Recently, in a vehicle's on-board self-diagnosis request, the vehicle must identify not only the presence or absence of the occurrence of an NG of disconnection, an earth fault and a supply interruption as previously required, but also three states of NG, OK and Undetermined.

[0014] As described in Patent Literature 2, the three states of NG, OK, and indeterminacy of disconnection, ground fault, and power interruption can be identified by the driving circuit; however, a means for identifying the three states by an operation processing device is not described therein, and there is no such technology yet.

[0015] Thus, since the drive period of the operation processing device is slower than that of the driver circuit, the diagnosis is performed; however, a mask signal may occur at the time of communication between the operation processing device and the driver circuit. In such a case, the operation processing device cannot determine whether an indeterminate state (no possibility of diagnosis) exists or whether the possibility of diagnosis exists and the diagnosis is performed.

[0016] If the operation processing section can accurately identify whether the indeterminate state exists, a diagnosis result generated in a state other than the indeterminate state can be effectively used, and self-diagnosis with high accuracy can be performed.

[0017] An object of the present invention is to provide an electronic control unit with a self-diagnosis function in which an operation processing section can identify not only the presence or absence of occurrence of NG, disconnection, ground fault, and power interruption, but also three states of NG, OK, and indeterminacy. Technical solution

[0018] To achieve the above object, the present invention is configured as follows.

[0019] An electronic control unit includes a drive circuit including a measuring unit for measuring a voltage of one end of an electromagnetic load connected to a power supply or the ground or a current of the electromagnetic load and determining whether a disturbance occurs, and a storage unit for storing disturbance occurrence information and information for distinguishing a state in which the disturbance is not generated and a state in which the disturbance cannot be diagnosed based on a measurement output of the measuring unit therein, and driving the electromagnetic load;and an operation processing section that sends an ON / OFF command signal for driving the electromagnetic load to the drive circuit, acquires the information for distinguishing between the state in which the disturbance is not generated and the state in which the disturbance cannot be diagnosed from the storage unit of the drive circuit, and determines the occurrence of the disturbance or the non-occurrence thereof to perform a disturbance diagnosis.; Advantageous effects of the invention

[0020] According to the present invention, an electronic control unit having a self-diagnosis function can be achieved in which an operation processing section can identify not only the presence or absence of occurrence of NG, disconnection, ground fault, and power interruption, but also three states of NG, OK, and indeterminacy. Short description of the drawings Fig. 1 shows a schematic overall configuration diagram of an electronic control unit (applied to a low-voltage drive system) of a first embodiment according to the present invention. Fig. 2 shows a flow diagram of a driver circuit according to the first embodiment of the present invention. Fig. 3 shows a flow diagram of the Fig. 2, in which a circuit of Fig. 1 is applied. Fig. 4 shows a flowchart of the mask processing in step 202 of Fig. 2, in which the Fig. The circuit shown in Figure 1 is applied. Fig. 5 shows a flow chart of step 204 of Fig. 2, in which the circuit with the in Fig. 1 shown configuration is applied. Fig. 6 shows a timing diagram in which a register generates a disconnect comparator register value and a voltage mask register value in the driver circuit when a disconnect occurs. Fig. Fig. 7 shows an operation flow diagram in an operation processing device in which the circuit of the Fig. 1 shown electronic control unit. Fig. Figure 8 shows a timing diagram in which the operation processing device generates OK, NG and uncertainty when disconnection, a ground fault and a supply interruption occur in the circuit of the Fig. 1 shown electronic control unit. Fig. 9 shows an overall configuration diagram of an electronic control unit (applied to a high-voltage drive system) of a second embodiment according to the present invention. Fig. 10 shows a flow chart of step 201 of Fig. 2, in which a circuit of the electronic control unit of Fig. 9 is applied. Fig. 11 shows a flow diagram of the Fig. 2, in which the circuit of the Fig. 9 shown electronic control unit is used. Fig. 12 shows a flow diagram of the Fig. 2, in which the circuit of the Fig. 9 shown electronic control unit is used. Fig. 13 shows a flow chart in an operation processing device in which the circuit of the Fig. 9 shown electronic control unit is used. Fig. 14 shows a timing diagram in which the operation processing device generates OK, NG and uncertainty when disconnection, a ground fault and a supply interruption occur in the circuit of the Fig. 9 shown electronic control unit. Description of the embodiments

[0021] Hereinafter, embodiments of the present invention are described in detail using the drawings. Embodiments (First Embodiment)

[0022] Below, a first embodiment of the present invention is described in detail using Fig. 1 to 8 described.

[0023] Fig. 1 shows a schematic overall configuration diagram of an electronic control unit 103 (applied to a low-voltage drive system) of the first embodiment according to the present invention.

[0024] In Fig. 1, one end of an electromagnetic load 101 is connected to a power supply 102 (voltage 14 V), and the other end is connected to a drive output terminal 104 of the electromagnetic load, which is a terminal for connecting to the electronic control unit (ECU) 103. The ECU 103 includes the drive output terminal 104 of the electromagnetic load, a ground terminal 105, an operation processing device (operation processing section) 106, a PWM generation unit 107, and a drive circuit 108.

[0025] The operation processing device 106 includes a power-on operation unit 109, a communication command unit 110, and a diagnosis unit 111. Further, the diagnosis unit 111 includes a power interruption diagnosis part 111a, a ground fault diagnosis part 111b, and a disconnection diagnosis part 111c.

[0026] The PWM generation unit 107 generates an ON / OFF command signal for the driver circuit 108 according to a duty ratio output from the duty operation unit 109. The driver circuit 108 opens / closes an FET (Field Effect Transistor) 112 based on the ON / OFF command signal from the PWM generation unit 107 to drive the electromagnetic load 101. A drain of the FET 112 is connected to a constant voltage source 117 (voltage 2.5 V) and the drive output terminal 104 of the electromagnetic load.

[0027] The driver circuit 108 is connected to the drive output terminal 104 of the electromagnetic load and the ground terminal 105. The ground terminal 105 is connected to the ground outside the ECU 103. The driver circuit 108 includes a current timer 113, a voltage timer 114, a mask detection unit 115, a comparator 116, the previously described constant voltage source 117, a voltmeter 118, an ammeter 119, and a register 120.

[0028] Constant voltage source 117 is connected to the drive output terminal 104 of the electromagnetic load and the drain of FET 112. Voltmeter 118 is arranged between the drive output terminal 104 of the electromagnetic load and FET 112 and between the ground terminal 105 and FET 112. Ammeter 119 is arranged between the ground terminal 105 and a source of FET 112.

[0029] The comparator 116 includes a supply interruption comparator 116a, an earth fault comparator 116b, and a disconnection comparator 116c, and generates comparator signals based on values ​​of the voltmeter 118 and the ammeter 119.

[0030] The mask detection unit 115 includes a current mask detection part 115a and a voltage mask detection part 115b, and generates comparison mask signals based on the ON / OFF command signal from the PWM generation unit 107, the comparison signals from the comparator 116, a timer value from the current timer 113, and a timer value from the voltage timer 114.

[0031] The current timer 113 is used in the current mask detection section 115a, and the voltage timer 114 is used in the voltage mask detection section 115b. They each output ON signals when a predetermined time has elapsed.

[0032] Register 120 stores therein a current mask register value 120a, a supply interruption comparator register value 120b, a voltage mask register value 120c, a ground fault comparator register value 120d, and a disconnect comparator register value 120e. Register 120 generates a mask register value and a comparator register value based on the comparison mask signal from mask detection unit 115 and the comparator signal from comparator 116.

[0033] The communication command unit 110 generates a communication permission signal for the operation processing unit 106 and the driver circuit 108. The diagnosis unit 111 acquires the mask register value (120a, 120c) and the comparator register value (120b, 120d, 120e) from the register 120 during a period from a time when the communication permission signal of the communication command unit 110 becomes OK to a time when the communication permission signal becomes NG.

[0034] Here, the electronic control unit 103 of the first embodiment includes the driver circuit 108 and the operation processing device 106 that sends the ON / OFF command signal to the driver circuit 108. The driver circuit 108 includes a measuring unit that measures a voltage at the end of the electromagnetic load 101 or a current of the electromagnetic load 101, and a storage unit for acquiring information by the operation processing device 106 for distinguishing a state in which a fault is not generated from a state (diagnostic indeterminate state) in which a fault cannot be diagnosed based on the output of the measuring unit. The measuring unit includes the voltmeter 118 and the ammeter 119. The storage unit includes the register 120.

[0035] Thus, the processing device 106 can identify an OK of the disconnection, a ground fault, and a supply interruption.

[0036] Here, the electronic control unit 103 of the first embodiment includes the driver circuit 108 and the operation processing device 106 that sends the ON / OFF command signal to the driver circuit 108. The driver circuit 108 includes the FET 112 (switching part) that switches the electromagnetic load 102, which is connected at one end to the power supply 102 or the ground, based on the ON / OFF command signal, and the storage unit that causes the operation processing device 106 to store, based on the output of the voltmeter 118 or ammeter 119, fault occurrence information indicating the occurrence of at least one element of the group including disconnection, ground fault, and power interruption of a path from the FET 112 to the electromagnetic load 101, and information (information (reset information) in step 504 of Fig. 5) to separate (distinguish) between a state in which no disturbance is generated and a state (indeterminate state) in which the disturbance cannot be diagnosed.

[0037] Thus, the operation processing device 106 can receive the information for performing the foregoing discrimination to identify NG, OK, and indeterminacy of the disconnection, ground fault, and supply interruption, and thereby perform a fault diagnosis.

[0038] Here, in the electronic control unit 103 of the first embodiment, the driving circuit 108 includes the constant voltage source 117 arranged between the electromagnetic load 101 and the FET 112 and applying a constant voltage for disconnection detection.

[0039] Thus, the driver circuit 108 can detect the disconnection in a path from the drive output terminal 104 of the electromagnetic load to the power supply 102 from the ON / OFF command signal from the PWM generation unit 107 and the value of the voltmeter 118.

[0040] The following is the feature of the first embodiment using Fig. 2 to 8 described.

[0041] Fig. 2 is a diagram showing an example of a flow chart in the driver circuit 108 according to the first embodiment of the present invention.

[0042] First of all, Fig. 2, the sequence of steps 201 to 204 is described. Step 201 is the comparator processing of the measured values ​​of the voltmeter 118 and the ammeter 119 in the mask detection unit 115 and generates comparator signals according to Fig. 3, which is described below.

[0043] Step 202 is the mask detection processing in the comparator 116 and generates mask signals according to Fig. 4, which is described below. The mask signal is a signal that indicates whether or not to perform a fault diagnosis.

[0044] Step 203 is the communication processing in the register 120 and receives a communication permission signal generated in the communication command unit 110.

[0045] Step 204 is the register processing in register 120 and generates mask register values ​​and comparator register values ​​according to Fig. 5, which is described below.

[0046] Fig. 3 shows a diagram showing an example of a flow chart of the Fig. 2, in which the circuit of Fig. 1 is applied.

[0047] In Fig. 3, in step 301, the power interrupt comparator 116a determines whether an ammeter reading is greater than a current threshold. If the answer is "yes" (the ammeter reading is greater than the current threshold) in step 301, processing proceeds to step 302, where a power interrupt comparator signal is set to ON, and processing continues to step 304. If the answer is "no" (the ammeter reading is not greater than the current threshold) in step 301, processing proceeds to step 303, where the power interrupt comparator signal is set to OFF, and processing continues to step 304.

[0048] In step 304, the ground fault comparator 116b determines whether a voltmeter reading is less than a voltage threshold 1. If the answer is "yes" (the voltmeter reading is less than the voltage threshold 1) in step 304, processing proceeds to step 305, in which a ground fault comparator signal is set to ON and a disconnect comparator signal is set to OFF, and processing is terminated.

[0049] If the answer is "No" (the voltmeter reading is greater than or equal to voltage threshold 1) in step 304, processing continues with the processing of step 306.

[0050] In step 306, the disconnect comparator 116c determines whether the voltmeter reading is less than a voltage threshold 2. If the answer is "yes" (the voltmeter reading is less than the voltage threshold 2) in step 306, processing proceeds to step 307, where the ground fault comparator signal is set to OFF and the disconnect comparator signal is set to ON, and processing ends. If the answer is "no" (the voltmeter reading is greater than or equal to the voltage threshold 2) in step 306, processing proceeds to step 308, where the ground fault comparator signal is set to OFF and the disconnect comparator signal is set to OFF, and processing ends.

[0051] Fig. Fig. 4 is a diagram showing an example of a flowchart of the mask processing in step 202 of Fig. 2, in which the Fig. The circuit shown in Figure 1 is used.

[0052] In Fig. 4, it is determined in step 401 whether the power interrupt comparator signal is ON. If the answer is "Yes" (the power interrupt comparator signal is ON) in step 401, processing proceeds to step 402, where the power timer 113 adds time, and processing proceeds to step 404.

[0053] If the answer is "No" (the power cut comparator signal is OFF) in step 401, the processing proceeds to step 403, in which the power timer 113 is set to 0, and the processing proceeds to the processing of step 406.

[0054] In step 404, the current mask determination part 115a determines whether a timer value of the current timer 113 is less than a time threshold 2. If the answer is "yes" (the timer value of the current timer 113 is less than the time threshold 2) in step 404, processing proceeds to step 405, where a current mask signal is set to "mask" (mask processing is performed). That is, the mask processing (the mask signal) indicates that diagnosis is not performed when the output of the measurement unit is unstable. If the answer is "no" (the timer value of the current timer 113 is equal to or greater than the time threshold 2) in step 404, processing proceeds to step 406, where the current mask signal is set to "not mask" (mask processing is not performed). After performing the processing of step 405 and step 406, the processing proceeds to the processing of step 407.

[0055] In step 407, it is determined whether an ON / OFF command signal from the PWM generation unit 107 is OFF. If the answer is "Yes" (the ON / OFF command signal is OFF) in step 407, the processing proceeds to the processing of step 408. If the answer is "No" (the ON / OFF command signal is not OFF) in step 407, the processing proceeds to the processing of step 410.

[0056] In step 408, it is determined whether a ground fault comparator signal is ON or a disconnect comparator signal is ON. If the answer is "Yes" (the ground fault comparator signal is ON or the disconnect comparator signal is ON) in step 408, processing proceeds to step 409, where a timer value of the voltage timer 114 is added, and processing proceeds to the processing of step 411. If the answer is "No" (the ground fault comparator signal and the disconnect comparator signal are both OFF) in step 408, processing proceeds to step 410, where the voltage timer 114 is set to 0, and processing proceeds to the processing of step 413.

[0057] In step 411, the voltage mask determination part 115b determines whether the timer value of the voltage timer 113 is less than a time threshold 1. If the answer is "yes" (the timer value of the voltage timer 113 is less than the time threshold 1) in step 411, the processing proceeds to step 412, where a voltage mask signal is set to "mask." That is, the mask processing (the mask signal) indicates that diagnosis will not be performed when the output of the measurement unit is unstable. If the answer is "no" (the timer value of the voltage timer 113 is greater than or equal to the time threshold 1) in step 411, the processing proceeds to step 413, where the voltage mask signal is set to "not mask." After performing steps 412 and 413, the processing proceeds to the processing of step 414.

[0058] In step 414, it is determined whether the ground fault comparator signal has switched from ON to OFF or the disconnect comparator signal has switched from ON to OFF. If the answer is "Yes" (the ground fault comparator signal has switched from ON to OFF or the disconnect comparator signal has switched from ON to OFF) in step 414, processing proceeds to step 415, where the timer value of the voltage timer 114 is set to 0, and processing ends. If the answer is "No" (the ground fault comparator signal has not switched from ON to OFF and the disconnect comparator signal has not switched from ON to OFF) in step 414, processing ends without further steps.

[0059] The following is a method for setting the voltage threshold 1, the voltage threshold 2, the current threshold, the time threshold 1 and the time threshold 2 used in generating the comparator signals and current and voltage mask signals of the disconnection, the earth fault and the supply interruption with respect to Fig. 3 and Fig. 4 described.

[0060] When the FET 112 is ON, both ends of the voltmeter 118 become equipotential, and thus, the detected voltage value of the voltmeter 118 becomes 0 [V] regardless of the absence or presence of noise. Thus, the noise cannot be identified by using the voltmeter 118 in the state where the FET 112 is ON.

[0061] On the other hand, when the FET 112 is OFF, the value measured by the voltmeter 118 becomes 14 [V] at a non-disturbed time because there is a difference in potential between the drive output terminal 104 of the electromagnetic load (14 [V] due to the connection to the power supply 102) and the ground terminal 105 (0 [V] due to the connection to the ground).

[0062] When the drive output terminal 104 of the electromagnetic load is subject to a ground fault, the value measured by the voltmeter 118 becomes 14 [V] because there is a difference in potential between the drive output terminal 104 of the electromagnetic load (0 [V] due to grounding) and the ground connection terminal 105 (0 [V] due to connection to ground).

[0063] When the drive output terminal 104 of the electromagnetic load is disconnected, the value becomes 2.5 [V] because there is a difference in potential between the drive output terminal 104 of the electromagnetic load (constant voltage source 117 = 2.5 [V] due to the disconnection) and the ground terminal 105 (0 [V] due to the connection to the ground).

[0064] When the drive output terminal 104 of the electromagnetic load is subjected to a power interruption, the value becomes 14 [V] because there is a difference in potential between the drive output terminal 104 of the electromagnetic load (power supply 102 = 14 [V] due to the ground fault) and the ground connection terminal 105 (0 [V] due to the connection to the ground).

[0065] Thus, during the undisturbed time and when the power interruption occurs, the value of the voltmeter 118 becomes 14 [V] and therefore only the voltmeter 118 cannot distinguish between the absence of disturbances and the power interruption.

[0066] Next, the readings of ammeter 119 during the undisturbed time and the power-off time when FET 112 is ON are examined. During the undisturbed time, a current flows through the electromagnetic load with a resistance value of 101 ÷ (power supply 102 = 14 [V]). However, during the power-off time, an overcurrent flows through it because the path from the drive output terminal 104 of the electromagnetic load to ground assumes a state of almost no resistance.

[0067] Furthermore, since the reliability of the voltage value to be measured is required when the value of the voltmeter 118 is used for disconnection / ground fault detection, the time required until the voltage value becomes stable after a change in voltage must be set by time threshold 1. Disconnection / ground fault detection cannot be performed until time threshold 1 elapses after the change in voltage. Even if the value of the ammeter 119 is used for supply interruption detection, reliability is required as with voltage. Therefore, the time required until the value becomes stable after a change in current must be set by time threshold 2. Supply interruption detection cannot be performed until time threshold 2 elapses after the change in current.

[0068] From the previous results, the voltage threshold 1 for detecting the earth fault, the voltage threshold 2 for detecting the disconnection and the current threshold for detecting the supply interruption are set, for example, with the following equations (1) to (3). Voltage threshold 1=constant voltage source 117 (2.5[V])÷2 Voltage threshold 2=(power supply 102(14[V])+constant voltage source 117 (2.5[V]))÷2 Current threshold = (power supply 102 (14[V]) ÷ electromagnetic load 101 resistance value) × 2

[0069] Furthermore, time threshold 1 and time threshold 2 each define a sufficient stable time from the voltage / current changes taking into account the circuit characteristics.

[0070] Here, in the electronic control unit 103 of the first embodiment, the information for separating the state in which the trouble is not generated and the state in which the trouble cannot be diagnosed is mask processing information in which no diagnosis is performed in a predetermined state.

[0071] Thus, erroneous detection can be prevented without performing diagnosis in the situation where the disconnection, earth fault and supply interruption cannot be properly identified.

[0072] Here, in the electronic control unit 103 of the first embodiment, the mask processing is processing in which the diagnosis is not performed when the ON / OFF command signal from the PWM generation unit 10 is in the predetermined state and when the outputs of the voltmeter 118 and the ammeter 119 are unstable.

[0073] This can prevent false detection of disconnection, earth fault and power interruption when the voltage and current are unstable.

[0074] Here, in the electronic control unit 103 of the first embodiment, one end of the electromagnetic load 101 is connected to the power supply 102. The register 120 performs mask processing in which the information of the occurrence of the power interruption of the path from the FET 112 to the electromagnetic load 101 is diagnosed based on the current output of the ammeter 119, and in which the diagnosis is not performed when the current output of the ammeter 119 is unstable.

[0075] Thus, in the configuration of the Fig. 1 shown low-voltage driver system NG of the supply interruption can be detected.

[0076] Here, in the electronic control unit 103 of the first embodiment, one end of the electromagnetic load 101 is connected to the power supply 102, and the register 120 performs mask processing in which the ON / OFF command signal from the PWM generation unit 10 is OFF, the information of the occurrence of the disconnection and / or ground fault of the path from the FET 112 to the electromagnetic load 101 is diagnosed based on the voltage output of the voltmeter 118, and the diagnosis is not performed when the ON / OFF command signal is ON and the voltage output of the voltmeter 118 is unstable.

[0077] Thus, in the configuration of the Fig. 1 shown low voltage driver system NG of the separation and the earth fault.

[0078] Fig. Fig. 5 is a diagram showing an example of a flowchart of step 204 (register processing) of Fig. 2, in which the circuit with the in Fig. 1 shown configuration is applied.

[0079] In Fig. 5, in step 501, the register 120 determines whether "The communication permission signal is OK." is correct. If the answer is "Yes" ("The communication permission signal is OK." is correct) in step 501, the processing proceeds to step 502, where the current mask register value 120a, the power interruption comparator register value 120b, the voltage mask register value 120c, the ground fault comparator register value 120d, and the disconnection comparator register value 120e are sent to the operation processing device 106, and the processing is terminated.

[0080] If the answer is "No" ("The communication permission signal is OK." is not proper) in step 501, the processing proceeds to the processing of step 503.

[0081] In step 503, it is determined whether "The communication permission signal is switched from OK to NG." is normal. If the answer is "Yes" ("The communication permission signal is switched from OK to NG." is normal) in step 503, processing proceeds to step 504, where the current mask register value 120a is set to "Mask" (Mask), the power interruption comparator register value 120b is set to OFF (Mask off), the voltage mask register value 120c is set to "Mask" (Mask), the ground fault comparator register value 120d is set to OFF (Mask off), and the disconnection comparator register value 120e is set to OFF (Mask off). If the answer is "No" ("The communication permission signal is switched from OK to NG." is not proper) in step 503, the processing proceeds to the processing of step 505.

[0082] In step 505, it is determined whether "The current mask signal is "No Mask"." is proper. If the answer is "Yes" ("The current mask signal is "No Mask"." is proper) in step 505, processing proceeds to step 506, where the current mask register value 120a is set to "No Mask" (unmasked), and processing proceeds to the processing of step 507. If the answer is "No" ("The current mask signal is "No Mask"." is OK." is not proper) in step 505, processing proceeds to the processing of step 509.

[0083] In step 507, it is determined whether "The power interrupt comparator signal is ON." is normal. If the answer is "Yes" ("The power interrupt comparator signal is ON." is normal) in step 507, processing proceeds to step 508, where the power interrupt comparator register value 120b is set to ON. If the answer is "No" ("The power interrupt comparator signal is ON." is not normal) in step 507 and after the processing of step 508, processing proceeds to the processing of step 509.

[0084] In step 509, it is determined whether "The voltage mask signal is "Not Mask"." is correct. If the answer is "Yes" ("The voltage mask signal is "Not Mask"." is correct) in step 509, processing proceeds to step 510, where the voltage mask register value 120c is set to "Not Mask" and processing continues with the processing of step 511. If the answer is "No" ("The voltage mask signal is "Not Mask"." is not correct) in step 509, nothing is done. (Processing is terminated.)

[0085] In step 511, it is determined whether "The ground fault comparator signal is ON." is normal. If the answer is "Yes" ("The ground fault comparator signal is ON." is normal) in step 511, processing proceeds to step 512, where the ground fault comparator register value 120d is set to ON. If the answer is "No" ("The ground fault comparator signal is ON." is not normal) in step 509, processing proceeds to the processing of step 513.

[0086] In step 513, it is determined whether "The separation comparator signal is ON." is normal. If the answer is "Yes" ("The separation comparator signal is ON." is normal) in step 513, processing proceeds to step 514, where the separation comparator register value 120e is set to ON. If the answer is "No" ("The separation comparator signal is ON." is not normal) in step 513, processing ends without further steps.

[0087] Here, in the electronic control unit 103 of the first embodiment, in order to separate the information of the occurrence of the trouble, the information in which no trouble is generated, and the information indicating the state in which the trouble cannot be diagnosed, the information stored in the register 120 is deleted when the operation processing device 106 and the driving circuit communicate with each other.

[0088] That is, in the prior art, since the drive period of the operation processing device 106 is slower than the drive period of the driver circuit 108, power interruption, ground fault, and disconnection are diagnosed. Even if the diagnosis results are stored in the register 120, the driver circuit 108 may trigger the "Mask" signal before the operation processing device 106 communicates with the driver circuit 108. Subsequently, when the operation processing device 106 communicates with the driver circuit 108, the mask signal is in a mask state, and thus, the possibility of diagnosis is determined to be absent.

[0089] Again, in the first embodiment of the present invention, when the diagnosis possibility exists, the mask signal maintains the "No Mask" state even if the mask signal is subsequently set to the mask state. When the operation processing device 106 requests the driver circuit 108 to communicate with it, the mask signal is set to the "Mask" state, and the information stored in the register 120 is cleared. Thus, the operation processing device 106 can detect the existence of the diagnosis possibility using the diagnostic information obtained at that time.

[0090] Further, when the mask signal is in the state of "mask" and the operation processing device 106 performs communication with the driver circuit 108, the operation processing device 106 can detect the lack of possibility of diagnosis, that is, the presence of the indeterminate state.

[0091] Thus, the operation processing device 106 can store the presence of the possibilities of diagnosing the disconnection, the ground fault, and the power interruption between communications with the driver circuit 108 and identify exactly three states.

[0092] Fig. 6 is a diagram showing an example of a timing chart in which the register 120 generates the disconnect comparator register value 120e and the voltage mask register value 120c in the driver circuit 108 when a disconnect occurs.

[0093] In Fig. 6, time 601 is the time at which the communication permission signal is first switched from OK to NG. The disconnect comparator register value 120e is OFF, and the voltage mask register value 120c is also "Mask."

[0094] Time 602 is the time at which the ON / OFF command signal is switched from ON to OFF and the value of the voltmeter 118 begins to rise. Since the voltage value of the voltmeter 118 is less than the voltage threshold 1 at time 602, the voltage timer 114 begins to count until the voltage value reaches the time threshold 1.

[0095] Time 603 is the time at which the value of the voltmeter 118 becomes greater than or equal to the voltage threshold 1 and less than the voltage threshold 2, and the disconnect comparator signal turns ON. Then, the count is reset once until the value reaches the time threshold 1 of the voltage timer 114, and the count is restarted.

[0096] Time 604 is a time at which only time threshold 1 elapses from time 603, and the voltage mask signal and the voltage mask register value 120c reach "Non-Mask." Subsequently, the disconnect comparator register value 120e becomes ON to satisfy "The disconnect comparator signal is ON and the voltage mask signal is "Non-Mask."."

[0097] A time point 605 is a time point at which the ON / OFF command signal turns ON and the reading of the voltmeter 118 begins to fall. At the same time, the voltage mask signal is switched from "Non-Mask" to "Mask."

[0098] A time 606 is a time at which the value of the measured value of the voltmeter 118 falls below the voltage threshold 1 and the disconnect comparator signal becomes OFF.

[0099] A time point 607 is a time point at which the communication permission signal changes from NG to OK at the second time point in Fig. 6 is switched. The voltage mask signal register value is switched from "No Mask" to "Mask," and the disconnect comparator register value is turned OFF. Here, the timing relationship between the communication permission signal and the voltage mask register value, the disconnect comparator signal, and the disconnect comparator register value has been Fig. 6; however, the timing relationship between the communication permission signal and the voltage mask register value, the ground fault comparator signal and the ground fault comparator register value is also similar Fig. 6. Furthermore, the timing relationship between the communication permission signal and the power interrupt comparator signal and the power interrupt comparator register value is also similar Fig. 6; but the voltage mask signal of Fig. 6 is a current mask signal and the voltage mask register value becomes a current mask register value.

[0100] Fig. Fig. 7 shows an example of an operation flow chart in the operation processing device 106, in which the circuit of the Fig. 1 shown electronic control unit 103 is used.

[0101] In Fig. 7, in step 701, the operation processing device 106 acquires the current mask register value 120a, the supply interruption comparator register value 120b, the voltage mask register value 120c, the ground fault comparator register value 120d, and the disconnection comparator register value 120e from the register 120 and proceeds to step 702.

[0102] The processing from steps 702 to 706 is performed in the power interruption diagnosis part 111a.

[0103] In step 702, a determination is made as to whether "The power interruption comparator signal register value is ON." is correct. If the answer is "Yes" ("The power interruption comparator signal register value is ON." is correct) in step 702, the operation processing device proceeds to step 703 to set a power interruption diagnosis result to NG and proceeds to the processing of step 707. If the answer is "No" ("The power interruption comparator signal register value is ON." is not correct) in step 702, the operation processing device proceeds to the processing of step 704.

[0104] In step 704, it is determined whether "The power mask register value is 'mask'." is proper. If the answer is "Yes" ("The power mask register value is 'mask'." is proper) in step 704, the operation processing device proceeds to step 705 to set a power interruption diagnosis result to indeterminate. If the answer is "No" ("The power mask register value is 'mask'." is improper) in step 704, the operation processing device proceeds to step 706 to set the power interruption diagnosis result to OK. After the processing of steps 705 and 706, the operation processing device proceeds to the processing of step 707.

[0105] The processing from steps 707 to 711 is performed in the ground fault diagnosis part 111b.

[0106] In step 707, it is determined whether "The ground fault comparator signal register value is ON." is normal. If the answer is "Yes" ("The ground fault comparator signal register value is ON." is normal) in step 707, the operation processing device proceeds to step 708 to set a ground fault diagnosis result to NG and proceeds to the processing of step 712. If the answer is "No" ("The ground fault comparator signal register value is ON." is not normal) in step 707, the operation processing device proceeds to the processing of step 709.

[0107] In step 709, it is determined whether "The voltage mask register value is 'mask'." is proper. If the answer is "Yes" ("The voltage mask register value is 'mask'." is proper) in step 709, the operation processing device proceeds to step 710 to set a ground fault diagnosis result to indeterminate. If the answer is "No" ("The voltage mask register value is 'mask'." is improper) in step 709, the operation processing device proceeds to step 711 to set a ground fault diagnosis result to OK. After the processing of step 710 and step 711, the operation processing device proceeds to the processing of step 712.

[0108] The processing from steps 712 to 716 is performed in the separation diagnosis part 111c.

[0109] In step 712, it is determined whether "The disconnect comparator signal register value is ON." is normal. If the answer is "Yes" ("The disconnect comparator signal register value is ON." is normal) in step 712, the operation processing device proceeds to step 713 to set a disconnection diagnosis result to NG, and the processing is terminated.

[0110] If the answer is "No" ("The disconnect comparator signal register value is ON." is not correct) in step 712, the operation processing device proceeds to the processing of step 714. In step 714, it is determined whether "The voltage mask register value is "Mask"." is correct. If the answer is "Yes" ("The voltage mask register value is "Mask"." is correct) in step 714, the operation processing device proceeds to step 715 to set a disconnection diagnostic result to indeterminate, and the processing is terminated. If the answer is "No" ("The voltage mask register value is "Mask"." is not correct) in step 714, the operation processing device proceeds to step 716 to set a disconnection diagnostic result to OK, and the processing is terminated.

[0111] Here, in the electronic control unit 103 of the first embodiment, as shown in Fig. As shown in the flowchart shown in Fig. 7, the operation processing device 106 determines the corresponding diagnosis results as NG when the corresponding comparator register values ​​are ON, determines the corresponding diagnosis results as OK when the corresponding comparator register values ​​are OFF and the corresponding mask register values ​​are "Not Mask", and determines the results as Undetermined when the corresponding comparator register values ​​are OFF and the corresponding mask register values ​​are "Mask". That is, when the abnormality occurrence information indicates the occurrence of a abnormality, the operation processing device 106 determines that the abnormality has occurred. When the abnormality occurrence information does not indicate the abnormality occurrence and the mask signal indicates the performance of the abnormality diagnosis, the operation processing device 106 determines that the abnormality has not been generated.When the failure occurrence information does not indicate the failure occurrence and the mask signal indicates that the failure diagnosis is not performed, the operation processing device 106 determines that the diagnosis has an indeterminate state.

[0112] Thus, the operation processing device 106 can identify the three states of disconnection, ground fault, and power interruption by using the comparator register values ​​and the mask register values.

[0113] Furthermore, in the above configuration, the driver circuit 108 has a driver circuit self-diagnosis function for diagnosing the failure of the driver circuit 108. When the driver circuit self-diagnosis function indicates a failure, the operation processing device 106 may determine a diagnosis result as indeterminate.

[0114] According to the above configuration, when there is a risk that the failure occurs in the driving circuit 108 and the operation processing device 106 misdiagnoses the three states, the operation processing device 106 can identify that the disconnection, the ground fault, and the supply interruption of the electromagnetic load 101 are indeterminate.

[0115] Furthermore, in the above configuration, the operation processing device 106 has an operation processing device self-diagnosis function for diagnosing the failure of the operation processing device 106. When the operation processing device self-diagnosis function indicates a failure, the operation processing device 106 may determine a diagnosis result as indeterminate.

[0116] According to the above configuration, when there is a risk that the failure occurs in the operation processing device 106 and the operation processing device 106 misdiagnoses the three states, the operation processing device 106 can identify that the disconnection, the ground fault, and the supply interruption of the electromagnetic load 101 are indeterminate.

[0117] Furthermore, in the above configuration, the power supply 102 has a power supply self-diagnosis function for diagnosing the failure of the power supply 102. When the power supply self-diagnosis function indicates a failure, the operation processing device 106 may determine a diagnosis result as indeterminate.

[0118] According to the above configuration, when there is a risk that the fault occurs in the power supply 102 and the operation processing device 106 misdiagnoses the three states, the operation processing device 106 can identify that the disconnection, the ground fault, and the supply interruption of the electromagnetic load 101 are indeterminate.

[0119] Furthermore, in the foregoing configuration, the register 120 can be used to identify the three states of supply interruption, ground fault and disconnection based on the flow chart of Fig. 7 and sending a result of the identification thereof to the operation processing device 106.

[0120] According to the above configuration, the number of signals to be sent to the operation processing device 106 increases more than that of the system of the present embodiment; however, a computing capacity corresponding to the diagnosis processing in the operation processing device 106 can be reduced.

[0121] The following is a timing chart of the first embodiment using Fig. 8 described.

[0122] Fig. Fig. 8 shows an example of the timing chart in which the operation processing device 106 identifies OK, NG and uncertainty when disconnection, a ground fault and a supply interruption occur in the circuit of the Fig. 1 shown electronic control unit 103.

[0123] In Fig. 8, the driver circuit 108 generates comparator register values ​​and mask register values ​​from the ON / OFF command signal, the measured value of the voltmeter 118 and the measured value of the ammeter 119 according to the flow chart of Fig. 2. Further, the operation processing device 106 acquires the comparator register values ​​and the mask register values ​​for each communication with the driver circuit 108 and identifies the three states of disconnection, ground fault, and power interruption according to the flowchart of Fig. 7.

[0124] One in Fig. Time 801 shown in Figure 8 is a time at which the disconnection, ground fault, and power interruption are not generated when communication is first performed in the electronic control unit 103. Furthermore, time 802 is a time at which the disconnection occurs at the time of communication. Time 803 is a time at which the ground fault is generated at the time of communication, but the ground fault cannot yet be identified by the driver circuit 108. Time 804 is a time at which the ON / OFF command signal turns OFF, and thus the ground fault can be identified.

[0125] Furthermore, times 805 and 806 are times at which the ON / OFF command signal is repeatedly turned ON / OFF in a cycle shorter than one communication interval. Times 807 to 810 are times that elapse until the power interruption is generated and then a state is restored in which the disconnection, ground fault, and power interruption are not generated.

[0126] At time 801, since the current mask register value 120a is "No Mask" and the power interruption comparator register value 120b is OFF, the power interruption diagnosis result is OK. Furthermore, since the voltage mask register value 120c is "No Mask", the disconnection comparator register value 120e is OFF, and the ground fault comparator register value 120d is OFF, the disconnection and ground fault diagnosis results of the operation processing device 106 become OK.

[0127] At time 802, the measured value of the voltmeter 118 is reduced to less than the voltage threshold 2 and greater than or equal to the voltage threshold 1 at time 801, and the disconnect comparator register value 120e becomes ON. Since the voltage mask register value 120c is "Non-Mask," the disconnection diagnostic result of the operation processing device 106 becomes NG.

[0128] At time 803, the ON / OFF command signal becomes ON, the voltage mask register value 120c becomes "mask," and the disconnection comparator register value 120e becomes OFF. Thus, the disconnection detection result of the operation processing device 106 becomes NG.

[0129] At time 804, the ON / OFF command signal becomes OFF, the disconnect comparator register value 120d becomes ON, and the voltage mask register value 120c becomes "No Mask." The ground fault diagnosis result of the operation processing device 106 becomes NG.

[0130] At time 805, the ON / OFF command signal turns ON, the voltage mask register value 120c becomes "Mask," and the ground fault comparator register value 120d turns OFF. Then, the ON / OFF command signal soon turns OFF, and after the time threshold 1 elapses, the voltage mask register value 120c becomes "Non-Mask" and the ground fault comparator register value 120d turns ON. Thereafter, during the period up to time 806, an operation is repeated in which the ON / OFF command signal repeatedly turns ON / OFF in a cycle shorter than that for communication, the ON / OFF command signal turns OFF again, and then the time threshold 1 elapses, whereby the ground fault comparator register value 120d turns ON.

[0131] At time 807, the voltage mask register value 120c becomes “No Mask”, the ground fault comparator register value 120d becomes OFF, and thus the ground fault diagnosis result of the operation processing device 106 becomes OK.

[0132] At time 808, the measured value of the ammeter 119 exceeds the current threshold, but time threshold 2 does not elapse, and thus the current mask register value 120a becomes "Mask" and the supply interruption comparator register value 120b becomes OFF. At this time, the ground fault diagnosis result of the operation processing device 106 becomes OK. Subsequently, after the measured value exceeds the current threshold during the period up to time 809, time threshold 2 elapses, and thus the current mask register value 120a becomes "Not Mask" and the supply interruption comparator register value 120b becomes ON. Thus, the supply interruption diagnosis result of the operation processing device 106 becomes NG at time 809.

[0133] Since at time 810 the voltage mask register value 120c becomes “Non-Mask”, the disconnection comparator register value 120e becomes OFF, and the ground fault comparator register value 120d becomes OFF, the disconnection and ground fault diagnosis results of the operation processing device 106 become OK.

[0134] According to the first embodiment of the present invention as described above, when the diagnosis possibility exists, the mask signal maintains the "No Mask" state even if the mask signal is subsequently set to the mask state. When the operation processing device 106 requests the driver circuit 108 to communicate with it, the mask signal is set to the "Mask" state, the information stored in the register 120 is sent, and then the information stored in the register 120 is cleared. When the mask signal is in the "Mask" state and the operation processing device 106 performs communication with the driver circuit 108, the operation processing device 106 can detect the lack of diagnosis possibility, that is, that the diagnosis is in the undetermined state.

[0135] Thus, the electronic control unit can be implemented with the self-diagnosis function (fault diagnosis function), in which the operation processing section can not only identify the presence or absence of the occurrence of NG of the disconnection, the ground fault and the power interruption (the occurrence and non-occurrence of the fault), but also the three states of NG, OK and indeterminacy. (Second embodiment)

[0136] The following is a second embodiment of the present invention using Fig. 9 to 14 described.

[0137] Fig. 9 shows an overall configuration diagram of an electronic control unit 903 (applied to a high-voltage drive system) of the second embodiment according to the present invention.

[0138] In Fig. 9, one end of an electromagnetic load 901 is connected to ground, and the other end is connected to an electromagnetic load drive output terminal 905, which is a terminal for connecting to the electronic control unit (ECU) 903. The ECU 903 includes the electromagnetic load drive output terminal 905, a power supply connection terminal 904, an operation processing device 906, a PWM generation unit 907, and a driver circuit 908.

[0139] Further, the operation processing device 906 includes a power-on operation unit 909, a communication command unit 910, and a diagnosis unit 911. The diagnosis unit 911 includes a ground fault diagnosis part 911a, a power interruption diagnosis part 911b, and a disconnection diagnosis part 911c.

[0140] The PWM generation unit 907 generates an ON / OFF command signal for the driver circuit 908 according to a duty ratio output from the duty operation unit 909. The driver circuit 908 opens / closes an FET (Field Effect Transistor) 912 based on the ON / OFF command signal from the PWM generation unit 907 to drive the electromagnetic load 901.

[0141] The driver circuit 908 is connected to the drive output terminal 905 of the electromagnetic load and the power supply terminal 904. The power supply terminal 904 is connected to a 14V power supply 902 external to the ECU 903. The driver circuit 908 includes a current timer 913, a voltage timer 914, a mask detection unit 915, a comparator 916, a 2.5V constant voltage source 917, a voltmeter 918, an ammeter 919, and a register 920. The mask detection unit 915 includes a current mask detection part 915a and a voltage mask detection part 915b. Register 920 stores therein a current mask register value 920a, a ground fault comparator register value 920b, a voltage mask register value 920c, a supply interruption comparator register value 920d, and a disconnection comparator register value 920e.

[0142] Furthermore, the comparator 916 includes a ground fault comparator 916a, a supply interruption comparator 916b and a disconnection comparator 916c.

[0143] The constant voltage source 917 is arranged between the drive output terminal 905 of the electromagnetic load and the FET 912. The voltmeter 918 is arranged between the drive output terminal 905 of the electromagnetic load and the FET 912 and between the power supply terminal 904 and the FET 912. The ammeter 919 is arranged between the drive output terminal 905 of the electromagnetic load and the FET 912.

[0144] The comparator 916 generates comparator signals based on values ​​from the voltmeter 918 and the ammeter 919. The mask determination unit 915 generates comparison mask signals based on the ON / OFF command signal, the signals from the comparator 916, a timer value of the current timer 913, and a timer value of the voltage timer 914.

[0145] Current timer 913 is used in current mask detection section 915a, and voltage timer 914 is used in voltage mask detection section 915b. They each output ON signals when a predetermined time has elapsed. Register 920 generates a mask register value and a comparator register value based on the previous mask signal and comparator signal.

[0146] The communication command unit 910 generates a communication permission signal for the operation processing unit 906 and the driver circuit 908. The diagnosis unit 911 acquires the mask register value and the comparator register value from the register 920 during a period from a time when the communication permission signal becomes OK to a time when the communication permission signal becomes NG.

[0147] The following is the feature of the second embodiment using Fig. 10 to 14. In the second embodiment, the timing relationship between the communication permission signal, the voltage mask signal, the voltage mask register value, the separation comparator signal, and the separation comparator register value is as shown in Fig. 6. Also, the timing relationship between the communication permission signal, the voltage mask signal, the voltage mask register value, the power interrupt comparator signal, and the power interrupt comparator register value is equivalent to the relationship shown in Fig. 6. Furthermore, in the timing relationship between the communication permission signal, the ground fault comparator signal, and the ground fault comparator register value, the current mask signal is used instead of the voltage mask signal, and the current mask register value is used as the voltage mask register value.

[0148] First, an example of an operational flow diagram of the driver circuit 908 similar to that shown in Fig. 2. Then, Fig. 10 an example of the flow chart of step 201 of Fig. 2, in which a circuit of the electronic control unit 903 of Fig. 9 is applied.

[0149] In step 1001 of Fig. 10, the ground fault comparator 916a determines whether an ammeter reading is greater than a current threshold. If the answer is "yes" (the ammeter reading is greater than the current threshold) in step 1001, processing continues to step 1002, where the ground fault comparator signal is set to ON. If the answer is "no" (the ammeter reading is not greater than the current threshold) in step 1001, processing continues to step 1003, where the ground fault comparator signal is set to OFF.

[0150] In step 1004, the supply interrupt comparator 916b determines whether a voltmeter reading is less than a voltage threshold 1. If the answer is "yes" (the voltmeter reading is less than the voltage threshold 1) in step 1004, processing proceeds to step 1005, where the supply interrupt comparator signal is set to ON and the disconnect comparator signal is set to OFF, and processing ends. If the answer is "no" (the voltmeter reading is greater than or equal to the voltage threshold 1) in step 1004, processing proceeds to the processing of step 1006.

[0151] In step 1006, the disconnect comparator 916c determines whether the voltmeter reading is less than a voltage threshold 2. If the answer is "yes" (the voltmeter reading is less than the voltage threshold 2) in step 1006, processing proceeds to step 1007, where the supply interruption comparator signal is set to OFF and the disconnection comparator signal is set to ON, and processing ends. If the answer is "no" (the voltmeter reading is greater than or equal to the voltage threshold 2) in step 1006, processing proceeds to step 1008, where the supply interruption comparator signal is set to OFF and the disconnection comparator signal is set to OFF, and processing ends.

[0152] Fig. 11 shows an example of the flow diagram of the Fig. 2, in which the circuit of the Fig. 9 shown electronic control unit 903 is used.

[0153] In Fig. 11, it is determined in step 1101 whether the "ground fault comparator signal ON" is normal. If the answer is "yes" ("ground fault comparator signal ON" is normal) in step 1101, processing proceeds to step 1102, where a timer value of the current timer 913 is added, and processing proceeds to step 1104. If the answer is "no" ("ground fault comparator signal ON" is not normal) in step 1101, processing proceeds to step 1103, where the timer value of the current timer 913 is set to 0, and processing proceeds to the processing of step 1106.

[0154] In step 1104, the current mask determination part 915a determines whether the current timer is less than a time threshold 2. If the answer is "yes" (the current timer is less than the time threshold 2) in step 1104, processing proceeds to step 1105, where the current mask signal is set to "mask." If the answer is "no" (the current timer is greater than or equal to the time threshold 2) in step 1104, processing proceeds to step 1106, where the current mask signal is set to "not mask." After performing steps 1105 and 1106, processing proceeds to the processing of step 1107.

[0155] In step 1107, it is determined whether the "ON / OFF command signal OFF" is normal. If the answer is "Yes" ("ON / OFF command signal OFF" is normal) in step 1107, processing proceeds to step 1108. If the answer is "No" ("ON / OFF command signal OFF" is not normal) in step 1107, processing proceeds to the processing of step 1110.

[0156] In step 1108, it is determined whether "power interrupt comparator signal ON or disconnect comparator signal ON" is normal. If the answer is "yes" (power interrupt comparator signal ON or disconnect comparator signal ON) in step 1108, processing proceeds to step 1109, where a timer value of voltage timer 914 is added, and processing proceeds to step 1111. If the answer is "no" ("power interrupt comparator signal ON or disconnect comparator signal ON" is not normal) in step 1108, processing proceeds to step 1110, where voltage timer 914 is set to 0, and processing proceeds to the processing of step 1113.

[0157] In step 1111, the voltage mask determination part 915b determines whether the voltage timer is less than a time threshold 1. If the answer is "yes" (the voltage timer is less than the time threshold 1) in step 1111, the processing proceeds to step 1112, where the voltage mask signal is set to "mask." If the answer is "no" (the voltage timer is greater than or equal to the time threshold 1) in step 1111, the processing proceeds to step 1113, where the voltage mask signal is set to "not mask." After performing steps 1112 and 1113, the processing proceeds to the processing of step 1114.

[0158] In step 1114, it is determined whether "The power interrupt comparator signal has switched from ON to OFF or the disconnect comparator signal has switched from ON to OFF." is normal. If the answer is "Yes" (The power interrupt comparator signal has switched from ON to OFF or the disconnect comparator signal has switched from ON to OFF is normal) in step 1114, processing proceeds to step 1115, where the timer value of the voltage timer 914 is set to 0, and processing ends. If the answer is "No" (The power interrupt comparator signal has switched from ON to OFF or the disconnect comparator signal has switched from ON to OFF is not normal) in step 1114, processing ends without further steps.

[0159] The following is a method for setting the voltage threshold 1, the voltage threshold 2, the current threshold, the time threshold 1 and the time threshold 2 used in generating the comparator signals and current and voltage mask signals of the disconnection, the earth fault and the supply interruption in the Fig. 10 and Fig. 11 described processing

[0160] If the Fig. When the FET 912 shown in Figure 9 is ON, both ends of the voltmeter 918 become equipotential, and thus the measured voltage of the voltmeter 918 becomes 0 [V] regardless of the absence or presence of noise. Thus, the noise cannot be identified by using the voltmeter 918 in the state where the FET 912 is ON.

[0161] On the other hand, when the FET 912 is OFF, the value measured by the voltmeter 918 becomes 14 [V] at a non-disturbance time because there is a difference in potential between the power supply terminal 904 (14 [V] due to the connection to the power supply 912) and the drive output terminal 905 of the electromagnetic load (0 [V] due to the connection to ground).

[0162] When the drive output terminal 905 of the electromagnetic load is subject to a ground fault, the value measured by the voltmeter 918 becomes 14 [V] because there is a difference in potential between the drive output terminal 905 of the electromagnetic load (0 [V] due to grounding) and the power supply connection terminal 904 (14 [V] due to connection with the power supply).

[0163] When the drive output terminal 905 of the electromagnetic load is disconnected, the value becomes 14 - 2.5 = 11.5 [V] because there is a difference in potential between the drive output terminal 905 of the electromagnetic load (constant voltage source 917 = 2.5 [V] due to the disconnection) and the power supply connection terminal 904 (14 [V] due to the connection to the power supply).

[0164] When the drive output terminal 905 of the electromagnetic load is subjected to a power interruption, the value becomes 0 [V] because there is a difference in potential between the drive output terminal 104 of the electromagnetic load (power supply 902 = 14 [V] due to the power interruption) and the power supply connection terminal 904 (14 [V] due to the connection with the power supply 912).

[0165] Thus, during the undisturbed time and when the power interruption occurs, the value of the voltmeter 918 becomes 14 [V] and therefore only the voltmeter 918 cannot distinguish between them.

[0166] Next, the readings of ammeter 919 during the undisturbed time and the power interruption time when FET 912 is ON are examined. During the undisturbed time, a current of the electromagnetic load resistance 901 ÷ (power supply 902 = 14 [V]) flows. At the time of a ground fault, an overcurrent flows through it because the path from the drive output terminal 904 of the electromagnetic load to the power supply 902 assumes a state of almost no resistance.

[0167] Furthermore, since the reliability of the voltage value to be measured is required when the measured value of the voltmeter 918 is used for disconnection / supply interruption detection, the time required until the voltage value becomes stable after a change in voltage must be set by time threshold 1. Disconnection / supply interruption detection cannot be performed until time threshold 1 elapses after the change in voltage. Even if the measured value of the ammeter 919 is used for ground fault detection, reliability is required as with voltage. Therefore, the time required until the value becomes stable after a change in current must be set by time threshold 2. Ground fault detection cannot be performed until time threshold 2 elapses after the change in current.

[0168] From the previous results, the voltage threshold 1 for detecting the supply interruption, the voltage threshold 2 for detecting the disconnection and the current threshold for detecting the earth fault are set, for example, with the following equations (4) to (6). Voltage threshold 1=constant voltage source 917 (2.5[V])÷2 Voltage threshold 2=(Power supply 902 (14[V])−(Constant voltage source 917 (2.5[V])÷2) Current threshold = (power supply 902 (14[V]) ÷ electromagnetic load 901 resistance value) × 2

[0169] Furthermore, time threshold 1 and time threshold 2 each define a sufficient stable time from the voltage / current changes taking into account the circuit characteristics.

[0170] Here, in the electronic control unit 903 of the second embodiment, one end of the electromagnetic load 901 is connected to the ground. The register 920 performs mask processing in which the information of the occurrence of the ground fault in the path from the FET 912 to the electromagnetic load 901 is detected based on the current output of the ammeter 919, and the detection is not performed when the current output of the ammeter 919 is unstable.

[0171] Thus, in the configuration of the high voltage driver system of Fig. 9 NG of the earth fault can be detected.

[0172] Here, in the electronic control unit 903 of the second embodiment, one end of the electromagnetic load 901 is connected to the ground, and the register 920 performs mask processing in which, when the ON / OFF command signal is OFF, the information of the occurrence of the disconnection and / or ground fault of the path from the FET 912 to the electromagnetic load 901 is detected based on the voltage output of the voltmeter 918, and the detection is not performed when the ON / OFF command signal is ON and the voltage output of the voltmeter 918 is unstable.

[0173] Thus, in the configuration of the electronic control unit based on the high voltage driver system of Fig. 9 NG of the separation and the earth fault are recorded.

[0174] Fig. 12 shows a diagram showing an example of the flow chart in Fig. 2, in which the circuit of the Fig. 9 shown electronic control unit is used.

[0175] In Fig. 12, it is determined in step 1201 whether "The communication permission signal is OK." is proper. If the answer is "Yes" ("The communication permission signal is OK." is proper) in step 1201, processing proceeds to step 1202, where the register values ​​of current mask register value 920a, ground fault comparator register value 920b, voltage mask register value 920c, supply interruption comparator register value 920d, and disconnection comparator register value 920e are sent to the operation processing device 906. If the answer is "No" ("The communication permission signal is OK." is not proper) in step 1201, processing proceeds to the processing of step 1203.

[0176] In step 1203, it is determined whether "The communication permission signal has switched from OK to NG." is proper. If the answer is "Yes" ("The communication permission signal has switched from OK to NG." is proper) in step 1203, processing proceeds to step 1204, where the current mask register value 920a is set to "Mask," the power interruption comparator register value 920b is set to OFF, the voltage mask register value 920c is set to "Mask," the power interruption comparator register value 920d is set to OFF, and the disconnection comparator register value 920e is set to OFF. If the answer is "No" ("The communication permission signal has switched from OK to NG." is not proper) in step 1203, processing proceeds to the processing of step 1205.

[0177] In step 1205, it is determined whether "The current mask signal is 'Not Mask'." is proper. If the answer is "Yes" ("The current mask signal is 'Not Mask'." is proper) in step 1205, processing proceeds to step 1206, in which the current mask register value 920a is set to "Not Mask," and processing proceeds to the processing of step 1207. If the answer is "No" ("The current mask signal is 'Not Mask'." is OK." is not proper) in step 1205, processing proceeds to the processing of step 1209.

[0178] In step 1207, it is determined whether "The ground fault comparator signal is ON." is normal. If the answer is "Yes" ("The ground fault comparator signal is ON." is normal) in step 1207, processing proceeds to step 1208, where the ground fault comparator register value 920b is set to ON. If the answer is "No" ("The ground fault comparator signal is ON." is not normal) in step 1207 and after the processing of step 1208, processing proceeds to the processing of step 1209.

[0179] In step 1209, it is determined whether "The voltage mask signal is 'Not Mask'." is proper. If the answer is "Yes" ("The voltage mask signal is 'Not Mask'." is proper) in step 1209, processing proceeds to step 1210, in which the voltage mask register value 920c is set to "Not Mask," and processing continues with the processing of step 1211. If the answer is "No" ("The voltage mask signal is 'Not Mask'." is not proper) in step 1209, processing ends without further steps.

[0180] In step 1211, it is determined whether "The power interrupt comparator signal is ON." is normal. If the answer is "Yes" ("The power interrupt comparator signal is ON." is normal) in step 1211, processing proceeds to step 1212, where the power interrupt comparator register value 920d is set to ON. If the answer is "No" ("The power interrupt comparator signal is ON." is not normal) in step 1211, processing proceeds to the processing of step 1213.

[0181] In step 1213, it is determined whether "The separation comparator signal is ON." is normal. If the answer is "Yes" ("The separation comparator signal is ON." is normal) in step 1213, processing proceeds to step 1214, where the separation comparator register value 920e is set to ON, and processing is terminated. If the answer is "No" ("The separation comparator signal is ON." is not normal) in step 1213, processing is terminated without further steps.

[0182] Fig. 13 shows an example of a flow chart in the operation processing device 906, in which the circuit of the Fig. 9 shown electronic control unit 903 is used.

[0183] In Fig. 13 In step 1301, the register values ​​of current mask register value 920a, ground fault comparator register value 920b, voltage mask register value 920c, supply interruption comparator register value 920d, and disconnection comparator register value 920e are acquired from register 920, and processing proceeds to step 1302.

[0184] The processing from step 1302 to 1306 is performed in the ground fault diagnosis 911a.

[0185] In step 1302, it is determined whether "The ground fault comparator signal register value is ON." is normal. If the answer is "Yes" ("The ground fault comparator signal register value is ON." is normal) in step 1302, processing proceeds to step 1303 to set a ground fault diagnosis result to NG and proceeds to the processing of step 1307. If the answer is "No" ("The ground fault comparator signal register value is ON." is not normal) in step 1302, processing proceeds to the processing of step 1304.

[0186] In step 1304, it is determined whether "The current mask register value is 'mask'." is correct. If the answer is "yes" ("The current mask register value is 'mask'." is correct) in step 1304, processing proceeds to step 1305 to set a ground fault diagnosis result to indeterminate. If the answer is "no" ("The current mask register value is 'mask'." is not correct) in step 1304, processing proceeds to step 1306 to set a ground fault diagnosis result to OK. After the processing of steps 1305 and 1306, processing proceeds to the processing of step 1307.

[0187] The processing from step 1307 to step 1311 is performed in the power interruption diagnosis 911b.

[0188] In step 1307, it is determined whether "The power interruption comparator signal register value is ON." is normal. If the answer is "Yes" ("The power interruption comparator signal register value is ON." is normal) in step 1307, processing proceeds to step 1308 to set a power interruption diagnosis result to NG and proceeds to the processing of step 1312. If the answer is "No" ("The power interruption comparator signal register value is ON." is not normal) in step 1307, processing proceeds to the processing of step 1309.

[0189] In step 1309, it is determined whether "The voltage mask register value is 'mask'." is proper. If the answer is "Yes" ("The voltage mask register value is 'mask'." is proper) in step 1309, processing proceeds to step 1310 to set a power interruption diagnosis result to indeterminate. If the answer is "No" ("The voltage mask register value is 'mask'." is improper) in step 1309, processing proceeds to step 1311 to set a power interruption diagnosis result to OK. After the processing of steps 1310 and 1311, processing proceeds to the processing of step 1312.

[0190] The processing from step 1312 to 1316 is performed in the separation diagnosis 911c.

[0191] In step 1312, it is determined whether "The disconnect comparator signal register value is ON." is normal. If the answer is "Yes" ("The disconnect comparator signal register value is ON." is normal) in step 1312, processing proceeds to step 1313 to set a disconnection diagnosis result to NG. If the answer is "No" ("The disconnect comparator signal register value is ON." is not normal) in step 1312, processing ends, and processing proceeds to the processing of step 1314.

[0192] In step 1314, it is determined whether "The voltage mask register value is 'mask'." is proper. If the answer is "Yes" ("The voltage mask register value is 'mask'." is proper) in step 1314, processing proceeds to step 1315 to set a disconnection diagnostic result to indeterminate, and processing ends. If the answer is "No" ("The voltage mask register value is 'mask'." is improper) in step 1314, processing proceeds to step 1316 to set a disconnection diagnostic result to OK, and processing ends.

[0193] The following is a timing chart of the second embodiment using Fig. 14 described.

[0194] Fig. Fig. 14 shows a timing diagram in which the operation processing device 906 generates OK, NG and uncertainty when disconnection, a ground fault and a supply interruption occur in the circuit of the Fig. 9 shown electronic control unit 903.

[0195] In Fig. 14, the driver circuit 908 generates comparator register values ​​(920b, 920d and 920e) and mask register values ​​(920a and 920c) from the ON / OFF command signal, the measured value of the voltmeter 918 and the measured value of the ammeter 919 according to the flow chart of Fig. 2 as in the first embodiment. The operation processing device 906 acquires the comparator register values ​​(920b, 920d and 920e) and the mask register values ​​(920a and 920c) for each communication with the driver circuit 908 and identifies the three states of disconnection, ground fault and power interruption according to the Fig. 13 shown flow chart.

[0196] One in Fig.Time 1401 shown in Figure 14 is a time at which the disconnection, ground fault, and power interruption are not generated when the operation processing device 906 and the driving circuit 908 initially communicate with each other in the electronic control unit 903. Time 1402 is a time at which the disconnection occurs at the time of communication between the operation processing device 906 and the driving circuit 908. Time 1403 is a time at which the power interruption is generated at the time of communication, but the power interruption cannot yet be identified by the driving circuit 908. Time 1404 is a time at which the ON / OFF command signal is switched from ON to OFF, and thus the power interruption can be identified.Times 1405 and 1406 are times when the ON / OFF command signal is repeatedly turned ON / OFF in a cycle shorter than one communication interval. Furthermore, times 1407 to 1410 are times that elapse until the ground fault is generated and then a state is restored in which the disconnection, ground fault, and power interruption are not generated.

[0197] At time 1401, since the voltage mask register value 920c is "No Mask" and the ground fault comparator register value 920b is OFF, the ground fault diagnosis result is OK. Furthermore, since the voltage mask register value 920c is "No Mask", the disconnection comparator register value 920e is OFF, and the supply interruption comparator register value 920d is OFF, the disconnection and supply interruption diagnosis results of the operation processing device 906 become OK.

[0198] At time 1402, the measured value of voltmeter 918 is reduced to less than voltage threshold 2 and greater than or equal to voltage threshold 1 at time 1401, and disconnect comparator register value 920e becomes ON. Since voltage mask register value 920c is "Non-Mask," the disconnection diagnostic result of operation processing device 906 becomes NG.

[0199] At time 1403, the ON / OFF command signal becomes ON, the voltage mask register value 920c becomes "Mask," and the disconnection comparator register value 920e becomes OFF. Thus, the disconnection detection result of the operation processing device 906 becomes NG.

[0200] At time 1404, the ON / OFF command signal becomes OFF, the power interruption comparator register value 920d becomes ON, and the voltage mask register value 920c becomes "No Mask." The power interruption diagnosis result of the operation processing device 906 becomes NG.

[0201] At time 1405, the ON / OFF command signal turns ON, the voltage mask register value 920c becomes "Mask," and the power cut comparator register value 920d turns OFF. Then, the ON / OFF command signal soon turns OFF, and after the time threshold 1 elapses, the voltage mask register value 920c becomes "Non-Mask" and the power cut comparator register value 920d turns ON. Thereafter, during the period up to time 1406, the ON / OFF command signal is repeatedly turned ON / OFF in a cycle shorter than that for communication between the operation processing device 906 and the driver circuit 908, and the ON / OFF command signal turns OFF again; and then the time threshold 1 elapses, causing the power cut comparator register value 920d to turn ON.

[0202] At time 1407, the voltage mask register value 920c becomes “Non-Mask”, the power interruption comparator register value 920d becomes OFF, and thus the power interruption diagnosis result of the operation processing device 906 becomes OK.

[0203] At time 1408, the measured value of the ammeter 919 exceeds the current threshold, but time threshold 2 does not elapse, and thus the voltage mask register value 920c becomes "Mask" and the ground fault comparator register value 920b becomes OFF. At this time, the power interruption diagnosis result of the operation processing device 906 becomes OK. Subsequently, after the measured value exceeds the current threshold during the period up to time 1409, time threshold 2 elapses, and thus the voltage mask register value 920c becomes "Mask" and the ground fault comparator register value 920b becomes ON. Thus, the ground fault diagnosis result of the operation processing device 906 becomes NG at time 1409.

[0204] Since at time 1410 the voltage mask register value 920c becomes “Non-Mask”, the disconnect comparator register value 920e becomes OFF, and the power interruption comparator register value 920d becomes OFF, the disconnection and power interruption diagnosis results of the operation processing device 906 become OK.

[0205] Also in the second embodiment of the present invention as described above, an electronic control unit can be implemented with a self-diagnosis function in which the operation processing device 906 can identify the three states of OK, NG and indeterminacy of the disconnection, a ground fault and a power interruption as in the first embodiment.

[0206] Although the constant voltage source 117 or 119 was used in the first and second embodiments of the present invention as described above, a circuit configuration without this constant voltage source 117 or 119 is also possible. Thus, the constant voltage source is not necessarily required in the present invention.

[0207] Furthermore, the above-described example is configured not to perform the diagnosis of power interruption, ground fault, and disconnection at the time of mask processing when the ON / OFF command is in a predetermined state and the output value of the voltmeter (118, 918) or the ammeter (119, 919) is unstable (the output of the measuring unit is unstable). A configuration is also considered in which the diagnosis of power interruption, ground fault, and disconnection is performed even at the time of mask processing, and only one result selected from the diagnosis results is used.

[0208] Although the embodiments of the present invention have been described in detail above, the present invention is not limited to the foregoing embodiments and can be modified in various forms. Furthermore, each component is not limited to the foregoing configuration as long as it does not impair the characteristic function of the present invention. List of reference symbols

[0209] 101, 901...electromagnetic load, 102, 902...power supply, 103, 903...electronic control unit, 104, 905...drive output terminal of the electromagnetic load, 105...ground terminal, 106, 906...operation processing device, 107, 907...PWM generation unit, 108, 908...drive circuit, 109, 909...power-on operation unit, 110, 910...communication command unit, 111, 911...diagnosis unit, 112, 912...FET, 113, 913...current timer, 114, 914...voltage timer, 115, 915...mask detection unit, 116, 916...comparison unit, 117, 917...constant voltage source, 118, 918...voltmeter, 119, 919...ammeter, 120, 920...register, 904...power supply terminal.

Claims

[1] Electronic control unit comprising: a driving circuit comprising: a measuring unit for measuring a voltage of one end of an electromagnetic load connected to a power supply or the ground or a current of the electromagnetic load and determining whether a disturbance occurs; and a storage unit for storing therein disturbance occurrence information and information for distinguishing a state in which the disturbance is not generated and a state in which the disturbance cannot be diagnosed, based on a measurement output of the measuring unit, wherein the driving circuit drives the electromagnetic load; and an operation processing section that sends an ON / OFF command signal for driving the electromagnetic load to the drive circuit, acquires the information for distinguishing between the state in which the disturbance is not generated and the state in which the disturbance cannot be diagnosed from the storage unit of the drive circuit, and identifies the occurrence of the disturbance and the non-occurrence thereof to perform a disturbance diagnosis. [2] The electronic control unit according to claim 1, wherein the driving circuit includes a switching part that drives the electromagnetic load based on the ON / OFF command signal, and the abnormality occurrence information is information indicating the occurrence of at least one of a disconnection, a ground fault, and a power interruption of a path from the switching part to the electromagnetic load. [3] The electronic control unit according to claim 1 or 2, wherein the driving circuit has a register that stores the abnormality occurrence information and the information for distinguishing between the state in which the abnormality is not generated and the state in which the abnormality cannot be diagnosed, and the operation processing section acquires the abnormality occurrence information and the information for distinguishing between the state in which the abnormality is not generated and the state in which the abnormality cannot be diagnosed, both of which are stored in the register when the driving circuit communicates with the operation processing section and then resets the operation processing section. [4] An electronic control unit according to claim 1 or 3, wherein the information for distinguishing between the state in which the trouble is not generated and the state in which the trouble cannot be diagnosed is a mask signal for indicating whether or not the trouble diagnosis is to be performed. [5] Electronic control unit according to claim 4, wherein the fault occurrence information indicates the fault occurrence and the operation processing section determines that the fault has occurred, wherein, when the failure occurrence information does not indicate the failure occurrence and the mask signal indicates the performance of the failure diagnosis, the operation processing section determines that the failure has not been generated, and wherein, when the failure occurrence information does not indicate the failure occurrence and the mask signal indicates non-performance of the failure diagnosis, the operation processing section determines that the diagnosis is an indeterminate state. [6] The electronic control unit according to claim 4, wherein the mask signal indicates not performing the diagnosis when the output of the measuring unit is unstable. [7] The electronic control unit according to claim 2 or 3, wherein the driving circuit comprises a constant voltage source arranged between the electromagnetic load and the switching part and applying a constant voltage for disconnection detection. [8] The electronic control unit according to claim 2 or 3, wherein the electromagnetic load is connected to the power supply, the storage unit detects the occurrence of the power interruption of the path from the switching part to the electromagnetic load on the basis of a current measured by the measuring unit, the information for distinguishing between the state in which the fault is not generated and the state in which the fault cannot be diagnosed is a mask signal for indicating whether the fault diagnosis is to be performed or not, and the mask signal indicates not performing the fault diagnosis when the current measurement output of the measuring unit is unstable. [9] The electronic control unit according to claim 8, wherein the electromagnetic load is connected to the power supply, wherein the storage unit detects the occurrence of the disconnection and / or the ground fault of the path from the switching part to the electromagnetic load on the basis of a voltage measured by the measuring unit when the ON / OFF command signal indicates OFF, and the mask signal indicates the failure diagnosis when the ON / OFF command signal indicates ON and the voltage measurement output of the measuring unit is unstable. [10] The electronic control unit according to claim 2 or 3, wherein the electromagnetic load is connected to the ground, the storage unit detects the occurrence of the ground fault of the path from the switching part to the electromagnetic load on the basis of a current measured by the measuring unit, the information for distinguishing between the state in which the fault is not generated and the state in which the fault cannot be diagnosed is a mask signal for indicating whether the fault diagnosis is to be performed or not, and the mask signal indicates not performing the fault diagnosis when the current measurement output of the measuring unit is unstable. [11] The electronic control unit according to claim 10, wherein the electromagnetic load is connected to the ground, wherein the storage unit detects the occurrence of the disconnection and / or the supply interruption of the path from the switching part to the electromagnetic load on the basis of a voltage measured by the measuring unit when the ON / OFF command signal indicates OFF, and the mask signal indicates the failure diagnosis when the ON / OFF command signal indicates ON and the voltage measurement output of the measuring unit is unstable.

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