JP6163448B2 - Electrical equipment and diagnostic method - Google Patents

Description

  The present invention relates to an electrical device and a diagnostic method, and is particularly suitable for application to an electrical device including a voltage monitoring device that monitors a power supply voltage and a diagnostic method for the voltage monitoring device.

  When an abnormality occurs in the power supply voltage, an electrical device configured by adding a voltage monitoring device that monitors the power supply voltage to the computing unit detects the abnormality by the voltage monitoring device and sends a reset signal to the computing unit. The calculator can be safely stopped. If the electrical equipment is equipped with a shut-off circuit that shuts off the power supply path, the voltage monitoring device sends a shut-off signal to the shut-off circuit and shuts off the power supplied to the computing unit to safely stop the computing unit. can do.

  When the voltage monitoring device operates normally, the arithmetic unit can be safely stopped as described above. On the other hand, when the voltage monitoring device fails for some reason and cannot operate normally, a reset signal or a cut-off signal is not transmitted from the voltage monitoring device. If an abnormality occurs in the power supply voltage in this state, the calculator cannot be stopped safely, and the calculator may be abnormally operated by supplying the abnormal voltage to the calculator.

  Therefore, Patent Document 1 discloses an electric device that diagnoses the presence or absence of a failure in the voltage monitoring device. Specifically, a switch is provided between the voltage monitoring device and a load such as an arithmetic unit, and this switch is opened at the time of diagnosis, and the voltage supplied to the voltage monitoring device is intentionally lowered to make the voltage monitoring device normal. An electrical device is disclosed that is configured to maintain the voltage of the reset input terminal by a capacitor for a certain period of time so that the load such as an arithmetic unit is not reset during the diagnosis. Yes.

JP 2012-3565 A

  However, in the technique described in Patent Document 1, although the voltage monitoring device can be diagnosed so that the arithmetic unit does not receive a reset signal unnecessarily during diagnosis, an abnormality has actually occurred in the power supply voltage. Therefore, it is impossible to make a diagnosis including whether or not the arithmetic unit can normally receive the reset signal transmitted by the voltage monitoring device. In the case of systems such as automobiles and railway vehicles that require extremely high safety, it is necessary for the computing unit to reliably receive the reset signal when the reset signal is properly transmitted.

  Here, various devices deployed in systems such as automobiles and railway vehicles do not normally operate continuously for several weeks or more, and the power supply is stopped once or more in several days. For example, a railway vehicle does not operate continuously for 24 hours, the power is stopped at midnight, and the power is turned on again in the early morning. Even if the arithmetic unit is intentionally reset by sending a reset signal to the arithmetic unit at the timing when this power is turned on again, various devices connected to the arithmetic unit (for example, railway vehicles and railroad crossings) are affected by the reset. Is not enough.

  The present invention has been made in consideration of the above points, and the arithmetic unit receives a reset signal transmitted from the voltage monitoring device by using a timing at which the influence of the reset does not reach various devices connected to the arithmetic unit. Proposed is an electric device and a voltage monitoring device diagnosis method that can diagnose the voltage monitoring device based on whether or not it is received.

In order to solve such a problem, in the electrical device of the present invention, an arithmetic unit including a power input terminal, a flag register value input terminal, a diagnostic instruction terminal, and a reset input terminal is connected to the power input terminal, and the power voltage is supplied. a power source for supplying a voltage monitoring device connected between the power source and the reset input pin is connected between a diagnostic indication terminal a voltage monitoring device, a voltage monitoring based on the voltage adjustment instruction from the operation unit A voltage regulator that regulates the voltage applied to the device, and is connected between the power source and the voltage monitoring device, and affects the voltage applied to the voltage monitoring device while affecting the voltage applied to the computing unit. and effect removal device that operates so as not to, between the power supply and the flag register value input terminal, and is connected between the power supply and the voltage regulator, and records whether to operate the voltage regulator Furagure The voltage monitoring device transmits a reset signal when the voltage applied by the voltage adjusting device is outside the predetermined range, and the computing unit receives the record of the flag register and whether the reset signal is received. Based on the above, a failure of the voltage monitoring device is diagnosed.

  In order to solve such a problem, in the diagnosis method of the present invention, the first step of recording whether or not the flag register operates the voltage regulator, and the influence removing device monitors the voltage when the voltage regulator is operating. A second step that operates so as not to affect the voltage applied to the computing unit while affecting the voltage applied to the device, and the voltage monitoring device detects an abnormal voltage during operation of the voltage regulator. A third step of transmitting a reset signal to the computing unit and a fourth step of diagnosing a failure of the voltage monitoring device based on whether the computing unit has received the reset signal during operation of the voltage regulator. It is characterized by providing.

  According to the present invention, the voltage based on whether or not the computing unit has received a reset signal transmitted from the voltage monitoring device, using the timing at which the influence of the reset does not reach the various devices connected to the computing unit. A monitoring device can be diagnosed.

It is a whole block diagram of the electric equipment in this Embodiment. It is a whole block diagram which shows an example of an electric equipment. It is a figure which shows the effect | action of an open drain buffer at the normal time, and the flow of an electric current. It is a figure which shows the effect | action of an open drain buffer at the time of diagnosis, and the flow of an electric current. It is a flowchart which shows a diagnostic process. It is a flowchart which shows the diagnostic process at the time of duplicating a flag register. It is a whole block diagram of the electric equipment which initializes a flag register other than at the time of power activation. It is a flowchart in the case of initializing a flag register other than at the time of power-on.

  Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.

(1) Overall Configuration FIG. 1 shows an overall configuration of an electric device 100 in the present embodiment. The electric device 100 includes an arithmetic unit 1 having a power input terminal, a flag register value input terminal, a diagnosis instruction terminal, and a reset input terminal, a power source 2, and a voltage monitoring device 3 that monitors a power source voltage supplied to the arithmetic unit 1. A voltage adjusting device 4 for changing the voltage value of the voltage applied to the voltage monitoring device 3, and supply of other circuit elements while affecting the voltage applied to the voltage monitoring device 3 during operation of the voltage adjusting device 4. It comprises an influence removing device 5 that does not affect the power supply, and a flag register 6 that indicates whether or not a failure diagnosis has been performed. Hereinafter, functions of each unit will be described.

  The computing unit 1 is, for example, a CPU (Central Processing Unit) or the like, and executes computation processing based on an external input and outputs a computation result. The arithmetic unit 1 includes a power input terminal, a flag register value input terminal, a diagnosis instruction terminal, and a reset input terminal as described above.

  When the power supply voltage applied to the computing unit 1 is within the monitoring threshold shown below, the computing unit 1 is not reset, and when it is outside the monitoring threshold, the computing unit 1 is operated by the operation of the voltage monitoring device 3. 1 is configured to be reset.

  In normal times, a voltage is applied to the reset input terminal, and when the voltage monitoring device 3 transmits an abnormal reset signal, the reset is applied by lowering the voltage of the reset input terminal to the ground level. When the calculator 1 is reset, the calculator 1 stops its operation.

  The power source 2 is a DC power source that outputs DC 3.3V, for example, and is a device that supplies a power source voltage to the computing unit 1. The power source 2 is connected to the voltage monitoring device 3 via the influence removing device 5.

  The voltage monitoring device 3 determines whether or not the monitoring voltage supplied via the influence removing device 5 is within the monitoring threshold value, and transmits a reset signal if it is outside the monitoring threshold value. The monitoring threshold is set to a range slightly narrower than the operable range so that the reset signal is transmitted before the abnormal voltage is applied to the computing unit 1.

  For example, when the operable range of the computing unit 1 is 3.0V to 3.6V, the lower limit of the monitoring threshold is set to 3.1V, and the upper limit is set to 3.5V. In this case, the voltage monitoring device 3 transmits a reset signal when the monitoring voltage becomes 3.1V or lower or 3.5V or higher.

  When the voltage adjustment device 4 receives a voltage adjustment instruction from the diagnosis instruction terminal of the arithmetic unit 1, the voltage adjustment device 4 sets the value of the monitoring voltage applied to the voltage monitoring device 3 based on the instruction to the upper limit of the monitoring threshold value of the voltage monitoring device 3. Change to above threshold or below lower threshold.

  Since the voltage adjustment device 4 only needs to be able to change the value of the monitoring voltage applied to the voltage monitoring device 3, an open drain buffer can be used. The open drain buffer pulls out the drain of FET (Field Effect Transistor) as output, the output when the input is “negative logic” becomes high impedance, and when the input is “positive logic” Current can be drawn from the output terminal, and the voltage of the line connected to the output can be lowered.

  The influence removing device 5 is, for example, a resistor, and changes the voltage applied to the voltage monitoring device 3 when the voltage adjusting device 4 is operating (during diagnosis), while suppressing fluctuations in the power supply voltage of the computing unit 1. When a resistor is used for the influence removing device 5, the voltage applied to the voltage monitoring device 3 drops at a ratio between the input impedance of the voltage monitoring device 3 and the resistance value of the resistor. The resistance value of the resistor is selected so as not to exceed a current value that can be drawn by the voltage regulator 4.

  For example, when the input impedance of the voltage monitoring device 3 is 10 kΩ, the current value that can be drawn by the voltage adjusting device 4 is 10 mA, and the power source voltage of the power source 2 is DC 3.3 V, the resistance is equal to voltage / current from Ohm's law. Therefore, in order not to exceed the current value that can be drawn by the voltage regulator 4, it is necessary to select a resistance value of the resistor of 330Ω or more from 3.3 V / 0.01 A.

  When the resistance value is 330Ω, when DC 3.3V is normally supplied from the power supply 2, the voltage applied to the voltage monitoring device 3 is the ratio of the input impedance of the voltage monitoring device 3 and the resistance value of the resistor. Since the voltage drops, 3.3V × (330Ω / 330Ω + 10000Ω) = 3.19V.

  When the lower limit of the monitoring threshold of the voltage monitoring device 3 is set to 3.1 V and the upper limit is set to 3.5 V, the voltage applied to the voltage monitoring device 3 is 3.1 V due to a voltage drop due to a resistor. The voltage drops to 00V and 3.5V drops to 3.39V. Therefore, it is necessary to change the lower limit of the monitoring threshold of the voltage monitoring device 3 to 3.00V and the upper limit to 3.39V.

  The flag register 6 is, for example, a flip-flop, and holds a flag indicating that a diagnosis execution instruction has been issued from the computing unit 1. The flag register 6 sets a flag when there is a diagnosis execution instruction from the computing unit 1, and holds the flag once set so that it is not cleared until the power is turned on again.

  FIG. 2 shows an overall configuration of an electric device 100 </ b> A as an example of the electric device 100. The same components as those in the electric device 100 are denoted by the same reference numerals. In the electric device 100A, the CPU 1A is applied to the arithmetic unit 1, the open drain buffer 4A is applied to the voltage adjusting device 4, the resistor 5A is applied to the influence removing device 5, and the flip-flop 6A is applied to the flag register 6. It differs from the electric device 100 in that it is.

  Both the electric devices 100 and 100A can perform failure diagnosis of the voltage monitoring device that can be confirmed up to the reception of the reset signal with the addition of a small number of circuits.

(2) Detailed Configuration The operation of the voltage regulator 4 will be described below with reference to FIGS. 3 and 4. Here, the case where the open drain buffer 4A is applied to the voltage adjusting device 4 and the resistor 5A is applied to the influence removing device 5 will be described.

  FIG. 3 shows the operation of the open drain buffer 4A when there is no diagnosis instruction from the computing unit 1. When there is no diagnosis instruction from the arithmetic unit 1, the output of the open drain buffer 4A is open. Therefore, current flows from the power source 2 to the voltage monitoring device 3 via the resistor 5A. In this case, the voltage drops as described above by the resistor 5 </ b> A, and the dropped voltage is applied to the voltage monitoring device 3.

  FIG. 4 shows the operation of the open drain buffer 4 </ b> A when there is a diagnostic instruction from the computing unit 1. When there is a diagnostic instruction from the arithmetic unit 1, the output of the open drain buffer 4A draws the current from the power source 2. When the current is limited by the resistor 5A and the current value flowing through the resistor 5A is smaller than the current value that can be drawn by the open drain buffer 4A, the voltage applied to the voltage monitoring device 3 is at the ground level.

  Further, when the current capacity of the power source 2 is sufficiently larger than the current value that can be drawn by the open drain buffer 4A, the supply voltage to other circuit elements does not drop and does not affect other elements.

(3) Flowchart FIG. 5 shows a processing procedure of diagnostic processing by the computing unit 1. First, the calculator 1 initializes the flag register 6 when the power is turned on (SP1), and starts diagnosis when the reset of the calculator 1 is released because the power supply 2 is established (SP2). In the diagnosis, the arithmetic unit 1 first checks the flag held in the flag register 6 (SP3).

  For example, when the arithmetic unit 1 confirms that the flag is set to 0, it determines that the diagnosis is not performed (SP3: diagnosis is not performed), and after the flag is set to 1, the voltage adjustment device 4 starts diagnosis. Is transmitted (SP4). When the voltage adjustment device 4 receives the diagnosis start instruction from the computing unit 1, the voltage adjustment device 4 adjusts the voltage applied to the voltage monitoring device 3 to be an abnormal voltage.

  The computing unit 1 waits after transmitting an instruction to start diagnosis to the voltage regulator 4 (SP5). The standby time is set to be longer than the response time from when the diagnosis start instruction is transmitted until the voltage value of the voltage applied to the voltage monitoring device 3 is changed, and is normally set to 1 s or less.

  When the voltage monitoring device 3 is normal without being out of order, the voltage monitoring device 3 that has detected the abnormal voltage transmits a reset signal to the calculator 1 that is on standby. When the arithmetic unit 1 receives the reset signal from the voltage monitoring device 3 (SP6: with reset), it initializes (resets) and then proceeds to step SP2 to start diagnosis again.

  The arithmetic unit 1 checks the flag held in the flag register 6 again after moving to step SP2 (SP3), but determines that the diagnosis has been performed since the flag is set to 1. (SP3: diagnosis completed), and the diagnosis ends normally (SP7).

  Returning to step SP6, if the voltage monitoring device 3 is out of order and not normal, the voltage monitoring device 3 cannot detect an abnormal voltage. In this case, the voltage monitoring device 3 does not transmit a reset signal to the waiting calculator 1. Since the arithmetic unit 1 does not receive the reset signal from the voltage monitoring device 3, it determines that the standby time has timed out (SP6: no reset) and the diagnosis has ended abnormally (SP8).

  In the above flowchart, the case where it is determined that the diagnosis has been terminated abnormally when the voltage monitoring device 3 has failed and the failure of the voltage monitoring device 3 has been detected has been described. Even if is a failure, the failure can be detected by the above flowchart. Hereinafter, a case where the voltage adjusting device 4, the influence removing device 5, or the flag register 6 fails will be described.

  First, the case where the voltage regulator 4 is out of order will be described. When the open drain buffer 4A is applied to the voltage adjustment device 4, the failure mode of the open drain buffer 4A is determined when the current to the input terminal of the voltage monitoring device 3 cannot be drawn at the time of diagnosis instruction (at the time of current drawing instruction) or the diagnosis There may be a case where current is drawn at a time other than the instruction (when an open output instruction is given).

  When current cannot be drawn at the time of diagnosis, the voltage monitoring device 3 does not detect an abnormal voltage, and therefore does not transmit a reset signal. Therefore, since the arithmetic unit 1 does not receive the reset signal, the standby time is timed out (SP6: no reset), and it can be determined that the diagnosis has ended abnormally and a failure can be detected.

  Further, when current is drawn other than at the time of diagnosis, the voltage monitoring device 3 detects an abnormal voltage during normal time and transmits a reset signal, so that a failure can be detected.

  Next, a case where the influence removing device 5 is broken will be described. When the resistor 5A is applied to the influence removing device 5, the failure mode of the resistor may be short or open. When the resistor 5A is open, the voltage monitoring device 3 detects an abnormal voltage during normal operation and transmits a reset signal, so that a failure can be detected.

  When the resistor 5A is short-circuited, the current value that can be supplied to the voltage monitoring device 3 exceeds the current value that can be drawn by the voltage adjusting device 4, so that the voltage cannot be lowered during diagnosis. That is, the voltage monitoring device 3 does not detect an abnormal voltage at the time of diagnosis, and therefore does not transmit a reset signal. Therefore, since the arithmetic unit 1 does not receive the reset signal, the standby time is timed out (SP6: no reset), and it can be determined that the diagnosis has ended abnormally and a failure can be detected.

  Finally, a case where the flag register 6 is broken will be described. The failure mode of the flag register 6 may hold a flag indicating that the diagnosis has not been performed even though the diagnosis has been performed, or may hold a flag indicating that the diagnosis has been performed even if the diagnosis has not been performed.

  When the flag indicating that the diagnosis has been performed but not performed is held, the diagnosis is repeated after the power is turned on, but the diagnosis is not normally terminated. On the other hand, when the flag indicating that the diagnosis has been performed is held even though the diagnosis has not been performed, the diagnosis ends normally without performing the diagnosis.

  In this case, the flag register 6 is duplicated for comparison and collation, and if the comparison does not match, it is determined that the diagnosis is abnormal. If the flag register 6 is duplicated, it is possible to avoid a problem that the diagnosis is permanently repeated when the flag indicating that the diagnosis has been performed but is not performed is held.

  FIG. 6 shows the procedure of the diagnostic process when the flag register is duplicated. The diagnostic processing of FIG. 6 is different from the diagnostic processing of FIG. 5 in that the duplicate flag register 6 is confirmed in step SP13. Specifically, when the flag register 6 is initialized when the power is turned on (SP11), the arithmetic unit 1 starts diagnosis (SP12), and checks the flags held in the duplicate flag register 6 ( SP13).

  For example, when the value of the set flag matches 1 (SP13: diagnosis has been performed), the computing unit 1 determines that the diagnosis is normally completed (SP17), and ends this diagnosis process. In addition, for example, when the value of the set flag matches with 0 (SP13: diagnosis not performed), the computing unit 1 executes the diagnosis process as described with reference to FIG. (SP14 to SP18), and the diagnosis process is terminated.

  For example, when the value of the flag set in one flag register 6 is 0 and the value of the flag set in the other flag register 6 is 1 (SP13: comparison mismatch) It is determined that the diagnosis is abnormally terminated (SP18), and this diagnosis process is terminated.

(4) Other Embodiments The electric devices 100 and 100A described above execute diagnostic processing (FIGS. 5 and 6) when power is turned on, but execute diagnostic processing when power is not turned on. It may be. Here, a configuration for executing a diagnostic process other than when the power is turned on will be described.

  FIG. 7 shows an electric device 100B according to another embodiment. The electric device 100B is configured such that the flag register 6 can be reset from the computing unit 1. The electric device 100B is different from the electric devices 100 and 100A described above in that the electric device 100B includes the arithmetic unit 1B and the OR gate 7.

  The computing unit 1B includes an initialization instruction terminal that transmits a reset signal for resetting the flag value to the flag register 6. The OR gate 7 receives reset signals from the arithmetic unit 1 </ b> B and the power supply 2 and transmits a calculation result obtained by calculating a logical sum of the two reset signals to the flag register 6.

  FIG. 8 shows the procedure of the diagnostic process when the flag register 6 is initialized at times other than when the power is turned on. The diagnostic process of FIG. 8 differs from the diagnostic process of FIG. 5 in that the process of initializing the flag register 6 is executed in step SP21A. Specifically, after the power is turned on (SP21), the arithmetic unit 1B executes various processes, and initializes the flag register at the diagnosis timing (SP21A). Thereafter, the arithmetic unit 1B executes the same process as the diagnostic process of FIG. 5, determines the normal end of diagnosis or the abnormal end of diagnosis (SP22 to SP28), and ends this diagnostic process.

(5) Effects of the present embodiment As described above, according to the electrical device of the present embodiment, the voltage applied to the voltage monitoring device is intentionally changed to an abnormal voltage at the time of diagnosis. When the voltage monitoring device is normal without failure, an abnormal voltage is detected and a reset signal is transmitted to the computing unit. Thus, it is possible to diagnose whether or not the voltage monitoring device is normal, and therefore it is possible to diagnose a failure of the voltage monitoring device including the time until the calculator receives the reset signal.

  In addition, according to the electric device in the present embodiment, it is possible to diagnose a failure of the voltage adjusting device, the influence removing device, or the flag register, which are constituent members other than the voltage monitoring device.

  Further, according to the electric device in the present embodiment, it is possible to diagnose a failure of the voltage monitoring device with a circuit configuration having a small number of parts.

Moreover, according to the electric equipment in the present embodiment , high safety can be ensured by applying it to a signal device or the like of a railway system.

DESCRIPTION OF SYMBOLS 1 Calculator 2 Power supply 3 Voltage monitoring apparatus 4 Voltage adjustment apparatus 5 Influence removal apparatus 6 Flag register 7 OR gate 1A CPU
4A Open drain buffer 5A Resistor 6A Flip-flop

Claims (7)

An arithmetic unit comprising a power input terminal, a flag register value input terminal, a diagnostic instruction terminal, and a reset input terminal;
A power supply connected to the power input terminal and supplying a power supply voltage;
A voltage monitoring device connected between the power source and the reset input pin,
A voltage adjusting device connected between the diagnosis instruction terminal and the voltage monitoring device, for adjusting a voltage applied to the voltage monitoring device based on a voltage adjustment instruction from the computing unit;
An influence removing device connected between the power supply and the voltage monitoring device and operating so as not to affect the voltage applied to the computing unit while affecting the voltage applied to the voltage monitoring device. When,
A flag register connected between the power source and the flag register value input terminal, and connected between the power source and the voltage regulator, and records whether or not the voltage regulator is operated;
The voltage monitoring device includes:
Sending a reset signal when the voltage applied by the voltage regulator is outside a predetermined range;
The computing unit is
An electrical device characterized by diagnosing a failure of the voltage monitoring device based on whether or not the flag register record and the reset signal have been received. The computing unit is
When diagnosis is started, the voltage adjustment device is operated to change the voltage applied to the voltage monitoring device to an abnormal voltage that is a voltage value outside the predetermined range, and the voltage monitoring device detects and transmits the abnormal voltage. When the reset signal is received, it is determined that the voltage monitoring device is operating normally, and when the reset signal is not received, it is determined that the voltage monitoring device is operating abnormally. The electric device according to claim 1. The computing unit is
The electrical apparatus according to claim 1, wherein it is determined whether or not the reset signal has been received in connection with a diagnosis based on an operation state of the voltage regulator recorded in the flag register. The voltage regulator is an open drain buffer;
The influence removing device is a resistor,
The electric device according to claim 1, wherein the flag register is a flip-flop. The electrical resistance according to claim 4, wherein a resistance value of the resistor is equal to or greater than a voltage value supplied from the power source, and a maximum current drawn value that can be drawn by the open drain buffer. machine. The electric device according to claim 1, wherein the flag register is duplicated. In the diagnostic method of electrical equipment for diagnosing a failure of a voltage monitoring device that monitors the power supply voltage
The electrical equipment is
A power supply for supplying the power supply voltage;
An arithmetic unit connected to the power source;
The voltage monitoring device;
A voltage adjusting device for adjusting a voltage applied to the voltage monitoring device;
An influence removing device installed between the power source and the voltage monitoring device;
A flag register installed between the power supply and the voltage regulator,
A first step of recording information indicating whether the flag register has operated the voltage regulator;
The influence removing device operates so as not to affect the voltage applied to the computing unit while affecting the voltage applied to the voltage monitoring device during the operation of the voltage adjusting device. And the steps
A third step in which the voltage monitoring device detects an abnormal voltage and transmits a reset signal to the computing unit when a voltage applied during operation of the voltage regulator is adjusted to a voltage value outside a predetermined range; ,
A diagnostic method comprising: a fourth step of diagnosing a failure of the voltage monitoring device based on whether the arithmetic unit receives the reset signal during operation of the voltage regulator.

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