JP6870555B2 - Monitoring device - Google Patents

Description

The present invention relates to a monitoring device that detects the state of a brake coil.

A control circuit for detecting a failure of an electronic component used for brake control of a motor is known. Patent Document 1 discloses a brake control circuit in which two switching transistors and a photocoupler are connected in series. The two switching transistors detect a drive signal (brake signal) for the brake, and when the brake signal is detected, the two switching transistors are turned on. Normally, when all the switching transistors are turned on, the photocoupler is turned on, and the detection signal output by the photocoupler changes from Hi level to Lo level. In this case, the brake is driven. When failure detection is performed, the brake signal is sequentially input to the switching transistor. Here, when any of the switching transistors fails in the open mode, the failed switching transistor maintains the off state. Therefore, the detection signal of the photocoupler maintains the Hi level. Next, when the upper switching transistor of the two switching transistors fails in the short mode, the detection signal of the photocoupler changes from the Hi level to the Lo level when the lower switching transistor detects the brake signal and turns on. On the other hand, when the lower switching transistor of the two switching transistors fails in the short mode, the detection signal of the photocoupler changes from Hi level to Lo level when the upper switching transistor detects the brake signal and turns on. Therefore, the brake control detection circuit can detect the failure of the switching transistor by monitoring the on / off state of the switching transistor and the state of the detection signal of the photocoupler.

Japanese Unexamined Patent Publication No. 2006-123118

The brake control detection circuit can detect a failure of the switching transistor, but has a problem that it cannot detect the state of the brake coil used for brake control.

An object of the present invention is to provide a monitoring device capable of detecting the state of a brake coil in addition to detecting a transistor failure.

Monitoring apparatus according to the first aspect of the present invention is a monitoring apparatus for monitoring the state of the coil of the brake system to activate the brake by outputting a signal to the coil when the input predetermined hours or more signals, the predetermined time An output unit that outputs a pulse signal less than or equal to the coil and a countercurrent force generated in the coil when the pulse signal is output to the coil by the output unit are detected, and an output signal corresponding to the countercurrent force is generated. A first determination unit that determines the state of the coil based on the first detection unit to be output, the pulse signal output by the output unit, and the output signal output by the first detection unit, and the output unit. A switching unit that is interposed between the coil and the switching unit that can switch to a transmission state in which the pulse signal output by the output unit is transmitted to the coil or a cutoff state in which the pulse signal is not transmitted to the coil, and the switching unit. A control unit that controls the unit to switch to the transmission state or the cutoff state and a second detection unit that detects the pulse signal to the coil are provided, and the first determination unit is the pulse signal by the output unit. When the first detection unit outputs the output signal in response to the above, the coil determines that the coil is normal, and when the control unit puts the switching unit in the transmission state, the first detection unit responds to the pulse signal by the output unit. When the second detection unit detects the pulse signal and the first detection unit does not output the output signal, the coil is determined to be abnormal, and the control unit puts the switching unit in the transmission state. In this case, when the second detection unit does not detect the pulse signal in response to the pulse signal by the output unit, the switching unit further includes a second determination unit that determines that the first abnormality is held in the cutoff state. It is characterized by that.

When the coil is normal, the monitoring device outputs an output signal according to the counter electromotive force generated in the coil based on the pulse signal output by the output unit. Further, when the coil is abnormal, the monitoring device does not generate a counter electromotive force in the coil, and the first detection unit does not output an output signal. Therefore, the monitoring device can determine whether the state of the coil is normal or abnormal by making a determination based on the output signal by the first determination unit. Further, since the pulse signal is a pulse signal capable of maintaining the state in which the braking device does not brake the motor, the monitoring device determines the state of the coil by the first determination unit while maintaining the state in which the braking device does not brake the motor. it can.

Further, in the braking device, when the switching unit fails in the cutoff state, the switching unit does not output the pulse signal even if the control unit transmits the switching unit. Therefore, the monitoring device can identify that the switching unit has failed in the cutoff state by detecting the state of the pulse signal.

The monitoring device according to the second aspect of the present invention is a monitoring device that monitors the state of the coil of the braking device that outputs a signal to the coil to enable braking when a signal for a predetermined time or longer is input. An output unit that outputs a pulse signal less than or equal to the coil and a countercurrent force generated in the coil when the pulse signal is output to the coil by the output unit are detected, and an output signal corresponding to the countercurrent force is generated. The first determination unit and the output unit that determine the state of the coil based on the first detection unit to be output, the pulse signal output by the output unit, and the output signal output by the first detection unit. A switching unit that is interposed between the coils and can be switched to a transmission state in which the pulse signal output by the output unit is transmitted to the coil, or a cutoff state in which the pulse signal is not transmitted to the coil, and the switching unit. A control unit that controls to switch to the transmission state or the cutoff state and a second detection unit that detects the pulse signal to the coil are provided, and the first determination unit uses the pulse signal from the output unit. When the first detection unit outputs the output signal, the coil determines that the coil is normal, and when the control unit puts the switching unit in the transmission state, the above-mentioned pulse signal is received by the output unit. When the second detection unit detects the pulse signal and the first detection unit does not output the output signal, the coil is determined to be abnormal, and the control unit puts the switching unit in the cutoff state. Further, when the second detection unit detects the pulse signal in response to the pulse signal by the output unit, the switching unit further includes a second determination unit that determines that the second abnormality is held in the transmission state. It is characterized by. At that time, according to the second aspect, the same effect as that of the first aspect is obtained. Further, in the braking device, when the switching unit fails in the transmission state, the switching unit outputs a pulse signal even if the control unit shuts off the switching unit. Therefore, the monitoring device can identify that the switching unit has failed in the transmission state by detecting the state of the pulse signal.
In the first aspect, in the second determination unit, when the control unit puts the switching unit in the cutoff state, the second detection unit detects the pulse signal in response to the pulse signal by the output unit. At this time, it may be determined that the switching unit holds the second abnormality in the transmission state. At this time, when the switching unit fails in the transmission state, the braking device outputs a pulse signal even if the control unit shuts off the switching unit. Therefore, the monitoring device can identify that the switching unit has failed in the transmission state by detecting the state of the pulse signal.

In the first aspect and the second aspect , the first detection unit is a photocoupler in which a diode connected to the coil and the back electromotive force acts in a reverse bias, and a light emitting element and a light receiving element are incorporated. The diode may be provided with a photocoupler in which the light emitting element emits light when the reverse bias occurs and the output signal is output from the light receiving element. At this time, the monitoring device detects the counter electromotive force generated in the coil by using a diode in the first detection unit. The diode outputs a predetermined voltage when the counter electromotive force acts in the reverse bias. Therefore, the first detection unit can reliably detect the counter electromotive force from the coil. Further, the monitoring device detects the reverse bias generated in the diode by using a photocoupler in the first detection unit. In the photocoupler, when a reverse bias occurs in the diode, the light emitting element emits light, and the light receiving element outputs an output signal by emitting light from the light emitting element. Therefore, the monitoring device can reliably detect the counter electromotive force generated in the coil. Further, the monitoring device can convert an output signal below the rating of the first determination unit by using a diode and a photocoupler. Therefore, the possibility that the first determination unit will fail due to overvoltage can be reduced.

In the first aspect and the second aspect , the output unit may repeatedly output the pulse signal at a predetermined cycle. At that time, the monitoring device can monitor the pulses generated at a predetermined cycle. Therefore, the monitoring device can determine that the state of the coil is normal when the first determination unit detects the output signal at a predetermined cycle. Further, the monitoring device can determine that the state of the coil is abnormal when the first determination unit does not detect the output signal at a predetermined cycle.

In the first aspect and the second aspect , the monitoring device depends on the drive unit that drives the motor that is the braking target of the braking device, and when the coil is determined to be abnormal by the first determination unit. A stop means for stopping the drive of the motor may be provided. In the monitoring device, when the switching unit fails, the braking device may enable braking of the motor. At this time, since the load on the motor and the braking device is large, the motor and the braking device may break down or the life may be shortened. When the first determination unit detects a failure of the switching unit, the monitoring device drives the drive unit to stop the motor. At that time, the monitoring device can minimize the load on the motor and the braking device. Therefore, the monitoring device can reduce the possibility of motor failure and shortened life.

The block diagram of the monitoring device 100 at the time of normal operation. Waveform of each signal in the monitoring device 100 during normal operation. The block diagram in the case where the electromagnet coil 7 is not connected or is disconnected. The waveform of each signal in the monitoring device 100 when the electromagnet coil 7 is not connected or disconnected. The block diagram of the monitoring device 100 when the FET 5 fails in the cutoff state. The waveform of each signal in the monitoring device 100 when the FET 5 fails in the cutoff state. The waveform of each signal in the monitoring device 100 when the FET 5 fails in the transmission state.

The monitoring device 100 of the present invention will be described. As shown in FIG. 1, the monitoring device 100 includes an FPGA 1, a power supply 2, a brake output control circuit 3, an FET 5, a connector 6, a Zener diode 8, a photocoupler 9, and a diode 11. The output terminal 1A of the FPGA 1 is connected to the input terminal 2A of the power supply 2. The output terminal 2B of the power supply 2 is connected to the source of the FET 5. The first output terminal 3A of the brake output control circuit 3 is connected to the gate of the FET 5. The second output terminal 3B of the brake output control circuit 3 is connected to the first input terminal 1B of the FPGA 1. The electromagnet coil 7 of the braking device 200 is detachably connected to the connector 6. The input terminal 6A of the connector 6 is connected to the drain of the FET 5. One end 7A of the electromagnet coil 7 is connected to the drain of the FET 5 via the input terminal 6A of the connector 6. The cathode of the Zener diode 8 is connected to the other end 7B of the electromagnet coil 7 via the output terminal 6B of the connector 6. The anode of the light emitting element of the photocoupler 9 is connected to the cathode of the Zener diode 8. The cathode of the light emitting element of the photocoupler 9 is connected to the anode of the Zener diode 8 via the resistor 9A. The light emitting element of the photocoupler 9 is connected in parallel to the Zener diode 8. The collector of the light receiving element of the photocoupler 9 is connected to the second input terminal 1C of the FPGA 1. The drain of the FET 5 is connected to the third input terminal 1D of the FPGA 1. The cathode of the diode 11 is connected to the input terminal 6A of the connector 6. The anode of the diode 11 is connected to the anode of the Zener diode 8 and is connected to the cathode of the light emitting element of the photocoupler 9 via a resistor 9A.

As shown in FIG. 2, the first signal 10 is a signal output from the output terminal 1A of the FPGA 1 to the input terminal 2A of the power supply 2. The second signal 20 is a signal output from the output terminal 2B of the power supply 2 to the source of the FET 5. The third signal 30 is a signal output from the drain of the FET 5 to the electromagnet coil 7. The fourth signal 40 is a signal output from the other end 7B of the electromagnet coil 7 to the Zener diode 8 via the output terminal 6B of the connector 6. The fifth signal 50 is a signal output from the collector of the light receiving element of the photocoupler 9 to the second input terminal 1C of the FPGA 1.

<Normal operation>
The monitoring device 100 controls the drive of the braking device 200 by outputting a third signal 30 to one end 7A of the electromagnet coil 7 via the FET 5 by a control signal from the first output terminal 3A of the brake output control circuit 3. .. When the third signal 30 input to one end 7A of the electromagnet coil 7 is High, the braking device 200 is in an released state without braking a motor (not shown). Further, the braking device 200 is in a driving state for braking a motor (not shown) when the third signal 30 input to one end 7A of the electromagnet coil 7 is Low. The monitoring device 100 monitors the state of the electromagnet coil 7 by outputting a pulse signal having a Low level time of a predetermined time or less as a third signal 30 to the electromagnet coil 7. When the pulse signal of the third signal 30 is input, the braking device 200 does not enter the driving state and can maintain the released state.

The monitoring device 100 generates the third signal 30 by the FPGA 1, the power supply 2, the brake output control circuit 3, and the FET 5. The FPGA 1 outputs the first signal 10 which is the basis of the third signal 30. The first signal 10 has an amplitude of 3.3 V and continues for 99 msec, and an amplitude of 0 V for 1 msec. The first signal 10 repeats a 1 msec wide 0 V pulse with a cycle of 100 msec. The power supply 2 level-shifts the first signal 10 output by the FPGA 1 to an amplitude of 24 V, and outputs the second signal 20 to the source of the FET 5. The second signal 20 has an amplitude of 24 V and continues for 99 msec, and an amplitude of 0 V continues for 1 msec. The second signal 20 repeats a 1 msec 0 V pulse with a cycle of 100 msec. The timing of the pulse of the second signal 20 is synchronized with the timing of the pulse of the first signal 10.

The brake output control circuit 3 outputs an on signal or an off signal to the gate of the FET 5 and the FPGA 1. The FPGA 1 monitors an on signal or an off signal to the gate of the FET 5. The FET 5 conducts between the drain and the source when an on signal is input to the gate. At this time, the FET 5 outputs the second signal 20 input to the source as the third signal 30 from the drain. When an off signal is input to the gate, the FET 5 makes the drain and source non-conducting. At this time, the FET 5 does not output the third signal 30 from the drain.

The third signal 30 has an amplitude of 24 V and continues for 99 msec, and an amplitude of −27.2 V for 1 msec. The third signal 30 repeats a 1 ms −27.2 V pulse with a period of 100 msec. Further, the pulse timing of the third signal 30 is synchronized with the pulse timing of the first signal 10 and the second signal 20. Since the counter electromotive force of the electromagnet coil 7, which will be described later, is superimposed on the third signal 30, the amplitude becomes −27.2V.

The FET 5 outputs the third signal 30 to one end 7A of the electromagnet coil 7 via the input terminal 6A of the connector 6. The electromagnet coil 7 releases the braking device 200 while the amplitude of the third signal 30 is 24V. Further, since the electromagnet coil 7 has a pulse width of −27.2V of the third signal 30 of 1 msec or less, the braking device 200 is released even while the amplitude of the third signal 30 is −27.2V.

When the amplitude is displaced from 24V to −27.2V at the third signal 30, the electromagnet coil 7 tries to maintain the state of 24V by self-induction. At that time, a counter electromotive force is generated in the electromagnet coil 7. The diode 11 protects the FET 5 from an overvoltage caused by a counter electromotive force generated in the electromagnet coil 7.

The counter electromotive force generated in the electromagnet coil 7 acts on the Zener diode 8 with a reverse bias. Due to this reverse bias, the Zener diode 8 causes a constant Zener current (yield current) to flow.

As shown in FIG. 2, when the amplitude of the third signal 30 is 24 V (waveform S1), no counter electromotive force is generated in the electromagnet coil 7, so that the fourth signal 40 becomes 0 V (waveform S2). Further, when the amplitude of the third signal 30 is −27.2 V (waveform S3), the counter electromotive force of the electromagnet coil 7 acts on the Zener diode 8. The fourth signal 40 includes a pulse having an amplitude of −27.2 V corresponding to the counter electromotive force (waveform S4). The pulse of the fourth signal 40 is output with the same period (100 msec) as the first signal 10, the second signal 20, and the third signal 30. Therefore, in the fourth signal 40, the state of 0V continues for 99msec, and the state of −27.2V continues for 1msec. The fourth signal 40 repeats a 1 ms −27.2 V pulse with a period of 100 msec. The pulse timing of the fourth signal 40 is synchronized with the pulse timing of the first signal 10, the second signal 20, and the third signal 30.

The light emitting element of the photocoupler 9 emits light by a reverse bias voltage acting on the Zener diode 8. Therefore, when the reverse bias corresponding to the pulse of −27.2 V of the fourth signal 40 acts on the Zener diode 8, the light emitting element of the photocoupler 9 emits light.

The light receiving element of the photocoupler 9 is turned on when the light emitting element of the photocoupler 9 emits light. At this time, the light receiving element outputs a signal from the collector. On the other hand, the light receiving element is turned off when the light emitting element does not emit light. At this time, the light receiving element does not output an output signal from the collector. A 3.3V power supply is connected to the collector of the light receiving element via a pull-up resistor. Therefore, when the light receiving element is in the off state, the photocoupler 9 outputs a 3.3V fourth signal 40 (waveform S5) from the collector of the light receiving element. Further, when the light receiving element is in the ON state, the photocoupler 9 outputs a 0V third signal 30 (waveform S6) from the collector of the light receiving element.

As shown in FIG. 2, in the fifth signal 50, the state of the amplitude 3.3V continues for 99msec, and the state of the amplitude 0V continues for 1msec. When the amplitude of the third signal 30 is 24 V, the counter electromotive force does not act on the Zener diode 8, so that the fifth signal 50 is in a state of 3.3 V (waveform S5). Further, when the amplitude of the third signal 30 is −27.2V, the back electromotive force of the electromagnet coil 7 acts on the Zener diode 8 with a reverse bias, so that the fifth signal 50 becomes 0V (waveform S6). The pulse timing of the fifth signal 50 is synchronized with the pulse timing of the first signal 10, the second signal 20, the third signal 30, and the fourth signal 40. FPGA1 detects the fifth signal 50. Therefore, the FPGA 1 detects a pulse of the fifth signal 50 having an amplitude of 0 V with a period of 100 msec.

A counter electromotive force is periodically generated in the electromagnet coil 7 in response to a pulse of −27.2 V of the third signal 30. The FPGA 1 detects the fifth signal 50 via the Zener diode 8 and the photocoupler 9. The pulse of the fifth signal 50 having an amplitude of 0 V substantially coincides with the timing of the pulse of the third signal 30 having an amplitude of 0 V.

<When coil is not connected and disconnection is detected>
A case where the electromagnet coil 7 is not connected or is disconnected will be described with reference to FIGS. 3 and 4. FIG. 3 shows that the electromagnet coil 7 is not connected or disconnected. At this time, even if the FPGA 1, the power supply 2, the brake output control circuit 3, and the FET 5 generate and output the third signal 30, no back electromotive force is generated by the electromagnet coil 7. Therefore, the Zener diode 8 and the photocoupler 9 do not detect the counter electromotive force. Therefore, when the electromagnet coil 7 is not connected or disconnected, the fifth signal 50 output by the photocoupler 9 is maintained in a state of an amplitude of 3.3 V and does not have a pulse having an amplitude of 0 V. Therefore, the FPGA 1 can detect the unconnected or disconnected state of the electromagnet coil 7 by determining whether or not the fifth signal 50 output by the photocoupler 9 contains a pulse having an amplitude of 0 V.

FIG. 4 shows each signal when the electromagnet coil 7 is not connected or disconnected. The alternate long and short dash line in FIG. 4 indicates when the electromagnet coil 7 is not connected or disconnected. The first signal 10 and the second signal 20 are the same as in normal operation (see FIG. 2) (waveforms S11 and S12). Since no counter electromotive force is generated in the electromagnet coil 7 after disconnection or disconnection, the third signal 30 repeatedly outputs a pulse in which the state of the amplitude 24V continues for 99msec and the state of the amplitude 0V continues for 1msec in a cycle of 100msec. (Waveform S13). On the other hand, since no counter electromotive force is generated in the electromagnet coil 7, the fourth signal 40 maintains a state of an amplitude of 0 V (waveform S14). Further, since the Zener diode 8 does not detect the counter electromotive force, the fifth signal 50 maintains a state of an amplitude of 3.3 V (waveform S15). That is, even when the third signal 30 has a pulse having an amplitude of 0 V, the fourth signal 40 does not have a pulse having an amplitude of 0 V, and the fifth signal 50 does not have a pulse having an amplitude of 0 V. Therefore, the FPGA 1 can detect the unconnected or disconnected state of the electromagnet coil 7 by determining whether or not the fifth signal 50 has a pulse having an amplitude of 0 V.

<Detection when FET 5 fails in a cutoff state>
A case where the FET 5 fails in the cutoff state will be described with reference to FIGS. 5 and 6. A failure in a cutoff state is a failure in which the drain and source are maintained in a non-conducting state. At this time, when the on signal and the off signal are input to the gate of the FET 5, the drain of the FET 5 does not output the pulse of the third signal 30.

If an on signal is input to the gate when the FET 5 is out of order in a cutoff state, the third signal 30 based on the second signal 20 input to the source is not output from the drain. Therefore, when the FET 5 is out of order in the cutoff state, the FPGA 1 detects the state of the on / off signal to the gate and the state of the third signal 30 output by the FET 5, so that the FET 5 operates normally. You can check if.

FIG. 6 shows each output signal when the FET 5 fails in the cutoff state. Further, the alternate long and short dash line in FIG. 6 indicates the time when a failure occurs in the cutoff state. In this case, the outputs of the first signal 10 and the second signal 20 are the same as in normal operation (see FIG. 2). Therefore, the FPGA 1 and the power supply 2 repeatedly output the first signal 10 and the second signal 20 in a cycle of 100 msec with a pulse having an amplitude of 0 V (waveforms S21 and S22), as in the normal operation. On the other hand, after the FET 5 fails in the cutoff state, the third signal 30 maintains the state of 0V (waveform S23). Further, since the output to the electromagnet coil 7 maintains 0 V (waveform S23), the fourth signal 40 maintains 0 V (waveform S24). Further, since the photocoupler 9 is not turned on, the fifth signal 50 maintains the state of 3.3 V (waveform S25). Therefore, when a failure occurs in the cutoff state, the FPGA 1 detects whether the FET 5 is operating normally by detecting the on / off state of the signal to the gate and the state of the third signal 30 output by the FET 5. You can check. That is, when the third signal 30 maintains 0 V even though the output to the gate is on, the FPGA 1 determines that the FET 5 has failed in the cutoff state.

<Detection when FET 5 fails in the transmission state>
A case where the FET 5 fails in the transmission state will be described with reference to FIG. 7. A failure in the transmission state is a failure in which the drain and source are maintained in a conductive state. Therefore, the drain of the FET 5 outputs a constant signal regardless of whether the on signal or the off signal is input to the gate of the FET 5.

On the other hand, when the FET 5 fails in the transmission state, the transmission state is maintained between the drain and the source of the FET 5. Therefore, regardless of whether the on signal or the off signal is input to the gate of the FET 5, the third signal 30 based on the second signal 20 input to the source is output from the drain of the FET 5. Therefore, when a failure occurs in the transmission state, the FPGA 1 determines whether the FET 5 is operating normally by detecting the on / off signal to the gate and the state of the third signal 30 output by the FET 5. it can.

FIG. 7 shows each output signal when the FET 5 fails in the transmission state. The alternate long and short dash line in FIG. 7 shows the time when a failure occurs in the transmission state. In this case, the outputs of the first signal 10 and the second signal 20 are the same as those at the time of normal operation and at the time of failure in the cutoff state. Therefore, the FPGA 1 and the power supply 2 repeatedly output the first signal 10 and the second signal 20 in a cycle of 100 msec with a pulse having an amplitude of 0 V (waveforms S31 and S32), as in the normal operation. Here, after the FET 5 fails in the transmission state, the third signal 30 is output from the drain of the FET 5 regardless of the state of the gate on / off signal, and maintains a constant state of 24V (waveform S33). The fourth signal 40 maintains 0 V (waveform S34) because the output to the electromagnet coil 7 maintains 24 V (waveform S33). Further, the fifth signal 50 maintains the state of 3.3 V because the photocoupler 9 does not turn on (waveform S35). Therefore, when the FET 5 is out of order in the transmission state, the FPGA 1 detects the on / off state of the signal to the gate and the state of the third signal 30 output by the FET 5, so that the FET 5 operates normally. You can check if. That is, when the third signal 30 maintains 24 V even though the output of the FET 5 to the gate is off, the FPGA 1 determines that the FET 5 has failed in the transmission state.

<Action, effect>
As described above, the monitoring device 100 outputs the third signal 30 including the pulse of less than the predetermined time to the electromagnet coil 7. The monitoring device 100 detects the counter electromotive force generated in the electromagnet coil 7 at this time by the Zener diode 8 and the photocoupler 9. The monitoring device 100 determines the state of the electromagnet coil 7 by the FPGA 1 based on the pulse of the third signal 30 and the pulse of the fifth signal 50 output by the photocoupler 9. The FPGA 1 determines that the electromagnet coil 7 is normal when the fifth signal 50 output by the photocoupler 9 contains a pulse, and the electromagnet coil 7 is abnormal when the fifth signal 50 output by the photocoupler 9 does not contain a pulse. Is determined. The abnormal state of the electromagnet coil 7 means, for example, that the electromagnet coil 7 is not connected or disconnected. Therefore, the monitoring device 100 can detect that the electromagnet coil 7 is not connected or disconnected. Since the pulse of the third signal 30 can maintain the released state of the braking device 200, the monitoring device 100 can determine the state of the electromagnet coil 7 while maintaining the braking device 200 in the released state.

In the monitoring device 100, when the FET 5 fails in the cutoff state, the FET 5 does not output the pulse of the third signal 30 even if the brake output control circuit 3 turns on the FET 5. Therefore, the monitoring device 100 can identify that the FET 5 has failed in the cutoff state by detecting the state of the third signal 30.

When the FET 5 fails in the transmission state, the monitoring device 100 outputs the third signal 30 even if the brake output control circuit 3 turns off the FET 5. Therefore, the monitoring device 100 can identify that the FET 5 has failed in the transmission state by detecting the state of the third signal 30.

The monitoring device 100 detects the counter electromotive force generated in the electromagnet coil 7 by the Zener diode 8. The Zener diode 8 outputs a predetermined yield voltage when the counter electromotive force acts in the reverse bias. Therefore, the Zener diode 8 can reliably detect the counter electromotive force from the electromagnet coil 7. Further, by using the photocoupler 9, the monitoring device 100 can output the fifth signal 50 when the counter electromotive force acts on the Zener diode 8 with a reverse bias. Therefore, the monitoring device 100 can reliably detect the counter electromotive force generated in the electromagnet coil 7. Further, the monitoring device 100 can convert a signal corresponding to the counter electromotive force to a voltage level equal to or lower than the rating of FPGA 1 by using the Zener diode 8 and the photocoupler 9. Therefore, the possibility that the FPGA 1 will fail due to overvoltage can be reduced. Further, in the photocoupler 9, the light emitting element and the light receiving element are not physically connected. Therefore, the monitoring device 100 can reduce the possibility that the FPGA 1 erroneously detects due to noise or the like.

The FPGA 1 repeatedly outputs the pulse of the first signal 10 at a predetermined cycle. At this time, the monitoring device 100 can monitor the pulse of the fifth signal 50 generated in a cycle of 100 msec. Therefore, the monitoring device 100 can determine that the electromagnet coil 7 is in a normal state when the FPGA 1 detects the pulse of the fifth signal 50 in a cycle of 100 msec. Further, the monitoring device 100 can determine that the coil is in an abnormal state when the FPGA 1 does not detect the pulse of the fifth signal 50 at a predetermined cycle.

<Modification example>
The present invention is not limited to the above embodiment. The monitoring device 100 may include a motor drive mechanism (not shown). As shown in FIG. 6, in the monitoring device 100, when the FET 5 fails in the cutoff state, the third signal 30 sets the braking device 200 in the driving state. At this time, the braking device 200 performs the motor stop operation while the motor drive mechanism rotationally drives the motor. At that time, an excessive load is applied to the motor and the braking device 200, and the motor and the braking device 200 may break down or the life may be shortened. On the other hand, when the monitoring device 100 detects that the FET 5 has failed in the cutoff state, the FPGA 1 drives the motor drive mechanism and stops the rotation drive of the motor prior to the motor stop operation of the braking device 200. At this time, the monitoring device 100 can suppress an excessive load from being applied to the motor and the braking device 200. Therefore, the monitoring device 100 can reduce the possibility that the motor will fail or the life will be shortened. The monitoring device 100 may control the motor drive mechanism to perform the motor stop operation even when the FET 5 fails in the transmission state or when a failure in another state is detected.

The first signal 10, the second signal 20, and the third signal 30 are generated by the FPGA 1, the power supply 2, the brake output control circuit 3, and the FET 5, but pulses may be generated by using a device such as a pulse generator. The FET 5 may be another switching element such as a MOS. Although the Zener diode 8 is used for detecting the counter electromotive force, it may be an element that operates with another reverse bias. The photocoupler 9 may be an element such as a transistor. The monitoring device 100 uses the FPGA 1 to determine the abnormality of the electromagnet coil 7, the failure of the FET 5 in the cutoff state, the failure of the transmission state of the FET 5, the operation of the motor drive mechanism, etc., but other control elements such as the CPU. May be performed using.

<Others>
FPGA 1 is an example of the "output unit" of the present invention. The Zener diode 8 and the photocoupler 9 are examples of the "first detection unit" of the present invention. FPGA 1 is an example of the "first determination unit" of the present invention. The FET 5 is an example of the "switching unit" of the present invention. The brake output control circuit 3 is an example of the "control unit" of the present invention. FPGA 1 is an example of the "second detection unit" of the present invention. Failure in the cutoff state is an example of the "first abnormality" of the present invention. Failure in the transmission state is an example of the "second abnormality" of the present invention. The motor drive mechanism is an example of the "drive unit" of the present invention. FPGA 1 is an example of the "stop means" of the present invention.

1: FPGA
3: Brake output control circuit 5: FET
7: Electromagnet coil 8: Zener diode 9: Photocoupler 100: Monitoring device 200: Braking device

Claims (6)

In a monitoring device that monitors the state of the coil of a braking device that outputs a signal to the coil when a signal of a predetermined time or longer is input to enable braking.
An output unit that outputs a pulse signal for less than a predetermined time to the coil,
A first detection unit that detects the counter electromotive force generated in the coil when the pulse signal is output to the coil by the output unit and outputs an output signal corresponding to the counter electromotive force.
A first determination unit that determines the state of the coil based on the pulse signal output by the output unit and the output signal output by the first detection unit.
A switching unit that is interposed between the output unit and the coil and can be switched to a transmission state in which the pulse signal output by the output unit is transmitted to the coil or a cutoff state in which the pulse signal is not transmitted to the coil. ,
A control unit that controls the switching unit to switch to the transmission state or the cutoff state,
A second detection unit for detecting the pulse signal to the coil and a second detection unit are provided.
The first determination unit
When the first detection unit outputs the output signal in response to the pulse signal from the output unit, it is determined that the coil is normal.
When the control unit puts the switching unit in the transmission state, the second detection unit detects the pulse signal in response to the pulse signal by the output unit, and the first detection unit outputs the output signal. When there is no output, the coil is judged to be abnormal and
When the control unit puts the switching unit in the transmission state, when the second detection unit does not detect the pulse signal in response to the pulse signal by the output unit, the switching unit holds the switching unit in the cutoff state. A monitoring device further provided with a second determination unit for determining one abnormality. In a monitoring device that monitors the state of the coil of a braking device that outputs a signal to the coil when a signal of a predetermined time or longer is input to enable braking.
An output unit that outputs a pulse signal for less than a predetermined time to the coil,
A first detection unit that detects the counter electromotive force generated in the coil when the pulse signal is output to the coil by the output unit and outputs an output signal corresponding to the counter electromotive force.
Based on the pulse signal output by the output unit and the output signal output by the first detection unit, the first determination unit for determining the state of the coil is interposed between the output unit and the coil. A switching unit capable of switching to a transmission state in which the pulse signal output by the output unit is transmitted to the coil or a cutoff state in which the pulse signal is not transmitted to the coil.
A control unit that controls the switching unit to switch to the transmission state or the cutoff state,
A second detection unit for detecting the pulse signal to the coil is provided.
The first determination unit
When the first detection unit outputs the output signal in response to the pulse signal from the output unit, it is determined that the coil is normal.
When the control unit puts the switching unit in the transmission state, the second detection unit detects the pulse signal in response to the pulse signal by the output unit, and the first detection unit outputs the output signal. When there is no output, the coil is judged to be abnormal and
When the control unit puts the switching unit in the cutoff state, when the second detection unit detects the pulse signal in response to the pulse signal by the output unit, the switching unit holds the switching unit in the transmission state. (Ii) A monitoring device further provided with a second determination unit for determining an abnormality. The second determination unit further
When the control unit puts the switching unit in the cutoff state, when the second detection unit detects the pulse signal in response to the pulse signal by the output unit, the switching unit holds the switching unit in the transmission state. (Ii) The monitoring device according to claim 1 , wherein the monitoring device is determined to be abnormal. The first detection unit
A diode that is connected to the coil and in which the counter electromotive force acts in a reverse bias,
A photocoupler incorporating a light emitting element and a light receiving element, characterized in that the light emitting element emits light when the reverse bias occurs in the diode, and the photocoupler outputs the output signal from the light receiving element. The monitoring device according to any one of claims 1 to 3. The monitoring device according to any one of claims 1 to 4, wherein the output unit repeatedly outputs the pulse signal at a predetermined cycle. A drive unit that drives the motor that is the braking target of the braking device, and
The monitoring according to any one of claims 1 to 5, wherein the first determination unit includes a stop means for stopping the drive of the motor by the drive unit when the coil is determined to be abnormal. apparatus.

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