JPH0660919B2 - Online diagnostic method and device for electromagnetic equipment - Google Patents

Description

The present invention relates to a method and apparatus for online diagnosis of electromagnetic equipment such as electromagnetic relays and switches.

[Conventional technology]

BACKGROUND OF THE INVENTION In various power plants such as nuclear power plants, steel plants, chemical plants, etc., electromagnetic devices such as electromagnetic relays and electromagnetic switches are often used. These electromagnetic devices are normally in a standby state, and are often used for so-called standby, which is operated when an operation request is made. In such a case, it is important for safe operation of the plant that it is possible to know beforehand whether or not it should actually operate without operating the electromagnetic device. And the diagnosis of the drive circuit is strongly demanded.

In the failure detection device for an electromagnetic device disclosed in JP-A-53-41971, when an operation command is given to the electromagnetic device, the inductance of the exciting coil of the electromagnetic device changes according to the operation of the movable part of the electromagnetic device. The extreme value of the exciting current generated according to the change is detected to determine whether or not the electromagnetic device has really operated, thereby detecting the failure of the electromagnetic device. A change in the exciting current is made by inserting a resistor in the drive circuit side, detecting the exciting current flowing in the resistor in the form of voltage, and comparing the detected signal with a signal obtained through a delay circuit. Have detected by.

In addition to this conventional example, JP-A-53-21392 and JP-A-54-159584
And JP-A-63-135679. Both are related to failure diagnosis of solenoid valves.

[Problems to be Solved by the Invention]

In the above-mentioned Japanese Patent Laid-Open No. 53-41971, the extreme value of the exciting current generated along with the operation of the electromagnetic equipment is detected to detect the failure of the electromagnetic equipment, but the test signal of the time width in which the electromagnetic equipment is not operated. When is applied to the drive circuit, the electromagnetic device does not operate as a matter of course, so that the inductance of the exciting coil does not change. As a result, although there is a slight change in the exciting current, no extreme value exists. Therefore, in such a case, there is a problem that the related art cannot detect an abnormality in the electromagnetic device and the drive circuit.

Further, in the above-mentioned conventional technique, a resistor is directly inserted in the drive circuit side in order to detect the exciting current. However, if the electromagnetic device is of a type that operates with the exciting current off, the resistor may fail in the disconnection side. However, there is a problem that the electromagnetic equipment malfunctions and the high reliability of the system cannot be ensured.

Further, JP-A-53-21392, JP-A-54-159584 and JP-A-6-
No. 3-135679 does not mention the application of the test signal of the time width in which the electromagnetic equipment is not operated.

The present invention has been made in view of the above points, and an object thereof is to first provide a method and an apparatus for diagnosing an electromagnetic device and its drive circuit without operating the electromagnetic device.

[Means for Solving the Problems]

The present invention applies a test signal of a time width during which the electromagnetic device does not operate to the drive circuit of the electromagnetic device, detects the current in the drive circuit, and comprises the level detection means, the delay means, and the comparison means. By inputting to the circuit, the response of the drive circuit at the time of applying the test signal is detected, and the detection result is compared and judged with the test signal.

[Work]

The present invention applies a test signal of a time width during which an electromagnetic device does not operate to a drive circuit of an electromagnetic device, and detects a minute change amount of a current flowing in the drive circuit in response to the test signal by a level shift unit and a delay unit. Since the detection can be performed by the circuit including the comparison means, the electromagnetic device and its drive circuit can be diagnosed without operating the electromagnetic device.

〔Example〕

Embodiments according to the present invention will be described below with reference to the drawings. The parts with the same numbers in each figure indicate the corresponding parts.

FIG. 1 is a diagram showing an embodiment of the present invention. The electromagnetic device 2 shown in the present embodiment is in a normally excited state and is in a non-excited state when the switch 3 as a drive circuit is in an open state. It is not limited to. The configuration to operate in this manner is generally called a fail-safe configuration. For example, even if the power source 1 is lost, the electromagnetic device operates, which is often the case when high safety is required. Used.

The diagnostic device configured as described above for determining whether or not the electromagnetic device 2 and its drive circuit are sound is configured as follows.

The test signal 11A generated by the test signal generation circuit 11 is applied to the drive circuit 3 while the current flowing through the drive circuit is being detected in the form of voltage through the resistor 4. The detection signal at this time is input to an input signal tracking type comparison circuit 6 composed of a level shift circuit 8 and a delay circuit 9 and a comparison circuit 10 for comparing these output signals, and an input signal tracking type output as a result is input. The failure determination circuit 14B determines a failure based on the output signal 7 of the comparison circuit. In addition to this, in the present embodiment, further, the logical product of the window signal 12 obtained by inputting the test signal 11A to the window circuit 12 and the output signal 7 is taken by the digital comparison circuit 13, and the result is obtained by the failure judgment circuit 14A. To judge and display the diagnosis result.

Now, the operation of the diagnostic device configured as described above will be described with reference to FIG.

FIG. 2 (a) is a diagram showing operation waveforms of each part when the drive circuit 3 and the electromagnetic device 2 are normal, and (b) is an operation waveform of each part when the drive circuit 3 fails in a closed state. It is the figure which showed.

First, the case where the drive circuit 3 is normal will be described with reference to FIG.

The test signal generation circuit 11 outputs the test signal 11A shown in (IV) of FIG. 2A to the drive circuit 3 and the window circuit 12. The test signal 11A is a pulse signal with a time width during which the electromagnetic device 2 does not operate. By applying this test signal,
The switch of the drive circuit 3 is open for a short time.
Therefore, the current flowing through the drive circuit 3 becomes zero during this period. Figure 2 (a) shows the current in the drive circuit, that is,
This is the case when the test signal is applied when the current flowing in the electromagnetic device is just zero, so the current detected by the resistor 4 is also the period during which the test signal is applied after the current becomes zero. , Zero continues. Then, when the test signal is released and the switch of the drive circuit 3 returns to the closed state, current flows from that point. Therefore, the current detected by the resistor 4 becomes the current detection signal 5 shown in (V) of FIG. 2 (a).

If the test signal is not applied, the electromagnetic device 2
The current flowing through is determined by the voltage of the power supply 1 and the impedance of the exciting coil of the electromagnetic device 2.

The current detection signal 5 is processed by the input signal tracking type comparison circuit 6 as follows. Current detection signal 5
Is input to the delay circuit 9. This delay circuit 9 can be realized by a filter circuit, and the output thereof becomes the delay signal 9A shown in (V) of FIG. 2 (a). In this way, the current detection signal 5 and the delayed signal 9A do not overlap at the time of applying the test signal. Therefore, it is determined whether or not the drive circuit 3 is operated by the test signal and no current flows in the electromagnetic device. It cannot be judged from the comparison. Therefore, the current detection signal 5 is also input to the level shift circuit 8, a signal lower than the current detection signal by a certain level is output from the level shift circuit 8, and this output signal and the delay signal 9A are crossed on the waveform. After doing so, I try to compare. The level-shifted signal 8A, which is the signal output from the level shift circuit 8.
Has a waveform shown in (V) of FIG. 2 (a). Therefore, when the test signal is applied, the magnitude relationship between the level-shifted signal 8A and the delayed signal 9A is inverted. Therefore, "in" of the inversion of the magnitude relationship indicates "normal" of the electromagnetic device and "absence" indicates "Abnormal" can be determined. Therefore, in the present embodiment, by comparing these two signals by the comparison circuit 10, the output signal 7 of the input signal tracking type comparison circuit shown in (III) of FIG. 1 "signal is output).

A failure can be determined by whether or not the output signal 7 becomes "1" when the test signal is applied. However, the magnitude relationship between the delayed signal 9A and the level-shifted signal 8A changes not only when the test signal is applied, but also as shown in (V) of FIG. There is also Therefore, also in this respect, the input signal tracking type comparison circuit 6 outputs a signal of logic "1". In this way, the input signal tracking type comparison circuit 6
Outputs a signal of logic "1" except when the test signal is applied, and therefore only the response corresponding to the application of the test signal needs to be extracted. Therefore, in this embodiment, the window circuit 12 and the digital comparison circuit 13 are provided so that only the response when the test signal is applied is extracted. The window circuit 12 is shown in FIG.
When the test signal 11A is input as shown in (II) of (a), the window signal 12A is output after a fixed time. This window signal 1
By calculating the logical product of 2A and the output signal 7 of the input signal tracking type comparison circuit by the digital comparison circuit 13A,
The response signal 13A shown in (I) is obtained. In other words, test signal 11A
If the drive circuit 3 and the electromagnetic device 2 are sound, the response signal 13A shown in (I) of FIG. 2 (a) can be obtained.

Next, regarding the case where the drive circuit 3 fails in the closed state,
This will be described with reference to FIG. 2 and FIG.

If the drive circuit 3 fails in the closed state, the drive circuit 3 will not be in the open state even if the test signal 11A is applied.
The current detection signal 5 detected by is (V) in FIG. 2 (b).
become that way. As a result, the level-shifted signal 8A and the delayed signal 9A become as shown in (V) of FIG. 2 (b). That is, the magnitude relationship between the signal levels of the level-shifted signal 8A and the delayed signal 9A does not change when the test signal is applied. Therefore, the output signal 7 of the input signal tracking type comparison circuit becomes as shown in (III) of FIG. 2 (b), and the logical product with the window signal 12A is taken by the digital comparison circuit 13 to obtain the second signal.
The response signal shown in (I) of FIG. In other words, if the drive circuit 3 fails in the closed state, it is not possible to obtain a response signal when the test signal is applied, and it can be determined that there is a failure. This judgment is executed by the failure judgment circuit 14A. This circuit is, for example, the fifth
It can be realized by the circuit configuration shown in the figure.

The failure determination circuit 14A is basically a pulse oscillation circuit 14A.
1. The counter 14A2, the flip-flop circuit 14A3, and the failure indicator 14A4 are used. The flip-flop circuit 14A2 is reset by a reset circuit 14A5 including a power supply 14A6, a resistor 14A7, and a switch 14A8.

The counter 14A2 counts the number of pulse signals output from the pulse oscillating circuit 14A1 and is reset when the response signal 13A is input to the reset terminal 14A9. The period of the pulse signal of the pulse oscillation circuit 14A1 is
It is predetermined such that it becomes longer than the cycle of the response signal (pulse-shaped signal of logic "1") obtained by applying the test signal when the drive circuit 3 and the electromagnetic device 2 are sound. That is, when the drive circuit circuit 3 and the electromagnetic device are normal, the counter 14A2 does not count the pulses output from the pulse oscillation circuit 14A1. And the drive circuit 3
If the fault occurs in the closed state, the response signal to the test signal application cannot be obtained, the signal of logic "1" is input to the reset terminal 14A9 of the counter 14A2, and the count mode is set. Therefore, the number of pulses from the pulse oscillation circuit 14A1 To count. In FIG. 5, when the count value reaches 4, the flip-flop 14A3 is operated to give a failure display signal to the failure indicator 14A4 to display the failure. As shown in FIG. 5, the counter 14A2 is used and the flip-flop 14A3 is operated when the count value becomes 4 in order to provide more reliable information that the drive circuit 3 has failed. Yes, it is arbitrary how much the count value should be.

Next, the detection of a failure when the drive circuit 3 fails in the open state, the exciting coil of the electromagnetic device 2 is broken, or the contact of the connector is bad will be described.

In both of these failures, no current flows to the electromagnetic device 2. The operation waveform of each part in this case is as shown in FIG.

As shown in FIG. 7 (II), when the test signal 11A does not apply a pulse signal of logic "1", that is, logic "0", a failure in which no current flows to the electromagnetic device 2 is detected. However, FIG. 6 shows operation waveforms in the case of normal operation, and FIG. 7 shows operation waveforms in the case of failure.

First, in FIG. 6, when the test signal 11A is logic "1", the current detection signal 5 obtained by this is
It looks like Figure (III). As a result, the level-shifted signal 8A and the delayed signal 9A are as shown in FIG. 6 (III). Therefore, each time the magnitude relationship of these signals changes, the signal shown in FIG. 6 (1) is output from the input signal tracking type comparison / determination circuit 6. This signal is the failure judgment circuit of FIG.
Input to 14B. The failure determination circuit 14B has the same configuration as the failure determination circuit 14A shown in FIG. 5, but only the input signal and the pulse oscillation circuit 14B1 are different. Specifically, first, the input signal is the output signal 7 of the input signal tracking type comparison circuit, and this is logically inverted by the inverting circuit 14B10 and input to the reset 14B9 of the counter. Next, the pulse oscillator circuit
Unlike the case of 14A, the oscillation cycle of 14B1 is set longer than the pulse output cycle of the signal shown in FIG.
It is set shorter than the application period of the pulse signal in the test signal shown in (IV) of FIG. (A) or (IV) of (b). With this configuration, as in the case of 14A, when the signal of FIG. 6 (I) is input to the input signal, this becomes the reset signal of the counter 14B2, so that the pulse from the pulse oscillation circuit 14B1 is counted. Without flip-flop 14B3 does not work. That is, it can be determined that the electromagnetic device 2 and the drive circuit 3 are normal. In addition, the reset circuit 14A5 is the same as in FIG.
It consists of 14B6, resistor 14B17, and switch 14B8.

Next, with reference to FIG. 7, the operation in the case where a failure such that no current flows in the electromagnetic device 2 will be described.

The test signal 11A is logic "1" as shown in FIG. 7 (II). When the current stops flowing in the electromagnetic device 2, the current detection signal becomes as shown in FIG. 7 (III). On the other hand, the level-shifted signal 8A and the delayed signal 9A are respectively shown in FIG. 7 (III).
It becomes like. As a result, the output signal 7 of the input signal tracking type comparison circuit becomes a signal of logic "1" as shown in FIG. Therefore, since the inverting circuit 14B10 inputs the signal of logic “0” to the reset terminal 14B9 of the counter 14B2, the failure determination circuit 14B enters the count mode of the counter 14B2 and outputs the pulse output from the pulse oscillation circuit 14B1. Count. When this value becomes 4, the flip-flop 14B3 is operated and the failure display signal is output to the failure display unit 14B4. In this way, the open failure of the electromagnetic device 2 or the drive circuit is determined,
indicate.

The specific circuit configuration of the input signal tracking type comparison circuit 6 described above will be described below.

A specific example is shown in FIG. The comparison circuit 9 is composed of a primary filter composed of a resistor 91 and a capacitor 92, and the level shift circuit is composed of a diode 81, a resistor 82, and a power supply 83. The power source 83 becomes a negative voltage source when the diode 81 and the resistor 83 are connected in this way. That is, a voltage lower than the input signal by the forward drop voltage V _{f of the} diode 81 is applied to the comparison circuit 10.

The output of the level shift circuit 8 may be connected to the plus side input terminal of the comparison circuit, and the output of the delay circuit 9 may be connected to the minus input terminal of the comparison circuit 10. However, in this case, the logic of the signal output from the comparison circuit 10 is inverted from that of the output signal in the case of FIG. 3, but the function of the input signal tracking type comparison circuit is the same. Further, the delay circuit may be another n-order type filter.

FIG. 4 shows another embodiment of the input signal tracking type comparison circuit 6, which may be the input signal tracking type comparison circuit 6 of FIG.

The input signal tracking type comparison circuit 6 of FIG. 4 connects the input signal to the minus input terminal of the comparison circuit 10, inputs this input signal to the delay circuit 9, and outputs the output signal of this delay circuit 9 to the level shift circuit 8 And the output signal of the level shift circuit is connected to the positive input terminal of the comparison circuit 10. This operation waveform is shown in FIG. 9 in comparison with (III) to (V) of FIG. 2 (a). The current detection signal 5 obtained for the test signal 11 is as shown in FIG. 9 (III). Therefore, the delay signal 9A becomes as shown in FIG. Level shift circuit 8
Which is different from the case of FIG. 1, outputs a signal which is higher by a certain level by the input signal of the level shift circuit. Therefore, the level-shifted signal 8A becomes as shown in FIG. 9 (III). Since the input signal and the level-shifted signal 8A are input to the comparison circuit 10, the signal shown in FIG. 9 (I) is output. That is, the same waveform as (III) in FIG. 2 (a) can be output from the input signal tracking type comparison circuit 6.

A specific circuit configuration of the input signal tracking type comparison circuit 6 will be described below.
Shown in Figure 10. The delay circuit 9 is composed of a primary filter of a resistor 91 and a capacitor 92, as in FIG. 3, and the level shift circuit is a positive power source by a diode 81, a resistor 82, and a power source 84. This power source is a positive polarity power source unlike FIG. By configuring the level shift circuit in this way, a voltage higher than the input signal of the circuit 8, that is, the delay signal 9A by the forward drop voltage V _{f of} the diode 81 can be applied to the comparison circuit 10.

By the way, the forward drop voltage V _f of the diode in FIG. 3 and this circuit is given by the following equation.

The relationship between V _f and I _f in the above equation is illustrated in FIG. That is, assuming that the point at which the forward current has a certain value is the operating point A, even if I _f changes at this point,
V _f becomes almost constant. Therefore, by configuring as shown in FIG. 3 and FIG. 10, a level-shifted signal can be obtained.

In FIGS. 3 and 10, a resistor may be used instead of the diode, but in this case, the level can be shifted by the voltage obtained by the resistance ratio of the resistor and the resistor 82. is there. However, when the voltage level of the input signal is high and when the voltage level of the input signal is low, the level-shifted levels have the same ratio but the level-shifted levels are different. That is, when the input signal is small, the level shift amount is small, and when the input signal is large, the level shift amount is large. As a result, in FIG. 2 (a) or FIG. 9, the comparison circuit is applied when the test signal is applied.
The inversion period of the magnitude relationship between the two signals input to 10 is shortened. That is, the period of the response pulse of the output signal from this comparison circuit is only shortened.

Next, in FIG. 1, instead of the resistor 4, a method of detecting the current flowing through the drive circuit by another detecting means will be described.

When the current is detected by using the resistor, the resistor is directly inserted in the drive circuit side of the electromagnetic device, so that there is a problem that the mobility of the system is lowered due to the failure of the resistor. In order to solve this problem, it is desirable to detect the current without contact.

Therefore, as shown in FIG. 12, the current transformer 15 can be used to extract the magnetic field generated by the current flow as a voltage signal by the current transformer 15. The output signal of the current transformer 15 is input to the input signal tracking type comparison circuit 6 described above. Since the current transformer is a so-called AC coupling element, the DC component is cut off. Therefore, for example,
Test signal 11A (pulse signal) continuously as shown in (I)
Is applied to the drive circuit, as a result, the current detection signal obtained by the current transformer 15 shifts the current off period to the plus side. This is because the Karen transformer is an AC coupling element, but the input signal tracking type comparison circuit is configured to detect a change in current and, as shown in FIGS. 3 and 10, Since the level shift circuit is designed to be able to shift by a constant level even if the level of the input signal changes, the input signal tracking type comparison circuit 6
Can accurately detect the response signal when the current is off, even if the input signal is a current detection signal as shown in FIG. 13 (II).

Further, in FIGS. 1 and 12, it is needless to say that when the level of the current detection signal is low, an amplifier circuit for amplifying the signal level may be provided at the input stage of the input signal tracking type comparison circuit. Is.

Note that, also in FIG. 13, the test signal is applied when the current flowing through the electromagnetic device becomes zero, but this is for the following reason.

For example, as shown in FIG. 14, when a pulse signal is applied as the test signal 11 when the current flowing through the electromagnetic device 2 is maximum, a large noise voltage is generated in the power supply voltage. This noise voltage E _n is given by the following equation.

Switching time of the drive circuit, depending on the element used, since it is considered that the number ms~ number .mu.s, E _n becomes very large value. Particularly, when driving a large electromagnetic device, because the current is large, the E _n becomes extremely high. Therefore, there is a problem that a protection circuit for controlling the noise voltage is newly required, the amount of hardware is increased, and the reliability of the system is deteriorated due to the failure of the protection circuit itself.

In order to solve this problem, it is sufficient to control so that i becomes zero in the equation (2). For this purpose, the current flowing through the electromagnetic device 2 may be detected, and a test signal may be applied when this current becomes zero. The configuration is as shown in FIG. In this figure, a current is detected by the current transformer 15, and the result is input to the phase detection circuit 16. The phase detection circuit 16 outputs a command signal for outputting the test signal 11A to the test signal generation circuit 11 when the current becomes zero. With the above configuration, it is possible to apply the test signal without generating a noise voltage.

Here, if the switch forming the drive circuit has a mechanical contact structure such as a relay or a contactor, the operation delay may be about several ms. If this delay time becomes a problem, the drive circuit may be composed of semiconductor switching elements. A transistor, a thyristor, etc. can be considered as the semiconductor switching element. In particular, in the case of using a thyristor, the following effects can be obtained.

As shown in FIG. 16, a drive circuit is configured by the amphoteric thyristor 3, the phase of the power supply voltage is detected by the phase detection circuit 16, and the test signal 11A is output when the power supply voltage becomes zero. The command signal of is output to the test signal generation circuit 11. The test signal generation circuit outputs a pulse signal having a time width longer than the pulse width of the test signal described above (the pulse width is predetermined) in consideration of the phase difference between the voltage and the current.

In general, the thyristor is switched off when there is no gate signal when the current falls below the holding current. In this case, when the current flowing through the bidirectional thyristor 3 falls below the holding current, the thyristor switches off. Then, when the test signal becomes logic "1", the switch is turned on again. As a result, as shown in FIG. 17 (III), the test signal 11A
The current of the electromagnetic device that responds to is detected by the current transformer 15.

In the case of FIG. 15, the phase is detected using the output signal of the current transformer 15. For this reason, if the test signal application cycle becomes shorter, the level of that signal changes as shown in Fig. 13 (II), so the phase point at which the current flowing through the electromagnetic device becomes zero is detected. However, if the voltage is detected, such a situation does not occur, and the application timing of the test signal 11A can be determined by a simple circuit.

FIG. 18 shows the present invention in Japanese Patent Application No. 62-226370 (JP-A-1-70802).
No.), which is applied to a redundant control and protection device with a diagnostic function. However, the output circuit is Japanese Patent Application No. 62-4834 (Japanese Patent Application Laid-Open No.
The target is the power circuit shown in the control and protection device of 3-140305). The scrum solenoid valve 2 has two exciting coils, and the test signals according to the above-described embodiment are separately sent to the exciting coils. Then, the failure diagnosis is performed for each exciting coil. This is known as the surveillance test.
FIG. 18 shows an example of such a surveillance test.

This circuit configuration is basically the same as that shown in FIG. 1, the output circuit-1 corresponds to the drive circuit 3, and the switching elements Sw1 to Sw1.
The drive circuit is composed of a series-parallel circuit of Sw8. However, the coil L _o in the output circuit -1 is coil current balance for the thyristor parallel circuit. The current transformers CT1 to CT4 are provided to detect the current flowing through the parallel circuit configuration in the output circuit, and the output circuit-1
By comparing the current detection signals obtained by the input signals a to d and CT1 to CT4 in a pattern by the state determination circuit 14 of the output circuit, the failure of the output circuit-1 or the scrum solenoid valve 2 can be detected. For this pattern comparison,
It is described in Japanese Patent Application No. 62-226370 (JP-A-1-70802). Further, since the window circuit 12 has four test signals a to d, the OR circuit 17 takes the logical sum of these signals and inputs the output signal to the input signal tracking type comparison circuit 61 to the test signal. 64 to digital comparison circuit 131
I'll try to get it at ~ 134.

Although not shown in the figure by configuring the above,
Accurate diagnosis is possible for a test signal output aperiodically from two diagnosis circuits. When a test signal is applied aperiodically, the output signal of each current transformer may be as shown in Fig. 13 (II), but the input signal tracking type shown in Fig. 3 or 10 may be used. The comparison circuit allows the system to diagnose without any problems.

〔The invention's effect〕

As described above, according to the present invention, a test signal having a time width in which an electromagnetic device does not operate is applied to a drive circuit, and a current flowing in the drive circuit is applied to an input signal tracking type comparison circuit to input a test signal and an input signal. By comparing with the output signal of the signal tracking type comparison circuit, it becomes possible to detect the slight current change generated by the application of the test signal, and detect the failure of the drive circuit or the electromagnetic device without operating the electromagnetic device. can do. Further, since it is possible to detect the above current in a non-contact manner by using a current transformer as the above current detecting means and perform the same diagnosis, it is possible to increase the reliability of the system and the engineering value is extremely high. high.

[Brief description of drawings]

FIG. 1 is an embodiment diagram of the present invention, FIG. 2 is a time chart thereof, FIGS. 3 and 4 and FIG. 10 are embodiment diagrams of a comparison circuit of the present invention, and FIGS. Example diagram of the determination circuit,
FIGS. 6, 7, and 9 are time charts of this embodiment.
FIG. 11 is a diode characteristic diagram, FIG. 12, FIG. 15, and FIG. 16 are diagrams of other embodiments of the present invention, and FIG. 13, FIG. 14, and FIG. The figure is an application example of the present invention. 2 ... Electromagnetic equipment, 8 ... Level shift circuit, 3 ... Drive circuit, 9 ... Delay circuit, 6 ... Input signal tracking type comparison circuit, 11A ... Test signal, 13 ... Digital comparison circuit.

Claims (6)

[Claims] 1. A magnitude of a signal obtained by detecting a current flowing when a test signal having a time width in which an electromagnetic device does not operate is applied to the electromagnetic device and shifting a level of the detected current signal and a signal obtained by delaying the current signal. And a normal / abnormal condition is determined depending on whether or not the result of the comparison is inverted when the test signal is applied. 2. A current flowing when a test signal having a time width in which an electromagnetic device does not operate is applied to the electromagnetic device is detected, and the detected current signal is compared with the signal obtained by delaying and level shifting the current signal. Then, an online diagnostic method for an electromagnetic device is characterized by determining normality / abnormality depending on whether or not the result of the comparison is inverted when the test signal is applied. 3. The electromagnetic device according to claim 1 or 2, wherein it is detected whether or not the result of the comparison is inverted within a predetermined time width from the time of applying the test signal. Online diagnostic method. 4. The online diagnostic method for an electromagnetic device according to claim 1, wherein the application of the test signal and the detection of the current are performed on a drive circuit of the electromagnetic device. 5. A test signal applying means for applying to the electromagnetic equipment a test signal having a time width during which the electromagnetic equipment does not operate, and a current detecting means for detecting a current flowing through the electromagnetic equipment when the test signal is applied. Comparing means for comparing the magnitude of a signal obtained by shifting the level of the current signal detected by the current detecting means and a signal obtained by delaying the current signal, and whether or not the comparison result by the comparing means is inverted when the test signal is applied. And a determination means for determining whether the electromagnetic device is normal or abnormal, and an online diagnostic device for an electromagnetic device. 6. A test signal applying means for applying to the electromagnetic equipment a test signal having a time width during which the electromagnetic equipment does not operate, and a current detecting means for detecting a current flowing through the electromagnetic equipment when the test signal is applied. Comparing means for comparing the magnitude of the current signal detected by the current detecting means with a signal obtained by delaying and level shifting the current signal, and detecting whether or not the comparison result of the comparing means is inverted when the test signal is applied. An on-line diagnostic device for an electromagnetic device, comprising: a determining unit that determines whether the electromagnetic device is normal or abnormal.