JPH03732B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of the Invention] The present invention relates to a relay operation diagnosis circuit that automatically diagnoses the operation of a relay.

[Prior art]

Since relay contacts are mechanical parts, they have a higher probability of failure than electric circuit parts such as ICs. On the other hand, since relays are often used at key points in electrical circuits, when a failure occurs, the circuit often stops working properly. By the way, conventionally there is no method for automatically diagnosing the presence or absence of a failure in a relay contact, and as a result, it has not been possible to quickly take action when an abnormality occurs in an electric circuit.

[Purpose of the invention]

The present invention has been made in view of these points, and is designed to automatically determine whether the operation of a relay contact to be measured is good or bad.

〔Example〕

Hereinafter, the present invention will be explained in detail using the drawings.
FIG. 1 is a circuit diagram showing an embodiment of the present invention.
In the figure, X is a relay contact to be tested, and 100 is a circuit diagram for diagnosing the operation of the relay according to the present invention. Relay contact X under test is connected to terminals 101 and 102. Cs1 to Cs3 are control signals input from outside the circuit 100, and Ds1 to Ds2 are output signals.

In the diagnostic circuit 100, 11 and 12 are each D.
21 is a transistor, 22 is a buffer amplifier, 23 and 24 are relay contacts, and 25 is a drive circuit for driving the relay contacts 23 and 24. This drive circuit 25
A signal Cs1 is applied to. 30 is a comparator circuit, 31 and 32 are comparators, 33 to 36
are each a resistance element. Control signal Cs2
is the transistor 2 via the buffer amplifier 22.
Added to 1. The emitter electrode of the transistor 21 is connected to the reference potential point COM via a voltage dividing circuit made up of resistive elements 33 to 35, and to one end of the relay contact X under test via a series circuit of the resistive element 36 and the relay contact 23. The other end of the relay contact X is connected to the reference potential point via the relay contact 24.
Connected to COM. A voltage dividing point B between the resistive elements 33 and 34 is connected to the - input terminal of the comparator 31, and a voltage dividing point C between the resistive elements 34 and 35 is connected to the + input terminal of the comparator 32. A connection point E between the resistance element 36 and the relay contact 23 is connected to the + and - input terminals of the comparators 31 and 32. The preset terminals PR of the flip-flops 11 and 12 are connected to the output terminals of the comparators 31 and 32, the D terminals are connected to the reference potential point COM, and the clear terminals CLR are connected to the +5V power supply terminal, respectively. A control signal Cs3 is applied to the clock terminal CK as a clock signal.

The relay contact X under test is incorporated into another electrical circuit (not shown). When diagnosing this relay contact X, the relay contacts 23 and 24 are closed and connected to the diagnostic circuit 100. When relay contact
and 24 open to connect the relay under test to diagnostic circuit 1.
Separate it from 00. Relay contacts 23 and 24
Closing and opening driving is performed by applying a control signal Cs1 to the drive circuit 25. Below, regarding the case where relay contacts 23 and 24 are closed and relay contact X under test is connected to diagnostic circuit 100, (1) presence or absence of a failure in relay contact X under test;
The operation of the circuit of the present invention will be described with respect to (2) determining whether the contact resistance and insulation resistance of the relay under test X are good or not, and (3) whether or not the relay under test X is chattering.

(1) Regarding the presence or absence of a failure in relay contact X.

The control signal Cs2 is applied to the transistor 21 via the buffer amplifier 22, and the voltage source V supplies current to the resistive elements 33, 34, and 35 forming a voltage dividing circuit in the comparator circuit 30. As a result, comparator levels are set at the voltage dividing points B and C. If the voltage at the voltage dividing point A is V, the potential at the voltage dividing point E is V when the relay contact X under test is open, and the reference potential point COM when it is closed.
The potential is the same as that of Here, the comparator 31 determines whether the relay contact X is indeed open when it should be open. That is, the potential at the connection point E is applied to the +input terminal of the comparator 31, and the potential at the voltage dividing point B is applied to the -input terminal. As a result, relay contact X is normal.
If it is open, the output level of the comparator 31 will be "H", and if it is abnormal, it will be "L" level.

Next, the comparator 32 determines whether the relay contact X is closed. That is, the potential at the connection point C is applied to the +input terminal of the comparator 32, and the potential at the connection point E is applied to the -input terminal. As a result, the output level of the comparator 32 will be "H" if the contact of relay
This output is applied to the preset terminal PR of flip-flop 11.

(2) Judging whether the contact resistance is good or bad.

As a characteristic of relays, connection contact resistance is a major problem. The contact resistance of relay contact X is r,
If the values of the resistive elements 33 to 36 are R1 to R4 and wiring resistance is ignored, then if the relationship is r<R4×{R3/(R1+R2)} (1), the comparator 32 determines this to be normal. do. That is, if the contact resistance of the relay contact X is normal, the output level of the comparator 32 is "H", and if the value of r exceeds equation (1), it is "L"
level. The output signal of comparator 32 is connected to the preset terminal PR of flip-flop 12.
added to.

Insulation resistance in relays when the contacts are open is also a problem. In the present invention, if the value of insulation resistance is smaller than a specified value, this can be detected. That is, if the value of the insulation resistance of the relay contact Outputs a level signal. This "H" level signal is applied to the PR terminal of flip-flop 11.

Even if a high level signal is applied to the preset terminal PR of the flip-flop 11, the Q
Although the output does not change, when an "L" level signal is applied, the Q output becomes "H" level. As described above, if the relay contact X is opened when it should be opened, the output level of the comparator 31 is "H", otherwise it is "L".
Also, when the insulation resistance and contact resistance of the relay contact X are good, the output level of the comparators 31 and 32 is "H", otherwise it is "L", and these levels are the preset terminals of the flip-flops 11 and 12. Added to PR. Therefore, from the levels of the signals Ds1 and Ds2 obtained from the Q output terminals of the flip-flops 11 and 12, it is possible to judge whether the operation of the relay contact X is good or not, and whether the insulation resistance and contact resistance are good or not. This judgment of pass/fail can be automatically processed by using a computer (not shown).

(3) Regarding the problem of chatter.

It takes several milliseconds from when a command is given to the relay contact X under test to open or close the contact until the contact actually opens or closes.
Furthermore, in the case of dry contact reed relays,
Chattering occurs for a while after opening and closing operations. FIG. 2 shows the state of chattering of relay X, where A and C show normal cases, and B and D show abnormal cases. In the present invention, it is possible to determine whether or not there is an abnormality in the operating time and return time of such a relay.

That is, in FIG. 2, t1 indicates the time when a signal to close the relay X is applied, and t2 indicates the time when a signal to open the relay X is applied. Δt1
is the time from time t1 until relay X stops chattering and closes normally, Δt2 is time t
The time it takes for relay X to be reliably open after a certain period of time has elapsed since 2 (Δt1 and Δt2 are 3 msec in the example).Now, at time t1, the signal that closes relay contact After Δt1 has elapsed since the application of the control signal Cs3, the control signal Cs3 is applied to the clock terminals CK of the flip-flops 11 and 12.This control signal Cs3 is used to clear the contents of the flip-flops 11 and 12.Control signal At the time when Cs3 is applied, the second
If the relay contact X is reliably closed as shown in FIG. On the other hand, the control signal
If the relay contact X is not yet closed as shown in FIG. 2B at the time when Cs3 is applied, the output of the flip-flop 12 becomes "H" level. That is, if the signal to close the relay contact X is applied and the relay contact X is normally closed without any chattering, the level of the output signal Ds2 is "H", and if there is an abnormality, the level of the output signal Ds2 is "L".

Here, after Δt2 has elapsed since the application of the signal to open the relay contact X at time t2 to open the relay contact X, the control signal Cs
3 is applied to the clock terminals CK of flip-flops 11 and 12. If the relay contact X is definitely open as shown in FIG. 2A at the time when the control signal Cs3 is applied, the output level of the comparator 31 is "H", so the output of the flip-flop 12 is " It becomes L” level. On the other hand, if the contact X of the relay is connected to a chatter as shown in FIG. 2D at the time when the control signal Cs3 is applied, the Q output of the flip-flop 11 becomes "H" level. That is, if the relay contact X is closed normally without any chattering after applying the signal to close it, the level of the output signal Ds1 is "L",
If it is abnormal, it becomes "H". These "H" and "L" level signals are processed by a computer.

〔Effect of the invention〕

As described above, in the present invention, if there is a problem with any one of the failure, contact resistance, insulation resistance, and chatter of the relay contact X under test, the diagnosis is automatically performed using a pair of flip-flops. You can get the equipment. As a result, if an abnormality occurs in the electrical circuit using the relay, the abnormality can be quickly dealt with.

[Brief explanation of the drawing]

FIG. 1 is a connection diagram showing an embodiment of the relay operation diagnostic circuit according to the present invention, and FIG. 2 is a waveform diagram for explaining the operation of the circuit shown in FIG. X... Relay contact to be measured, 11, 12... Flip-flop, 23, 24... Relay, 3
1, 32... Comparator.

Claims (1)

[Claims] 1 A relay contact to be measured, a voltage divider circuit driven by a control signal, a resistive element and a first relay contact connected in series between the drive source of this voltage divider circuit and the relay contact to be measured, the said to be measured a second relay contact connected between the relay contact and a reference potential point, the voltage at the connection point of the resistive element and the first relay contact and the divided voltages of different values in the voltage divider circuit are opposite to each other; A pair of comparators are applied to their respective input terminals, and the outputs of the pair of comparators are applied to their respective preset terminals, a control signal is applied to the clock terminal, and the Q terminal controls the operation of the relay contact under test. A relay operation diagnostic circuit consisting of a D-type flip-flop that determines whether it is good or bad and extracts a signal.