JPH0575272B2 - - Google Patents

Description

[Detailed description of the invention] [Industrial application field]

The present invention relates to a fault detection device for detecting which interlock contact is actuated in a control circuit of an industrial machine, and more particularly to a fault detection device capable of detecting even instantaneous actuation of an interlock contact.

[Conventional technology]

As is well known, in industrial machines such as press machines, interlock contacts are placed between the busbars of the control circuit in series with the operating circuit, and when an abnormality occurs during operation, the interlock contacts are cut off in response to the abnormal location. It is designed to cut off the power to the operating circuit and perform an emergency stop. If an emergency stop occurs due to the operation of an interlock contact during operation, it is necessary to determine which interlock contact was cut off and repair the abnormality before restarting operation. A tester is generally used as a defect detection device, and by checking the conduction state of each contact, the operating location of the interlock contact can be determined.

[Problems to be solved by the invention]

However, since the tester is a general-purpose inspection device, its handling is complicated, and there is a risk of destruction if the range is changed incorrectly. Therefore, if the interlock contact is instantaneously cut off and automatically restored immediately, there is a problem in that it is not possible to detect the operating point of the interlock contact by subsequent tracking.

[Means to solve the problem]

The present invention has been made in view of these problems, and it is an object of the present invention to provide a new defect detection device that is free from handling errors and is capable of detecting even instantaneous interlock contact operation. With the goal. To summarize, the defect detection device of the present invention has a first terminal 1 connected to one line of a control bus of a control circuit of a device to be detected, and a control bus in the control circuit connected in series together with an operating circuit. a second terminal 3 connected to the one line side of the plurality of safety driving interlock contacts; and: the first terminal 1.
and a manually operated automatic return contact 5a provided between the second terminal 3; and a relay contact 7 that is established by electrical continuity between the first terminal 1 and the second terminal 3; and the relay contact 7. through the first
and a display 5d connected between the terminal 1 and the second terminal 3, and a defective location can be detected based on the lighting state of the display 5d.

[Effect]

That is, in the defect detection device of the present invention, terminal 1 is connected to the TC line of the control circuit, and check pin 3 is connected to the TC line of the control circuit.
When the automatic return contact 5a is made by connecting the contact to the TC line side of the safety driving interlock contact, the A contact 7 is made and the lamp indicator 5d lights up.
After that, when the detected device starts operating and the interlock contact for safe operation operates, even if it is a momentary operation, the A contact 7 breaks and the lamp indicator 5d goes out, and the interlock contact operation can be detected.

【Example】

Hereinafter, one embodiment of the present invention will be described in detail with reference to the drawings. In Figure 1, 1 is the control circuit of the machine tool.
The power terminal 2 is connected to the TC line, the power terminal 2 is also connected to the RC line of the control circuit, and the check pin 3 is connected to the interlock contact. Further, 4 is a changeover switch for selecting either continuity check or instantaneous operation check of the interlock contact, and has contacts 4a and 4b. Reference numeral 5 designates a check switch consisting of a push button switch with a lamp, and contacts 5a and 5c are made by pressing a push button switch (not shown) provided on the case, and contacts 5a and 5c are made by pressing the push button switch. It has a breaking contact 5b and a lamp 5d provided within the push button switch. In the check switch 5, the contact 5a is a starting contact, the contact 5b is a contact that is made during a defect detection operation, and the contact 5c is a contact that tests continuity of the lamp 5d itself. Furthermore, 6 is a relay coil that is excited by pressing the check switch 5, and 7 is a relay coil 6.
It is an A contact that self-holds. Next, the operation of the embodiment shown in FIG. 1 will be explained with reference to FIG. 2. Incidentally, FIG. 2 is a circuit diagram showing parts directly related to the present invention extracted from _the control circuit of a machine tool whose interlock operation parts are detected by the defective part detection device of the present invention. _I6 is the interlock contact, PB1 is the run button, PB2 is the stop button,
OL is overload relay, 11 is operation button
The relay coil is excited by the make of PB1,
Reference numeral 12 indicates A contacts that self-hold the relay coil 11, and the relay coil 11 is energized to operate. First, in the control circuit of the machine tool shown in FIG. 2, all interlock contacts _I1 to _I6 are made in a normal state. Therefore, when the operation button PB1 is pressed, the relay coil 11 is energized,
It is self-held by the A contact 12 and operation is started. Then, when the stop button PB2 is pressed or any of the interlock contacts I ₁ to I ₆ breaks, the A contact 12 is activated as the relay coil 11 is demagnetized.
is broken and operation stops. The defect detection device of this embodiment shown in FIG.
The power supply terminal 1 is connected to the TC line of the control circuit, the power supply terminal 2 is connected to the RC line of the control circuit, and the check pin 3 is connected to any one of the interconnection points of the interlock contacts _I1 to _I6 . The defect detection device of this embodiment includes (1) lamp 5d;
It has three operating modes: (2) continuity check of each interlock contact, and (3) instantaneous operation check of each interlock contact. First, when checking the continuity of the lamp 5d itself in (1), after connecting the power terminals 1 and 2 to the TC line and RC line, respectively, press the check switch 5 to make the contact 5c. At this time, as long as lamp 5d is normal, power terminal 1 - lamp 5 - contact 5c - power terminal 2 are connected.
The TC line and the RC line are electrically connected and the lamp 5d lights up. Therefore, if the lamp 5d does not light up, it can be discovered that there is an abnormality in the lamp 5d, such as a disconnection. Next, the case (2) of checking the continuity of each interlock contact will be explained. The following explanation assumes that interlock contact _I4 was activated during operation of the control circuit of FIG. 2, and that interlock contact _I4 remained broken. When checking the continuity of the interlock contact, connect the changeover switch 4 to the contact 4a side,
Check pin 3 of the intended interlock contact.
Make contact with the TC line side. First, when check pin 3 is connected to the TC line side of interlock contact I ₁ , interlock contact I ₁
is connected, so check pin 3 is electrically connected to the RC line side. Therefore, check pin 3 - changeover switch 4
- via contacts 5b - lamp 5d - power supply terminal 1,
Since the RC line and TC line are conductive, lamp 5
d lights up. Even when the check pin 3 is brought into contact with the TC line side of the interlock contacts _I2 and _I3 , the check pin 3 is electrically connected to the RC line, so the lamp 5d lights up. Now, the broken interlock contact _I4
When the check pin 3 is brought into contact with the TC line side, the check pin 3 is not electrically connected to the RC line, so the lamp 5d does not light up, and as a result, it can be discovered that the interlock contact _I4 is broken. If the interlock point cannot be found even after conducting the continuity check of each interlock contact in this manner, perform the instantaneous operation check of each interlock contact as described in (3) below. In the following explanation, it is assumed that the interlock contact _I4 was activated during operation of the control circuit shown in FIG. 2 and the apparatus was stopped, but that the interlock contact _I4 was instantly restored to the make state. When performing an instantaneous operation check of the interlock contact, connect the changeover switch 4 to the contact 4b side, bring the check pin 3 into contact with the TC line side of the interlock contact, press the check switch 5, and then Press operation button PB1. In the case of instantaneous operation of interlock contacts, all interlock contacts are closed, so when check switch 5 is pressed and contact 5a is closed,
Relay coil 6 is energized and self-held by A contact 7. Therefore, check pin 3-A contact 7-changeover switch 4-contact 5b-lamp 5d-power terminal 1
Through this, conduction is established between the RC line and the TC line, and the lamp 5d is lit. In addition, by pressing the operation button PB1, the relay coil 11 is excited and self-held by the A contact 12, and the operation of the detected device is started.
If the interlock contact _I4 operates instantaneously as described above, there is some kind of trouble in the part related to the interlock contact _I4 , so after the start of operation, the interlock contact _I4 operates instantaneously and the detected device stops, and interlock contact _I4 immediately returns to the make state. Now, check pin 3 is connected to interlock contact _I1.
When connected to the TC line side, even if the detected device stops due to the instantaneous operation of interlock contact _I4 as described above, check pin 3-A contact 7
-Switch 4-Contact 5b-Lamp 5d-
Since the path of the RC line and TC line via power terminal 1 is not interrupted even for a moment, the lamp 5d
remains lit. Similarly, when check pin 3 is connected to the TC line side of interlock contacts I ₂ and I ₃ , RC is connected via check pin 3 - A contact 7 - changeover switch 4 - contact 5b - lamp 5d - power supply terminal 1.
The line and TC line routes are interlock contacts.
Since the lamp 5d is not cut off even for a moment by the break of _I4 , the lamp 5d remains lit. Now, when the check pin 3 is connected to the TC line side of the interlock contact _I4 , the check pin 3 is momentarily disconnected from the RC line by the instantaneous operation of the interlock contact _I4 . Therefore, since the relay coil 6 is demagnetized and the A contact 7 is broken, the lamp 5d goes out, and as a result, it can be discovered that the interlock _I4 has momentarily broken. In addition, in the above example, when carrying out a continuity check or an instantaneous operation check of each interlock contact, the check pin 3 is brought into contact with the TC line side of each interlock contact in sequence. If the devices shown in the figure are connected at the same time, the interlock location can be found at once. Similarly, even if a plurality of defect detection devices shown in FIG. 1 are arranged in parallel in one case, the interlock location can be detected at once in the same way as described above. In this case, it goes without saying that the power supply terminals 1 and 2 can be shared. In addition, if the changeover switch 4 is connected to the contact 4a side and the check pin 3 is directly connected to the RC line of the control circuit, the power terminal 2 and the A contact 5
Even if c is omitted, it is possible to check the continuity of the lamp 5d. Also, in the above example, the lamp 5d is turned on by the check switch 5.
Although an example has been shown in which the lamp 5d is disposed within the lamp, the location where the lamp 5d is disposed is not limited to the above as long as it is a visible location. Further, in the above example, the continuity check and the instantaneous operation check of each interlock contact are performed by switching the switch 4.
Even if the power supply terminal 2 is opened and the changeover switch 4 is fixed to the contact 4b side, if omitted, the continuity of each interlock contact can be checked by sequentially moving the check pin 3 while pressing the check switch 5. can.

【effect】

As explained above, according to the fault detection device of the present invention, the operating location of the interlock contact can be detected by simply bringing the check pin into contact with AND-connected interlock contacts one after another without any complicated operations. Furthermore, it is possible to reliably detect a case where the interlock contact is momentarily cut off and automatically restored immediately.

[Brief explanation of the drawing]

Figure 1 is a circuit diagram showing one embodiment of the present invention, Figure 2 is a circuit diagram showing one embodiment of the present invention.
The figure is a circuit diagram showing locations directly related to the present invention extracted from the control circuit of the device detected by the defective location detection device of the present invention. 1, 2...Power terminal, 3...Check pin, 5
...Check switch, 5d...Lamp, 6...
Relay coil, 7...A contact.

Claims (1)

[Scope of Claims] 1. A first terminal connected to one line of a control bus of a control circuit of a detected device, and a plurality of safe driving circuits connected in series together with a driving circuit between a control bus in the control circuit. a second terminal connected to the one line side of the interlock contact; a manually operated automatic return contact provided between the first terminal and the second terminal; A defective point detection device comprising: a relay contact that is established by conduction between two terminals; and an indicator connected between the first terminal and the second terminal via the relay contact.