JPH0575273B2 - - 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 activated in a control circuit of an industrial machine.

[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 the interlock contacts are cut off in response to abnormal locations where an abnormality occurs during operation. 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 for such a purpose, 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 that can be used by arbitrarily switching between resistance ranges, voltage ranges, current ranges, etc., when handling the tester, extreme care must be taken when switching the ranges. If you make a mistake in changing the range due to careless operation, there is a risk that the device will be destroyed.

[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 novel defect detection device that is less prone to handling errors and allows anyone to easily detect defective locations. In summary, the defect detection device of the present invention has a first defect detection device connected to one line of the control bus of the device to be detected.
A second power supply terminal 2 is connected to the other line of the control bus of the detected device; and a second power terminal 2 is connected to the second power terminal 2 to form an OR logic, and the second power terminal 2 is connected to the other line of the control bus of the detected device a check pin 4 which is connected at any time to the one line side of a plurality of interlock contacts which are AND-connected together with the operating circuit between the control bus bars of the control bus; and: select either the second power terminal 2 or the check pin 4. a manual operation contact 7 that is connected to the second power supply terminal 2 or the check pin 4 and the first power supply terminal 3, and an indicator light 6 that lights up when a control current flows between the manual operation contact and the first A resistance adjusting mechanism is provided in the circuit leading to the power supply terminal of the circuit and changes the resistance value in the circuit.When the check pin 4 is connected to either of the interlock contacts, the pilot lamp Depending on the lighting state, it is possible to check whether the interlock contact has operated or not.

[Effect]

That is, the defect detection device of the present invention is basically a circuit in which a parallel circuit of a second power supply terminal and a check pin is connected in series with a first power supply terminal, a pilot lamp, and a resistance value adjustment circuit. It is possible to respond to changes in the power supply voltage of the control circuit simply by adjusting the resistance value adjustment circuit to adjust the circuit resistance. Further, by connecting the first power terminal and the second power terminal to the control bus of the detected device, and activating the second power terminal and the second power terminal of the check pin, the pilot lamp is activated. It lights up and you can check the pilot lamp itself. Further, the first power supply terminal is connected to one of the control buses of the detected device, the second power supply terminal and the check pin of the check pins are enabled, and the check pin is connected to the one of the interlock contacts of the detected device. If the interlock contact is connected to the line side, it can be detected whether the interlock contact is activated or not based on whether the pilot lamp lights up or not.

【Example】

Hereinafter, one embodiment of the present invention will be described in detail with reference to the drawings. FIG. 1 is a plan view showing an example of the external appearance of the defect detection device of the present invention, in which an R-phase connection terminal 2, a T-phase connection terminal 3, and a check pin 4 are each led out from a housing 1 by lead wires. The R-phase connection terminal 2 is connected to the R-phase line of the control circuit of the press machine and other machine tools, the T-phase connection terminal 3 is connected to the T-phase line of the control circuit of the machine tool, and the check pin 4 is connected to the control circuit of the machine tool. These are connected to the T-phase line side of the interlock contacts that are subject to the continuity check. Further, on the surface of the housing 1, there is a changeover switch 5 for switching between 200V and 100V ranges, a pilot lamp 6 that lights up to indicate the continuity state of the interlock contact to be checked, and a test lamp 6 that tests the lighting state of the pilot lamp 6 itself. Test buttons 7 are positioned appropriately. Note that the location of these members on the housing 1 is not an important issue for the present invention. Next, FIG. 2 is a circuit diagram showing a specific circuit example of the defect detection device of the present invention. In FIG. 2, 2, 3, 4, 5, 6, and 7 are already explained in FIG. The R-phase connection terminal 2, T-phase connection terminal, check pin 4, selector switch 5, pilot lamp 6, and test button 7 are shown, respectively. Further, in Fig. 2, 8 indicates a resistor selected when the control voltage of the detected device is 200V, and 9 indicates a resistor selected when the control voltage of the detected device is 100V. 5, the series circuit of the contact 5a, the resistor 9 and the changeover switch 5
The series circuit of contact 5b is connected in parallel, and by making contact 5a of changeover switch 5,
The resistor 8 for 200V and the resistor 9 for 100V can be effectively selected by making the contact 5b of the changeover switch 5. Also, the test button 7 has a B contact 7a and an A contact 7b.
The B contact 7a is connected to the check pin 4, and the A contact 7b is connected to the R phase connection terminal 2. Furthermore, in FIG. 2, 10 is a rectifier circuit using a diode bridge, 11 is a shunt resistor, and 1 is a rectifier circuit using a diode bridge.
2 shows Zener diodes for constant voltage, and it is possible to check the operation status of the target interlock contact depending on whether a forward voltage is applied to the pilot lamp 6. There is. Next, the operation of this embodiment will be explained with reference to the above matters and FIG. 3. Incidentally, FIG. 3 is a circuit diagram showing the parts directly related to the present invention extracted from the control circuit of a machine tool in which the operating part of the interlock contact is detected by the defective part detection device of the present invention. ₁ to _I6 are interlock contacts, PB1 is a run button, PB2 is a stop button, OL is an overload relay, 21 is a relay coil that is excited by the make of the run button PB1, and 22 is an A contact that self-holds the relay coil 21. The relay coils 21 are shown to be operated by energizing the relay coils 21. First, in the control circuit of the machine tool shown in FIG. 3, all interlock contacts _I1 to _I6 are made in a normal state. Therefore, when the operation button PB1 is pressed, the relay coil 21 is energized,
It is self-held by the A contact 22 and operation is started. Then, the stop button PB2 is pressed, or
When any of the interlock contacts _I1 to _I6 is broken, the relay coil 21 is broken and the operation is stopped. In the defect detection device of the embodiment shown in FIGS. 1 and 2, the T-phase connection terminal 3 is connected to the T-phase line of the control circuit, and the R-phase connection terminal 2 is connected to the R-phase line of the control circuit.
A check pin 4 is used connected to any one of the interconnection points of each interlock contact _I1 to _I6 . Also, when the power supply for the control circuit of the detected device is 200V, the contact 5a of the changeover switch 5 is made and the resistor 8 for 200V is selected, and when the power supply is 100V, the contact 5b of the changeover switch 5 is made.
Resistor 9 for 100V is selected. The defect detection device of this embodiment has two operating modes: (1) checking the continuity of the pilot lamp 6 itself, and (2) checking the continuity of each interlock contact. First, when performing a continuity check of the pilot lamp 6 itself in (1), connect the T-phase connection terminal 3 and the R-phase connection terminal 2 to the T-phase line and R-phase line of the control circuit shown in FIG. 3, respectively. After that, test button 7
Press to make contact 7b. Therefore, R phase connection terminal 2 - contact 7b - contact 5a
(or contact 5b) - Resistor 8 (or Resistor 9) - Rectifier circuit 10 - Current flows from the rectifier circuit 10 to the parallel circuit of light 11, pilot lamp 6, and Zener diode 12 by the alternating current flowing in the path of flows. Therefore, if the pilot lamp 6 is normal, the pilot lamp 6 lights up, and if the pilot lamp 6 does not light up, it is possible to detect an abnormality in the pilot lamp 6. Next, the case (2) of checking the continuity of each interlock contact will be explained. The following description assumes that interlock contact _I4 was activated during operation of the control circuit of FIG. 3, and that interlock contact _I4 remained broken. When checking the continuity of an interlock contact, the check pin 4 is brought into contact with the T-phase line side of the interlock contact. First, when check pin 4 is connected to the T-phase line side of interlock contact _I1 , since the normal interlock contact I1 is closed, check pin ₄ is connected to R.
Conducts with the phase line. Therefore, check pin 4-contact 7a-contact 5a
(or contact 5b) - Resistor 8 (or Resistor 9) - Rectifier circuit 10 - Current flows from the rectifier circuit 10 to the parallel circuit of resistor 11, pilot lamp 6, and Zener diode 12 due to the alternating current flowing in the path of is played and the pilot lamp 6 lights up. When the check pin 4 is brought into contact with the T-phase line side of the interlock contacts _I2 and _I3 , the check pin 4 is electrically connected to the R-phase line, so the pilot lamp 6 lights up in the same manner as described above. Now, when the check pin 4 is brought into contact with the T-phase line side of the broken interlock contact I ₄ , the check pin 4 is not electrically connected to the R-phase line, so the pilot lamp 6 does not light up, and as a result, the interlock contact You can find that I ₄ is breaking. Furthermore, even if the control power supply of the detected device is 200V due to an error in the setting of the changeover switch 5, even if the resistor 9 for 100V is selected, the voltage applied to the pilot lamp 6 will be suppressed by the Zener diode 12, and excessive voltage will not occur. The risk of damage to the pilot lamp 6 is avoided. Although the example above shows one circuit as shown in Fig. 2 housed in one housing 1, if similar circuits are placed in parallel and multiple check pins are used at the same time, the circuit can be checked at once. Interlock points can be found. In this case, it goes without saying that the R-phase connection terminal and the T-phase connection terminal can be shared. Furthermore, although the above example shows an example in which the R-phase connection terminal 2 and the test button 7 are provided to check the continuity of the pilot lamp 6, even if the R-phase connection terminal 2 and the post button 7 are omitted, the T-phase connection The continuity of the pilot lamp 6 can be checked by connecting the terminal 3 to the T-phase line of the control circuit of the device to be detected and the check pin 4 to the R-phase line of the control circuit of the device to be detected. However, if the R-phase connection terminal 2 and the test button 7 are provided as in the above embodiment, it is thought that operational errors will be reduced.

【effect】

As explained above, according to the defect detection device of the present invention, the interlock contacts can be detected by simply bringing the check pin into contact with AND-connected interlock contacts one after another and making a very simple judgment as to whether or not the pilot lamp lights up. The operating location can be reliably detected. Further, as described above, the defective location detection device of the present invention has the following features:
The range switching is simply a matter of switching the resistance range according to the power supply voltage of the detected circuit.
There is less risk of switching the range incorrectly. Furthermore, even if the range is switched over, if the input voltage becomes low, the brightness of the pilot lamp will only decrease, and if the input voltage becomes high, the pilot lamp will not be activated by the high voltage due to the zener voltage. Destruction will be prevented. Furthermore, according to the defect detection device of the present invention, it is also possible to easily confirm whether the pilot lamp itself is good or bad.

[Brief explanation of drawings]

Fig. 1 is a plan view showing one embodiment of the present invention, Fig. 2 is a plan view showing one embodiment of the present invention;
The figure is a circuit diagram showing one embodiment of the present invention, and FIG. 3 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... Housing, 2... Terminal, 3... Terminal, 4...
Check pin, 5... Changeover switch, 6...
Pilot lamp, 7...Test button, 8, 9
……resistance.

Claims (1)

[Scope of Claims] 1. A first power terminal connected to one line of a control bus of the detected device; a second power terminal connected to the other line of the control bus of the detected device; a check pin which is connected to the second power supply terminal forming an OR logic, and which is connected at any time to the one line side of a plurality of interlock contacts which are AND-connected between the control bus of the detected device together with its driving circuit; and a manual operation contact for selecting either the second power terminal or the check pin, and lighting by a control current flowing between the second power terminal or the check pin and the first power terminal. and a resistance adjustment mechanism that is provided in a circuit extending from the manual operation contact to the first power supply terminal and changes a resistance value in the circuit. 2. In the defect detection device according to claim 1, the resistance adjustment mechanism includes a parallel circuit of a plurality of resistors corresponding to the power supply voltage of the control circuit, and a switch for selecting one of the plurality of resistors. What is claimed is: 1. A defect detection device comprising: a switch, and a power supply voltage is displayed on an operation panel of the changeover switch.