JP2586279Y2 - Failure detection device for solenoid valve control circuit - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a device for detecting a failure of a solenoid valve control circuit, and more particularly, to an on / off control of a processing machine.
The present invention relates to a failure detection device for an electromagnetic valve control circuit for detecting a failure of an electromagnetic valve on / off means for operating an electromagnetic valve for controlling the turning off.

[0002]

2. Description of the Related Art Conventionally, when detecting a failure in a solenoid valve control circuit, it is common to turn on / off a transistor in response to an open / close signal, and to confirm whether or not the circuit has actually operated based on an open / close monitor signal.

[0003]

However, in such a conventional technique, in a machine in which the solenoid valve is turned off by turning off the transistor as the solenoid valve on / off means, the machine operation is stopped. During the operation, the transistor is turned on, that is, the solenoid valve is also turned on, so that when a check signal for turning off is issued, the machine stops and the operation is interrupted. If a failure occurs while the transistor is on during operation, the solenoid valve remains on because the transistor does not operate even if the transistor is turned off by an open / close signal.

Accordingly, when the solenoid valve is turned off by means other than the transistor after detecting an abnormality based on the signal of the open / close monitor as the operation checking means, the time from when the open / close signal is turned off until the solenoid valve is turned off is turned off. Since the time is longer than in a normal state, there is a possibility that the machine does not stop immediately and operates to a dangerous state.

The purpose of the present invention is to pay attention to such a conventional technique, and to confirm the operation of the solenoid valve on / off means without interrupting the operation during the operation of the processing machine. An object of the present invention is to provide a failure detection device for an electromagnetic valve control circuit that can be used.

[0006]

In order to achieve the above object, a failure detection device for a solenoid valve control circuit according to the present invention turns on / off a solenoid valve coil by means of a solenoid valve on / off means.
A spool-type solenoid valve that controls off and confirms operation of said solenoid valve on / off means by operation check means provided in parallel with said solenoid valve coil, wherein said spool moves after said solenoid valve coil is turned off. A pulse generator is provided which periodically emits a check opening / closing signal to the solenoid valve on / off means during the operation of the solenoid valve, which is turned off for a shorter time than the time delay until the operation.

It is desirable that the operation check means checks the operation of the solenoid valve coil by measuring the voltage or current applied to the solenoid valve on / off means.

[0008]

In the spool type solenoid valve, the solenoid valve is turned on / off.
By operating the solenoid valve coil by the off means, the spool is moved to open and close the solenoid valve. At this time, the spool moves after a certain time delay after the electromagnetic coil is turned on. By utilizing this characteristic, the spool remains in the ON state even if the pulse generator periodically sends a check opening / closing signal to the solenoid valve on / off means during the operation of the solenoid valve, which is turned off for a time shorter than the time delay. As a result, the solenoid valve is kept on. When the solenoid valve on / off means is operating normally, when the check opening / closing signal is turned off, the solenoid valve on / off means is also turned off. By measuring the voltage or current applied to the means, it is confirmed that the solenoid valve on / off means is normal.

On the other hand, if the solenoid valve on / off means is abnormal, the solenoid valve on / off means remains on even if the check opening / closing signal is turned off. By confirming, it is possible to detect abnormality of the solenoid valve on / off means.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A preferred embodiment of the present invention will be described below with reference to the drawings.

As shown in FIG. 1, an electromagnetic valve for turning on / off the processing machine is provided with an electromagnetic valve coil 1 for moving a spool, and an electromagnetic valve for operating the electromagnetic valve coil 1 is turned on. A transistor 3 as an on / off means is provided in series with the solenoid valve coil 1. Further, a photocoupler 5 is provided in parallel with the solenoid valve coil 1 as an operation checking means for checking the operation of the solenoid valve coil 1.

A processing machine switch 9 is connected to the base 7 of the transistor 3.
Sends an on / off signal to the transistor 3 by turning on / off. The switching operation of the transistor 3 causes a current to flow through the solenoid valve coil 1 to operate it, and the spool is moved to open and close the solenoid valve to stop the operation of the processing machine.

Further, a pulse generator 11 for generating an open / close signal for transistor check is connected to the base 7 of the transistor 3. This pulse generator 11 is shown in FIG.
As shown in (1), the on-check signal 13 and the off-check signal 15 are periodically generated.

Although not shown, an emergency stop means for urgently turning off the solenoid valve when the photocoupler 5 does not turn off even when the solenoid valve opening / closing signal is turned off is provided in the solenoid valve. Have been.

Here, as shown in FIG. 3, in the ordinary solenoid valve, the off-check signal 15 is issued from the transistor 3 to the solenoid valve coil 1 (T0 in the figure) and the spool is operated slightly. Time delay (Toff; about several tens of msec), the time shorter than this time delay
The spool does not move even if the solenoid valve coil 1 is turned off by (Tcheck).

By utilizing this characteristic, the off-check signal 1
5 is shorter than the time delay (Tcheck), even if it is confirmed that the transistor 3 is turned off by the off-check signal 15 in a normal state, the solenoid valve coil is again turned on by the next on-check signal 13. 1, the ON check signal 13 is issued, so that the spool does not move, and the solenoid valve 1 keeps the ON state. For this reason, the processing machine can work continuously without causing any trouble.

On the other hand, when an abnormality occurs in the transistor 3, the transistor 3 is not turned off even though the off-check signal 15 is issued, so that the photocoupler 5 keeps on. Thus, abnormality of the transistor 3 can be detected.

Next, a failure detecting operation of the solenoid valve control circuit will be described with reference to FIGS.

First, the operation when the transistor 3 is normal will be described with reference to FIGS. While the processing machine is working, an open / close signal for transistor check is sent, and the solenoid valve open / close signal is turned off for a short time at a predetermined interval (step S1 in FIG. 4, point A1 in FIG. 5). This turns off the transistor 3 (A2 in FIG. 5).
Point), the solenoid valve coil 1 is turned off (point A3 in FIG. 5), and the photocoupler 5 is turned off (step S2, FIG. 5).
Middle A4 point). Thus, it can be confirmed that the transistor 3 is operating normally. Since the solenoid valve opening / closing signal is immediately turned on again (step S3, point A5 in the figure), the spool remains on without moving. When a predetermined time has elapsed since the photocoupler 5 was turned off (step S4), the process returns to step S1 and repeats the above process.

As described above, when the transistor 3 is normal, the solenoid valve opening / closing signal is turned off and the photocoupler 5 is turned off, thereby confirming that the transistor 3 is normal. Since the time of 15 is short, the spool continues to be in the ON state, so that the machining operation is not interrupted.

On the other hand, if the transistor 3 is abnormal, the open / close signal for transistor check is turned off as shown in FIGS. 4 and 6 (step S1 in FIG. 4, point B1 in FIG. 6). However, the transistor 3 keeps on (the point B2 in FIG. 6). Therefore, the solenoid valve coil 1 and the photocoupler 5 also keep the ON state (B3 in FIG. 6,
4 points). As a result, it can be confirmed that the transistor 3 is not operating normally (point B5 in FIG. 6), so that an emergency stop signal is issued to the emergency stop means to turn off the solenoid valve coil 1 (step S4, B6 in FIG. 6). point). The spool is Toff
The solenoid valve can be turned off by moving backward (point B7 in FIG. 6).

As described above, the off-check signal 15 having a time (Tcheck) shorter than the time delay Toff from the issuance of the off-check signal 15 to the solenoid valve coil 1 to the operation of the spool is periodically sent to the transistor 3. Since the operating state of the processing machine is confirmed, it is possible to check without stopping the operation of the processing machine.

Further, since the check is performed as needed at predetermined intervals, an abnormality of the transistor 3 can be found at an early stage, and work safety can be ensured.

It should be noted that the present invention is not limited to the above embodiment, but can be implemented with appropriate modifications. That is, in the above-described embodiment, the photocoupler 5 is used as the operation checking means, but any other device that can detect the voltage or current applied to the solenoid valve coil 1 may be used. For example,
Similar effects can be obtained by using a current transformer or the like.

Further, a transistor that performs a switching operation like a relay may be used instead of the transistor 3.

Further, as shown in FIG. 7, a circuit for accelerating the operation when the solenoid valve is turned off is added to the ordinary solenoid valve, so that the present invention is applied to such a solenoid valve as shown in the figure. By doing so, the failure of the additional circuit can be found at an early stage.

[0027]

The failure detection device for the solenoid valve control circuit according to the invention has the above-described configuration, and has a characteristic that there is a slight time delay from when the electromagnetic coil is turned on until the spool moves. Therefore, even if the pulse generator periodically issues a check opening / closing signal to the solenoid valve on / off means that the pulse generator is turned off for a time shorter than the time delay, the spool does not move and the solenoid valve remains in the on state. Hold. Therefore, there is no need to stop the processing machine for checking the solenoid valve on / off means.

When the solenoid valve on / off means is operating normally, the solenoid valve on / off means is turned off when the check opening / closing signal is turned off. This is confirmed by the operation check means. This confirms that the solenoid valve on / off means is normal.

On the other hand, if the solenoid valve on / off means is abnormal, the solenoid valve on / off means remains on even if the check opening / closing signal is turned off. By confirming, it is possible to detect abnormality of the solenoid valve on / off means.

[Brief description of the drawings]

FIG. 1 is a circuit diagram showing a failure detection device for an electromagnetic valve control circuit according to the present invention.

FIG. 2 is an explanatory diagram showing an open / close signal for transistor checking.

FIG. 3 is a graph showing a state of a current flowing through a solenoid valve coil.

FIG. 4 is a flowchart illustrating a failure detection operation of the solenoid valve control circuit.

FIG. 5 is a time chart showing a state of each part of the failure detection device of the solenoid valve control circuit when the transistor is normal.

FIG. 6 is a time chart showing the state of each part of the failure detection device of the solenoid valve control circuit when the transistor is abnormal.

FIG. 7 is a circuit diagram showing another embodiment.

[Explanation of symbols]

 Reference Signs List 1 solenoid valve coil 3 transistor (solenoid valve on / off means) 5 photocoupler (operation check means) 11 pulse generator

Claims (2)

(57) [Scope of request for utility model registration] 1. A spool type in which a solenoid valve coil is turned on / off by a solenoid valve on / off means and an operation of the solenoid valve on / off means is checked by an operation check means provided in parallel with the solenoid valve coil. A check opening / closing signal, which is turned off for a shorter time than a time delay from when the solenoid valve coil is turned off to when the spool moves, is periodically transmitted to the solenoid valve on / off means during operation of the solenoid valve. 1. A failure detection device for a solenoid valve control circuit, comprising a pulse generator for generating a pulse. 2. The solenoid valve control circuit according to claim 1, wherein the operation check means checks the operation of the solenoid valve coil by measuring a voltage or a current applied to the solenoid valve on / off means. Failure detection device.