JPH0614083B2 - Detection switch structure - Google Patents

Description

The present invention relates to various detection switch structures such as a proximity switch for confirming an object to be detected, a pressure switch, a limit switch, and the like, and more specifically to the detection switch itself. The present invention relates to a detection switch structure capable of easily diagnosing a failure and a failure of a wiring system such as a power supply line and an output signal line of the detection switch by a failure diagnosis device.

(Prior Art) A conventional detection switch 12 will be described with reference to FIG. 9. The switch case 2 includes a sensor 3 for detecting an object to be detected.
Is provided, and the operational amplifier 4 for amplifying the detection signal S1 output from the sensor 3 and comparing and discriminating between the open state and the closed state is connected to the same sensor 3, and the operational amplifier 4 has an output switching element 5 It is connected. The case 2 is provided with DC power supply terminals A and C and a signal output terminal B. In the usage state shown in FIG. 10, a DC power supply 6 is connected between the terminals A and C, and a load resistor 7 of the switching element 5 is connected between the positive terminal of the power supply 6 and the signal output terminal B. Are connected. An indicator lamp or a relay is used as the load resistor 7.

When the detected object W approaches the sensor 3, the detection signal S1 output from the sensor 3 is input to the operational amplifier 4 for amplification discrimination, and the operation signal S2 (voltage) output from the operational amplifier 4 is equal to or more than a predetermined value. Is applied to the output switching element 5, the terminals B and C are closed, and the current i flows from the power source 6 through the load resistor 7 as shown in FIG.
, And the indicator lamps and relays are activated. Further, when the object W to be detected is separated from the sensor 3, the detection signal S1 is not output from the sensor 3, the operation signal S2 from the operational amplifier 4 is also stopped, and the terminals B and C are closed to generate the current i. It becomes zero, and it is detected that the detected object W does not exist.

(Problems to be Solved by the Invention) However, even when the conventional detection switch 12 is in the closed state as a result of the normal operation of the switching element 5, there is a short circuit between the terminals B and C due to a failure. , For example, when the external wiring l connected to the terminals B and C is in a short-circuited state, or the component inside the detection switch 12 has a failure,
For example, when the switching element 5 burns out, the terminals B and C are
Even in the short-circuited state, the current i flows in the same manner as shown in FIG. 11, so that the difference between the two, that is, whether the detection switch 12 is normally operated or short-circuited due to the failure is distinguished. I can't. Similarly, when the switching element 5 is in an open state as a result of normal operation, when there is a non-conduction state between the terminals B and C due to a failure, for example, when the wiring 1 is in a disconnection state, or the detection switch 12 Even when the terminals B and C are in an open state due to a failure of an internal component, for example, the wiring of the switching element 5 is burnt out, the current i becomes zero as shown in FIG. It is not possible to distinguish whether the normal operation was performed or the open state was caused by a failure. As a result, in order to confirm whether the detection switch 12 is normal or abnormal, regarding the output state of the detection switch 12 under both operating conditions of the closed state and the open state, Not only is there a problem of having to go through the troublesome and complicated procedure of making a confirmation, but it is difficult for a mechanical device that uses a detection switch to confirm whether it is normal during operation. was there.

Configuration of the Invention (Means for Solving the Problems) In order to solve the above problems, the present invention provides a sensor for detecting an object to be detected, and an opening / closing signal output which is closed or opened by a detection signal from the sensor. Means and failure diagnosis signal applying means for applying a failure diagnosis signal to the detection signal output from the sensor to the opening and closing signal output means, the failure diagnosis signal applying means, from the sensor to the opening and closing signal output means A forced closing switch for forcibly and periodically applying a closing signal to the detection signal when the detecting means to be output is in an open state, and forcibly and periodically applying an opening signal to the detection signal when the detection signal is in a closed state. And a forced opening / closing operation control device that operates both of the switches.

(Operation) The present invention operates as follows by adopting the above means.

When the detection signal output from the sensor is forcibly and periodically closed in the open state, and when the detection signal is in the closed state, the open signal is periodically provided as the failure diagnosis signal.
The failure diagnosing device promptly and reliably determines whether the failure is inside the detection switch or the wiring outside the detection switch.

(Embodiment) An embodiment embodied as a case-integrated detection switch of the present invention will be described below with reference to FIGS. 1 to 3. In the detection switch 1 of this embodiment, members having the same functions as those of the conventional detection switch 12 described above are designated by the same reference numerals, and the description of the configuration will be omitted.

The sensor 3 is connected in parallel with a forced opening / closing operation control device 9 composed of an oscillator. Further, a forced opening switch 1 is provided between the output terminal E of the sensor 3 and the positive power source terminal A.
0 is connected so that the opening operation is performed by the operation signal S3 from the forced opening / closing operation control device 9. Similarly, the output terminal E of the sensor 3 and the negative power supply terminal C
A forcible closing switch 11 is connected between the and, and a closing operation is performed by an operation signal S4 from the forcible opening / closing operation control device 9.

In the use state (see the chain line in FIG. 1), when the detection signal S1 and the operation signal S2 of the detection switch 1 are in the closed state, that is, as shown in FIG. 2, they flow between the terminals B and C of the detection switch 1. When a current (hereinafter referred to as the output signal S of the detection switch 1) is flowing by a predetermined value i, the forced opening switch 10 is opened by the operation signal S3 from the forced opening / closing operation control device 9 to forcefully and By periodically providing the open signal S5 as the fault diagnosis signal for a short time (for example, 1 msec or less) to the detection signal S1,
The open signal S5 is added to the subsequent operation signal S2 and output signal S.

On the contrary, when the output signal S is in the open state, that is, when the current is zero as shown in FIG. 3, the operation signal S4 from the forcible opening / closing operation control device 9 operates the forcible closing switch 11 to forcibly And periodically for a short time (for example, 1 ms)
The closing signal S6 as a failure diagnosis signal (e.c. or less) is given to the detection signal S1, and the closing signal S6 is given to the subsequent operation signal S2 and output signal S. Note that the forced opening / closing operation is performed by a control device (not shown) such as a relay or a programmable controller having a response of several msec if it is operated for a short time within a range that can be discriminated from the normal output signal S of the switch as described above. It has no effect when used.

Further, the operation of applying the failure diagnosis signals S5 and S6 can be performed arbitrarily or independently periodically by applying a control signal to the forced opening / closing operation control signal 9 from the outside.

In this embodiment, the forced opening / closing operation control device 9, the forced opening switch 10 and the forced closing switch 11 constitute a failure diagnosis signal giving means. Further, the operational amplifier 4 and the output switching element 5 constitute an opening / closing signal output means that is closed or opened by the detection signal S1 from the sensor 3.

Next, the fault diagnosis device 13 for diagnosing the fault of the detection switch 1 will be described with reference to FIG.

In the case 14 of the failure diagnosis device 13, the output signals S to be output from the above-described plurality of detection switches 1 to 1 respectively.
A plurality of input terminals 15a to 15n for inputting S are provided.

On the other hand, at the input terminals 15a to 15n, edge detection circuits 16a to 16 for detecting whether or not the failure diagnosis signals S5 and S6 are present in the output signals S to S, respectively.
n are connected. Further, the edge detection circuits 16a-
16n outputs a low voltage when an edge is detected in the closed state or the open state, and when the edge is not detected,
Retriggerable one-shot multivibrators 17a to 17n for outputting a high voltage are connected in series. Further, the retriggerable one-shot multivibrators 17a to 17n include light emitting diodes 18a to 1n.
When 8n is connected and the detection switches 1 to 1 are normal, that is, when an edge is detected, the switch is turned on and turned on, and when no edge is detected, it is turned off.

On the other hand, each of the one-shot vibrators 17a to 17n
Outputs a signal capable of determining the presence or absence of a failure for each failure diagnosis device 13, that is, outputs a high voltage when an edge is detected,
When the edge is not detected, the gate circuit 20 for outputting the low voltage is connected, and the output terminal 21 thereof is provided in the case 14.

Then, the failure diagnosis device 13 detects the detection switches 1 to
The presence or absence of the open signal S5 or the closed signal S6 included in the output signal S of 1 is determined and displayed. That is, the output signal S
If any one of the signals S5 and S6 is present, the edge detection circuits 16a to 16n and the Worsted multivibrator 17a to 17n diagnose that the detection switch 1 is operating normally, and within a certain time, the signal S5 is detected. ，
If S6 does not exist, it is diagnosed that the detection switch 1 is abnormal, and the diagnosis result is the light emitting diodes 18a-18
It is indicated by n and is input to the external control device from the output terminals 19a to 19n.

Further, the output signal S is applied to the force terminals 15a to 15n.
~ Digital or analog filter circuit 22a for removing the open signal S5 or the closed signal S6 in
22n are connected to the filter circuits 22a to 22n.
The output signal S that has passed through the
3n is output to the external control device.

In the embodiment of the present invention, the forced open switch 10 and the forced close switch 11 are provided in the path from the sensor 3 to the operational amplifier 4,
When this is controlled by the control opening / closing operation control device 9 and the detection signal S1 is in the closed state, a short-time open signal S5 is given at a predetermined cycle, and when the detection signal S1 is in the open state, the close signal is given. Since S6 is added, the failure diagnosis device 13
Thus, a failure of the detection switch 1 itself and a failure based on an external factor such as a short circuit or a disconnection of the wiring l connecting the detection switch 1 and the control device can be easily and easily determined.

The above embodiment can be modified as follows.

(1) As shown in FIG. 5, a failure diagnosis pulse generator 25 as a failure diagnosis signal providing means and a pulse coincidence detection circuit 26 are housed in a case 27, and a failure diagnosis is made from an output terminal 28 to a detection switch 29. The pulse signal S7 is output, and the output signal S provided with the open signal S5 or the close signal S6 by the forced open switch 10 or the forced close switch 11 in the detection switch 29 is input to the input terminal 30. Provide a terminal 31 for inputting the command signal S8 and a terminal 32 for outputting the failure diagnosis signal S9.

In this embodiment, the original detection switch 29 and the failure diagnosis signal providing means are separately provided, but in this case as well, the failure of the detection switch 29 itself and the failure due to an external factor can be discriminated.

(2) As shown in FIG. 6, in addition to the embodiment shown in FIG. 5 described above, a failure diagnosis pulse cancel circuit 33 is built-in, and an output terminal 34 outputs an output without the closed signal S6 or the open signal S5. It must be configured so that the signal S can be taken out.

In the case of this embodiment, the forced opening / closing operation does not appear in the output signal S of the failure diagnosis device, and the output of the detection switch 29 is not delayed.

(3) As shown in FIG. 7, the magnetic detection switch 35 and the compulsory switching magnetic field generator 3 as the failure diagnosis signal giving means 3
It is also possible to separate 6 and. That is, the case 37
A magnetic sensor 39 is provided for the sensor main substrate 38 inside, and a magnetism generating coil 41 is built in the other case 40 so as to give an open signal or a closed signal to the signal output from the magnetic sensor 39. . In this another example, the function of the detection switch 35 after the sensor 3 and the abnormality of the wiring can be diagnosed.

(4) As shown in FIG. 8, to use the input unit 42 with a failure diagnosis function for inputting the output signal S output from the detection switches 1 to 1 and inputting it to the control device (not shown). . Explaining the input unit 42, the case 43 is provided with input terminals 44a to 44n for inputting the output signals S of the detection switches 1 to 1, and an insulating circuit 45 for extracting only a signal is connected to each of the input terminals. There is. Further, a filter circuit 46 and an edge detection circuit 47 are connected in parallel with each other to the insulating circuit 45, and a display circuit 48 for displaying an open state or a closed state is further connected.

A data selection circuit 49 is connected to the filter circuit 46, an address decoder 50 is connected to the selection circuit 49, and is connected to a mother board connector 51. From this connector 51 to a control device (not shown), the detection switches 1 to 1 are connected.
The signal S from 1 is input without the open signal S5 or the closed signal S6.

A retriggerable one-shot multivibrator 52 is connected to the edge detection circuit 47, a data selection circuit 53 is connected to the multivibrator 52, and is connected to a mother board connector 51 via a data bus buffer 54. Further, a gate circuit 55 is connected to the retriggerable one-shot multivibrator 52, and a signal for discriminating normality / abnormality of the detection switch 1 for each input unit 42 is output to the connector 51.

In this another embodiment, the input unit 42 with a failure diagnosis function is used.
The wiring from the control device to the control device can be omitted.

Effect of the Invention As described in detail above, according to the present invention, it is possible to reliably and quickly discriminate between a failure inside the detection switch and a failure such as wiring outside the detection switch by the failure diagnosis device while the detection switch is in use. There is an effect that can be.

Furthermore, by shortening the change time of the output for detecting the failure, there is an effect that the relay and the programmable controller, which are conventional control devices, can be directly connected.

Even in a complicated control device, the failure location can be easily identified by the detection switch, and since the detection switch can easily notify the control device side of the failure content, secondary damage due to switch failure can be prevented, Moreover, there is an effect that the efficiency of the maintenance work can be realized.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing an embodiment of the present invention, FIGS. 2 and 3 are graphs showing output signals of a detection switch in a closed state and an open state, and FIG. 4 is a failure diagnosis of the detection switch. FIG. 5 is a block circuit diagram showing an apparatus, FIG. 5 is a block circuit diagram showing another example of the present invention, FIG. 7 is a sectional view showing another example of the present invention, and FIG. FIG. 9 is a circuit diagram showing the unit, FIG. 9 is a circuit diagram showing a conventional detection switch, FIG. 10 is a circuit diagram showing the usage state of the detection switch, and FIG. 11 is a graph explaining the operation of the detection switch. Detection switch 1, switch case 2, sensor 3, operational amplifier 4, output switching element 5, DC power supply 6, load resistor 7, forced opening / closing operation control device 9 constituting a failure diagnosis signal providing means, forced open switch 10, forced Close switch 1
1. Fault diagnostic pulse generator 25 as fault diagnostic signal providing means, detection switch 29, magnetic detection switch 3
5, forced switching magnetic field generator 36, detection signal S1, power supply terminals A, C, signal output terminal B, operation signals S2, S3, S
4, a current i as an output signal S, an open signal S5 as a failure diagnosis signal, a closed signal S6, and a failure diagnosis pulse signal S7.

Claims (3)

[Claims] 1. A sensor for detecting an object to be detected, an opening / closing signal output means for closing or opening according to a detection signal from the sensor, and a failure diagnosis for a detection signal output from the sensor to the opening / closing signal output means. And a failure diagnosis signal applying means for applying a detection signal, wherein the failure diagnosis signal applying means forcibly and periodically converts the detection signal output from the sensor to the open / close signal output means into a detection signal in an open state. A forced closing switch for giving a closing signal, a forced opening switch for forcibly and periodically giving an opening signal to the detection signal when the detection signal is in a closed state, and a forced opening / closing operation control device for operating both switches. Configured detection switch structure. 2. The detection switch structure according to claim 1, wherein the forced opening / closing operation control device is an oscillator. 3. The detection switch structure according to claim 1, wherein the sensor, the opening / closing signal output means, and the failure diagnosis signal giving means are integrally housed in a switch case.