JPS5961226A - Device for discriminating fault of optical switch - Google Patents

Abstract

PURPOSE:To prevent an object to be controlled from runaway in an optical switch circuit accomodated in a radio operation device by detecting outputs from photodetectors when light emitting elements are made non-emitting status to discriminate whether the poststage circuit is defective or not. CONSTITUTION:The light emitting elements 5a-5n in optical switches 5a-5n are intermittently emitted, and when the light emitting elements 5a-5n are not emitted or are not sufficiently emitted, the outputs of the photodetectors 9a- 9n corresponding to the light emitting elements are detected. In accordance with the level of the outputs, H level or not, the titled device discriminates whether the fault is generated in the optical switches or the poststage circuit to detect the faults of the optical switches. Even if a fault is generated in an element constituting the optical switch, the object to be controlled, a large-sized machine or the like, can be prevented from runaway.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a failure determination device for an optical switch having a light emitting element and a light receiving element. The present invention relates to a failure determination device for an optical switch that detects an output and determines whether or not a light receiving element and a subsequent circuit connected to the light receiving element have failed based on the detection result.

As is well known, a portable radio control device for remotely controlling large-scale equipment such as a ceiling crane uses an optical switch to detect the angle of a control lever provided on the housing of the radio control device. The signal obtained by this is output.

FIG. 1 is a circuit diagram showing an example of the configuration of an optical switch circuit provided in such a radio control device.

As shown in this figure, when an operating lever (not shown) is operated, the optical sight plate 1 moves accordingly, and the optical switches 23 to 211 corresponding to the angle of this operating lever are turned on (this on state is This refers to the state in which the receiving element receives light. As a result, the optical switch 7 turns on, and a q'' level signal indicating this on state is outputted from the optical switch 7 and supplied to the tristate buffer 3, where it is supplied to the microcomputer 4 with timing. The microcomputer 4 determines the operation content of the control panel based on this -L'' level signal, and remotely controls a large device (not shown) in accordance with the result of this determination.

By the way, such an optical switch circuit is shown in Figure 2 (a).
As shown in the figure, since each of the light emitting elements of optical suites 28 to 2n is constantly emitting light, it is possible that for some reason these light emitting elements and the corresponding light receiving elements break down and these light receiving elements become short-circuited at time to. As shown in the same figure (b), the output terminal voltage of these photodetectors becomes −
When the microcomputer 4 outputs the read pulse Pt (see the same figure)
As shown in FIG. 2, the microcomputer 4 reads the state of the optical switch, and as a result, the large device starts controlling itself, posing the risk of causing the large device to run out of control.

In view of the above points, the present invention provides a failure determination device for an optical switch that can prevent a controlled object such as a large device from running out of control even if a ticket forming the optical switch fails. Check whether the output of the light receiving element corresponding to the light emitting element is at -H'' level when the light emitting element of the optical switch is caused to emit light intermittently, and the light emitting element is not emitting light or is not emitting sufficient light yet. This feature is characterized in that a failure of the optical switch is detected by detecting whether or not the optical switch is present.

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 3 is a circuit diagram showing one configuration of the original switch failure determination device according to the present invention. In this design, the optical switch 2a is for detecting the operating angle of an operating lever (not shown). A"y 1 f17'J is connected to the control terminal 4a, and its anode is connected to the power supply input terminal 8 via the resistor 7a, and the emitter of the phototransistor 9a constituting the reed switch 2a is grounded, and The collector is connected to the power supply input terminal 8 via a resistor 10a, and is also connected to the data terminal a1 of the tri-state buffer 3.The other optical switches 2i) to 2n are also connected to the optical switch 2a described above. The terminals 2b] to 20-1 of these optical switches 2b to 2n are connected to the first control terminal of the microcomputer 4 via the inverter 6, and the terminals 2b-2 to 2n-2+2b are similarly configured. 3-2
1s are the corresponding resistances '7b to 7n, respectively.

101] to 10n, and the output terminals 2b-4 to 2n-4 of the optical switches 2b to 2n are connected to the data terminals b1 to nl of the tristate buffer 3, respectively. ing.

In addition, the drifting plate 1 that controls these optical switches 23 to 211 is provided with a cutout at one place, and when the operating lever is moved, these optical switches 28 to 211 are controlled according to the angle of this operating lever. From any one of them -L
The tri-state buffer 3, from which a level signal is output and supplied to the tri-state buffer 3, is for connecting the optical switches 28 to 2n and the microcomputer 4. 3a is connected to the second control terminal 4b of the microcomputer 4, and each data terminal a2 to n2 is connected to each data terminal a to n of the microcomputer 4.The microcomputer 4 is connected to each part of the device. Each part of the device is controlled according to the outputs of the provided switches, sensors, etc. and a preset program, and the signals obtained thereby are wirelessly transmitted to a large-sized device to control it.

Next, the actual operation of the above-described structure will be explained with reference to the timing diagram shown in FIG.

First, when the microcomputer 4 outputs a ridge signal from the first suppressing terminal 4a at time tl (see FIG. 4 (a))
At this time, the light emitting diodes 56 to 5n of all the optical switches 23 to 2n are turned off. Next, at time t2, when a sufficient period of time has elapsed from time t1, the microcomputer 4 outputs a read pulse P+ (see figure m4 (b)) from its second control terminal 4b to open the tri-state Haranoa 3. Each optical swing f2a~2n (7) Reads the appearance. At this point, any one of the optical switches 93 to 9n constituting the optical switches f2a to 2n is short-circuited, and the output terminal voltage is 11 as shown in FIG. 4 (/9). The microcomputer 4 determines that the original switch that outputs this %L" level signal is malfunctioning, operates an alarm circuit (not shown), notifies the operator of this, and The subsequent reading operation is prohibited.This allows the phototransistors 9a to 9a to
This prevents large equipment from running out of control due to a short circuit of 9n. Furthermore, in the above-described operation, the optical switch 2a
~2n are all normal, and the microcomputer 4 has all bits 1)H〃 as shown in Figure 4)! If VH is being supplied, the microcomputer 4 determines that all of these original switches 2a to 2n are normal and executes the next reading Stella f"f. This reading Stella f will be explained below. First, In this reading step, at time t3, the microcomputer 4 outputs a tt HIf level signal from the first suppressing terminal 4a (see (a) in the figure) and lights up all the light emitting diodes 5a to 5n. At time t4, when a sufficient period of time has elapsed from time L3, the tristate buffer 3 is opened and the outputs of the original switches 2a to 2n are read. As shown in FIG. 4 Qυ, bit i of b shift
If it is at the E'L' level, the microcomputer 4 detects this and controls the large equipment according to this bit/turn (this control is, for example, travel start control, etc.). In addition, in this case, the light emitting diode of the optical switch that should be in the on state does not light up.
The photodiode corresponding to this light emitting diode may be in an open state, or an all-out state as shown in Figure 4 (e).
1] is detected, the microcomputer 4 determines that at least one of the optical switches 2a to 2n is out of order and prohibits subsequent processing. For this,
It is possible to prevent control errors caused by opening of the phototransistors 9a to 9n and opening of the light emitting diodes 53 to 5n.

FIG. 5 is a timing diagram for explaining another embodiment of the optical switch failure determination device according to the present invention. Although not shown, the circuit in this embodiment is also the same as that in the embodiment described above.

The difference between the embodiment shown in this figure and the embodiments shown in Figs. 3 and 4 is that the read signal P3 is output immediately after the lighting of each light emitting diode (see Fig. 5 (a)) is started. (See FIG. 5(b)) The first reading is performed, and the second reading is performed after a sufficient period of time has elapsed. Even if this is done, the output patterns of the light emitting diodes and phototransistors will be as shown in Figures 5(c) and 5(b), respectively.
If these are normal, all bows will be ready at the first reading.
is detected, and at the second read, a signal is output in which only one bit indicating the position of the operating lever is 1 or #, and all other bits are 1H. If so, either a signal in which any bit of Cτ is low is detected during the first read, or all -1 (〃) is detected during the second read. A failure of the optical switch can be detected based on the detection result.

Furthermore, in each of the embodiments described above, it is determined whether or not the optical switches 2a to 2n are out of order depending on the results of the first and second reading operations. In order to avoid serious control errors such as the above, these large devices may be directly controlled using the data obtained by the second reading operation. As a result, it is possible to determine the failure of an optical switch for which the bit number obtained at the second read time t is not known.As explained above, the optical switch failure determination device according to the present invention A drive circuit that causes a light emitting element of the switch to emit light intermittently; a signal acquisition circuit that receives the output of a light receiving element corresponding to the light emitting element at least when the light emission intensity of the light emitting element is below a predetermined level; and this signal acquisition circuit. Since a determination circuit is provided to determine whether or not the optical switch is malfunctioning based on the output of It is possible to prevent the controlled object from running out of control, such as the above, and to ensure greater safety.

[Brief explanation of drawings]

FIG. 1 is a circuit diagram showing an example of the configuration of a general optical switch circuit, FIG. 2 is a timing diagram for explaining FIG. 1, and FIG. 3 is a configuration of an optical switch failure determination device according to the present invention. FIG. 6 is a circuit diagram showing an example, and an optical timing diagram illustrating another embodiment of the first ゜/'/. l...Light shielding plate, 23~2n...Light switch, 3...
・Tri-state buffer (signal reading circuit), 4...
Microcomputer (discrimination circuit), 53-5n...
Light emitting diode (light emitting element), 93-9n... phototransistor (light receiving element). Patent applicant Norimitsu Nishimura, patent attorney representing Anritsu Electric Co., Ltd.

Claims (1)

[Claims] Determines the failure of an optical switch that includes a light-emitting element and a light-receiving element that receives light from the light-emitting element, and switches the output by controlling light between the light-emitting element and the light-receiving element. The failure determination device includes a drive circuit that causes the light emitting element to emit light intermittently, a signal acquisition circuit that takes in the output of the light receiving element, and a failure determination device that determines whether at least the light emitting element is in a predetermined state based on the output of the signal acquisition circuit. Is the light switch malfunctioning when the light emission intensity is below? 1. A failure determination device for an optical switch, comprising a determination circuit for determining a failure.