JPS6331303Y2 - - Google Patents

Description

[Detailed explanation of the idea]

This invention relates to a circuit that prevents malfunctions due to operation switch failure, which is effective for use in portable controllers used for radio control of transport machines. Conventionally, in portable controllers that wirelessly control transport equipment, if the operation switch malfunctions and the machine goes out of control (for example, if the machine runs at high speed when it should have been operated at low speed), a separate emergency controller is installed. The machine is stopped by pressing a button. This occurs when the operation switch (for high-speed operation) is short-circuited. However, when such a separate emergency button is provided, the driver's judgment is involved in its operation, which may delay the stopping operation and cause an accident. This idea was made in view of the above-mentioned circumstances, and if an unnecessary short-circuit failure of the operation switch occurs, it can be automatically detected and an emergency control signal can be generated to prevent malfunctions caused by the operation switch failure. The purpose is to provide circuits. An embodiment of this invention will be described below with reference to the drawings. The figure shows an embodiment of this invention, in which the plurality of operation switch means C1, C2,...CK,...CN each consist of two circuits, and the first and second switches A
1, B1, A2, B2,...AK, BK...AN, BN
has. Here, one first switch A1, A2,...AK,...AN in each operation switch means
The output contacts of are connected to the corresponding input terminals D1, D2,...DK,...DN of a control signal generator 16 which generates signals corresponding to each operating switch means. Further, the output contacts of the first and second switches A1 and B1 are connected to the first and second switches of the exclusive OR circuit E1, respectively.
It is connected to the second input terminal. Similarly, the first and second switches A2, B2...AK, BK...AN, BN in other operating switch means C2...CK...CN also correspond to the respective first and second switches of exclusive OR circuits E2...EK...EN,
It is connected to the second input terminal. First and second switches A1, B1, A2, B2...AK, BK...AN,
The other input side contact of the BN is connected to a common line 17 commonly connected to a power source or the like. The exclusive OR circuits E1, E2...EK...EN
The truth tables for are as shown below, and if either switch (first or second switch) is short-circuited, a logic output of 1 is derived.

[Table] Next, each exclusive OR circuit E1, E2...EK...
The output terminal of EN is connected in parallel to the OR circuit 11. Therefore, from the output terminal of this OR circuit 11, if any one of the exclusive logic circuits outputs "1", a logic "1" is output. The output terminal of the OR circuit 11 is connected to the input terminal of the integrating circuit 12. In this integration circuit 12, one operation switch means is operated for one operation, and in that case, the first and second
Since there is a time difference between both switches forming a closed circuit, this circuit compensates for the time difference. In other words, since the contact portions of the first and second switches are mechanically independent from each other, there is a time difference between the two contacts forming a closed circuit during operation, and this causes the output of the exclusive logic circuit to change. This circuit prevents the output from becoming 1, and thus the output of the OR circuit from becoming 1. The output terminal of the integrating circuit 12 is connected to the self-holding circuit 1.
Connected to the input terminal of 3. This self-holding circuit 13
is a circuit in which when the integrating circuit 12 outputs logic "1" even once, it self-holds as an abnormal state of the switch and uses this as a stop command. Self-holding circuit 13
The output terminal of is connected to the display drive circuit 14 and also to the stop command input terminal of the control signal generator 16. Therefore, when the self-holding circuit 13 enters the self-holding state and outputs an alarm signal, the display drive circuit 14 drives the display 15 to notify the driver. Further, the control signal generator 16 outputs, for example, an emergency stop signal of the machine with priority. In this case, instead of outputting an emergency stop signal, the command signal currently being input to the control signal generator from the operation switch means, that is, the command signal that is erroneous due to a switch failure or the control signal caused by it, is cut off. You can do it like this. This method is effective when it is preferable to continue the current operating state rather than stopping it. According to the malfunction prevention circuit of this invention constructed as described above, there is provided a two-circuit operation switch means that operates in response to one operation, and the output contacts of the first and second switches correspond to one operation. It is provided with a detection means for determining whether both are operating normally, and outputting an alarm signal if one is abnormal. Further, circuit means is provided to turn off the control signal corresponding to the operation in response to the alarm signal. As a result, switch failures are automatically detected and dangerous operational controls are prevented. As described above, this invention can automatically detect an unnecessary short-circuit accident of the operation switch and provide a malfunction prevention circuit that can generate an alarm signal when the operation switch malfunctions.

[Brief description of the drawings]

The figure is a configuration explanatory diagram showing an embodiment of this invention. C1~CN...operation switch means, A1~AN
...First switch, B1-BN...Second switch, E1-EN...Exclusive logic circuit, 11...
OR circuit, 12... Integrating circuit, 13... Self-holding circuit, 14... Display drive circuit, 15...
Display unit, 16...control signal generation circuit.

Claims (1)

[Scope of utility model registration request] An operating switch means having two circuits including first and second switches that operate in response to one operation, and each output contact of the first and second switches operating normally in response to one operation. detecting means for detecting whether or not the output contact is abnormal and outputting an alarm signal if one of the output contacts is abnormal;
What is claimed is: 1. A circuit for preventing malfunctions caused by a failure of an operating switch, characterized in that the circuit comprises at least circuit means for cutting off a control signal corresponding to an operation.