JP3160911B2 - Switch device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a switch device used for detecting an object such as a limit switch.

[0002]

2. Description of the Related Art For example, in the case of a limit switch, poor return of an operating body lever that comes into contact with an object occurs, or water intrudes into the limit switch and the circuit portion is insulated. If this happens, the switch will be in a so-called failure state, and a normal switch signal will not be obtained.

[0003] Therefore, a failure detection mechanism is provided in the limit switch so that those signals are separately taken out and an alarm is issued by an alarm device.

[0004]

Therefore, in the conventional switch device, it is necessary to wire each of the failure detection signal lines to the switch device in addition to the switch output signal line, which complicates the wiring structure and makes the wiring work very difficult. There was a problem that took time.

The present invention has been made in view of such circumstances, and an object of the present invention is to provide a switch device in which a switch output signal and a failure detection signal can be extracted by the same signal line and wiring can be easily performed. And

[0006]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides an operation body for operating a switch device by contact with an object, and an operation detection means for detecting an operation amount of the operation body. A switch signal output unit for outputting a switch signal based on an operation amount detection signal from the operation detection unit; a failure signal output unit for diagnosing a failure of the switch and outputting a failure signal; and the switch signal and the failure signal. , An analog signal output means for outputting an analog signal having an output level corresponding to each signal.

[0007]

According to this configuration, an analog signal having an output level corresponding to the switch signal and the failure signal is output.

[0008]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a block circuit diagram of a switch device according to the present invention. The switch device S includes an operation body 1 that operates by contact with an object, and an operation detection unit 2 that detects an operation amount of the operation body 1. A switch circuit 4 serving as a switch signal output unit for outputting a switch signal based on an operation amount detection signal from the operation detection unit 2;
Diagnostic circuits 6a and 6b as failure signal output means for diagnosing a failure based on the detection signals from the respective detection units 2 and 5 and outputting a failure signal; and the switch circuit 4 and the diagnostic circuits 6a and 6b, respectively. An output circuit 8 as an analog signal output means for outputting an analog signal having an output level corresponding to each signal based on the switch signal and the failure signal, and a power supply circuit 10.

Reference numeral 12 denotes a circuit for determining the analog signal output from the output circuit 8 of the switch device S. Reference numeral 14 denotes a determination circuit 12
This is a control device that outputs a switch signal and a failure signal to a device to be controlled based on a determination signal from the controller.

The operation detecting section 2 is composed of a light reflection sensor, a potentiometer, and the like, and outputs a current signal or a resistance value signal as an operation amount detection signal in accordance with a displacement of an operation mechanism inside a switch that is interlocked with the operation body 1, The water detection unit 5 is constituted by a pair of electrode plates which are relatively arranged below the inside of the switch, and outputs a water detection signal when water enters the inside of the switch and conducts between the respective electrodes.

Next, the output operation of the analog signal of the switch device S will be described with reference to FIG.

When the operating body 1 operates normally and water does not enter the switch device S, and when the operating body 1 is stopped at the initial position, the output circuit 8 outputs the current consumed in the circuit. For example, 5 mA is output as an analog signal. When the operation body 1 operates and the operation amount detection signal from the operation detection section 1 reaches the set level, the switch circuit 4
Is a switch signal, and a voltage signal (ON) is output.
FIG. 2 shows the internal configuration of the output circuit 8. When a voltage signal is applied to the transistor 20a, a current of, for example, 8 mA flows, thereby outputting an analog signal of 13 mA in total.

On the other hand, if the operating body 1 is malfunctioning, and if the operating body 1 does not completely return to the initial position or goes too far, a failure signal is output from the diagnostic circuit 6a. Similar to the transistor 20a, a current of 4 mA flows through the transistor 20b. Therefore, when a failure due to malfunction occurs, the operating body 1
Is not completely returned to the initial position, a total of 9 mA is output.

If there is a detection signal from the water detector 5, a failure signal is output from the diagnostic circuit 6b. In this case, the transistor 20c conducts 2 mA. Currents of 7 mA and 15 mA are output with the operation of the operating body 1, and 11 mA and 19 mA when the operating body 1 has a malfunction,
Is output.

As described above, from the output circuit 8, the operation of the operating body 1 is associated with the malfunction of the operating body 1 and the failure of water intrusion. , 17,
An analog signal including eight output levels of 19 mA is output, that is, the output of the switch output signal and the output of the failure detection signal are provided by one line (actual wiring requires a power supply line and becomes two lines). It becomes possible.

The discriminating circuit 12 to which the switch device S is connected discriminates whether or not the analog signal is in each set area as shown in FIG. 3, and sends the discrimination signal to the control device 14 sequentially. . In the discriminating operation, when the signal of the output level in the water detection range, the failure prediction range, and the water detection failure prediction range between the normal OFF range and the normal ON range is obtained, the obtained time is compared with the set value. Then, the discrimination signal is output only when the set value is reached, whereby the failure signal is not output when the output value merely passes the level with the operation of the operating body 1. ing. In the determination circuit 12, when the output current is 4 mA or less, disconnection of the circuit in the switch device S, 2
When the current is 0 mA or more, a determination signal indicating that the circuit in the switch device S is short-circuited is output. Then, the control device 14 appropriately outputs a switch output signal and a failure detection signal in response to the given determination signal, whereby the operation of the control target device is performed and a failure alarm is issued.

The output level of the analog signal from the switch device S may be set as appropriate. Correspondingly, as shown in FIG. 4, for example, as shown in FIG. What is necessary is just to set suitably.

FIG. 5 is a wiring diagram when a plurality of switch devices S are used. In this example, a communication circuit 30 is used between the plurality of discriminating circuits 12 and the control device 14 so that the discriminating circuit 12 and the control device 14 are used. The configuration can be simplified by one line of wiring.

[0019]

As described above, according to the present invention,
An analog signal having an output level corresponding to the switch signal and the fault signal is output, whereby the switch output signal and the fault detection signal can be extracted by the same signal line, and a switch device capable of simplifying wiring can be provided. can get.

[Brief description of the drawings]

FIG. 1 is a block circuit diagram of the present invention.

FIG. 2 is a circuit diagram of the output circuit shown in FIG.

FIG. 3 is a correlation diagram between an output current and an operation amount of an operation body.

FIG. 4 is a correlation diagram of another embodiment between an output current and an operation amount of an operation body.

FIG. 5 is a wiring diagram when a plurality of switch devices are used.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Operating body 2 Operation detection part (operation detection means) 4 Switch circuit (switch signal output means) 6 Diagnostic circuit (fault signal output means) 8 Output circuit (analog signal output means)

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H01H 21/28 H01H 9/00

Claims (1)

(57) [Claims] An actuating body (1) which is activated by contact with an object, an operation detecting means (2) for detecting an actuating amount of the operating body (1), and an actuating amount from the operation detecting means (2). Switch signal output means (4) for outputting a switch signal based on the detection signal; failure signal output means (6a) (6b) for diagnosing a failure of the switch and outputting a failure signal; , An analog signal output means (8) for outputting an analog signal having an output level corresponding to each signal.