JPH11345052A - Signal input device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a signal input device capable of coping with any case of non-voltage input, DC voltage input or AC voltage input as an input signal without changing a circuit. SOLUTION: This device is provided with a power source circuit 25 for supplying a voltage to external contact points 31 and 32, a power source terminal 21 applied with voltage from the power source circuit 25, signal terminals 22, 23 and 24 for receiving the external contact point ON/OFF signals of the non-voltage input, the DC voltage input or the AC voltage input, etc., signal transmission means 28 and 29 for insulating and transmitting the ON/OFF signals to the digital signal processing circuit of a poststage depending on whether or not a current flows, a diode bridge circuit 26 provided with plural diodes 26a-26d connected so as to rectify and supply the AC input impressed to the signal terminals 22 and 24 to the signal transmission means 28 and a diode bridge circuit 27 provided with plural diodes 27a-27d connected so as to rectify and supply the AC input impressed to the signal terminals 23 and 24 to the signal transmission means 29.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a signal input device such as a control device or a monitoring device including a microcomputer.

[0002]

2. Description of the Related Art On / off signals inputted from external contacts to a signal input device of a control device such as a refrigerator and a monitoring device include:
There are types such as a non-voltage input, a voltage DC input, and a voltage AC input. Therefore, the conventional signal input device has an internal circuit corresponding to the type of input signal.

FIG. 3 shows an example of a conventional signal input device in which an on / off signal composed of a non-voltage input is input from two external contacts. The signal input device 10 includes a power supply circuit 4 for supplying a voltage to the external contacts 7 and 8, a power supply terminal 1 to which a voltage from the power supply circuit 4 is applied, and ON / OFF from the external contacts 7 and 8. Signal terminals 2 and 3 to which signals are input, and signal transmission means for insulating and transmitting on / off signals input to these signal terminals 2 and 3 to a subsequent digital signal processing circuit, that is, photocouplers 5 and 6 It has. In addition, 9 is a ground.

When the external contact 7 is turned on, current from the power supply circuit 4 flows through the photodiode 5a of the photocoupler 5 from the anode to the cathode via the power supply terminal 1, the external contact 7, and the signal terminal 2. After that, the photocoupler 5 is driven and then flows to the ground 9. Thus, the photocoupler 5
Operates to insulate and transmit that the input signal is on to the subsequent digital signal processing circuit.

Similarly, when the external contact 8 is turned on, a current from the power supply circuit 4 flows through the photodiode 6a of the photocoupler 6 from the anode to the cathode via the power supply terminal 1, the external contact 8, and the signal terminal 3. Then, after flowing the photocoupler 6, it flows to the ground 9. Thus, the photocoupler 6 operates to insulate that the input signal is on and transmit it to the subsequent digital signal processing circuit.

FIG. 4 shows an example of a conventional signal input device in which an on / off signal consisting of a voltage DC input is input from two external contacts. The signal input device 20 includes signal terminals 11, 12, 13 to which on / off signals composed of a voltage DC input from external contacts 18, 19 are input, and signal terminals 11, 12,
Signal transmission means, that is, photocouplers 14 and 15, which insulate and transmit the on / off signals input to the digital signal processing circuits 12 and 13 to the subsequent digital signal processing circuit, are provided. Here, 16 and 17 are external DC power supplies.

When the external contact 18 is turned on, the current from the external DC power supply 16 flows through the photodiode 14a of the photocoupler 14 via the signal terminal 11, and
3. It flows to the external DC power supply 16 via the external contact 18. Thus, the photocoupler 14 operates to insulate that the input signal is on and transmit it to the subsequent digital signal processing circuit.

Similarly, when the external contact 19 is turned on, the current from the external DC power supply 17 passes through the signal terminal 12 to the photocoupler 15.
After passing through the photodiode 15a, the current flows through the signal terminal 13 and the external contact 19 to the external DC power supply 17. Thus, the photocoupler 15 operates to insulate that the input signal is on and transmit it to the subsequent digital signal processing circuit.

[0009]

In the above-mentioned conventional signal input device, a different input signal device must be manufactured each time the type of input signal changes. In the monitoring device, the cost is increased and there is a possibility that an error occurs in the wiring work.

[0010]

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and its gist is to provide a power supply circuit for supplying a voltage to external contacts, A digital signal processing circuit at the subsequent stage depending on whether a current flows and a power supply terminal to which a voltage is applied, a signal terminal to which an external contact on / off signal such as a no-voltage input, a voltage DC input, and a voltage AC input is input and whether a current flows. A signal transmission unit that insulates and transmits an on / off signal to the signal transmission unit; and a diode bridge circuit including a plurality of diodes connected so as to rectify and apply an AC input applied to the signal terminal to the signal transmission unit. Provided in the signal input device.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention is shown in FIG. This signal input device 30 has two external contacts 3
An example is shown in which ON / OFF signals composed of no-voltage inputs are input from 1 and 32, respectively. The signal input device 30 includes a power supply circuit 25 for supplying a voltage to the external contacts 31 and 32, and a power supply circuit 25.
Power terminal 21 to which the voltage from
3, 24, and signal processing means that insulates and transmits an on / off signal to a subsequent digital signal processing circuit depending on whether or not current flows, that is, photocouplers 28 and 29, and diode bridge circuits 26 and 27. I have it. The external contact 31 is connected between the power supply terminal 21 and the signal terminal 22, and the external contact 32
Is connected between the power terminal 21 and the signal terminal 23, and the ground 33
Is connected to the signal terminal 24.

The diode bridge 26 has four diodes.
26a, 26b, 26c and 26d, and these diodes 26a
26d are connected so that when an AC input is applied between the signal terminal 22 and the signal terminal 24, it is rectified and applied to the photocoupler 28.

Similarly, the diode bridge 27 has four diodes 27a, 27b, 27c and 27d, which are connected to each other when an AC input is applied between the signal terminals 23 and 24. This is rectified and photocoupler 29
Connected to give to.

When the external contact 31 is turned on, the current from the power supply circuit 25 flows through the diode 26a of the diode bridge 26 from the anode to the cathode through the power supply terminal 21, the external contact 31, and the signal terminal 22. . Next, after flowing through the photodiode 28a of the photocoupler 28 from the anode to the cathode, the diode 26d of the diode bridge 26 flows from the anode to the cathode, and flows to the ground 33 via the signal terminal 24. Thus, the photocoupler 28 operates to insulate and transmit that the input signal is on to the subsequent digital signal processing circuit.

Similarly, when the external contact 32 is turned on, the current from the power supply circuit 25 is supplied to the power supply terminal 21, the external contact 32, and the signal terminal 2.
3, diode 27a of diode bridge 27, photodiode 29a of photocoupler 29, diode bridge 27
Through the diode 27d in this order and to the ground 33 via the signal terminal 24. Thus, the photocoupler 29 operates to insulate that the input signal is on and transmit it to the subsequent digital signal processing circuit.

A second embodiment of the present invention is shown in FIG. In the second embodiment, the external circuit is the first circuit shown in FIG.
Unlike the third embodiment, external contacts 34 and 35 for generating an on / off signal composed of a voltage input are used. The external contact 34 is connected between the signal terminal 22 and the signal terminal 24, and the external contact 35 is connected between the signal terminal 22 and the signal terminal 24.

When the DC voltage rises by turning on the external contact 34, this current is applied to the signal terminal 22, the diode 26a of the diode bridge 26, the photodiode 28a of the photocoupler 28, and the diode of the diode bridge 26.
26d, the signal flows through the signal terminal 24 in this order, and returns to the external contact 34.

Similarly, when the DC voltage rises when the external contact 35 is turned on, this current is applied to the signal terminal 23, the diode 27a of the diode bridge 27, the photocoupler 29.
Through the photodiode 29a, the diode 27d of the diode bridge 27, and the signal terminal 24 in this order to form an external contact 35.
Return to

When the AC voltage rises by turning on the external contacts 34 and 35, when the voltage is positive, a current flows through the same path as the DC voltage.

When the voltage is negative, the current generated from the external contact 34 is applied to the signal terminal 24 and the diode of the diode bridge 26.
26c, the photodiode 28a of the photocoupler 28, the diode 26b of the diode bridge 26, and the signal terminal 22 flow in this order, and return to the external contact 34.

Similarly, the negative voltage current generated from the external contact 35 is applied to the signal terminal 24 and the diode 27 of the diode bridge 27.
c, the diode 29a of the photocoupler 29, the diode 27b of the diode bridge 27, and the signal terminal 23 flow in this order, and return to the external contact 35.

In place of the photocouplers 28 and 29 of the above embodiments, any relay such as a relay can be used as long as it can insulate and transmit an on / off signal to a subsequent digital processing circuit depending on whether or not a current flows. Means can be used.

The signal terminals, signal transmission means and diode bridge circuits may be arranged according to the number of external contacts, that is, the number of input signals.

[0024]

According to the present invention, a common signal input device can be used regardless of whether the external contact on / off signal is a non-voltage input, a voltage DC input, or a voltage AC input. The simplification and common use of the signal input device can reduce the manufacturing cost of the control device and the monitoring device and the mistake of wiring work.

[Brief description of the drawings]

FIG. 1 is a circuit diagram showing a first embodiment of the present invention.

FIG. 2 is a circuit diagram showing a second embodiment of the present invention.

FIG. 3 is a circuit diagram of a conventional signal input device.

FIG. 4 is a circuit diagram of another conventional signal input device.

[Explanation of symbols]

 30 Signal input device 25 Power supply circuit 21 Power supply terminal 22, 23, 24 Signal terminal 28, 29 Signal transmission means 26, 27 Diode bridge circuit 31, 32 External contact 33 Earth

Claims (1)

[Claims] A power supply circuit for supplying a voltage to an external contact;
A power supply terminal to which a voltage from the power supply circuit is applied, a signal terminal to which an external contact on / off signal such as a no-voltage input, a voltage DC input, and a voltage AC input is input, and whether or not a current flows. A signal transmission unit that insulates and transmits an on / off signal to a digital signal processing circuit at a subsequent stage, and a plurality of diodes connected so as to rectify and apply an AC input applied to the signal terminal to the signal transmission unit. 1. A signal input device comprising: a diode bridge circuit.