JPS5931723B2 - input/output device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is a process control device that is installed to maintain insulation voltage between a controlled object and a control device and to prevent external noise when performing process control of power systems, industrial plants, etc. It relates to the input/output device of the device.

A conventional input/output device is configured as shown in FIG.

That is, when the contact point 11 indicating the state of the controlled object is closed, a current signal 1a is conducted from the power supply device 12 via the light emitting element 13, and the light emitting element 13 emits light due to the energy and emits a specific wavelength. . The phototransistor element 514 that receives this wavelength becomes conductive, and the state of the controlled object 11 is inputted thereto. In such an interface circuit, when checking whether the light emitting element 13 and the phototransistor element 14 are operating normally, 1.
0 The operation of the controlled object 11 itself must be performed.

However, in process control of power systems, industrial plants, etc., it has been practically impossible to operate actual equipment in an operating state. The present invention makes it possible to inspect between a light emitting element and a phototransistor element connected to a controlled object without operating an actual device in operation, regardless of the state of the controlled object. figure,
The purpose is to obtain an input/output device that can simulate a controlled object. A second embodiment of the present invention below 20
This will be explained with reference to the figures.

The input/output device shown in FIG. 2 constitutes a closed circuit in which a current signal 1a flows through a power supply device 12 and a light emitting element 13 in order to incorporate the state of the controlled object, and a specific wavelength is emitted depending on the presence or absence of the current signal 1a. It has a light emitting element 13 that emits light and a phototransistor element 14 that conducts conduction and non-conduction in response to the wavelength of the light. Furthermore, in addition to a switch 15 (hereinafter referred to as 5-switch) that simulates the state of the controlled object 11 and a switch 16 (hereinafter referred to as T-30 switch) that commands whether or not to perform inspection, the T-switch When the T switch becomes ``1'', the state of the 5-switch is output as is, and when the T switch becomes ``00'', the output maintains a high impedance state regardless of the state of the 5-switch. Switch element Example 35 Three-value state gate element 1
7. Table 1 shows the truth table of this ternary state gate element IT. Note that this three-value state gate element 17 is already commercially available as TC-5012P (manufactured by Toshiba), DM8O97 (manufactured by National Semiconductor), and the like.
18 is an external output circuit, and the phototransistor element 1
It may be constructed so that the electrical signal of No. 4 is directly taken out, or it may be constructed from a buffer amplifier circuit 19, an external relay circuit 20, a power supply 21, and an external output contact 22 as shown in FIG.

Next, the operation of the embodiment shown in FIG. 2 will be explained.

When the T-switch 16 is in the "O" state (indicating that no inspection is to be performed), the output of the ternary state gate element 17 is in a high impedance state, and the base potential of the phototransistor element 14 connected to the output is also low. In a high impedance state, the phototransistor element 14 becomes conductive when light of a specific wavelength is emitted, and becomes non-conductive when light of a specific wavelength is not emitted. In such a state, if the controlled object 11 is in a closed (or open) state, the power supply device 12
Since the current signal 1a flows (or does not flow) through the light emitting element 13, the light emitting element 13 emits light (or does not emit light).

When the light emitting element 13 emits light due to the flow of the current signal 1a and emits light of a specific wavelength, the phototransistor element 14 that receives the wavelength becomes conductive. In this way, the state of the controlled object 11 is expressed as the output of the phototransistor element 14.

Next, when the T-switch 16 is in the "1" state (indicating that inspection is to be performed), the output of the ternary state gate element 17 is the S-
The input state of the switch 15 is varied to control the base potential of the phototransistor element 14. S-switch 15 is set to T
If ``, then the output of the three-value state gate element 17 also becomes ``r,'' and the phototransistor element 14 becomes conductive.In this way, the operation can be performed as if the controlled object had become 6r.Next, If the S-switch 15 is "0", the output of the ternary state gate element 17 is also "0", and the phototransistor element 14 becomes non-conductive.

In this way, the controlled object 11 can be made to perform an operation as if it had become "0".
4 can be confirmed by the presence or absence of the output voltage of the transistor element or by the operation of the external output contact 22.

In the above explanation, the signal connected to the base circuit of the phototransistor 14 was explained as the output of the three-value state gate 17, but any circuit can be used as long as the three-value state can be realized. For example, the T-switch 16 is in the "1" state. If so, it goes without saying that the same effect can be obtained even if the contacts are replaced with operating relay contacts.

Control equipment that performs process control such as power system and industrial plant control often uses semiconductor elements for monitoring the status of controlled objects and for output circuits. There is a growing demand for the use of coupling elements. The present invention makes it possible, in such an interface circuit between a controlled object and a control device, to cause a phenomenon in the operating state of the control device to occur as if the controlled object had been operated, thereby improving the control of the control device itself. In addition to checking the operation, it is also possible to diagnose the failure of the phototransistor element used as an interface circuit between the controlled object and the control device.

[Brief explanation of drawings]

FIG. 1 is a block diagram of a conventional control device, FIG. 2 is a block diagram of a control device using the present invention, and FIG. 3 is a diagram showing an example of an external output circuit. 11...Contact information indicating the state of the controlled object, 12
...Power supply device, 13... Light emitting element, 1
4...Phototransistor element, 15...
A switch that simulates the state of the controlled object, 16...
Switch 17 for specifying whether or not to perform inspection
...Three-state gate element.

Claims (1)

[Claims] 1. A switch part that responds to the state of a controlled object, a light emitting element that lights up when the switch part is in a closed state, a phototransistor element provided opposite to this light emitting element and having a base terminal, and an output of this phototransistor element. an external output circuit that takes out a signal, a simulating switch that simulates the state of the controlled object, an inspection command switch that instructs whether or not to inspect the phototransistor element, and when the inspection command switch is in a closed state, A switch configured to supply the output of the simulated switch to the base terminal of the phototransistor element, and to block the output of the simulated switch so as not to supply the base signal to the phototransistor when the inspection command switch is in an open state. An input/output device consisting of elements.