JPH01295522A - Optical fiber for solid-state relay - Google Patents

Abstract

PURPOSE:To suppress noise and surge caused at load switching and to prevent malfunction by arranging a light emitting element and a photodetector separately in a solid-state relay of zero cross type and coupling optically both by an optical fiber. CONSTITUTION:In case of direct mount of a solid-state device 13 to load devices 11, 12, the solid-state device 13 of an output circuit section B is arranged very nearly to the load devices 11, 12 causing excess noise and surge and a power line 19a. Since the light emitting element 16 of an input circuit section A is provided remotely by using an optical fiber 17, the sneaked noise from a noise generating source is prevented to prevent the occurrence of malfunction of a low voltage control circuit 20. Furthermore, a zero cross circuit 14 is provided to the output circuit section B and the load switching is implemented near zero phase. Thus, noise and surge caused in load switching are suppressed in advance and noise and surge withstanding characteristic is improved more.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a solid state relay, more specifically, an optical fiber type solid state relay (hereinafter referred to as SSR) that can perform remote operation between an input and an output using an optical fiber.
Regarding.

[Conventional technology]

Conventionally, this type of SSR, as shown in FIG. 3, has an input circuit section consisting of a photocoupler light emitting diode 2 which is a light emitting element that operates at a low DC voltage, and a photocoupler which is a light receiving element driven by the optical output of the light emitting diode 2. It consists of an output circuit section consisting of a try book 5 of an output semiconductor switching element which is switched by the phototransistor 3 via a phototransistor 3 of a coupler and a zero cross circuit 4, and each circuit section is housed in one SSR 1. It is arranged. The appearance of SSR1 is based on, for example, Japanese Utility Model Publication No. 53-70356 (Fig. 1) and Japanese Utility Model Publication No. 57-70.
As disclosed in Japanese Patent No. 536 (FIG. 1), it is arranged in one housing.

[Problem to be solved by the invention]

The SSR1 explained in the conventional example has the advantage of being able to suppress the inrush current and back electromotive force that occur when switching the load because the zero-cross circuit 4 can switch the load near zero phase. The connection points between the two circuit sections are located in the same 5SRI housing, and are installed in a photocoupler, which is one electronic component, so the input and output circuit sections are very close together, and there is no electrical connection between the two. Even though the optical coupling is done so as not to be affected by external noise and surge, the noise and surge generated in the load device 7 and the power supply line 6a can be transmitted between the terminals of the photocoupler and the outer surface of the package, etc., and input. 5SR wraps around to the circuit side
If the low voltage control circuit 8 connected to the input of I malfunctions and the noise and surge are large, the 5SRI
There was also a problem that the device itself would malfunction.

The present invention has been made to address the above-mentioned problems and aims to provide an optical fiber type solid state relay that does not malfunction due to noise.

[Means to solve the problem]

In order to achieve the above object, the SSR of the present invention optically connects the isolated light emitting element and light receiving element with an optical fiber.

[Effect]

Since the output circuit section, which generates noise and surges when the load is switched on and off, is separated from the input circuit section using optical fibers, it is possible to prevent noise and surges from entering the input circuit section as much as possible.

〔Example〕

An embodiment of the present invention will be described below based on the drawings.

As shown in FIGS. 1 and 2, the solid state device 13, which is the output circuit section B, is connected to a light receiving element 15 such as a phototransistor driven by optical input and a zero cross circuit 14 for switching the load at zero cross phase. It consists of a triac 18 that is switched by the light receiving element 15. Reference numeral 11 denotes a load device (for example, a solenoid) that is opened and closed by the triac 18 and is connected in series to a power source 19 .

The light receiving element 15 is optically connected to one end of an optical fiber 17 that is not affected by electrical noise and surges,
The optical fiber 17 is extended by a required length, and a light emitting element 16 such as a light emitting diode of the input circuit section A is optically stably connected to the other end. 20 is a low voltage control circuit connected to the input circuit section, which controls the present SSR.

FIG. 2 shows the solid state device 13 as a load device II.
, 12 is shown. In this case, the solid state device 13 of the output circuit section B is installed very close to the load equipment 11, the workpiece 2, and the power line 19a that generate excessive noise or surges. However, since the light emitting element 16 side of the input circuit section A is provided far away by the optical fiber 17, it is possible to prevent noise from entering the noise source and prevent malfunction of the low voltage control circuit 20. As mentioned above, the zero cross circuit 14 is provided in the output circuit section B.
Since load switching is performed near zero phase, noise and surge generated during load switching can be suppressed as much as possible in advance, and noise resistance and surge characteristics can be further improved.

[Effects of the present invention]

As described above, the present invention deals with noise generated by load switching,
By isolating the input circuit section to which the low-voltage control circuit is connected from the output circuit section close to the surge source using optical fiber, it is possible to prevent noise and surges generated from loads, etc. from entering the input circuit section. Since the noise and surge during load switching can be suppressed as much as possible by the zero cross circuit provided in the section, it is possible to obtain an optical fiber type solid state relay with stable operation without -N malfunction.

[Brief explanation of the drawing]

1 and 2 each show an embodiment of the present invention, in which FIG. 1 is an internal circuit diagram, and FIG. 2 is a circuit diagram including a partially actual side view. 3 to 4 each show conventional examples,
FIG. 3 is an internal circuit diagram, and FIG. 4 is a circuit diagram including a partial side view of the actual structure. 15... Light receiving element, 16... Light emitting element, 17...
Optical fiber, I8...triac, A...input circuit section, B...output circuit section

Claims (1)

[Claims] 1) A zero-cross type solid state relay consisting of an input circuit section consisting of a light emitting element, etc., and an output circuit section consisting of a light receiving element that receives light from the light emitting element and drives a triac via a zero cross circuit, in which the light emitting element An optical fibre-type solid-state relay characterized by separately arranging a light-receiving element and a light-receiving element and optically coupling the two with an optical fiber.