Starting circuit and method for relay protection switching value output circuit

Abstract

The invention provides a starting circuit for a relay protection switching value output circuit. The starting circuit can reliably protect a relay protection device from sending outlet instructions by mistake. According to the technical scheme of the starting circuit, a GPIO pin of a processor and an IO pin of a programmable device are connected with an input pin of a single stable-state multivibrator, an output pin of the multivibrator controls on-off of an optocoupler, a relay is controlled to start and be locked through on-off of the optocoupler, and the relay starts and is locked to control a power supply of a switching value output relay. On the condition, switching value output instructions are sent out normally only when the processor is completely initialized and complete operation, the programmable device completes configuration completely, a system operates normally, and the power supply of the switching value output circuit is turned on. If processing failures, or operation system abnormality or programmable device failures occur, the power supply of the switching value output circuit is cut off, the protection device can not send out switching value output instructions, so that risks, of sending switching value output instructions by mistake, caused by failures of the relay protection device are reduced.

Description

technical field [0001] The invention relates to a starting circuit and a method for a switching value output circuit of relay protection, belonging to the field of industrial automation, especially the field of electric relay protection. Background technique [0002] In the field of relay protection, the automation device realizes the output of the switching value by driving the relay, and controls the operation of the controlled system by this. Especially after the relay protection has entered the era of microcomputer protection, the switch output of the relay output is basically realized by the IO pin of the microprocessor of the protection device, which is isolated by the optocoupler and driven by the switch output relay. However, the available IO resources of general microprocessors are relatively limited. In order to realize the input and output control of more switches, the usual method is to use programmable devices (such as FPGA, CPLD, etc.) to realize the expansion ...

AI Technical Summary

Problems solved by technology

However, in practical applications, since the microprocessor of the automation device generally runs the operating system and handles various complex algorithms

If the microprocessor does not handle the above-mentioned time beat and various pin control well, or the microprocessor is in the initialization state at the beginning of power-on, and the state of the pin controlling the start relay is in an uncertain state, it is likely to cause the start relay to start. This in turn causes the automation device to issue commands incorrectly

Therefore, there are certain risks and disadvantages in this commonly used starting circuit.

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