Input/output overcurrent and overvoltage protective module of microcomputer distributed control system

Abstract

The invention relates to an input/output overcurrent and overvoltage protective module of a microcomputer distributed control system, comprising a primary measurement equipment connecting end and a protected equipment fastener connecting end. A measurement signal working circuit is connected with a fuse tube F1; in the measurement signal working circuit, the positive half cycle of alternating current voltage passes through diodes D1 and D3 and the negative half cycle passes through diodes D2 and D4 to form a full-wave rectifier circuit, the rectified direct current voltage is sampled by a sampling diode W1 and enters a control electrode of a triode VT; and a collector electrode of the triode VT is respectively connected with the diodes D1 and D2, and an emitting electrode of the triode VTis respectively connected with the diodes D3 and D4. The input/output overcurrent and overvoltage protective module of the microcomputer distributed control system is protective equipment which is specially used for protecting various fasteners in a DSC measuring system from being damaged by overvoltage or overcurrent of alternation current or direct current. The protective module is applicable tovarious channels of 24VDC positive and negative logic circuits, is free from an additional power source and can be directly serially connected with a 24VDC circuit according to a positive electrode and a negative electrode. The invention can completely and effectively provide protection for various channels.

Description

technical field [0001] The invention relates to a protection device used to protect various clamps in a DCS measurement system from being damaged due to AC or DC overvoltage and overcurrent, in particular to an input / output overcurrent and overvoltage protection module of a microcomputer distributed control system. Background technique [0002] With the rapid development of science and technology, the level of automatic control of industrial measurement has been greatly improved. Among them, the most representative DCS (distributed control system) is the highest level of the current automatic control system. But from the point of view of actual operation, DCS does not have the function of self-protection, once an accident occurs, it will bring different degrees of losses to the enterprise. [0003] The module (that is, the card) in the micro-control system is a key device that converts the analog signal of the primary measurement device into a digital signal and transmits i...

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Problems solved by technology

However, the leakage of AC power equipment occurs from time to time during the working process, which can easily cause the AC voltage to enter the card from the 4-20mA signal line, causing the card to be burned by the strong voltage, and the damage of the card will directly affect the enterprise. normal operation of

[0004] In the actual work of the power plant, it is found that when the DCS control system is used, the clamps used in the DCS, when the voltage and current are slightly high, the clamps have limited voltage and current resistance and are easy to be burned and broken down. After damage, it will affect The working status of each channel of the entire card (the card is at least 15 channels), which directly affects the normal operation of the generator and boiler

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