自动控制系统可编程逻辑控制器的可靠性中英文互译.doc

The 2011 International Conference of Youth Communication Reliability of Automatic Control System PLC Abstract: Programmable controller as anti-interference ability, high reliability, simple programming, high cost performance, in the field of industrial control to be more widely applied. Keywords: reliability; automatic control system; PLC 1. Introduction Date of machine industry as the central control unit, equipped with configuration software, use large-screen real-time monitoring interface, the achievement of the control points of the dynamic display, data modification, fault diagnosis, automatic alarm, but also show the query record of historical events, the system of major parts total running time, the device process flow diagram, the device structure and so on. Central control unit and slave serial communications between the PLC data exchange, usually selected from the 485 in less than 1000m twisted pair communication, fiber can choose from more frequent communication, more long-distance wireless communication can also be used. PLC control of the lower computer use, according to the number of control objects, control the scope of the object, the choice of one or more control PLC, PLC data exchange between the registers is to use internal links, data exchange and sharing. The PLC real-time monitoring of the site into a high reliability, and programming is simple, flexible, and therefore more and more people attention. 2. The main reason of control system reliability reduce Although the industrial control and programmable controller itself has a high reliability, but if the input switch signal to the PLCs error, the analog signal to a larger deviation, PLC output port to control the implementation of the institutions were not required action, These mistakes can make the control process, resulting in irreparable economic losses. Live input signals to the PLC of the main reasons for errors include: 1) The signal transmission line caused a short circuit or open