CC-TAON01 HONEYWELL 技术文章 _ 山西润盛进出口有限公司

There are two main trends in the development of modern PLCs: one is to develop towards smaller size, faster speed, stronger functions and lower prices; the other is to develop towards large-scale networking, high reliability and good compatibility Sexuality and multifunctional development.

The large-scale network is mainly developed in the direction of DCS, so that it has some functions of the DCS system. Strong networking and communication capabilities are an important aspect of PLC development. Downwards, multiple PLCs and I/O frames can be connected; upwards, it can be connected with industrial computers, Ethernet, and MAP networks to form the automation control system of the entire factory.

Multi-function With the emergence of modules such as self-adjustment, stepper motor control, position control, and servo control, the PLC control field is wider.

For example, Siemens has developed a multi-loop closed-loop control module, a stepper motor control module, a simulation module and a communication processing module as early as the 1980s. In 1995, Siemens successfully developed the S7200 and S7300 series. It has TD 200 and COROS OPS operation template (OPS) to provide users with a convenient man-machine interface, three-level password protection for user programs, strong computing performance, and perfect The instruction set, MPI interface and network capability through industrial field bus PROFIBUS and Ethernet networking, strong internal integration function, comprehensive fault diagnosis function; modular structure can be used for performance expansion everywhere, pulse output thyristor stepper motor and DC motor; fast instruction processing greatly shortens the cycle period, and high-speed counters are used, and high-speed interrupt processing can respond to process events separately, which greatly reduces costs.

High reliability As the reliability of the control system has been paid more and more attention by people, some companies have widely applied self-diagnosis technology, redundancy technology, and fault-tolerant technology to existing products, and launched a high-reliability redundant system. And adopt the working mode of hot standby or parallel work and majority voting. S7400 PLC can work normally even in harsh and unstable working environment, and the sturdy and fully sealed template can still be hot-swapped during operation.

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