(1) High reliability because the environmental conditions of industrial production are far worse than those of general-purpose computers, PLC is required to have strong anti-interference ability, and it should be able to operate reliably in a relatively harsh operating environment (such as high temperature, overvoltage, strong electromagnetic interference, high humidity, etc.) for a long time.
(2) Easy to use
① Convenient operation: the operation of PLC includes the operation of program input and program change. Most PLCs use programmers for program input and change operations. The operation of changing the program can also be directly searched or searched in sequence according to the required address number, relay number or contact number, and then changed.
② Convenient programming: PLC has ladder diagram, Boolean mnemonic, function table diagram and other program control design languages for use.
③ Convenient maintenance: when the system has a fault, through the self diagnosis of hardware and software, the maintenance personnel can quickly find the location of the fault according to the indication of the relevant fault signal lamp and the display of the fault code, or through the display of the programmer and CRT screen, which saves time for rapid troubleshooting and repair.
(3) High flexibility the flexibility of PLC is shown in the following three aspects:
① Flexibility of programming: the programming languages used by PLC include ladder diagram, Boolean mnemonic, function table diagram, function module diagram, etc. as long as you master one of these languages, you can program.
② Flexibility of expansion: according to the continuous expansion of the application scale, PLC can not only increase the number of points by adding input and output cards, expand the capacity and function through the expansion unit, but also expand the capacity and function through the communication of multiple PLCs.
③ Flexibility of operation: flexibility of operation means that the workload of design is greatly reduced, the workload of programming and installation construction is greatly reduced, the operation is very flexible and convenient, and the monitoring and control become easy.
(4) Mechatronics PLC is a control equipment specially designed for industrial process control. Its volume is greatly reduced, its function is constantly improved, and its anti-interference performance is enhanced. Mechanical and electrical components are organically combined in one equipment, integrating the functions of instrument electronics and computer.