(1) High reliability. Since most PLCs use single-chip microcomputers, they have high integration. Coupled with the corresponding protection circuits and self-diagnosis functions, the reliability of the system is enhanced. [8]
(2) Easy programming. PLC programming mostly adopts relay control ladder diagrams and command statements. The number of these is much less than that of microcomputer instructions. Except for mid-to-high-end PLCs, the small-sized PLCs usually have only about 16 lines. Due to the graphic and simple nature of the ladder diagram, it is easy to master and use, and even without computer expertise, programming can be done. [8]
(3) Flexible configuration. Since PLCs adopt a modular structure, users only need to simply combine to flexibly change the functions and scale of the control system. Therefore, it can be applied to any control system. [8]
(4) Complete input/output function modules. One of the greatest advantages of PLC is that for different on-site signals (such as DC or AC, switch quantity, digital quantity or analog quantity, voltage or current, etc.), there are corresponding templates that can be directly connected to the devices in the industrial field (such as buttons, switches, current sensing transmitters, motor starters or control valves, etc.) and connected to the CPU mainboard through a bus. [8]
(5) Easy installation. Compared with computer systems, the installation of PLCs does not require a dedicated machine room or strict shielding measures. When using, simply connect the detection devices, actuators and the I/O interface terminals of PLC correctly, and it can work normally. [8]
(6) Fast operation speed. Since the control of PLC is executed by program, both its reliability and operation speed are incomparable to relay logic control. [8]
In recent years, the use of microprocessors, especially with the large-scale adoption of single-chip microcomputers, has greatly enhanced the capabilities of PLCs, and the difference between PLCs and microcomputer control systems has become smaller, especially for high-end PLCs.