PLC can be divided into the following three categories:
(1) Integrated PLC
The integrated PLC integrates the power supply CPU, input/output interfaces, and other components into a single chassis, with the characteristics of compact structure, small size, and low price.
(2) Modular PLC
Modular PLC is the process of dividing each component of the PLC into several separate modules, such as CPU module, input/output module, power module (some included in CPU module), and various functional modules.
(3) Stacked PLC
Combining the characteristics of integrated PLC and modular PLC forms the so-called stacked PLC. The CPU, power supply, input/output interfaces, etc. of the stacked PLC are also independent modules, but they are connected by cables, and each module can be stacked layer by layer. This system can not only be flexibly configured, but also be made compact in size.