The combined PLC consists of three modules. Therefore, this question chooses three answers: A, B, and C. They are the main control head part, the IO function block part, and the terminal module.
The combined PLC is mainly composed of the following modules:
1. Main control head part: it integrates communication interface, power interface, program download interface, which can be connected with the function block IO, the core of the entire PLC system.
2. IO function block part: may be digital IO function block, may be analog IO function block, may also be power module, communication module, this part is the main body of PLC function implementation.
3. Terminal module: the main purpose is to close the circuit of the entire PLC, and all modules can be supported by power supply.