The basic unit generally refers to the CPU unit. If the number of points in the CPU unit is insufficient, it can be expanded according to actual needs, such as analog modules, digital modules, etc., commonly known as expansion units or expansion modules
Expansion modules can be specifically divided into communication modules, temperature modules, digital input/output modules, analog input/output modules, and some modules with specific functions. It is mainly based on one’s own needs to finalize the modules.
The expansion module is used to increase the number of I/O points and change the I/O ratio. It has no internal power supply and requires power supply from either the basic unit or the expansion unit. Due to the lack of CPU inside the expansion unit and expansion module, it must be used together with the basic unit.
The expansion module can achieve some special functions, such as high-speed pulse expansion, analog and digital expansion, communication expansion, and so on.
Of course, there are also many modules with special applications. The high-speed pulse module is used for various high-speed counting, the servo control module is used for servo motors, the communication module realizes communication connection with various equipment and instruments, high-speed pulse triggering, and the AD module realizes the mutual conversion of analog and digital quantities.
