Rockwell AB module refers to a specific functional component composed of multiple basic functional components, which is used to form a fully functional system, equipment, or program. Usually named after their functions and purposes, such as heat dissipation modules, memory modules, game modules, etc. It is a component of a larger system that can be independently designed by designers while also functioning as a whole within the system. Splitting a large system into independent and different small systems can reduce the necessary communication frequency for those who do not meet frequently.

In addition, an old version module can be replaced by a new version module without affecting the operation of the entire system. In this way, the added functions in the new module can be reflected in the existing system in a timely manner, without the need to change other modules in the system. The highly modular source code structure brings significant benefits to both software and users. It is possible to independently develop modules with specific functions without spending time coordinating relationships with other modules.

The Rockwell AB module has two basic features: external features and internal features.

External features refer to the interface between a module and the external environment (i.e. the way other modules or programs call the module, including input/output parameters, referenced global variables) and the functionality of the module; Internal features refer to the characteristics of the internal environment of a module, including its local data and program code.

Main performance indicators: 1) Storage capacity; 2) Control capacity: It is the I0 capacity, also known as I0 capability, usually measured in the number of discrete quantities (digital quantities); 3) Scanning cycle; 4) Command functions and software support; 5) Network and Communication.

Rockwell AB modules are often installed on universal input-output frameworks. A framework equipped with CPU modules is called a basic framework, while others are extension frameworks. If the distance between the basic framework and the extension framework is relatively close (generally not exceeding 30m), it can be connected to multiple local extension frameworks through an extended local IO communication port; If the distance is far (usually less than 3000m), remote I0 connection can be used.