The YOKOGAWA DFAN is a Module.

A programmable logic controller (PLC) is an industrial control computer used for automated electrical and mechanical systems. It consists of programmable microprocessors, input/output (I/O) modules, communication interfaces, and power supply components. The PLC module is an important component of the PLC system, used to expand the functionality and performance of the PLC.

There are various types of PLC modules, which can be divided into the following categories according to their functions:

• Digital I/O module: used to process digital signals from devices such as sensors and switches, and send digital signals to devices such as actuators and indicators.
• Analog I/O module: used to process analog signals from sensors and transmitters, and send analog signals to devices such as actuators and indicators.
• Communication module: used to connect PLC to other devices, such as computers, human-machine interfaces (HMI), and remote I/O devices.
• Specialized module: used to perform specific functions such as motion control, PID control, and image processing.