Analog and digital interfaces

Analog and digital input and output modules, MODBUS interfaces.

Every Programmable Logic Controller must have some means of receiving and interpreting signals from real-world sensors, such as switches and encoders, and be able to effect control over real-world control elements, such as solenoids, valves, and motors.

This is generally known as input/output or I/O capability. PLCs can include analog and digital inputs and outputs in the single module, or through expansion modules.

Another way to acquire the input signals and act on the output devices is through analog and digital interfaces.