A PLC (Programmable Logic Controller) is a much more versatile control system. It is capable of handling digital and analogue inputs/outputs and is used for control of complicated machinery, as well as entire process control systems. PLCs can be as small as DDCs, with input/output count ranging from only 8 to a few thousand for large and complicated PLCs. Unlike DDCs, PLCs are highly scalable, have superior reliability and better security features.
