What device is described as a microprocessor-based controller with programmable memory used to control equipment and processes?

• A. PLC
• B. SCADA
• C. DCS
• D. Microcontroller

Answer: (A)

A Programmable Logic Controller. This description matches a PLC because it is a microprocessor-based controller that stores its control program in programmable memory and uses that program to manage equipment and processes in real time. PLCs are built for industrial use, offering rugged I/O interfaces to sensors and actuators and the ability to be reprogrammed to handle different control sequences. They’re designed specifically for controlling machines and processes, unlike SCADA which is supervisory software for monitoring, or a distributed control system which uses multiple controllers across a plant, or a microcontroller which is typically a single-chip embedded device not aimed at wide-scale industrial control.