What essential components do PLCs require?

The essential components that Programmable Logic Controllers (PLCs) require include a power source, a central processing unit (CPU), and software.

The power source is critical because it provides the necessary energy for the PLC to operate. Without it, the system cannot function. The CPU acts as the brain of the PLC, processing input signals, executing the programmed instructions, and producing output signals. It is responsible for the logic operations and control tasks that the PLC is designed to carry out.

Software is equally important, as it is used to program the PLC's functions and operations. This software allows users to create, modify, and manage the logic necessary for automation processes.

While other components listed in the options, such as sensors or display screens, can enhance a PLC's functionality or user interface, they are not fundamental for its core operation. The three core components—power source, CPU, and software—are what make a PLC capable of performing its intended control functions.