What hosts the PLC logic, memory, and communications?

The Central Processing Unit (CPU) is the component responsible for hosting the PLC logic, memory, and communications in a programmable logic controller (PLC) system. The CPU acts as the brain of the PLC, executing the control program, processing inputs from the field devices, and managing outputs based on the programmed logic. It utilizes memory to store the executed program, data, and necessary parameters for operation.

The way the CPU applies its logic includes interpreting the input signals, making decisions based on the programmed instructions, and sending commands to the corresponding outputs. This central role is critical for the functioning of PLC systems, enabling them to automate industrial processes reliably.

In contrast, random access memory (RAM) is a type of memory used by the CPU to temporarily store data that is being actively used or processed, but it does not inherently contain the logic or communications aspects by itself. Inputs and outputs refer to the devices interfacing with the PLC, where inputs are signals from sensors or switches that inform the PLC of the current state of a system, and outputs are signals sent to actuators or indicators to perform actions based on the logical decisions made by the CPU. Thus, the CPU is the right answer for its comprehensive role in logic processing and communication in a PLC environment