PLCs and RTUs are both electronic devices; their functionalities overlap with each other. RTCs are sold with PLC-like features, and PLCs are sold with RTC-like features.

About RTU

“RTU” stands for “Remote Terminal Units.” They are also referred to as “Remote Telemetry Units.”

An RTU is an electronic device which is controlled by a microprocessor.

The main function of an RTU is to interface the SCADA to the objects present physically.

The RTU does not support control loops and control algorithms.

The functionality of RTUs and PLCs has started overlapping because of cheaper hardware, and thus the industry standardized the language for programs on which RTUs run.

It is different from a PLC because it is considered more suitable as it uses wireless communication and is suited to a wider geographical telemetry

About PLC:

PLCs are better with local controls, for example, production lines or plants, etc.

“PLC” stands for “programmable logic controller.” PLCs are digital computers.

They are used mainly for automating the electromechanical processes, for example, assembly lines in factories, light fixtures, amusement rides, etc.

Some of the functions of PLCs are:

Process control,
Relay control,
Motion control,
Networking, etc

They have started matching the desktop computers in storing, processing, communicating, and handling data.