Understanding software/program in PLCs
Before looking into PLC programming languages, which this chapter is all about, let’s get some knowledge of the software/program in PLCs.
In computing, generally, software is a set of instructions written in a language the computer understands to perform a task. Software can also be reffered to as program.
A PLC requires two types of software that must be executed by the CPU for the PLC to function. They are as follows:
- The operating system (firmware)
- User program
The operating system is the program written by the PLC manufacturers and designed to run automatically in the PLC once powered. It is responsible for executing the user program, establishing communication between devices, memory management, and updating the output.
A PLC user program is a set of instructions in either textual or graphical form that represents the control function that will be carried out for a specific industrial task or application. It is the program that the...
