PLCs (Programmable Logic Controllers) use a number of programmable languages, depending on the PLC’s model and manufacturer.
However, the following are the most commonly utilized programming languages in PLCs:
1). Ladder Logic (LD)
2). Structured Text (ST)
3). Function Block Diagram (FBD)
4). Instruction List (IL)
5). Sequential Function Chart (SFC)
1). Ladder Logic (LD)
The most established and often utilized programming language in PLC is ladder logic. It based its graphical representation of the logic processes on electrical ladder diagrams utilized in relay-based control systems.
2). Structured Text (ST)
High-level text-based programming languages like structured text resemble traditional languages like Pascal or C. It is suitable for performing mathematical computations and manipulating data, and it enables more complicated programming.
3). Function Block Diagram (FBD)
By implementing several function blocks together, users of the graphical programming language FBD can construct complex functions. It is helpful for illustrating complex control procedures and has a visual resemblance to electrical schematics.
4). Instruction List (IL)
A text-based, low-level programming language called Instruction List uses mnemonic codes for representing specific instructions. Reading and writing it is more difficult, but it has its uses where memory minimization is important.
5). Sequential Function Chart (SFC)
In order to make the control flow more understandable, SFC is the graphical programming language that enables to break down complex control processes into a series of logical phases or states.
It’s important to keep in consideration that some PLCs accept other programming languages (or) have proprietary languages that are unique to the manufacturer. To ascertain the accessible programming languages, it is essential to review the PLC’s documentation & software architecture.