The 5 Most Common PLC Programming Languages

Programmable logic controllers (PLCs) are an essential part of any automated industrial process, and the chances are good that you’re looking to get one for your own facilities. But for these devices to function properly, you must program your PLC using a specific language. The language you use can greatly impact how your PLC performs. So, it’s vital that you choose one compatible with your needs and purchased PLC model. These are five of the most common PLC programming languages used in the professional world today.

1) Ladder Logic

Ladder logic is one of the most popular PLC programming languages. It’s based on the idea of an electrical ladder diagram. In ladder logic, each rung of the ladder represents a specific instruction or set of instructions. Inputs and outputs are the contacts and coils along each rung, and you, as the programmer, need to fill in the details of each to ensure the PLC functions correctly. This type of programming is very visual, making it easy to understand and debug.

2) Function Block Diagram (FBD)

Function block diagram is another graphical type of programming language. In FBD, each function appears as a block. These blocks interconnect to create the overall program, and each step of the program flows into another in the chain. FBD is generally helpful in conjunction with other types of programming languages because it can aid in the organization of inputs and outputs.

3) Structured Text (ST)

Structured text is another common PLC programming language to know about. This textual programming language uses control structures similar to those found in other high-level languages such as C++ or Java. ST programs are easy to read and understand, making them perfect for complex applications. However, they can be more difficult to debug than other types of programs.

4) Instruction List (IL)

Instruction list is a simple yet powerful textual programming language that many older systems use. IL programs consist of a list of instructions that your PLC executes in order from top to bottom. This type of programming is very efficient and can help with both simple and complex applications.

5) Sequential Function Chart (SFC)

Sequential function chart is a graphical type of programming language that uses state transition diagrams to represent the different states and transitions in a system. SFC lends itself to complex applications where multiple states need tracking and controlling. But while the initial programming process can prove complicated, it’s always worth the performance quality you gain as a result.

As you can see, there are many different types of PLC programming languages available, each with its own strengths and weaknesses. The best language for your needs will depend on your application, chosen PLC device, and your own preferences as a programmer. Shop with PLC Direct to ensure you get the right equipment for your goals. We carry many top-selling Omron PLCs and premium Allen Bradley models. This way, you’re sure to find something that works with your level of programming prowess.