The standardized language of PLCs, collectively known as IEC 61131-3, has five different languages for creating PLC programs, all of which TwinCAT supports.
IL (instruction list):
Each instruction begins with a new line and contains an operation and one or more operands. A label followed by a colon can be placed before an instruction. The comment must be the last element in a line.
ST (Structural Text):
Similar to PC Basic or C language, it can create powerful command strings with simple instructions.
FBD (function block diagram):
The idea of functional block diagram programming is that programs are structured, function-oriented, and logically sequenced. In a network, the direction of execution always goes from left to right, and all input values must be generated before the function block executes. Only when all element output values have been calculated can the network be evaluated.
LD (Ladder Diagram):
The logical sequence comes from factory electrical engineering, and this expression method is very suitable for implementing relay switch operations in PLC programs.
SFC (Sequence Function Chart):
When sequential programming is required, it is appropriate to choose a sequential function diagram. Complex tasks are divided into parts and the order between these steps is graphically defined. The steps themselves can be created in different programming languages, and can also be represented again using SFC. The program of SFC consists of steps, transition conditions, and connections between them. The steps and transition conditions can be written in any selected language.
The following program lists four simple language comparisons
IL (instruction list):
Each instruction begins with a new line and contains an operation and one or more operands. A label followed by a colon can be placed before an instruction. The comment must be the last element in a line.
ST (Structural Text):
Similar to PC Basic or C language, it can create powerful command strings with simple instructions.
FBD (function block diagram):
The idea of functional block diagram programming is that programs are structured, function-oriented, and logically sequenced. In a network, the direction of execution always goes from left to right, and all input values must be generated before the function block executes. Only when all element output values have been calculated can the network be evaluated.
LD (Ladder Diagram):
The logical sequence comes from factory electrical engineering, and this expression method is very suitable for implementing relay switch operations in PLC programs.
SFC (Sequence Function Chart):
When sequential programming is required, it is appropriate to choose a sequential function diagram. Complex tasks are divided into parts and the order between these steps is graphically defined. The steps themselves can be created in different programming languages, and can also be represented again using SFC. The program of SFC consists of steps, transition conditions, and connections between them. The steps and transition conditions can be written in any selected language.
The following program lists four simple language comparisons