From a programming perspective, the control systems are largely identical. They possess a main routine that runs in a cycle and contains calls for the subtasks. The subtasks are organized into functions or program blocks. The data required for processing is stored in predefined data areas.
However, the structuring of the program code sometimes exhibits major - platform-dependent - differences in the various programming environments. For this reason, the following sections will also examine platform-specific features.
Platform-specific objects can be used in modeling the PLC program code.