Glossary
What is PROGRAM?
The top program organization unit: bound to a task, executed cyclically, and keeping its variables between scans.
The program is what ties your logic to the hardware: its variables map to field inputs and outputs, and it calls the function blocks you wrote.
A typical project has several programs: fast control in a 10 ms task, alarms and communications in a slower one.
Related terms
- Program organization unit (POU)
- The unit every piece of PLC code lives in. The standard defines three: PROGRAM, FUNCTION and FUNCTION_BLOCK.
- Task
- The scheduling unit in a controller: which programs run, how often, and at what priority.