Glossary · FUN
What is Function (FUN)?
A unit that takes inputs and returns one value with no memory at all: the same inputs always give the same result.
It suits maths: scaling a signal, converting a unit, an engineering formula. Because it keeps nothing, it cannot contain a timer, a counter or an edge detector.
The standard functions include ABS, SQRT, MIN, MAX, LIMIT, SEL, MUX and the type conversions.
Related terms
- Function block (FB)
- A unit with inputs, outputs and internal memory that persists between scans, used by declaring an instance of it.
- Program organization unit (POU)
- The unit every piece of PLC code lives in. The standard defines three: PROGRAM, FUNCTION and FUNCTION_BLOCK.