A function calculates a result according to the current value of its inputs. A function has no internal data and is not linked to declared instances. - Scaling - linear conversion.
Inputs
IN : REAL Real value
IMIN : REAL Minimum input value
IMAX : REAL Maximum input value
OMIN : REAL Minimum output value
OMAX : REAL Maximum output value
Outputs
OUT : REAL Result: OMIN + IN * (OMAX - OMIN) / (IMAX - IMIN)
Truth table
| Inputs | OUT |
|---|---|
|
IMIN >=IMAX |
= IN |
|
IN < IMIN |
= IMIN |
|
IN >IMAX |
= IMAX |
|
other |
= OMIN + IN * (OMAX - OMIN) / (IMAX - IMIN) |
Remarks
- In FFLD language, the operation is executed only if the input rung (EN) is TRUE. The output rung (ENO) keeps the same value as the input rung.
- In IL "Instruction list"
This is a low-level language and resembles assembly, the
input must be loaded in the current result before calling the function.
ST Language
OUT := ScaleLin (IN, IMIN, IMAX, OMIN, OMAX);
FBD Language
FFLD Language
(* The function is executed only if EN is TRUE *)
(* ENO keeps the same value as EN *)
IL Language
Op1: LD "Ladder diagram"
Ladder logic is a method of drawing electrical logic schematics. It is now a very popular graphical language for programming Programmable Logic Controllers (PLCs). It was originally invented to describe logic made from relays. The name is based on the observation that programs in this language resemble ladders, with two vertical "rails" and a series of horizontal "rungs" between them IN
ScaleLin IMAX, IMIN, OMAX, OMIN
ST OUT
