MIDPLCopen motion icon

FunctionClosedA 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. - Extract characters of a string at any position.

Inputs

IN : STRING   Character string
NBC : DINT    Number of characters to extract
POS : DINT     Position of the first character to extract (first character of IN is at position 1)

Outputs

Q : STRING    String containing the first NBC characters of IN.

Remarks

The first valid position is 1. 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 ILClosed"Instruction list" This is a low-level language and resembles assembly, the first input (the string) must be loaded in the current result before calling the function. Other arguments are operands of the function, separated by comas.

ST Language

Q := MID (IN, NBC, POS);

FBD Language

MidFbd.gif (1328 octets)

FFLD Language

(* The function is executed only if EN is TRUE *)
(* ENO keeps the same value as EN *)
MidLd.gif (1597 octets)

IL Language:

Op1: LDClosed"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
     MID  NBC, POS
     ST   Q

See also

+   MLEN   DELETE   INSERT   FIND   REPLACE    LEFT   RIGHT