CODESYS TRUNC

TRUNC is an IEC operator in the CODESYS Development System that converts a REAL value into the DINT data type. It keeps only the integer part of the number, discarding the fractional part. For example, TRUNC(1.9) gives 1 and TRUNC(-1.4) gives -1.

Source checked2/2 values · 2026-10-26

Specification

2 sources

Language	iec 61131 3
Code	TRUNC
Dialect	CODESYS

Study notes

TRUNC converts the REAL data type into the DINT data type and takes only the integer part of the number.
In CODESYS V2.3 the TRUNC operator converts REAL into INT; importing a V2.3 project automatically replaces TRUNC with TRUNC_INT.
If DINT or INT cannot represent the input value, the result of the function is undefined and the behaviour is platform-dependent.
Example in ST: diVar := TRUNC(1.9); (* Result: 1 *).
Example in ST: diVar := TRUNC(-1.4); (* Result: -1 *).