CODESYS LT

LT is an IEC comparison operator that performs the "less than" function. If the first operand is less than the second operand, the operator yields TRUE; otherwise it yields FALSE. The operands may be of any basic data type.

Source checked2/2 values · 2026-10-26

Specification

2 sources

Language	iec 61131 3
Code	LT
Dialect	CODESYS

Study notes

Permitted data types of the operands: any basic data type.
The operator result is boolean: TRUE when the first operand is less than the second, otherwise FALSE.
Source example in ST: Var1 := 20 < 30; where 20 < 30 yields TRUE.