CODESYS SHL

SHL is an IEC operator that shifts the bits of an operand to the left by a specified number of positions. It is written as erg := SHL(in, n), where in is the value to shift and n is the number of bit positions. The result is assigned to erg.

Source checked7/7 values · 2026-10-26

Specification

2 sources

Language	iec 61131 3
Code	SHL
Group	Operator
Syntax	erg := SHL (in, n)
Dialect	CODESYS

Parameters

Name	Description
in	Operand which is shifted to the left
n	Number of bits to shift in to the left

Study notes

CODESYS uses the data type of the input variable in to determine how many bits are used for the operation.
If n exceeds the data type width, the target system determines padding for BYTE, WORD, DWORD, and LWORD operands: padding with zeros or n MOD <register size>.
Example: in_byte := 16#45 shifted by n := 2 gives erg_byte := 16#14; in_word := 16#0045 shifted by 2 gives erg_word := 16#0114.