IEC LAD Bit Logic Instructions

Bit Logic

Normally Open

Normally Closed

Normally Open Immediate

Normally Closed Immediate


Positive Transition

Negative Transition


Output Immediate

Set (1 bit)

Set Immediate (N bits)

Reset (1 bit)

Reset Immediate (N bits)

No Operation

Set Dominant Bistable

Reset Dominant Bistable


A red diamond by each SIMATIC style instruction identifies an extension to the standard IEC 1131-3 instruction set.