TechTalk – RSLogix : AFI Intorduction

The AFI (Always False Instruction) is an instruction that always evaluates as false. You can look at it as a coil that has been forced to always be open or bit to stay low (logic zero). The AFI instruction does not override other instructions or force the rung to scan as false. If an AFI instruction has a be introduced to the rung, any instruction set after the AFI instructions, it will “ignored”.

Xybernetics RSLogix - AFI Introduction