What does an XIO instruction represent?

An XIO instruction represents an input condition that is false. In programmable logic controllers (PLCs), the XIO (exclude if open) instruction is used primarily to evaluate the status of an input. Specifically, it checks if a particular input or condition is off or inactive. When the input being monitored is indeed false (or OFF), the XIO instruction allows the program to continue processing the instructions that follow in the logic sequence. This is crucial in control processes where certain actions or outputs should only occur based on the absence of a certain input condition.

In contrast, an XIC instruction would evaluate whether an input condition is true, meaning active or ON. Understanding these distinctions is fundamental for programming and designing effective logic sequences in PLC systems.