Use the Examine if closed (XIC) instruction in your ladder program to determine if a bit is on.
When the XIC instruction is executed, if the bit addressed is on (1), then the instruction is evaluated as TRUE.
When the XIC instruction is executed, if the bit addressed is off (0), then the instruction is evaluated as FALSE.
Alternate name: Normally open contact
Examine if closed (XIC) Instruction
The “Examine if Closed” (XIC) instruction is a fundamental instruction used in programmable logic controllers (PLCs). It is typically employed to check the status of an input (bit) and determine if it is energized or turned on.
The XIC instruction is a logical instruction and is represented by a symbol such as a contact or a coil. It is often referred to as a “normally open” (NO) contact in ladder logic programming.
Input Status Check: The XIC instruction examines the status of a specific input or bit. It checks whether the input is in an “on” or “true” state.
Output Condition: If the input being examined by the XIC instruction is energized (i.e., it is on), the XIC instruction allows the logic to flow to the output connected to it.
Output Activation: When the XIC instruction determines that the input is energized (on), it activates the output connected to it. The output can be used to control other devices or trigger specific actions within the PLC program.
The XIC instruction is often used in conjunction with other instructions such as “Examine if Open” (XIO), “Output Energize” (OTE), timers, and counters to create complex control sequences and logic.
The XIC instruction enables the programmer to conditionally activate outputs based on the status of inputs, allowing for flexible control and decision-making within the PLC program.