Two XIC instructions placed in series with an output instruction define which logic?

Two XIC instructions placed in series with an output instruction define which logic?

• A. OR
• B. AND
• C. NAND
• D. NOR

Answer: (B)

In ladder logic, how elements are arranged determines the logic. When you place two XIC contacts in series before a coil, you’re creating an AND condition: both inputs must be ON for the circuit to complete and energize the output. XIC stands for Examine If Closed, meaning the contact is true when its input is ON. If either input is OFF, the path to the output coil is broken and the coil won’t energize. That’s why this arrangement implements AND logic. Choosing OR would require the contacts to be in parallel so either one could complete the path. NAND or NOR would involve inverted behavior on inputs or outputs, which isn’t present here.

In ladder logic, how elements are arranged determines the logic. When you place two XIC contacts in series before a coil, you’re creating an AND condition: both inputs must be ON for the circuit to complete and energize the output.

XIC stands for Examine If Closed, meaning the contact is true when its input is ON. If either input is OFF, the path to the output coil is broken and the coil won’t energize. That’s why this arrangement implements AND logic.

Choosing OR would require the contacts to be in parallel so either one could complete the path. NAND or NOR would involve inverted behavior on inputs or outputs, which isn’t present here.