A technician is troubleshooting a PLC ladder logic program. A physical emergency stop button is wired normally closed (NC) in the field. In the ladder logic, what instruction should be used to allow the machine to run when the E-stop is NOT pressed?

Question

Accepted Answer

Examine If Closed (XIC / Normally Open contact). Since the physical button is NC, it constantly supplies 24V to the input card. An XIC instruction looks for this "True" state to allow the logic to flow and the machine to run.

Answer

Examine If Open (XIO / Normally Closed contact)

Answer

One-Shot Rising (OSR)

Answer

Output Energize (OTE)

A technician is troubleshooting a PLC ladder logic program. A physical emergency stop button is wired normally closed (NC) in the field. In the ladder logic, what instruction should be used to allow the machine to run when the E-stop is NOT pressed?

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