Picture for Normally Open (NO) and Normally Close (NC) Switch :
Picture for Normally Open (NO) and Normally Close (NC) Limit Switch :
Definition Contact Normally Open (NO) :
For Switch or Limit Switch Without Lamp :
If Switch In Depressed then signal into PLC is ON ( 1).
If Switch is Not In Depressed then signal into PLC is OFF ( 0).
For Limit Switch With Lamp :
If Lamp Light Then signal into PLC is ON ( 1).
If Lamp Not Light Then signal into PLC is OFF ( 0).
Definition Contact Normally Closed (NC) :
For Switch or Limit Switch Without Lamp :
If Switch In Depressed then signal into PLC is OFF ( 0).
If Switch is Not In Depressed then signal into PLC is ON ( 1).
For Limit Switch With Lamp :
If Lamp Light Then signal into PLC is OFF ( 0).
If Lamp Not Light Then signal into PLC is ON ( 1).