* check to ensure main power is on( 110 VAC)

* check 24V dc power available

* identify problem area

* check sensor operation in problem area

* check sensor Inputs to PLC

* check on PLC that a change in sensor state causes the corresponding Input LED on the PLC to go on or off

* identify Output controlled by Input on PLC ladder diagram

* ensure that Output LED is cycling on/off with Input

* check that Output voltage is correct and cycling on/off with Input

* locate Output device and ensure that voltage...
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