* 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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