Troubleshooting Basics
4-9
KVAL 990-F4 Service Manual
• Does the
Position Feed Back
agree with the
Load
position?
In other words are the correct photo eyes, limit switches or ferrous sensors acti
-
vated? Check the controller inputs to insure the proper sensors are activated. If the
controller is a PLC, an activated input is lit. Some touch screens have inputs status
also.
3.
Common Position Feedback failures:
•
Photo Eye:
Bad element or bad cable
•
Limit Switch:
Stuck, or failure
•
Wiring:
Broken, worn insulation
•
PLC:
Bad input port.
4.
Check
the
Positioning System
Follow the circuit from the
Controller
output to the
Load
and check for component
failures.