Emerson Damcos, Service Manual

Page: 72 / 144

Service Manual Damcos LPU: Troubleshooting Guide LPU
SM 8000-100-01 Ed 04 February 2017
72
Position indicator errors
Fault: • ON/OFF position indicator is not functioning correctly:
– Check the control cable connections.
– Check the function of the position indicator, measured on the position indicator wire connec-
tion. Possibly replace position indicator.
• Analogue position indicator cannot be calibrated
– Disconnect the wires from the position indicator, check the adjustment of the potentiometer,
and possibly re-adjust the indicator according to the relevant instruction
(*
.
• Analogue position indicator not functioning correctly
For power controlled LPU:
– Check supply voltage at 4 - 20 mA transmitter which has to be 15 - 27 VDC.
– Disconnect the wires from the position indicator.
– Check the adjustment of the potentiometer, and possibly re-adjust the indicator according to
the relevant instruction
(*
.
– Check the function of the potentiometer, measured on the indicator.
– Check the cable entry in cable glands. Shield has to be connected in both ends. If the indicator
and cable mounting is OK, replace the printed circuit board (see “Replace Printed Circuit
Board” on page 105). Otherwise replace the position indicator.
*) 300-350 Ohm between the "closed" and the "wiper" connection, while the valve is fully closed.