Troubleshooting - Flowserve Logix 3200MD Installation, Operation And Maintenance Manual

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15 Troubleshooting

Failure
No LED is blinking
Erratic communications
Unit does not respond to analog
commands
Valve position reading is not
what is expected
Position is driven fully open or
closed and will not respond to
command
Sticking or hunting operation of
the positioner
*M.P.C.: Minimum position cutoff
User instructions - Digital Positioner 3200MD LGENIM0059-01 10/08
Probable Cause
Current source below 3.6 mA without AO card or 3.7 mA
with AO card
Incorrect wiring polarity
Voltage of current source is not high enough
Current source bandwidth not limited to 25 Hz
Maximum cable length or cable impedance exceeded
HART modem connected to PC RS-232 port not receiv-
ing enough power
Interference with I.S. barrier
Current Source stripping (filtering) HART signal.
Unit is in digital command mode
Error occurred during calibration
Positioner tubing backwards
Stem position sensor mounting is off 180°
Stroke not calibrated
Tight shutoff (M.P.C)* is active
Customer characterization or soft stops active
Stroke not calibrated
Inner-loop hall sensor not connected
Wrong air action entered in software
Actuator tubing backward
Electro-pneumatic converter malfunctioning
Control parameter inner-loop offset is too high/low
Contamination of the driver module
Control tuning parameters not correct
Packing friction high
Corroded or dirty spool valve
Corrective Action
Verify current source is outputting at least 3.6 mA with
AO card or 3.7 mA with AO card
Check wiring for correct polarity
Verify that current source can supply at least 10 V
Maximum allowable current source rate of change is
924 mA per second
Check cable conduction size, length and capacitance.
Refer to Section 6.4, "Cable Requirements"
Verify laptop battery is not low
Must use HART-compatible I.S. barrier
Use the HART filter (VHF) available from Flowserve
Switch to analog command mode by doing a Command
Source Reset from the local interface or with a handheld
communicator or ValveSight (please refer to Section 7.9,
"Command Source Reset," or the quick start guide for
detailed instructions).
Check blink codes on positioner and correct
calibration error. Recalibrate
Re-tube the actuator
Remount position sensor
Perform QUICK-CAL
Verify settings using PC or handheld software
Verify customer characterization and soft stops
Check DIP switch settings and calibrate valve stroke
Verify hardware connections
Check ATO (Air-to-open) and ATC
(Air-to-close) settings. Recalibrate
Verify ATO/ATC actuator tubing
Replace electro-pneumatic converter
Adjust inner-loop offset and see if proper control
resumes
Check air supply for proper filtering and meeting ISA
specifications ISA-7.0.01. Check the spool valve for
contamination
Adjust gain settings using local gain switch
Enable the stability DIP switch on the local interface
and recalibrate. If problem persists, enable pressure
control with handheld communicator or ValveSight and
recalibrate
Disassemble and clean spool valve
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