Instruction Manual

Instruction Manual
D103434X012
Maintenance & Troubleshooting
November 2014
60
Instrument Troubleshooting
If communication or output difficulties are experienced with the instrument, refer to the troubleshooting information
provided in 7‐2.
Table 7‐2. Troubleshooting
Symptom Possible Cause Corrective Action
1. Output Drifting while at fixed process
input.
1.a Sensor 1.a1 Check torque tube spring rate change versus
process temperature. Use appropriate material for
process temperature.
1.b Configuration Data Connect the Field Communicator and:
1.b1 Check stored Specific Gravity values against
independent measurement of process density. If
process SG has changed from calibration values,
correct configuration data to match process
2. Instrument will not communicate. 2.a No power to device
2.a1 Ensure device is connected to the segment (see
host system documentation).
2.a2 Measure the terminal voltage. Terminal voltage
should be between 9 and 32 VDC.
2.a3 Check to be sure device is drawing current. There
should be approximately 19 mA.
2.c Incompatible network settings 2.c Change host parameters. Refer to host
documentation for procedure.
2.d Defective terminal box. 2.d Check continuity from each screw terminal to the
corresponding PWB connector pin. If necessary, replace
the terminal box assembly (see Replacing the Terminal
Box on page 56).
2.e Defective Field Communicator or
modem cable.
2.e If necessary, repair or replace cable.
2.f Fieldbus card defective or not compatible with PC. 2.f Replace Fieldbus card.
3. Device does not stay on segment. 3.a Incorrect signal level.
3.a1 Wrong cable type or segment length too long. See
Site Planning Guide.
3.a1 Bad power supply or conditioner.
3.b Excess noise on segment.
3.b1 Check integrity of wiring connections. Make sure
cable shield is grounded only at the control system.
3.b2 Check for corrosion or moisture on terminals in
terminal box (refer to page 55 for terminal box
information).
3.b3 Check for bad power supply.
4. A value cannot be written to a
parameter.
4.a Resource block parameter Write Lock may be set to
Locked.
4.a Change Write Lock to Not Locked
(refer to page 35).
4.b If a transducer block parameter, the mode may be
incorrect or other parameter settings might be
preventing a write.
4.b1 Check table B‐54. If necessary change the
transducer block target mode to Manual.
4.b2 Check table B‐54. If necessary adjust parameter
settings.
4.c You have attempted to write a value that is outside
the valid range.
4.c Check the range values listed for the parameter
(refer to the appropriate parameter definition table in
Appendix B).
3.d Function block or in/out block mode may be
incorrect.
3.d. Confirm that block is in correct mode for writing to
any given parameter.
-Continued-