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Troubleshooting 73
I
nstruction Manual
S
ection 4: Troubleshooting
PN 51-6888Xi December 2012
Once an alarm condition is identified, the 6888Xi offers a number of diagnostics to interpret the
specific alarm.
Alarm indications are available via the 6888Xi or the 475 Field Communicator and Rosemount
Analytical's Asset Management software. When the error is corrected and/or power is cycled, the
diagnostic alarms will clear or the next error on the priority list will appear.
4.4 Identifying and Correcting Fault Indications
There are two types of alarms; recoverable and non recoverable. If an existing alarm is recover-
able, the alarm-active indication will disappear when the alarm condition no longer exists. If an
alarm is not recoverable, the alarm indication will continue to be displayed after the cause of the
alarm condition is corrected. AC power to the 6888Xi must be cycled to clear a non-recoverable
alarm.
Alarm messages are displayed on the 6888Xi display window when the alarm status display is
accessed via the 6888Xi menu. A listing of the alarm/fault messages and the related fault status
descriptions are shown in Table 4-2.
Fault conditions that give no fault indication and that allow the probe to pass calibration are list-
ed and discussed after Table 4-2.
Table 4-2 - Diagnostic/Unit Alarm Fault Definitions (1 of 2)
NOTE
For correct operation, ensue the Distributed Control System is configured to interpret these signal
l
evels correctly.
Message Status Alert
Self
Clearing
NV Memory Fail
A checksum error was detected in the nonvolatile memory configuration data
when the unit was turned on. Default values have been loaded. Check to see that
your configurations have not been changed. Cycle the power to clear alarm.
Failed NY
Board Temp High
The electronics board temperature reading is above the threshold. The board
may not function correctly. The predefined temperature threshold is 86°C for IO
board or 126°C for Transmitter board.
Failed NY
Heater Ramp
Rate
Heater ramp rate is greater than the defined warm-up ramp rate. Heater may be
out of control. Alarm condition: If the heater ramp rate stay above 3.5°C/sec for
30 seconds continuously.
Failed NY
O2 Sensor Open
The cell impedance voltage is reading less than -1.0 VDC indicating the O2 sensor
wires may be disconnected or the O2 sensor junction may be open. Check wiring.
Maint YY
O2 T/C Open
The O2 sensor heater thermocouple voltage is reading more than 0.065 volt indi-
cating the thermocouple wires may be disconnected or the thermocouple junc-
tion may be open. Check wiring.
Maint YY
O2 Temp Low
The sensor heater temperature is below the low temperature threshold.
If Extended Temperature feature is not enabled, the predefined low temperature
threshold is the 726°C.
If Extended Temperature feature is enabled, the predefined low temperature
threshold is the 726°C if the “Heater SP” is set to “Normal” or 540°C for it is set to
“Low”.
Maint YY
4-20 mA
Critical
Alarm