Emerson Rosemount 370XA, System Reference Manual

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370XA Gas Chromatograph System Reference Manual
APRIL 2014 7P00370-H01
4 - 39
4.4.4 Warm-start mode
When power is reinstated after being lost while the GC is in auto-
analysis mode, the GC will enter
warm-start mode and try to go back
on line. In warm-start mode, the GC monitors the oven temperature
until it is stabilized at the set point, runs calibration gas, and checks
that all of the components are detected correctly. Once the calibration
gas has been analyzed correctly, the GC will re-enter auto-analysis
mode.
If the warm-start mode fails to complete within 2 hours, a warm start
failure alarm will be triggered, and the GC will go into Idle mode.
4.4.5 Maintenance mode
Maintenance mode allows you to work on the GC while alerting the
supervisory system that the current analysis may not be valid, and
should not be used. Maintenance mode triggers a system alarm that
can be read as a Modbus Register (bit 0 on Register 3046 in the
SIM_2251 Modbus map), and on the Common Alarm digital output.
To enable maintenance mode, select its check box on the System
window from the LOI or MON2020.
When maintenance mode is active, the analysis in the Modbus
registers will still be updated so that communication to the supervisory
system can be tested; however, the analysis results during
maintenance mode will not be included in the averages calculated by
the GC.