Hydrogen Sensor; Instrument Logs; Calibration; Status Information - Agilent Technologies 7820A Advanced User's Manual

Hydrogen Sensor

Instrument logs

Calibration

Status information

Advanced User Guide
The Hydrogen Sensor module checks for uncombusted free
hydrogen in the GC column oven. During normal operation with
hydrogen as a carrier gas, leaks from the inlets or detectors
could possibly put hydrogen gas directly into the oven.
Hydrogen–air mixtures are potentially explosive in
concentrations of 4–74.2% hydrogen by volume. The sensor
monitors the free hydrogen level in the oven and will trigger a
shutdown of all hydrogen gas flows if the hydrogen level in the
oven is > 1%.
In the event of a hydrogen safety shutdown, the GC records the
event in its Event log.
See the Troubleshooting manual for more information about GC
shutdown events and how to clear them.
The GC can only shut down hydrogen gas flows that have been
configured properly. Always configure the gas types used for
the inlets, detectors, and so forth.
The GC will log the following hydrogen sensor events in its event
logs:
• Hydrogen safety shutdowns initiated by the hydrogen sensor
• Calibrations
• Hydrogen sensor tests
The hydrogen sensor requires periodic calibration for optimal
performance. See the Operation Manual for details. If the sensor
is not calibrated on schedule or if a calibration fails for any
reason (for example, a lack of calibration gas), the sensor
continues to use its existing calibration data.
By default, the hydrogen sensor current reading (in percent)
appears in the GC status display.
If a calibration fails, the GC's Service Due indicator lights. Press
[Service Mode] on the GC keypad. The first line will indicate that
the hydrogen sensor calibration failed.
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Columns and Oven
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