Sun Microsystems DGA 5000, Operator'S Manual, Page: 38 / 84

6.2.4 Zero-calibration
Zero-calibration, which allows the Gas Module to determine the correct
zero reference and gain settings.
During this time:
- The zero-calibration pop-up screen will be displayed showing the
elapsed calibration time.
An zero-calibration may be triggered in three ways:
- As part of the start-up procedure or on return from standby mode
(initial zero-calibration).
- Automatically by the Gas Bench as required (automatic zero-
calibration; see note below).
- Manually by the operator from Operation - The Free
Measurement Procedure (see 8 ) (manual zero-calibration).
An initial or manual zero-calibration (but not an automatic zero-
calibration) will be followed by a HC residue check (see below).
If the system is configured to require a Daily Leak Check , the unit will
prompt the operator to perform this at the end of the zero-calibration
period. Until a successful leak check has been performed all
measurements will be blocked and it will not be possible to proceed
beyond the
Gas Analyser Menu (see
6.3: „Daily Leak Check‟
below
for further details).
Note:
The gas bench automatically assesses the stability of the zero reference
and gain settings and will perform an zero-calibration as and when
required. The frequency with which an automatic zero-calibration is
performed will depend on the stability of the environment in which the
analyser is operated. If a CO
2
concentration of 0.5 % vol. or greater is
detected at the time the gas bench determines that an automatic zero-
calibration is necessary, the software will assume that gas
measurements are currently being taken. In this case the zero-
calibration will be delayed until the CO
2
measurement has fallen below
0.5% vol. or for a maximum of 30 minutes. The Error/Warning toolbar
button will be displayed. If this button is pressed, error/warning code 06
will be seen, advising that a zero-calibration is pending
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