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Instruction Manual
748374-F
March 2003
Rosemount Analytical Inc. A Division of Emerson Process Management Startup and Operation 3-3
Model NGA2000 TO2
3-3 STARTUP PROCEDURE
Establish sample or zero gas flow through the
analyzer module at a nominal flow rate of 2
SCFH (1 l/min). Allow gas to flow for 15 to 30
seconds before applying power. Apply power to
the TO2 Analyzer Module.
Upon initial startup, the separate modules, Con-
troller Board and network "self-install." The dis-
play shows the progress of the automatic
installation routine, together with a button
marked RE_INIT. If the initialization hangs up,
pressing the RE_INIT button will restart it, but
will cause all the binding information to be
erased. The Display will then appear as above.
For details on binding, please consult the Plat-
form instruction manual.
Establish that sample flow rate is within specifi-
cations (see Section 1-5 SPECIFICATIONS on
page 1-4). Input security codes (see NGA Ref-
erence manual), calibrate, and begin routine
operation as following subsections indicate.
3-4 QUICK START FEATURE
This analyzer module is equipped with a quick
start feature which allows the sensor to begin
measuring low ppm oxygen faster. This feature
can be used when the analyzer is first turned on
to decrease the time required for the sensor to
reach equilibrium. This function is most effec-
tive for gas sample measurements below 100
ppm. To maintain sensor life, it is recom-
mended that this feature be used no more than
two times in any 24 hour period.
Under the Basic Controls sub-menu, move the
cursor to Initiate quick start! and press the ↵
key. The unit will begin the quick start function
immediately. This procedure will last for ap-
proximately 45 seconds. The last measured
value is held for the duration of the procedure to
prevent false reading fluctuations.
3-5 GAS SCALE FACTOR (GSF)
The Gas Scale Factor is used to correct for
background gases other than nitrogen. When
the background of the sample is other than ni-
trogen, the diffusion rate of oxygen into the sen-
sor changes. By correcting for the background
difference, the diffusion change can be com-
pensated in software. The GSF can be entered
manually or calculated automatically. Calcula-
tion of the GSF requires the user to enter the
sample gas composition. In most applications,
the GSF is not required. However, some back-
grounds exhibit significantly different diffusion
characteristics versus nitrogen (such as helium
or hydrogen) and the GSF may improve per-
formance.
Under the Technical Level Configuration sub-
menu, select Diagnostic menus... and then se-
lect Analyzer Module Diagnostics…. In the
Analyzer Module Diagnostics sub-menu select
Calibration Parameters.... In the Ad-
vanced/Expert Calibration sub-menu select Gas
Scale Factor.... To use the GSF, enter the
volumetric percentages of each component pre-
sent in the sample gas. To view more back-
ground components, press the MORE softkey.
The total must add up to 100 or a new factor will
not be computed. If you have a background
component which is not shown in this menu,
please consult the factory for assistance.
Once you have entered all the background
composition information, move the cursor to
Compute new adjusted gas scale factor! and
press the ↵ key and the analyzer module will
automatically calculate the new gas scale factor.
3-6 CALIBRATION
The TO2 analyzer module is fully factory cali-
brated using certified gas standards prior to
shipment. If the analyzer is operated within its
specified operating conditions, no calibration is
required. The zero calibration is very stable and
does not require checking more than once a
year. Depending upon the nature of your appli-
cation, it may be beneficial to verify the span
calibration of the analyzer module every 3-4
months. The following procedure illustrates
how to initiate a zero/span calibration.
Under the Expert Controls sub-menu select Ex-
pert Analyzer Controls and Measurement…, set
the Range Number to the range that will be
used during sample analysis. Return to the
Main Menu by pressing the HOME softkey.