Specifications

Trace Oxygen Analyzer Module
Rosemount Analytical NGA 2000
748420-A
August 1999
15
S
TARTUP AND
O
PERATION
3
3.3 S
TARTUP
P
ROCEDURE
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, Controller Board and network "self-install." The
display 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 Platform instruction manual.
Establish that sample flow rate is within specifications (see the Specifications page in this
manual). Input security codes (see reference manual), calibrate, and begin routine operation
as following subsections indicate.
3.4 Q
UICK
S
TART
F
EATURE
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 effective for gas sample measurements below 100 ppm. To maintain sensor life, it is
recommended 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
approximately 45 seconds. The last measured value is held for the duration of the
procedure to prevent false reading fluctuations.
3.5 G
AS
S
CALE
F
ACTOR
(GSF)
The Gas Scale Factor is used to correct for background gases other than nitrogen. When
the background of the sample is other than nitrogen, the diffusion rate of oxygen into the
sensor changes. By correcting for the background difference, the diffusion change can be
compensated in software. The GSF can be entered manually or calculated automatically.
Calculation of the GSF requires the user to enter the sample gas composition. In most
applications, the GSF is not required. However, some backgrounds exhibit significantly
different diffusion characteristics versus nitrogen (such as helium or hydrogen) and the GSF
may improve performance.