Teledyne 2120XL - Trace Nitrogen Analyzer - Manual (Page 66)

Operation Model 2120XL
Teledyne Analytical Instruments 54
polynomial once all data has been entered. The screen will return to the
AUTO/MAN screen with the upper right number incremented by 1.
If ESCAPE is pressed, the data will be rejected and the screen will
return to the AUTO/MAN screen without incrementing the sample
number in the right corner.
Repeat the above procedures for each prepared linearization
sample making sure to adequately flush or purge the lines each time a
new sample is connected. The linearization process must include a zero
and full span value. Up to 11 data samples are to be entered.
When all 11 data points have been entered, change the ‘Accept’
field to ‘finish’ and press Enter to leave data entry mode.
Some Notes about Calibration: For the analyzer to preserve good
linearity throughout the 0-100 ppm scale, users must try to calibrate near
the top of the highest range (0-100 ppm). If calibration gas is low value,
for example 10 ppm, to improve accuracy at that level, you can expect to
have less accuracy when readings surge much higher than that.
4.5.2 The Zero and Span Functions
The Model 2120XL is designed to provide a linear response over
the analysis range for nitrogen in argon. Therefore, once the
linearization procedure has been performed as described in 4.5.1.12 , a
two-point (zero and span) calibration is sufficient to define the
calibration curve .
Prior to shipment, the analyzer was calibrated by the factory in
accordance with the calibration data shipped with your analyzer. Use
these settings to verify that the unit is in calibration, or re-calibrate the
analyzer as outlined in this section.
4.5.2.1 B EFORE C ALIBRATION
Note: To minimize consumption of zero and span gases, careful
attention to the purging of the analyzer, as described in
Chapter 3, is critical.
1. Ensure that the analyzer is fully purged and warmed up.
2. Check that the sample gas flow rate is correct. Default
setting is 100 ccm See Section 2.2. Adjust the pressure