User guide

Trace Nitrogen in Argon Analyzer Operation
Teledyne Analytical Instruments 59
4.5.3 The Range Function
The Model 2120XL has three user programmable ranges extending
from 0-1 ppm to 0-100 ppm. The Range function is used to set the three
analysis ranges and to set whether the instrument functions on a fixed
range (1, 2 or 3) or uses auto ranging.
To set the range properties for your instrument, press the RANGE
button. The following screen appears:
R1: 1.00
p
p
m R2: 10.00
p
p
m
R3: 100.0
p
p
m Rng: Auto
where either the 1.00, 10.00, 100.0, or Auto is blinking.
Use the ◄►arrow keys to position the blinking over the range
value to be changed . Then use the ▲/▼ arrow keys to modify the range
value. Continue with the ◄►arrow keys to position the blinking over
the next range value to be changed and modify with the ▲/▼ arrow
keys.
Move the blinking to the field at the far right of the second line and
set whether fixed analysis or auto-ranging is to be used. The field can be
toggled between these values:
1 (Fixed range analysis on range 1)
2 (Fixed range analysis on range 2)
3 (Fixed range analysis on range 3)
Auto Auto-ranging.
Press ENTER when the range properties have been correctly set.
Use ESCAPE to return to the Analyze mode without altering the range
settings.
Note: Range 1 must be set lower than range 2 and range two
less than range 3. Only the upper bound of the range may
be changed. The lower value will always remain at 0.
When auto-ranging is selected, the analyzer will automatically
switch to the appropriate range based on the concentration of the sample
gas under test.