Ultra Trace Oxygen Analyzer Operation 4
4-21
Teledyne Analytical Instruments
Use the ∆∇ arrow keys to enter the upper value of the range (all ranges
begin at 0). Repeat for each range you want to set. Press
Enter
to accept the
values and return to
Analyze
mode. (See note below.)
Note: The ranges must be increasing from low to high, for example, if range
1 is set as 0–500 ppb and range 2 is set as 0–10 ppm, range 3 cannot
be set as 0– 5 ppm since it is lower than range 2.
Ranges, and alarms, are set in ppb or ppm units depending on concen-
tration. All concentration-data outputs change from ppb units to ppm when
the concentration is above 1.0 ppm. Range Low (L) is always a ppb range
and cannot be set higher than 1000 ppb nor lower than 10 ppb. Ranges
medium (M) and High (H) can only be set in ppm. The Medium (M) range
can be set between 1 and 10 ppm, while the high (H) range can be set
between 10 and 1000 ppm.
4.7.2 Fixed Range Analysis
The autoranging mode of the instrument can be overridden, forcing the
analyzer DC outputs to stay in a single predetermined range.
To switch from autoranging to fixed range analysis, enter the range
function by pressing the
Range
button on the front panel.
Use the < > arrow keys to move the blinking over AUTO.
Use the ∆∇ arrow keys to switch from AUTO to FX/L, FX/M, or FX/H to
set the instrument on the desired fixed range (low, medium, or high).
L—250ppb M—1 ppm
H—10 ppm Mode—FX/L
or
L—250 ppb M—1 ppm
H—10 ppm Mode—FX/M
or
L—250 ppb M—1 ppm
H—10 ppm Mode—FX/H
Press
Escape
to re-enter the
Analyze
mode using the fixed range.
NOTE: When performing analysis on a fixed range, if the oxygen concentra-
tion rises above the upper limit (or default value) as established by the
operator for that particular range, the output saturates at 1 Vdc (or 20
mA). However, the digital readout and the RS-232 output continue to
read the true value of the oxygen concentration regardless of the
analog output range.