Teledyne 3000TB-XL - Trace oxygen analyzer - Manual (Page 60)

4 Operation Model 3000TB
­XL
4-20 Teledyne Analytical Instruments
Note: The ranges must be increasing from low to high, for example,
if range 1 is set as 0–100 ppm and range 2 is set as 0–1,000
ppm, range 3 cannot be set as 0– 500 ppm since it is lower
than range 2.
Ranges, alarms, and spans are always set in ppm units (over the entire
0-250,000 ppm range), even though all concentration-data outputs change
from ppm units to percent when the concentration is above 10,000 ppm.
4.6.2 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
Δ∇ arrow keys to switch from AUTO to FX/LO, FX/MED, or
FX/HI to set the instrument on the desired fixed range (low, medium, or
high).
L—1 M—10
H—100 Mode—FX/LO
or
L—1 M—10
H—100 Mode—FX/MED
or
L—1 M—10
H—100 Mode—FX/HI
Press Escape to re-enter the Analyze mode using the fixed range.
NOTE:When performing analysis on a fixed range, if the oxygen
concentration rises above the upper limit (or default value) as
established by the operator for that particular range, the
output saturates at 1 V dc (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.