Teledyne 3000TA - General purpose trace oxygen analyzer - Manual (Page 52)

4 Operation Model 3000TA
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—100 M—1000
H—10000 Mode—FX/LO
or
L—100 M—1000
H—10000 Mode—FX/MED
or
L—100 M—1000
H—10000 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 concentra-
tion 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.
4.7 The Analyze Function
Normally, all of the functions automatically switch back to the Analyze
function when they have completed their assigned operations. Pressing the
Escape button in many cases also switches the analyzer back to the Ana-