Ultra Trace Oxygen Analyzer Operation 4
4-5Teledyne Analytical Instruments
In the first line, TRACK or HOLD should be blinking. The operator
can toggle between TRACK and HOLD with the Up or Down keys. When
TRACK is selected, the analog outputs (0-1 VDC and 4-20 ma) and the
range ID contacts will track the instrument readings during calibration (either
zero or span). TRACK is the factory default.
When HOLD is selected, the analog outputs (0-1 VDC and 4-20 ma)
and the range ID contacts will freeze on their last state before entering one of
the calibration modes. When the instrument returns to the Analyze mode,
either by a successful or an aborted calibration, there will be a three-minute
delay before the analog outputs and the range ID contacts start tracking
again.
The concentration alarms freeze on their last state before entering
calibration regardless of selecting HOLD or TRACK. But, when HOLD is
selected the concentration alarms will remain frozen for the time displayed in
the second line of the TRAK/HLD menu after the analyzer returns to the
Analyze mode.
The factory default is three minutes, but the delay time is program-
mable. To adjust to delay time use the Left or Right arrow keys. When the
time displayed on the second line blinks, it can be adjusted by Pressing the
Up or Down keys to increase or decrease its value. The minimum delay is 1
minute, the maximum is 30.
This preference is stored in non-volatile memory so that it is recovered
if power is removed from the instrument.
4.3.2 Setting up an Auto-Cal
When proper automatic valving is connected (see chapter 3, installa-
tion), the Analyzer can cycle itself through a sequence of steps that automati-
cally calibrates the instrument.
Note: If you require highly accurate Auto-Cal timing, use external Auto-Cal
control where possible. The internal clock in the Model 3000-XL is
acurate to 2-3 %. Accordingly, internally scheduled calibrations can
vary 2-3 % per day.
To setup an AutoCal cycle:
CAUTION:
We do not recommend frequent Zero adjustments of the cell. A newly
installed cell may take 7-10 days of operation to reach a steady Zero
(typically less than 0.2 ppm). If required, the instrument may be zeroed