Select the option, either ‘Fast Sample’, ‘Display Sample’ or ‘Continuous’ to suit the application.
If a continuous stream of the sample gas is available, then ‘Continuous’ will allow the alarms to trip on the steady state
oxygen level. Set-up step 38 (Reset Level), will be ignored if ‘Continuous’ is selected here.
If however, the gas is coming from a short duration sample, (eg. food packaging sample withdrawn through
hypodermic needle), the minimum value of oxygen may be retained until another sample is read by selecting ‘Fast
Sample’ or ‘Display Sample’. When the valley figure has been confirmed by five further values above the minimum,
the date/time and minimum oxygen value, and the CO
2
peak value (if fitted with the CO
2
option ), will be sent to the
printer port. The high oxygen alarm will be activated by a high sample level.
‘Display Sample’ mode is very similar to ‘Fast Sample’, except the readings are only taken once per second (10 per
second for Fast Sample). This means for small head space packets (<100 cc (12 scfm) ) the true valley may be missed.
The ‘Fast Sample’ mode is the more precise mode of operation but will not update the display until the valley and peak
values have been found.
If the value in set-up 38 (Reset Level) is above 20.9%, and if a sample hold mode (Fast Sample or Display Sample) is
selected here, the oxygen peak (not valley) will be held as the sample. If the carbon dioxide module is installed, the
peak of carbon dioxide will still be held.
Set-up step 57 (Damping Factor), will only be used if ‘Continuous’ is selected here.
27. DISPLAY MODE
Options
1. Oxygen % *
2. ppm
3. O
2
/ CO
2 (only available if a CO2 module is installed)
4. O
2
/ CO
2
% only
(only available if a CO2 module is installed)
The top line of the LCD always shows the oxygen content, but the user may select whether the oxygen will be
displayed as a percentage or in parts per million form. If the CO
2
option has been installed, both O
2
and CO
2
may be
displayed. If option 1 (Oxygen %) is chosen, below 0.1% the display will revert to the ppm form automatically. This
selection also affects other displays such as the 4–20 mA output ranges, gas calibration checking, reset level and alarm
trip levels.
If ‘O
2
/CO
2
%/PPM’ or ‘O
2
/CO
2
% only’ is selected here in set-up step 27, and ‘Fast Sample’ or ‘Display Sample’ was
selected in set-up step 26, the SAMPLE on the lower line of the display will also show the peak level of CO
2
.
Using ‘O
2
/CO
2
% only’ option restricts the display to the percentage form only. The display will not go into the ppm
mode automatically.
Teledyne Analytical Instruments 9070 Oxygen Analyzer Page 35
