Advanced Instruments Inc.
Note: For calibration purposes, use of the AUTO SAMPLE mode and ambient air (20.9% oxygen on the 0-25% range
which meets the 80% of FS recommendation described below) is recommended. However, the user can select the
full scale MANUAL SAMPLE RANGE for calibration as dictated by the accuracy of the analysis required – for example,
a span gas with an 80 PPP oxygen concentration in nitrogen would dictate the use of the 0-100 PPM full scale range
for calibration and a 0-100 PP measuring range.
Auto/ Manual Sampling
Access the MAIN MENU by pressing the MENU key.
Advance the reverse shade cursor using the ARROW keys to highlight SELECT RANGE and press ENTER
The display will show *AUTO and the actual range of analysis. Press the ENTER to select MANUAL RANGE and
advance the cursor to the desired RANGE and press ENTER.
The following display appears:
The display returns to the sampling mode:
MAIN MENU
SELECT RANGE
CALIBRATION
VIEW HISTORY
SYSTEM OPTIONS
30.0 PPM
AUTO SAMPLING
100 PPM RANGE
76 F 100 KPA
The display will shift to the next higher range when the oxygen reading exceeds 99.9% of the upper limit of the
current range. The display will shift to the next lower range when the oxygen reading drops to 85% of the upper
limit of the next lower range.
For example, if the transmitter is reading 5 PPM on the 0-10 PPM range and an upset occurs, the display will shift to
the 0-100 PPM range when the oxygen reading exceeds 9.99 PPM. Conversely, once the upset condition is corrected,
the display will shift back to the 0-10 PPM range when the oxygen reading drops to 8.5 PPM.
Pressing SELECT RANGE and then pressing ENTER will toggle between AUTO and MANUAL sampling
When MANUAL range is selected and If the oxygen value goes above the selected range, display will not shift to the
next higher range. Instead, when the oxygen reading exceeds 110% of the upper limit of the current range, an
OVER RANGE warning will be displayed.
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5 PPM
OVER RANGE
MANUAL SAMPLING
10 PPM RANGE
76 F 100 KPA
Once the OVER RANGE warning appears the user must advance the transmitter to the next higher range.
NOTE: With oxygen reading above 110% of the selected range, the mA signal output will increase but will freeze at
a maximum value of 24 mA. After the oxygen reading falls below the full scale range, the mA signal will become
normal.
Analyzer Calibration
The electrochemical oxygen sensors generate an electrical current that is linear or proportional to the oxygen
concentration in a sample gas. In the absence of oxygen the sensor exhibits an absolute zero, i.e., the sensor does
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