Analytical Industries GPR-1200 MS ATEX Portable PPB Oxygen Analyzer - Manual (Page 16)

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Range Selection:
The GPR-1200 MS analyzer is equipped with five (5) standard measuring ranges (see specification) and provides
users with a choice of sampling modes. By accessing the MAIN MENU, users may select either the AUTO SAMPLING
(ranging) or MANUAL SAMPLING (select one fixed range) mode.
Note: For calibration purposes, use of the AUTO SAMPLE mode 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 ppm oxygen concentration with the balance nitrogen would dictate the use of the
0-100 ppm full scale range for calibration and a 0-1 ppm measuring range.
Procedure - Auto Sampling:
1. Access the MAIN MENU by pressing the MENU key.
2. Advance the reverse shade cursor to highlight AUTO SAMPLE.
3. Press the ENTER key to select the highlighted menu option.
4. The display returns to the sampling mode:
MAIN MENU
AUTO SAMPLE
MANUAL SAMPLE
CALIBRATION
>>>
00.00 PPM
AUTO SAMPLING
1 PPM RANGE
24.5 C
The display will shift to the next higher range when the oxygen reading (actually the sensor’s signal output)
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 analyzer is reading 1% on the 0-10% range and an upset occurs, the display will shift to the 0-
25% range when the oxygen reading exceeds 9.9%. Conversely, once the upset condition is corrected, the display
will shift back to the 0-10% range when the oxygen reading drops to 8.5%.
Procedure - Manual Sampling (Lock on Single Range):
1. Access the MAIN MENU by pressing the MENU key.
2. Advance the reverse shade cursor to highlight MANUAL SAMPLE.
3. Press the ENTER key to select the highlighted menu option.
4. The following displays appear:
MAIN MENU
AUTO SAMPLE
MANUAL SAMPLE
CALIBRATION
>>>
MANUAL RANGE
1000 PPM
100 PPM
10 PPM
1 PPM
5. Advance the reverse shade cursor to highlight the desired RANGE.
6. Press the ENTER key to select the highlighted menu option.