Analytical Industries GPR-3500 MO Portable Oxygen Analyzer - Manual (Page 18)

Advanced Instruments Inc.
18
Output Zero
Accuracy due to manufacturer tolerances may result in a slight difference between the LCD display and the 0-1V analog output.
However, the difference is less than 0.25% of range and falls well below the specified accuracy of the analyzer. In rare instances the 0-
1V analog signal output may not agree to the reading displayed by the LCD. This feature enables the user to adjust the 0V analog
signal output when the LCD displays 00.00. Note: Adjust the 1V analog signal output with the OUTPUT SPAN option described below.
1. Access the MAIN MENU by pressing the MENU key.
2. Advance the reverse shade cursor using the ARROW keys to highlight CALIBRATION.
3. Press the ENTER key to select the highlighted menu option and the following displays appear:
MAIN MENU
AUTO SAMPLE
MANUAL SAMPLE
CALIBRATION
>>>
CALIBRATION
SPAN CALIBRATE
ZERO CALIBRATE
DEFAULT SPAN
DEFAULT ZERO
OUTPUT SPAN
OUTPUT ZERO
4. Advance the reverse shade cursor using the ARROW keys to highlight DEFAULT ZERO.
5. Press the ENTER key to select the highlighted menu option.
6. The following display appears:
100.0
OUTPUT ZERO OFFSET
PRESS UP OR DOWN
TO CHANGE VALUE
ENTER TO SAVE
MENU TO RETURN
7. Compute the adjustment value as described in Appendix B or consult the factory. The true adjustment value must be determined
empirically by trial and error. Adjust the initial adjustment value for additional percent errors.
090.0
OUTPUT ZERO OFFSET
PRESS UP OR DOWN
TO CHANGE VALUE
ENTER TO SAVE
MENU TO RETURN
8. Press the ENTER key to advance the underline cursor right or press the MENU key to advance the underline cursor left to reach to
the desired digit of the OUTPUT ZERO OFFSET value.
9. Press the ARROW keys to enter the OUTPUT ZERO OFFSET value.
10. Repeat until the complete OUTPUT ZERO OFFSET value has been entered.
11. Save the adjustment value by pressing the ENTER key or abort by pressing the MENU key.
12. The system returns to the SAMPLING mode.