Analytical Industries GPR-1500 A Series Trace PPM Oxygen Analyzer - Manual (Page 23)

Advanced Instruments, Inc
23
MAIN MENU
AUTO SAMPLE
MANUAL SAMPLE
CALIBRATION
CONFIG ALARMS
BYPASS ALARMS
>>>
MANUAL RANGE
25%
1%
1000 PPM
100 PPM
10 PPM
Advance the reverse shade cursor using the ARROW keys to highlight the desired MANUAL RANGE.
Press the ENTER key to select the highlighted menu option.
The following display appears with the range selected and oxygen concentration of the sample gas:
MANUAL RANGE
25%
1%
1000 PPM
100 PPM
10 PPM
>>>
0.3 %
MANUAL RANGE
0-1% RANGE
76 F 100 KPA
If the oxygen value goes above the full scale range selected, 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.
12.5
PPM
OVERRANGE
MANUALRANGE
10 0-10 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.
Calibration of Transmitter
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 not generate a current output in the absence of oxygen. Given the properties of linearity
and an absolute zero, a single point calibration is possible.