Analytical Industries GPR-1535 GB Trace PPM Oxygen Transmitter - Manual (Page 17)

Advanced Instruments Inc.
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PASSED
CALIBRATION OR
FAILED
CALIBRATION
Satisfying users that the zero offset is reasonably acceptable for their application can be accomplished much quicker. Unless the
zero gas is contaminated or there is a significant leak in the sample connections, the transmitter should read less than 100 ppm
oxygen within 5 minutes after being placed on zero gas.
The maximum zero calibration adjustment permitted is 60% of the lowest full scale range available, which normally is 1 ppm.
Thus the maximum zero calibration adjustment or zero offset is 6 ppm oxygen. Accordingly, the transmitter’s ZERO has not
been adjusted prior to shipment because the factory conditions are different from the application condition at the user’s
installation.
Factory Default Zero:
The software will eliminate any previous zero calibration adjustment and display the actual the signal output of the sensor at a
specified oxygen concentration. For example, assuming a zero gas is introduced, the display will reflect an oxygen reading
representing basically the zero calibration adjustment as described above. This feature allows the user to test the sensor’s signal
output without removing it from the sensor housing.
MAIN MENU
AUTO SAMPLE
MANUAL SAMPLE
CALIBRATE
24.5 C 100 KPA
>>>
CALIBRATION
SPAN CALIBRATE
ZERO CALIBRATE
DEFAULT SPAN
DEFAULT ZERO
24.5 C 100 KPA
Span Calibration
Maximum drift from calibration temperature is approximately 0.11% of reading per °C. The transmitter has been calibrated at
the factory. However, in order to obtain reliable data, the transmitter must be calibrated at the initial start-up and periodically
thereafter. The maximum calibration interval recommended is approximately 3 months, or as determined by the user’s
application.
Calibration involves adjusting the transmitter electronics to the sensor’s signal output at a given oxygen standard, e.g. a
certified span gas with an oxygen content (balance nitrogen) approximating 80% of the next higher full scale range above the
intended measuring range is recommended for optimum accuracy, see Calibration and Accuracy. Calibration with ambient or
instrument air (20.9% or 209,000 ppm) is recommended when installing a new sensor or when a certified gas is not available.
Factory Default Span
The software will set the SPAN adjustment based on the average oxygen reading (actually the sensor’s signal output) at a
specified oxygen concentration. For example, when a span gas is introduced, the micro-processor will display an oxygen reading
within +50% of the span gas value. This feature allows the user to test the sensor’s signal output without removing it from the
sensor housing.
Access the MAIN MENU by pressing the MENU key.
Advance the reverse shade cursor using the ARROW keys to highlight MANUAL SAMPLE.
Press the ENTER key to select the highlighted menu option.
The following displays appear: