Analytical Industries GPR-2500 Series Oxygen Transmitter - Manual (Page 25)

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6. Press the ENTER key to calibrate or MENU key to abort and return to SAMPLING mode.
0.000 PPM
ZERO
CALIBRTION
ENTER TO CALIBRATE
MENU TO ABORT
7. Allow approximately 60 seconds for the calibration process while the processor determines whether the signal
output or reading has stabilized within 60% of the full scale low range.
8. Both the Zero Calibrate and Span Calibrate functions result in the following displays:
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.
The maximum zero calibration adjustment permitted is 60% of the lowest full scale range available, which normally
is 1%. Thus the maximum zero calibration adjustment or zero offset is 0.6% oxygen. Accordingly, the transmitters’
ZERO has not been adjusted prior to shipment because the factory conditions are different from the application
condition at the user’s installation.
Accuracy due to manufacturer tolerances may result in a slight difference between the LCD display and the analog
output of the 4-20mA integrated circuit. However, the difference is less than 0.25% of range and falls well below
the specified accuracy of the transmitters.