Analytical Industries GPR-2500 Series Oxygen Transmitter - Manual (Page 27)

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Non-medical grade oxygen: Assuming the initial zero is performed according to the procedure described herein,
the transmitter should not require zeroing again until the either the sensor is replaced or a change is made to the
sample system or gas lines. In most cases, a zero gas of 99% nitrogen purity and a span gas of 95-100% oxygen
purity are sufficient. Following the initial zero and calibration, the transmitters should not require span calibration
again for up to 3 months under “normal” application conditions as described in the published specifications.
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.
1. Access the MAIN MENU by pressing the MENU key.
2. Advance the reverse shade cursor using the ARROW keys to highlight MANUAL SAMPLE.
3. Press the ENTER key to select the highlighted menu option.
4. The following displays appears:
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
Manual Span
The user must ascertain that the oxygen reading (actually the sensor’s signal output) has reached a stable value
within the limits entered below before entering the span adjustment. Failure to do so will result in an error.
Preparation - Required components: Refer to Installing Span Gas section above.
1. Certified span gas cylinder with an oxygen concentration, balance nitrogen, approximating 80% of the full scale
range above the intended measuring range.
2. Regulator to reduce pressure to between 5 and 30 psig.
3. Flow meter to set the flow between 1-5 SCFH,
4. 2 lengths of 1/8” dia. metal tubing measuring 4-6 ft. in length.
5. Suitable fittings and 1/8” dia. metal tubing to connect the regulator to the flow meter inlet
6. Suitable fitting and 1/8” dia. metal tubing to connect to the flow meter vent
7. 1/8” male NPT to tube adapter fitting to connect the 1/8” dia. metal tubing from the flow meter vent to the
mating male quick disconnect fitting supplied with the GPR-2500/2500MO.