MODEL 54eA | SECTION 7.0 |
| CALIBRATION - DISSOLVED OXYGEN |
8. Press Exit (F1) four times to return to the main display.
NOTE
If Hold was activated during calibration, “Hold Mode Activated” will continue to flash in the main display. Return the sensor to normal and deactivate Hold. Refer to Section 5.6, step 11.
9.During calibration, the analyzer stores the measured current and cal- culates the sensitivity. Sensitivity is the sensor current in nA divided by the saturation concentration of oxygen in ppm. The table gives typical sensitivity for Rosemount Analytical dissolved oxygen sensors.
| Sensor | Current in air at 25°C | Sensitivity (nA/ppm) | |
| 499ADO |
| ||
| 499A Tr DO |
| ||
| Hx438 and Gx448 |
| ||
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|
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To view the sensitivity from the main display, press any key to enter the main menu. Press the ê key once. Then press Enter (F4) to display the diagnostic variables. The sensitivity is the third line on the screen. Note the units: nA is nanoamps, μA is microamps.
NOTE
During calibration, ERROR and WARNING messages may appear. If an ERROR message appears, press Exit (F1) to leave and return to the previous screen. If a WARNING message appears, press Cont (F3) to continue the calibration or press Abort (F1) to leave. Continuing the calibration after a warning message appears may cause substantial errors in the subsequent measurement. Refer to Section 15.4 for assis- tance.
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