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MODEL 54eA SECTION 7.0
CALIBRATION - DISSOLVED OXYGEN
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.
To view the sensitivity from the main display, press any key to enter the
main menu. Press the 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.
Sensor Current in air at 25°C Sensitivity (nA/ppm)
499ADO 15-25 μA 1,800-3,100
499A Tr DO 30-50 μA 3,600-6,100
Hx438 and Gx448 40-80 nA 4.8-9.8
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.
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.