Procedure - Air Calibration Using Deltav - Emerson ROSEMOUNT 5081-A Instruction Manual

MODEL 5081-A
9.5 PROCEDURE — AIR CALIBRATION USING Deltav
1. Remove the sensor from the process liquid. use a soft tissue and a stream of water from a wash bottle to clean
the membrane. Blot dry. the membrane must be dry during air calibration.
2. Pour some water into a beaker and suspend the sensor with the membrane about 0.5 inch (1 cm) above the
water surface. to avoid drift caused by temperature changes, keep the sensor out of the direct sun.
3. Monitor the dissolved oxygen reading and the temperature. once readings have stopped drifting, begin the
calibration. It may take 10 -15 minutes for the sensor reading in air to stabilize. Stabilization time may be even
longer if the process temperature is appreciably different from the air temperature. For an accurate calibration,
temperature measured by the sensor must be stable.
4. Access: deltaV Explorer/Context Menu
Air Calibrate oxygen Sensor (method_oxygen_air_cal)
Method Steps:
a. displayed: Current oxygen Measurement
Current temperature Measurement
Prompt: Are values stable?: Yes; No; Abort
If "No" is chosen, current values are re-read.
b. If "Yes" is chosen:
Prompt: Select Pressure units.
Enter desired pressure units.
c. Prompt: Enter barometric pressure.
d. displayed: Current oxygen Measurement
Current temperature Measurement
New Sensitivity Value
Method concludes.
typical values for sensitivity at 25C are given in the table:
Sensor
499Ado
499Atrdo
Hx438 and Gx448
64
nA/ppm
1,800 - 3,100
3,600 - 6,100
4.8 - 9.8
SECTION 9.0
CALIBRATION — OxyGEN