ATI Q46D Dissolved Oxygen System Part 7 - Calibration
44
O&M Manual
Rev-N (4/21)
6. If the data remains unstable for 10 minutes, the calibration will fail and the message Cal
Unstable will be displayed.
7. The screen will display the last measured ppm value and a message will be displayed
prompting the user for the lab value. The user must then modify the screen value with the
arrow keys and press ENTER. The system then performs the proper checks.
8. If accepted, the screen will display the message PASS with the new slope reading, then it will
return to the main measurement display. If the calibration fails, a message indicating the
cause of the failure will be displayed and the FAIL icon will be turned on.
7.13 D.O. Air Span Cal (% sat)
This is the recommended method for air temperatures greater than about 10C; however, it
requires that the sensor be removed from the process and cleaned. Once cleaned, the sensor is
held in air and allowed time to adjust to the air temperature. As the sensor temperature
equilibrates, the transmitter automatically calculates the new 100% saturation point utilizing the
temperature readings and the barometric pressure user data located on page 64. This method
therefore requires no user input during calibration. Note: It is very important to allow enough
time for the sensor to completely temperature equilibrate with the surrounding air. This
time is at least 10 minutes.
This method requires that the sensor be removed from the process, cleaned, and Covered,
shielding the sensor from direct sunlight. The sensor membrane must be dry for this procedure,
and not submerged in liquid. This method requires no user input during calibration; however, if
this is the first time the system is being installed and calibrated, make sure to enter the proper
atmospheric pressure data and process conductivity data prior to calibration.
1. Remove the sensor from the process. Clean and rinse if necessary, with water, paying
particular attention to cleaning the membrane.
2. Cover the sensor, if necessary, to shield it from the direct rays of the sun. Remember, the
membrane must not be submerged - it must be in the air letting the sensor hang, membrane
downward, while powered.
3. Allow the system to operate undisturbed for at least 20 minutes. If the system is stable, the
value on the display will increase to some PPM value and remain at that level. At that point,
calibration can continue.
4. Scroll to the CAL menu section using the MENU key and press ENTER or the UP arrow key.
Cal D.O. will then be displayed.
5. Press the ENTER key. The screen will display a flashing 1-spl for 1-point, a 2-%sat for
Saturation air calibration, or a 3-zer for zero calibration. Using the UP arrow key, set for a 2-
%sat span calibration and press ENTER.
6. The display will prompt the user to hold the sensor in air and press ENTER. If the sensor has
already been removed from the process and reached temperature equilibrium, press the
ENTER key.
To Next Page
Loading...
Need help?
General
