145 Measuring with Galvanic Dissolved Oxygen (DO) Probes
Procedure
A two‑point calibration uses water‑saturated air and zero oxygen solution to calibrate.
1. Press CAL to enter calibration mode.
2. At prompt, with the password enabled, input the passcode.
The controller recognizes the currently selected measurement unit.
3.
To calibrate at 100 % saturation (or 8.26 mg/L) suspend the probe in air above a water surface and wait
at least 15 minutes for the air to become saturated with water vapor.
4. Press CAL.
5. Press CFM when displayed (once the reading has stabilized) followed by Next.
6. Submerge the probe into HI7040 Zero oxygen solution and stir gently for 2‑3 minutes.
Wait for the temperature and probe values to become stable.
The controller automatically recognizes the 0 % (ppm) standard and the value is displayed.
7. When the reading is stable CFM is displayed. Press CFM to save.
“Wait” is displayed at the bottom of the LCD until the calibration is saved.
“Calibration DONE” message is displayed and the controller returns to the menu.
23.5.2. Process Calibration
A process calibration is a single‑point calibration performed with the probe installed in the process. This type of
calibration allows the user to adjust the measured DO value to match the value determined with the reference meter.
Preparation
• Determine process DO value using a calibrated reference meter and probe.
•
The process controller and the probe should have previously been calibrated with two standards (probe
slope determined).
Procedure
1. Press CAL to enter calibration mode.
At prompt, with the password enabled, input the passcode.
To Next Page
Loading...
