MODEL 54eA | SECTION 12.0 |
| CALIBRATION - OZONE |
12.3FULL SCALE CALIBRATION
1.Place the sensor in the process liquid. Adjust the sample flow until it is within the range recommended for the sensor. Refer to the sensor instruction sheet.
2.Adjust the ozone concentration until it is near the upper end of the control range. Wait until the controller read- ing is stable before starting the calibration.
Calibrate main sensor Zero main sensor Adjust temperature
ExitEnter
1.100ppm
Stabilizing . . . Wait
Abort Cont
1.100ppm
Calibrate : 1.100 ppm
ExitEdit
3.From the main display, press any key to obtain the main menu. With the cursor on “Calibrate,” press Enter (F4).
NOTE
If Hold was enabled in Section 5.6, the hold screen will appear. To activate hold, refer to Section 5.6, step 11.
Press Enter (F4).
4.Press Cont (F3). “Wait” flashes until the sensor is stabilized.
If the controller appears locked, the reading is not stable enough. Wait until the process readings are stable before starting the cali- bration.
Alternatively, increase the stability concentration or reduce the sta- bility time. See Section 5.11. Calibrating while readings are unsta- ble may substantially reduce accuracy.
5.Once the reading is stable, the screen at left appears. Sample the process liquid. Make a note of the reading before taking the sam- ple. Immediately determine ozone. Note the controller reading again. If the present reading (X) differs from the reading when the sample was taken (Y), calculate the value to enter (C) from the fol- lowing formula:
C = (X/Y) (A)
where A is the concentration of ozone measured in the grab sample.
Press Edit (F4). Use the arrow keys to change the concentration in the second line of the display to the desired value. Press Save (F4) to store the value.
6.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.
7.During the calibration, the analyzer stores the measured current and calculates the sensitivity. Sensitivity is the sensor current in nA divided by the measured concentration. The sensitivity of the 499AOZ (ozone) sensor is about 350 nA/ppm at 25°C.
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
72measurement. Refer to Section 16.8 for assistance.
