21
of at least ½ foot per second (16 cm per second) during the entire
calibration process. A stir plate may be helpful in this calibration.
Allow the dissolved oxygen and temperature readings to stabilize. This
may take 5 to 15 minutes, depending on the age of the instrument,
type of sensor, and condition of the sensor.
Press the Calibrate
key. Highlight mg/L and press enter
.
Use the up and down arrow keys to adjust the mg/L reading to the value
of the titrated sample. Press enter to confirm the value and calibrate or
press the Cal key to cancel the calibration.
Calibration Successful
will display for a few seconds to indicate a
successful calibration and then the instrument will return to the run
screen.
If the calibration is unsuccessful, an error message will display on the
screen. Press the Cal key to exit the calibration error message and
return to the run screen. See the Troubleshooting guide for possible
solutions.
SALINITY COMPENSATION CALIBRATION
The Pro20/Pro20i uses a user inputted salinity value in ppt (parts per
thousands) to compensate dissolved oxygen mg/L values. The salinity
compensation value entered in the Pro20/Pro20i should be the salinity
value of the water you are testing.
To adjust the salinity compensation value, use the up or down arrow
keys to highlight the salinity box on the run screen, and then press
enter (Figure 10). Next, use the up or down arrow keys to adjust the
salinity compensation value to the salinity of the water you are testing.
You may enter a value between 0.0 and 70.0 parts per thousand (ppt).
Press enter to confirm and to save the new salinity compensation value.
The salinity compensation value can be adjusted any time without the
need to recalibrate dissolved oxygen.
