20
Calibrating in Percent (DO Local% Enabled)
Perform this calibration procedure when DO Local% is enabled in the
System Setup menu.
Prepare a 100% humid environment for the sensor as described in the
One Touch Calibration section.
Power the instrument on and wait approximately 5 to 15 minutes for
the storage chamber to become completely saturated and to allow the
sensor to stabilize if using a Polarographic sensor. If using a Galvanic
sensor, wait approximately 5 to 10 minutes for the chamber to become
completely saturated. Auto Shutoff time should be disabled or set to
at least 20 minutes, see System Setup menu for more information on
adjusting the Auto Shutoff.
Ensure the barometer reading is accurate. If necessary, perform a
barometer calibration.
Press and hold the Calibrate
key for 3 seconds. %Local will be
automatically highlighted, press enter
. The Pro20/Pro20i will
display the current DO% and temperature readings along with the %
calibration value. The % calibration value will always be 100% for DO
Local%.
Wait at least 3 seconds, then, once the DO% and temperature readings
are stable, press enter to complete the calibration. 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.
Calibrating in mg/L
Power the instrument on and place the sensor into a sample that
has been titrated to determine the dissolved oxygen concentration.
Continuously stir or move the probe through the sample at a rate
