Chapter VII
ORP Technique
All meters with pH measurement capability include a mV, relative mV and ORP
function . Measure the raw millivolt (mV) values of an electrode in the mV mode .
Calibrate the relative millivolt (RmV) values of a redox electrode for oxidation-
reduction potential (ORP) measurements in the relative mV/ORP mode .
Note: The mV measurements are raw readings and cannot be calibrated. Use the
relative mV mode to calibrate mV measurements.
Relative mV and ORP Calibration
1 . Prepare the electrode according to the electrode user guide .
2 . In the measurement mode, press
press
until the RmV icon is shown and press
3 . Rinse the electrode with distilled water and place it into the standard .
4 . Wait for the RmV icon to stop flashing . If the raw mV reading of the electrode
is 220 mV ± 60 mV, when the RmV icon stops flashing the meter will
automatically calculate and display the E
measured temperature . If the raw mV reading of the electrode is outside of
the 220 mV ± 60 mV range, when the RmV icon stops flashing the meter will
display 000 .0 RmV . Press
press
/
the digits until the meter displays the millivolt value of the standard . To change
the value to negative or positive number, press
blinking and the arrow icon is blinking and then press
the millivolt value .
5 . Press
to save and end the calibration . The millivolt offset will be displayed
and the meter will automatically proceed to the measurement mode .
Thermo Scientific Orion Star
mV, Relative mV/ and
until the first digit to be changed is flashing,
to change the value of the flashing digit and continue to change
and Star Plus Series Meter User Guide
™
until the arrow icon points to the top line,
mV value for the electrode at the
H
until none of the digits are
to begin the calibration .
to change the sign of
EN-23