6Redox/ORP Electrode User Guide
Electrode CalibrationORP readings can be reported using the absolute mV values
or the EH mV values. EH mV values give the corresponding
mV values that would be obtained using a Standard Hydrogen
Electrode (SHE), also known as the Normal Hydrogen Electrode
(NHE). Orion ORP standard, Cat. No. 967901 or 967961, allows
operators to correlate measurements to the EH mV value with
an Orion ORP electrode.
The relative mV mode can be used to calibrate the ORP
electrode so the electrode reads the EH mV values in samples.
When an ORP electrode is calibrated to read EH mV values, the
resulting sample readings can be compared among multiple
meter and electrode systems.
Note: If the meter can perform an automatic ORP calibration
using an EH mode, refer to the meter user guide for detailed
instructions on the meter calibration procedure.
1. Set the meter to the relative millivolt mode. Refer to the
meter user guide for detailed instructions.
2. Place the ORP electrode in ORP standard, Cat. No. 967901
or 967961.
3. Set the meter to the EH mV value of the ORP standard at
the measured temperature using the information in Table 1.
Table 1– ORP Standard Values
Absolute mV values may vary by ± 60 mV
Temperature
(°C)
EH Value
(mV)
Absolute Value
with Cat. No.
900011 Filling
Solution (mV)
Absolute Value
with Cat. No.
900001 Filling
Solution (mV)
0 438 218 176
1 437 218 176
2 437 218 176
3 436 218 176
4 435 218 176
5 435 218 176
6 434 218 176
7 433 218 176
8 433 218 175
9 432 219 175