Chapter 4
pH, pH/ISE and pH/LogR Measurement Modules
Thermo Scientific
Orion Versa Star Pro Meter User Manual
55
ORP Calibration
Versa Star Pro meters with pH, pH/ISE or pH/LogR modules offer a simple, automatic
calibration to the E
H
value (relative to the Standard Hydrogen Electrode, 420 mV at 25°C) in the
ORP mode when using the following items:
Thermo Scientific Orion ORP standard (Catalog Number 967901 or 967961)
Thermo Scientific Orion ORP electrode (Catalog Number 9678BNWP, 9778BNWP,
9180BNMD or 9179BNMD)
Thermo Scientific Orion 4 M KCl filling solution (Catalog Number 900011) or 4 M KCl gel
(in the 9179BNMD electrode)
Orion ORP standard is nonhazardous, stable and will not change over time, so it is an ideal
standard for any ORP measurement system. One ORP standard can be used for calibration.
Always use fresh ORP standard. Prepare the ORP electrode according to the instructions in the
electrode user manual. Connect the ORP electrode and any other electrodes to be used to the
module inputs on the selected channel.
In the measurement mode, press the channel key until the channel with the pH, pH/ISE or
pH/LogR module with ORP electrode connected is shown. If needed, press the mode key until
ORP Measurement is shown as the measure mode.
1.
Press the f1 (Cal) key to start the calibration.
a.
If more than one channel is displayed in the measurement mode, press the
or
key to highlight the desired channel and press the f3 (Select) key.
2.
Rinse the ORP electrode and any other electrodes in use with distilled water, blot dry with
a lint-free tissue and place into the standard.
3.
When the electrode and standard are ready, press the f3 (Start) key.
a.
If using a stirrer probe, the stirrer probe will start stirring when the f3 (Start) key is
pressed and stop stirring when the reading stabilizes.
4.
Wait for the mV value on the meter to stabilize, indicated by the flashing stabilizing or
solid Ready icons. When the solid Ready icon appears, press the f2 (Accept) key to
confirm the ORP standard value.
5.
The meter will display the calibration summary including the mV offset. Press the
f3 (Cal Done) key to save the calibration and then press the measure (esc) key to return
to measurement mode.
