Ph Calibration; Ph Calibration Editing - Thermo Scientific Orion Versa Star Pro User Manual

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Chapter 4 pH, pH/ISE and pH/LogR Measurement Modules
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52 Orion Versa Star Pro Meter User Manual

pH Calibration

One to six pH buffers can be used for calibration (up to six for a custom buffer group, up to five
for USA buffer group and up to four for DIN buffer group). Always use fresh pH buffers and
select buffers that bracket the sample pH and are one to four pH units apart.
Prepare the pH electrode according to the instructions in the electrode user manual. Connect
the pH 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 pH electrode connected is shown. If needed, press the mode
key until pH 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 pH electrode and any other electrodes in use with distilled water, blot dry with a
lint-free tissue and place into the pH buffer.
3. When the electrode and buffer 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 pH value on the meter to stabilize and perform one of the following actions:
a. Press the f2 (Accept) key to accept the displayed value.
or
b. Press the f3 (Edit) key and use the numeric keypad to enter the pH value. Press the
f2 (Accept) key to confirm the entered value.
5. Press the f2 (Next) key to proceed to the next buffer and repeat steps 2-4 or press the
f3 (Cal Done) key to save and end the calibration.
a. If a one point calibration is performed and the displayed slope needs to be edited,
press the f3 (Slope Edit) key and press the f3 (Clear) key, use the numeric keypad to
enter the new slope value and press the f2 (Accept) key.
6. The meter will display the calibration summary including the slope and export the data to
the calibration log. Press the measure (esc) key to proceed to the measurement mode.

pH Calibration Editing

Once the f3 (Cal Done) key is pressed and the calibration is saved, press the f2 (Cal Edit) key
to edit the calibration data and fix individual points without a full recalibration. In the calibration
edit mode, press the  or  key to highlight a calibration point and press the f2 (Delete) key
to delete the point or press the f3 (Re-Measure) key to re-measure the point. Follow the
onscreen text prompts and instructions to edit the selected calibration point.
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