21
ELECTRODE CALIBRA
TION
7. ELECTRODE CALIBRATION
It is recommended to calibrate the instrument frequently, especially if high accuracy is required.
The pH electrode should be recalibrated:
a) Whenever the pH electrode is replaced
b) At least once a week, but daily is advised
c) After testing aggressive chemicals and after the electrode is cleaned
d) When high accuracy is required
e) If the pH calibration expired warning is displayed during measurement
Every time you calibrate the instrument use fresh buffers and clean the electrode.
7.1. PREPARATION
A one, two or three-point calibration can be performed, using four predefined buffers 4.01, 7.01, 8.20
and 10.01 pH. For a single point calibration 8.20 pH is recommended, however any of the buffers
may be used.
Note:
The HI84534 will not accept other pH buffers for calibration.
• Pour small quantities of selected buffer solutions into clean beakers. For accurate calibration use
two beakers for each buffer solution, the first one for rinsing the electrode and the second one
for calibration.
• Put a magnetic stir bar in the beaker that will be used for calibration.
• Remove the protective cap and rinse the electrode with some of the buffer solution to be used
for the first calibration point.
• Put the first beaker with calibration buffer in the beaker holder.
• Place the electrode holder on the top of the beaker and secure it by turning clockwise and press
the
STIR
key.
• Immerse the pH electrode and the temperature probe approximately 2 cm (0.8”) into the buffer,
paying attention not to touch the stir bar.
• To enter the electrode calibration, press
CAL
then
Electrode
.
• Press
Clear
to delete the previous calibration and return to the calibration menu.
