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7. Select pH Calibration. (
F1:Cal.
F2:pH
)
8. When the reading has stabilised, press the
key to calibrate. If a 1
point calibration has been performed, the
“
” will not be removed until
a full 2 point calibration has been performed.
9. Rinse the pH and Conductivity sensors in distilled water and blot them
dry.
10. Place both sensors into a small sample of pH4.01, pH9.18 or pH10.01
Buffer, so that the bulb and reference junction are both covered, as
per the diagram in step 6, above.
DO NOT
place the sensors directly
into the buffer bottle.
pH9.18 and pH10.01 buffers are unstable once the bottles have
been opened. Discard immediately after use
.
11. Select pH Calibration. (
F1:Cal.
F2:pH
)
12. When the reading has stabilised, press the
key to calibrate. The
“
” will now be replaced by a decimal point, if calibration was
successful.
13. The
WP-81
is calibrated for pH and is ready for taking pH
measurements. Discard the used samples of buffer.
5.2 Calibration Notes
1. A 1-point calibration should be performed at least weekly. In
applications where the sensor junction can become blocked, such as
dairy products, mining slurries etc., a 1-point calibration may have to
be done daily.
2. A full 2-point calibration should be performed at least monthly. Of
course, more frequent calibration will result in greater confidence in
results.
3. All calibration information is retained in memory when the
WP-81
is
switched off, even when the battery is removed. This information can
be recalled or printed later using the GLP function (see section 8).
4. The
WP-81
displays the value of the pH buffer to which it will attempt
to calibrate. Ensure that the buffer value displayed corresponds to the
buffer that you are using.