20
MW160
Bench Meter
8. pH
8.1. PREPARATION
Up to three-point calibration can be performed with a choice of 7 standard buffers
(1.68, 4.01, 6.86, 7.01, 9.18, 10.01 and 12.45 pH).
1. Prepare two clean beakers. One beaker is for rinsing and one for calibration.
2. Pour small quantities of the selected buffer solution into each beaker.
3. Remove the protective cap and rinse the probe with buffer solution used for the first
calibration point.
If necessary, press RANGE until the display changes to pH measurement range.
8.2. CALIBRATION
General Guidelines
For better accuracy, frequent calibrations are recommended. The probe should be
recalibrated at least once a week, or:
y
whenever is replaced
y
after testing aggressive samples
y
when high accuracy is required
y
when the calibration time out has expired
Procedure
1. Immerse the pH and the temperature probes approximately 4 cm (1 ½”) into the buffer
solution and stir gently. Make sure the temperature probe is positioned close to the
pH probe.
2. Press CAL. The CAL, BUFFER, CALIBRATION tags, the buffer number and the buffer
value (7.01) are displayed along with WAIT tag blinking. If needed, press the
keys
to select a different buffer value.
3. When the reading is stable and close to the selected buffer, READY and ACCEPT tags
are displayed blinking. Press GLP/ACCEPT to confirm calibration.
