Hach sensION3, Instruction Manual, Page: 28 / 52

28
SECTION 3,
continued
3.2.1 Performing a Calibration Using pH 4, 6.86, 7, and 10 Buffers
1. If using a probe without a temperature sensor, see Section
2.3.2 on page 20 and 2.6 on page 21 for information about
obtaining and using a default temperature.
2. Prepare two or three of the auto-recognizable pH buffers
according to the electrode instruction manual.
Note: Use a 6.86 or 7.0 pH buffer for the mid-range buffer. To view or
change the setting for the mid-range buffer see Section 3.1.5.
Note: The pH values for the buffers are given for 25 °C. If the sample
temperature is not 25 °C, the pH values displayed for the buffers will
reflect the correct pH value for the sample temperature.
3. Press the
I/O/EXIT
key to turn the instrument on. If necessary,
press the
pH/mV
key to get into the pH reading mode (
pH
will
be displayed).
4. From the pH reading mode, press
CAL
.
CAL
and
?
will
appear in the upper display area, along with
Standard
and
1
.
5. Place the pH electrode in one of the buffers. Do not use a stir
bar or swirl or stir during pH measurements.
6. Press
READ/ENTER
. The temperature and pH values will be
updated until a stable reading is reached.
Note: If the meter is measuring in pH mode, it automatically moves to the
next calibration step when stabilization is reached (indicated by
three beeps). If measuring in mV mode, the three beeps will still
sound when the stabilization occurs, but you must press
ENTER
to
accept the reading. This lets the operator control the acceptance
point of the buffer.
7. When the reading has been accepted, the standard number
will change to
2
.
8. Remove the probe from the first buffer and rinse. Place the
probe in the second buffer.
9. Press
READ/ENTER
. The temperature and pH values will be
updated until a stable reading is reached.