3
pH Calibration Using Automatically Recognized Buffers
Note:
Use a 6.86 or
7.0 pH buffer for the
mid-range buffer.
Choose the pH setup
option in Table 1.
1.
Prepare two or three pH buffers according to the electrode
instruction manual. Choose from 1.68, 4.01, 7.00 (or 6.86), 10.01,
and 12.45 pH buffers.
2.
Turn the instrument on. From the pH reading mode, press
CAL
.
CAL
and flashing
?
will appear in the upper display area, along
with
Standard
and
1
.
3.
Place the pH electrode into one of the buffers.
4.
Press
READ
. The instrument will automatically recognize the
calibration buffer value. The temperature and pH values will be
updated until a stable reading is reached.
Note:
The pH values for the buffers are given for 25 °C. If the calibration buffer
temperature is not 25 °C, the pH values displayed for the buffers will reflect
the correct pH value for the calibration buffer temperature.
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
ENTER
must be pressed to accept the reading. This
lets the operator control the acceptance point of the buffer.
5.
When the reading has stabilized or been accepted, the standard
number will change to
2
.
6.
Remove the probe from the first buffer and rinse with deionized
water. Place the probe into the second buffer.
7.
Press
READ
. The temperature and pH values will be updated until a
stable reading is reached.
8.
When the reading has stabilized or been accepted, the standard
number will change to
3
. (To accept this calibration after two
points, press
EXIT
. Press
ENTER
to accept the calibration or
EXIT
to
cancel the calibration without saving it.)
9.
Remove the probe from the second buffer and rinse with deionized
water. Place the probe in the third buffer.
10.
Press
READ
. The temperature and pH values will be updated until a
stable reading is reached.
11.
When the reading has stabilized or been accepted, the slope value
and the
Store
and
?
icons will appear.
12.
To save the calibration and return to the reading mode, press
ENTER
. To exit the calibration without saving it and return to the
reading mode, press
EXIT
.
