11
I
A120/130
pH Calibration
The A series meter allows 1 to 5 points pH calibration. We recommend
that you perform at least 2 points calibration for high accuracy
measurement. The meter will automatically recognize and calibrate to
following standard buffer values.
USA Standard Buffers
pH 1.68, 4.01, 7.00, 10.01, 12.45
NIST Standard Buffers
pH 1.68, 4.01, 6.86, 9.18, 12.45
DIN Standard Buffers
pH 1.09, 3.06, 4.65, 6.79, 9.23, 12.75
If the Custom
option is selected, the meter will allow 2 to 5 points
calibration. Single point calibration should only be carried out with
pH 7.00, 6.86 or 6.79, otherwise calibration will not be accepted.
Make sure to calibrate the meter when attaching a new pH electrode
or during first use. Do not reuse the buffer solutions after calibration,
contaminants in solution will affect the calibration and eventually the
accuracy of the measurement.
For better result, we recommend to enable the automatic temperature
compensation. If the manual temperature compensation is selected,
all buffer and sample solutions must be at the same temperature and
you have entered the correct temperature value to the meter.
Stir the standards and samples at a uniform rate that will help you get
most accurate readings.
Setting the Number of Calibration Points
1. Press and hold the
key to enter the setup menu.
2. Press the
key to highlight
Calibration Points
, press the
Enter
key to confirm.
3. Press the
/
key to select the number of calibration points,
press the
Enter
key to save.
Single Point Calibration
1.1 Ensure that you have selected 1 point calibration in the setup
menu.
1.2 Press the
Cal
key, the screen shows "Calibration Point 7.00" (or
6.86, 6.79, depending on the selected pH buffer group).
1.3 Rinse the pH electrode with distilled water, place the electrode
(and temperature probe) into the pH 7.00 buffer solution, stir
gently to create a homogeneous solution.
1.4 Press the
Enter
key, the status bar shows "Calibrating
…
"
1.5 Wait for the mV reading to stabilize, the meter will automatically
show "Calibration is completed" and return to the measurement
mode.
Multipoint Calibration
2.1 Ensure that you have selected 2 to 5 points calibration in the
setup menu.
2.2 Repeat steps 1.2 through 1.4 above. When the first calibration
point is completed, the screen will show "Calibration Point 2",
the meter prompts you to continue with second point calibration.
