Extech Instruments 341350A User Manual page 5

pH Calibration (1, 2, or 3 points)
A two point calibration with a buffer of 7 plus 4 or 10 (whichever is nearest to the expected
sample value) is always recommended. A one point calibration (choose the value closest
to the expected sample value) or a three point calibration is also valid. For best accuracy,
always calibrate at the sample temperature. Frequency of calibration is dependent on how
often the meter is used, care of the electrode and strength of the samples tested. Typically,
it is recommended that calibration be performed once a day or before each use if the meter
is not used on a daily basis.
1. Connect the pH probe and place it into a pH7 buffer.
2. Press the POWER button to turn the meter on and press the
the PH icon appears. (Note: disable the Auto Power Off feature to avoid an automatic
power off during calibration)
3. If MTC icon appears next to the temperature display, press the
the temperature of the pH buffer. If the optional temperature probe is used, insert the
probe into the buffer solution.
4. Press and HOLD the MODE/CAL button until the display begins to flash 7.00. The
meter automatically recognizes the buffer and calibrates itself to that value. At the end
of the calibration cycle, SA and End will briefly appear on the display and then the
meter returns to the normal operating mode
5. When a calibration is performed, the calibration icons
be cleared (calibration data is not erased) and will be replaced when a successful
calibration is performed for each buffer
indicate what calibration levels were last performed. They do not indicate how
recently the calibration was performed or if the calibrations are still valid.
6. Remove the electrode from the pH7 buffer, rinse in a rinse solution and insert it into
the pH4 or pH10 buffer solution.
7. Repeat step 4 for the second calibration point and then the third point if desired.
Note: If the output of the electrode falls outside predetermined limits, the meter will
cancel the calibration, indicate
happens when the electrode has aged and needs replacement.
Note: To avoid cross contamination, always rinse the electrode in a rinse solution
when changing from one buffer or sample to the next buffer or sample.
MODE/CAL
(pH10)
within one power on cycle. These icons
End and the RENEW icon will flash. This typically
5
button until
▼ or ▲ buttons to set
(pH7) (pH4) will
341350A V1.1 1/09
www.burntec.com