Teledyne LXT-280 - Manual (Page 34)

Calibration LXT-280
Teledyne Analytical Instruments 24
large differences between calibrations may indicate coating or damage to
the membrane.
4.6 Automatic Buffer Calibration
Once the calibration points have been defined in the LXT-280 by
performing the zero and span calibration, the Automatic Buffer
Calibration feature can be utilized. This feature allows calibrations to be
performed without making any adjustments. The procedure is the same
for the zero and span calibrations.
Procedure:
1. Go to the appropriate calibration menu and locate the cursor on
the top line
2.
Insert the sensor in the known solution as defined by the
calibration point on the top line.
3. Magnetically activate the RIGHT HORIZONTAL ►arrow key
to enter the calibrate mode.
4. Wait for the real-time mV to reach its minimum value (zero
calibration) or wait for the real-time mV value to stabilize (span
calibration).
5. Magnetically activate the LEFT HORIZONTAL ◄ arrow key
until the cursor is all the way to the left and the term “Cal”
appears on the second line. This will store the calibration data.
4.7 Calibration Error Detection
If the calibration performed in section 4.5 is not within the
predetermined limits of the instrument, a flashing asterisk (*) will
appear behind the full scale millivolt value.
The presence of the asterisk indicates a potential calibration
problem and can be ignored if there are special considerations allowing
this condition to be valid. In general, if the asterisk appears, the integrity
of the electrode, the calibration procedure or the handling procedure
should be questioned.