Xylem Lab 870 - Manual (Page 28)

Operation Lab 870
28 ba75555e04 11/2009
Note
The buffer set is selected in the menu for measurement settings (see
page 44).
A list of the stored buffer sets can be downloaded to the interface (Set
1 ... 16) with
_
> while selecting the buffer set in the menu for
measurement settings.
Calibration points Calibration can be performed using one, two or three buffer solutions in
any order (single-point, two-point or three-point calibration). The meter
determines the following values and calculates the calibration line as
follows:
Note
You can display the slope in the units, mV/pH or %.
You can display the zero point in the units, mV or pH.
AutoCal is adapted to the permanently programmed buffer solutions as a fully
automatic single-, two- or three-point calibration. The buffer solutions
are automatically recognized by the meter.
Stability control The calibration procedure automatically activates the stability control
function.
The current measurement with stability control can be terminated at
any time (accepting the current value) by pressing .
Calibration record When finishing a calibration, the new calibration values are first
displayed as an informative message and stored.
For ID sensors, the calibration data is stored in the sensor (see
page 11)
Determined
values Displayed calibration data
1-point ASY z Zero point = ASY
z Slope = Nernst slope
(-59.2 mV/pH at 25 °C)
2-point ASY
SLO z Zero point = ASY
z Slope = SLO
3-point ASY
SLO z Zero point = ASY
z Slope = SLO
The calibration line is calculated
by linear regression.