Xylem ProLab 1000 BENCH TOP pH METER - Manual (Page 55)

ProLab 1000 Operation
55 ba75576e04 01/2011
4.6.4 Calibrating for ISE measurements
Why calibrate? Ion-selective electrodes age and are temperature-dependent. This
changes the slope. As a result, an inexact measured value is displayed.
Calibration determines the current value of the slope of the electrode
and stores it in the instrument.
Thus, you should calibrate before each measurement and at regular
intervals.
When to calibrate? z Before any measurement if possible
z After connecting another ISE electrode
z When the CalClock flashes, e. g. after a voltage interruption
Standard solutions Use two to seven different standard solutions. The standard solutions
have to be selected in either increasing or decreasing order.
Note
The unit of the standard solution and measurement result is selected in
the Calibration / Unit menu.
Menu item Possible
setting Description
Calibration /
Calibration record - Displays the calibration
record of the last calibration.
Calibration /
Calibration history - Displays the calibration
history of the last calibrations.
Man. temperature -20 ... +130 °C Entry of the manually
determined temperature. For
measurements without
temperature sensor only.
Ion type Ag, Br, Ca, Cd,
Cl, CN, Cu, F,
I, K, Na, NO3,
Pb, S, NH3,
NH4, CO2 Selection of the ion type to be
measured
Unit mol/l, mg/kg,
ppm, %, mg/l Selection of the unit for the
display of the measurement
result and calibration
standards.
Density 0.001 ... 9.999
g/ml, kg/l Adjustable density of the test
sample (only with
Unit: mg/kg, ppm, %)