wtw Multi 350i, Руководство по эксплуатации, Страница: 44 / 108

Operation Multi 350i
42
Preparatory activities Perform the following preparatory activities when you want to measure:
Note
While no valid calibration is available, e.g. in the delivery condition, "Er-
ror" appears in the measured value display.
4.5.2 Measuring the ion concentration
AutoRead
(drift control)
The AutoRead function (drift control) continually checks the stability of
the measurement signal. The stability has a considerable impact on the
reproducibility of measured values. The display of the measured vari-
able flashes until a stable measured value is available.
Criteria With identical measurement conditions, the following applies:
Temperature while cali-
brating and measuring
For precise ISE measurements the temperature difference between
measurement and calibration should not be greater that 2 K. Therefore,
1 Connect the ISE combination electrode to the measuring in-
strument. The pH/ISE measuring window is displayed.
2 If necessary, select the ISE display (unit, mg/l) with <M> .
3 Measure the temperature of the test sample using a thermom-
eter.
4 Calibrate or check the measuring instrument with the elec-
trode.
1 Perform the preparatory activities according to section 4.5.1.
2 Immerse the electrode in the test sample.
ISE
0.157
mg/l
25
°C
Measuring signal Reproducibility Response time
Electrode
voltage better than 0.1 mV > 30 seconds