JUMO 202710, Operating Manual

Page: 46 / 58

46
9 Maintenance
9.1 Good laboratory practice (GLP)
Good laboratory practice involves regularly monitoring the device and the
accessories. In the case of pH measurements, the correct pH calibration must
be ensured in particular. The device provides support in this regard with the
functions "C.int" (calibration timer) and "rEAD CAL" (calibration data display).
A prerequisite for applying the GLP functions is ensuring that the combination
electrode is not changed. The data is saved in the device, but refers to the
respective combination electrode.
9.1.1 Calibration timer ("C.int")
You can enter a fixed interval upon which the device will automatically remind
you that a new calibration needs to be performed, see "Parameter "C.int": cal-
ibration timer", page 37.
The length of the interval depends on your application and the stability of the
combination electrode.
Once the interval has elapsed, "CAL" flashes in the display.
9.1.2 Reading the calibration data ("rEAd CAL")
The last calibration is stored in the device with the date and calibration values
and can be called up as follows.
✱
Press the key for at least 2 seconds.
"Set ConF" appears in the display.
✱
Keep pressing the key until "rEAd CAL." appears in the display.
✱
Briefly press the key to switch the display between:
"CAL." and "U.ASY" are displayed alternately in the main dis-
play.
The value of the asymmetry voltage in mV is shown in the
subsidiary display.
"Cal." and "SL.1" are displayed alternately in the main dis-
play.
The slope in the acidic range in mV/pH is shown in the sub-
sidiary display.
1
"Cal." and "SL.2" are displayed alternately in the main dis-
play.
The slope in the alkaline range in mV/pH is shown in the sub-
sidiary display.
1
rH mV mV
H
pH
ATC ok AL Logg pH CAL
rH mV mV
H
pH
ATC ok AL Logg pH CAL
rH mV mV
H
pH
ATC ok AL Logg pH CAL
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