Sartorius DCU 3, Руководство оператора

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Operators Handbook DCU3 – System
5., Main Function „Calibration“
BAEDCU3 - Rev. 4.6 - 0504 5 - 3
Additional touch keys, tags and entries displayed depending on the selected function:
Tag Entry Displayed value or function, required input
TMPCO degC Input of temperature for manual temperature compensation
BUFFZ pH Input of pH-value of zero buffer
−
note pH-value on the buffer bottle for the actual temperature
BUFFS pH Input of pH-value of slope buffer
−
note pH-value on the buffer bottle for the actual temperature
5.2.2 Calibration
The pH - electrode is calibrated before installation into the culture vessel, e.g. prior to the sterilization.
Tip: Since the heat impact during the sterilization and chemical compounds of the culture me-
dium may effect the measurement characteristics of the electrode, it must be calibrated and
checked for proper function regularly (i.e. prior to any new fermentation run).
1. Start the calibration routine by pressing the „Start Calibration“ touch key.
2. Follow the instructions given in the related submenus.
5.2.3 Recalibration
Via these steps you can adapt the pH-measurement function to changing measuring char-
acteristics of the electrode, as it may be caused by heat impact during the sterilization or by
chemical reactions of the electrolyte with the culture medium, for instance:
1. Measure the actual pH-value in a sample taken from the running fermentation, using con-
ventional pH-measuring techniques.
2. Start the calibration by pressing the „Start Recalibration“ touch key.
3. Follow the instructions given in the related submenus.
The DCU-system automatically recalculates the zero drift caused by the sterilization and
displays the corrected pH-value.
5.2.4 Special Notes
If necessary the values for „zero drift“ and „slope“ can also be entered directly in the corre-
sponding sections of the display.
The electrode has a restricted maximum lifetime which depends on the operating conditions
and the application. The electrode should be serviced or replaced, whenever the functional
check and the calibration indicate a malfunctioning.
The pH - electrode must be serviced or replaced if :
– the zero drift is beyond the range of -30 ...+30 mV
– the slope is beyond the range of 56...59 mV/pH
You'll find specific information about recommended service periods and estimated lifetime of
the electrode in the manufacturer´s documentation included in the delivery of the electrode.
Depending on the type of fermentor and the delivered pH-electrode, the operation and main-
tenance measures required for the electrode may differ from the information herein. You'll
find more detailed information about proper handling of the electrode during calibration and
installation into the culture vessel in the Operating Manual of the fermentor.