29.11 Electrode test for pH electrodes (ELT)
￭￭￭￭￭￭￭￭￭￭￭￭￭￭￭￭￭￭￭￭￭￭
406
￭￭￭￭￭￭￭￭
900 Touch Control
29.11.4 Stirrer
The parameters for the stirrer are edited under [Stirrer].
Stirrer
Selection of the MSB connector the stirrer is connected to. Every MSB
connector will always be displayed.
Selection 1 | 2 | 3 | 4
Default value 1
Stirring rate
Setting the stirring rate. It can be set in steps of –15 to +15. The default
setting 8 corresponds to 1000 rpm. The formula for calculating the rota-
tional speed is specified in chapter 32.4, page 494. The optimum stirring
rate can be tested in the manual control.
The algebraic sign of the stirring rate changes the direction in which the
stirring is done. When the stirrer is viewed from above, this means:
￭ "+": counterclockwise rotation
￭ "–": clockwise rotation
Input range –15 to 15
Default value 8
29.11.5 Additional information
Table 18
Limit values of the three electrode types
Rating
Excellent electrode Good electrode Usable electrode
Electrode type "Standard"
Streaming potential 2.5 mV 3.0 mV 4.0 mV
Drift 2.0 mV/s 2.5 mV/s 3.0 mV/s
Min. slope 96.5% 96.0% 95.0%
Max. slope 101.0% 102.0% 103.0%
Response time 45 s 50 s 60 s
Lower limit Uoff –15 mV
Upper limit Uoff 15 mV
Electrode type "Gel"
Streaming potential 3.0 mV 3.5 mV 4.5 mV
Drift 2.5 mV/s 3.0 mV/s 4.0 mV/s
Min. slope 96.5% 96.0% 95.0%
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