Metrohm 900 Touch Control Manual - Manual (Page 372)

29.7 STAT titrations (STAT)
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900 Touch Control
Min. rate in µL/min = 0.1 · expected reaction rate in µL/min
Input range 0.01 - 9999.00 µL/min
Default value 10.00 µL/min
Table 12 Default values of the predefined titration rates for STAT
Reaction rate
50 µL/min 100 µL/min 500 µL/min
Dynamics
– pH
– U
1.000
60.0 mV
1.000
60.0 mV
1.000
60.0 mV
Max. rate 0.25 mL/min 0.75 mL/min 2.00 mL/min
Min. rate 5.00 µL/min 10.00 µL/min 40.00 µL/min
Dosing and control range
Outside the control range the dosing rate is mainly characterized by the
maximum rate. The parameters Max. rate and Dynamics should be opti-
mized together in such a way that the titration does not overshoot too
much when the control point is reached. The control range should be
selected in such a way that the measured value remains within this range
when dosing stops. A slightly larger control range should be defined for
slow reactions (e.g. pH = 3, U = 180 mV). The setpoint value is often set
with a SET pretitration before the substrate is added. This means that the
STAT titration can be started with a small deviation from the control point.
Within the control range the dosing rate is mainly characterized by the
minimum rate.
29.7.3 Titration parameters
Under [Titration parameters], the parameters influencing the sequence
of the entire titration are defined.
Titration direction
The titration direction is normally determined automatically from the start
measured value and the set control point. It is recommended that, when-
ever possible, a positive or negative modification of the measured value is
entered.
Selection + | - | auto
Default value auto
+
Positive measured value modification, i.e. in the direction of a higher
pH value or greater voltage.