Metrohm 726 Titroprocessor - Manual (Page 155)

8. Command reference 8. Command reference
726 Titroprocessor, Instructions for use 149 149
Start conditions
The start conditions correspond to those of the KFT mode, see page 159f.
Titration conditions
These are the actual titration parameters which control the measurement re-
cording and the dosing behavior during the titration itself.
Direction
Direction of the potential jump
pos. | neg. | auto
The direction of the potential jump is important for titration
control in the SET mode. Normally the 'auto' setting should
be used. The titration direction is then determined from the
initial measured value and preset target endpoint. The titra-
tion direction can also be fixed in advance. The possible
settings 'pos.' and 'neg.' refer to the numerical measured
value alterations.
End-point
Target endpoint
for SET_PH* pH -20…20
for SET_U*, SET_IPOL* -2000…2000 mV
for SET_UPOL* -200 …200 µA
The target endpoint defines the measured value which the
titration control is aiming for. The endpoint should have
been previously determined by a dynamic (DET) titration
before the method is drawn up. Correct calibration of the
sensor used is highly recommended.
Adjustment
Predefined parameter sets
slow | medium | fast
A selection can be made from three different sets of pa-
rameters for the simplified setting of the titration parame-
ters. Each of these sets includes proven controller settings
which are suitable for most requirements.
slow for chemically inhibited reactions requiring
a longer period of time, or if the EP has to be
located in a steep section of the curve
medium standard parameters for unproblematic
titrations, optimized for the commonest
applications
fast speed-optimized control parameters for
non-critical titrations where no steep
potential jumps are expected
If the titration parameters have to be adapted for specific ti-
tration problems the different control parameters can be
altered individually.