Metrohm 900 Touch Control Manual - Manual (Page 313)

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29 Parameters
900 Touch Control
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Volume increment
Volume that is dosed in each dosing step. The choice of the correct vol-
ume increment is a basic requirement for achieving high accuracy. A good
guideline is 1/20 of the expected EP volume. For steep jumps the volume
increment should tend toward 1/100 and for flat jumps toward 1/10 of
the EP volume.
Small volume increments are used for determining blank values or with
very asymmetrical curves.
NOTE
The accuracy of the evaluation cannot be increased by using smaller
increments as the measured value modifications between two measur-
ing points are then of the same order of magnitude as the noise.
Input range 0.00005 - 999,900 mL
Default value 0.10000 mL
Dosing rate
Rate at which the volume increments are dosed.
Input range 0.01 - 166.00 mL/min
Selection maximum
Default value maximum
maximum
The maximum dosing rate depends on the cylinder volume (see Chap-
ter 32, page 488).
Signal drift
Maximum permissible drift for the measured value acceptance, i.e. maxi-
mum change of the measured value per minute. This type of titration is
often referred to as equilibrium titration. For this value, a suitable maxi-
mum waiting time is automatically calculated except you already have
modified this waiting time.
NOTE
A constant measured value is often only reached after a certain time, as
mixing and the reaction itself require a certain time. The response time
of an electrode can also increase with time, i.e. reaching a constant
measured value takes longer and longer. Drift-controlled measured
value acceptance is particularly advisable in such cases, as the measured
values are only accepted when equilibrium has almost been reached.