Metrohm 840 PC Control 5.0 / Touch Control - Manual (Page 221)

4 Parameters
PC Control / Touch Control
209
The parameters for the titration sequence are edited under Titration
parameters :
• Titration direction (d): The titration direction is normally deter-
mined automatically from the initial measured value and the set
endpoint. It is recommended that, whenever possible, a positive or
negative alteration of the measured value is entered. If two end-
points have been set then the titration direction will be defined
automatically. In this case the setting will be ignored.
• Extraction time (d): The titration takes place during this time. The
titration will not be stopped until the extraction time has elapsed
(even if the EP has already been reached). The entry of an extrac-
tion time may be advisable, e. g. for the titration of sparingly soluble
samples.
• Temperature (d): Manually entered titration temperature. If a tem-
perature sensor is connected and temperature measurement is set
to automatic or continuous under Sensor (see Section 4.1.5) then
the temperature will be measured continuously. The value is used
for temperature compensation in pH measurements.
• Time interval MP (d): Time interval for entering a measuring point
in the list of measuring points.
The conditions for terminating the titration are defined under Stop con-
ditions if this does not occur automatically because either the set
endpoint has not been reached or the stop criterion has not been ful-
filled:
• Stop volume (d): Stops when the preset volume has been added
since the start of the titration. You should adapt the stop volume to
suit the size of your titration vessel in order to prevent it from over-
flowing.
• Stop time (d): Stops when the preset time has elapsed after the
start conditions have been fulfilled.
If several stop conditions have been set then the first criterion to be ful-
filled will stop the titration.
• Filling rate (d): Rate at which the dosing cylinder is refilled after
the titration. The maximum filling rate depends on the cylinder vol-
ume of the exchange or dosing unit used (see Section 3.8.6).
Under Conditioning (d) the conditions for pre- and reconditioning are
defined. With conditioning switched on, the first time that the method is
started only the command to start conditioning will be executed. None
of the other commands will be processed yet. The solution in the titra-
tion cell is titrated to the endpoint with the given control parameters and
is then kept there continuously. The method sequence itself only starts
when [Start] is pressed again.
• Start drift (d): As soon as this volume drift is undercut "Condi-
tioning OK" appears and the titration method can be started.
• Drift correction (d): The EP-volume can be drift-corrected. With
auto the volume drift value at the start of the titration will be taken
over automatically, multiplied by the drift correction time and sub-
tracted from the EP-volume. The drift correction time is the time in-