Metrohm 840 PC Control 5.0 / Touch Control - Manual (Page 226)

4.1 Titrations
214
PC Control / Touch Control
when the EP has already been reached). The entry of an extraction
time is advisable for samples which only release their water slowly.
• Temperature (d): Manually entered titration temperature. If a tem-
perature sensor is connected and the temperature measurement is
set to automatic or continuous under Sensor (see Section 4.1.5)
then the temperature will be measured continuously.
• Time interval MP (d): Time interval for entering a measuring point
in the list of measuring points.
Under Stop conditions the conditions for stopping the titration are de-
fined should this not take place “normally”. This could happen when the
set endpoint is not reached or if the stop criterion is not fulfilled.
• Stop volume (d): Stops when the entered volume has been added
since the start of the titration. Adapt the size of the stop volume to
the size of your titration cell to prevent an overflow.
• Stop time (d): Stops when the entered time has elapsed after the
start conditions have been fulfilled.
If several stop conditions have been set then the first of them to occur
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-
terval between the end of conditioning and the end of the determi-
nation. If the drift is known for a longer period of time then this can
be calculated for the EP-volume by manual drift correction. The re-
sult always indicates whether it has been drift-corrected or not.
• Drift value (d): Volume drift for manual drift correction
• Measured value display: The volume drift can be shown continu-
ously during conditioning.
Editing the conditioning options:
• Cond. stop volume: If the entered volume has been added before
conditioning has been completed then the process will be stopped.
If conditioning is continued by pressing [Start] again then the ti-
trant volume that has already been added will not be taken into ac-
count; addition starts again from zero. The stop volume should be