Metrohm 840 PC Control 5.0 / Touch Control User Manual

Page 241

Parameters

PC Control / Touch Control

229

• Pause before meas. (d): If stirring is carried out before the meas-

urement, a pause interval can be entered here. No stirring or meas-

uring occurs during this time.

The parameters for the dosing device are defined under Dosing de-

vice

• Dosing device: Selects the dosing device to be used for the stan-

dard addition. All the dosing device connections (MSB) are always

shown.

• Standard: Standard to be used for the dosing. The standard can be

selected from the list of titrants which have been defined under

System/Titrants

. In order to cope with the special situation of the

standard addition the titrants are called standards here. If intelligent

exchange or dosing units are used then a check will be made in the

method sequence that the correct standard is present on the con-

nected dosing device and whether the type of dosing device is cor-

rect. With non-intelligent exchange or dosing units the cylinder vol-

ume is checked. At the start of the dosing the validity of the titer and

the expiry date of the selected standard will be checked as well as

the GLP test interval for the exchange or dosing unit. The titer (Vari-

able TITER) and the concentration (Variable CONC) are also avail-

able for calculation (CALC command, see Section 4.5.1).

• Dosing rate: Three predefined sets of parameters can be selected

for the dosing rate.
With slow the dosing rate is at 10 % of the maximum dosing rate.
With medium the dosing rate is at 50 % of the maximum dosing rate.
With fast the dosing rate is equivalent to the maximum dosing rate.
The maximum dosing rate depends on the cylinder volume of the

exchange or dosing unit used (see Section 3.8.6).

• Delta U: This input field is only editable with the addition method

"auto". The individual addition increments are calculated and added

in such a way that this constant potential difference is achieved.

The volume of the individual increments is defined under Addition in-

crements

• Volume: Volume that is added in each addition step.
• Take over current value or all: If this checkbox is activated,

the volume entered for the first increment is adopted for all incre-

ments.

Note!

The sample size must be entered in mL for the correct calculation of

the concentration.

The parameters for Control device, Sensor and Stirrer are de-

scribed in Section 4.1.5. The selection of the Direct parameters is car-

ried out as described in Section 4.1.6.