Metrohm 796 Titroprocessor - Manual (Page 121)

7. Titration and measuring modes
796 Titroprocessor, Instructions for use 115 115
7.8 MEAS Extended measuring functions
Application:
MEAS modes are universal measuring functions with which various meas-
urable variables of a sample can be recorded. Their features are drift or
time-controlled recording from one or more measuring points over a par-
ticular period of time.
7.8.1 Measuring modes
The following variables can be recorded:
• potentiometric pH measurement ( MEAS_PH*)
• potentiometric voltage measurement ( MEAS_U*)
• amperometric measurement with polarization voltage ( MEAS_UPOL*)
• voltametric measurement with polarization current ( MEAS_IPOL*)
In each of these measuring modes the sample solution temperature can be
determined in parallel for each measuring point and for pH measurements
the value recorded can be appropriately corrected.
• drift or time-controlled temperature measurement ( MEAS_T*)
7.8.2 Standard measurement
The standard measurement represents a simple individual measurement
which may be drift-controlled or time-controlled. For example, in order to re-
cord the reaction behavior of a sensor it is possible to record the raw data of
the measurement at short time intervals (sampling time) and to assess them
as a measuring curve.
Note: these raw data are not exact measuring data; they are unfiltered and
influenced by the background noise of the measuring system.
The 'smoothed', i.e. filtered final measurement value (variable CM) should
be used for calculations.
Drift / time-controlled measurement acceptance
Measurement acceptance is carried out to the same principles as in a mo-
notonic (
MET) titration. In drift-controlled measurement acceptance the
measurement drift of the sensor must be less than a defined amount in or-
der to be accepted as a valid measurement. If after a defined waiting period
has elapsed this measurement drift has not been undercut then the mo-
mentary measurement will be accepted. For time-controlled measurement
acceptance the measurement drift must be switched off. In this case only
the set waiting period is decisive for the measurement.