Metrohm 781 pH/Ion Meter - Manual (Page 82)

6.5 Direct ion measurement (781 only: Conc mode)
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780/781 pH/Ion Meter, Manual
conc.unit: mol/L, %, ppm, g/L, mg/L,
µg/L, mEq/L, own
The analyte concentration unit is defined here. It is used in both the cal-
ibration and the measurement itself.
Under '
own ' you can also define your own unit with 5 ASCII characters:
unit 5 ASCII characters
Please note that this unit does not form part of the measured value itself
but is only a supplement. This means that it cannot be used for calcula-
tion, for example to compensate for changes in order of magnitude. For
this reason the concentration information in the following method pa-
rameters is given without mentioned the unit.
6.5.3 Measuring parameters
PARAMETER Conc
:
├
measuring parameters
: ├
electr.id
├
drift
├
temperature*
├
method
├
delta measurement
└
stirrer
(* only appears if no temperature sensor is connected)
The measuring parameters describe the settings which are of direct
importance for the measurement.
electr.id: 12 ASCII characters
You can assign any name you want to the connected ion-selective elec-
trode. This electrode Id is then contained in the report header for meas-
ured values. Each time that the electrode is calibrated the resulting cal-
ibration data will be assigned to this entered electrode Id.
In this way you can enter several electrode Ids for each type of ion. This
allows you to switch between various electrodes and to select their as-
sociated calibration data. However, a requirement is that each new
electrode Id is linked with a new calibration. Then you can use <SE-
LECT> under the measuring parameter electr.id to select one of the
stored electrode Ids which has been calibrated with the current type of
ion.
In order to delete an electrode Id and the calibration data linked with it
this must be reset under <CAL.DATA> ( Reset cal. , see Sec-
tion 7.1.2).
drift: 0.1...1.0...999.9 mV/min, OFF
A measuring signal which changes as a function of time is regarded as
being sufficiently constant when its drift drops below the value defined
here. This can be used as criterion for the pH/Ion Meter if a displayed