Metrohm 781 pH/Ion Meter - Manual (Page 85)

6 Methods / Parameters
780/781 pH/Ion Meter, Manual
75
) old ( value Measured
size . smpl
V
factor ) new ( value Measured total ⋅ ⋅ =
Please note that the unit of the measured value is not altered in this cal-
culation. The Meas. value(new) will therefore always have the same unit
as Meas. value (old), i.e. the unit which has been set under PARAMETER
CONC/ion parameters and with which the calibration has been carried
out.
For example, if you use the
smpl.size unit: mL , then the quotient
V
total
/smpl.size will represent the dilution of the sample when it is larger
than one. It can also describe the concentration of a sample if it is
smaller then one.
You can also weight out your liquid sample before dilution and then se-
lect the sample size unit g. For a correct calculation the density of the
sample in g/mL should be entered as the factor.
For a more individual input of the sample data you can also have the
program automatically request the sample size and sample size unit di-
rectly before each measurement (see Preselections, Section 6.5.9 and
Section 6.6.2).
6.5.5 Calibration parameters
(applies only for measurement type: direct)
PARAMETER Conc
:
├
calibration parameters
: ├
temperature*
├
drift
├
report
├
cal.interval
├
no.of standards
└
addition
┬
manual
-
conc.1...n
└
auto
┬
min.conc.
├
max.conc.
├
V init
├
no.of Exchange Units
├
conc.1...n
└
V Exchange Unit 1...n
(* only appears if no temperature sensor is connected)
In the direct measurement of the concentration the calibration parame-
ters primarily describe the exact presentation of the calibration stand-
ards. The evaluation of the calibration is described in Section 9.2.2.
temperature 0.0...25.0...99.9 °C
Just as for the measuring temperature, the calibration temperature
should be entered if no temperature sensor is connected. If the measur-
ing and calibration temperatures are different then this is absolutely
necessary for the automatic temperature correction of the electrode
slope. The temperature is then stored and indicated by the suffix ' man-
ual ' in the report header.