Metrohm 820 IC Separation Center - Manual (Page 62)

3 Operation
819 IC Detector / 820 IC Separation Center
54
Full scale The full scale range (operating range) sets the
desired sensitivity for the analog output. The
possible values of the full scale range in
µ S/cm
depend on the preset measuring Range .
This value can be reduced in a total of 11 stages by a factor 1 (low-
est sensitivity) up to maximum a factor of 2000 (highest sensitivity).
The full-scale range is primarily used to increase the sensitivity for
the recording of the chromatogram following the electronic back-
ground compensation of the eluent sensitivity (auto-zero function,
see also description of the auto-zero function above.
For the selected full-scale range (FS), the linearity of the conductivity
measurement is assured in the range –1.8 Full Scale … +1.8 Full
Scale. If the measured value violates these limits, the live display of
Conductivity in the WATCH WINDOW changes it’s color to the settings
for Out of range . (default: red). At the same time the absolute conduc-
tivity is displayed instead of the auto-zero value.
The full-scale range determines the limits for the output of the analog
signal at analog output 5 (0 … 1 V). The polarity of the output signal
can be changed at any time with the parameter Polarity to +
(0 … +Full Scale) or – (0 … –Full Scale).
Fig. 27: Diagram of measuring and full-scale range
Full-scale-range Measuring range Analog output
Conductivity
0
R
1.1 R
0
+ FS
– FS
+ 1.8 FS
– 1.8 FS
0
+
–
0 V
10 mV
10 mV
Conductivity Out of Range
abs. Cond.
Out of Range
Conductivity Out of Range