Metrohm viva 1.1 (ProLab) - Manual (Page 941)

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7 Devices
viva 1.1 (for process analysis)
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Lower limit Lower limit at which the integration is stopped and the output is limited
(ARW measure).
NOTE
This is not a guaranteed limit for the total output.
Output slope Following calculation of the actual control value, the value is multiplied
with this scaling factor for output at the analog output. The result must be
the correct value for the output.
NOTE
This value is NOT the factor between the physical value ranges. This fac-
tor is automatically multiplied as well.
Output offset Following calculation of the actual control value, this scaling offset is
added to the value for the output at the analog output. The result must
be the correct value for the output.
NOTE
The relationship to possibly different value ranges for input and output
must be observed for the interaction between upper/lower limit and
output slope / offset.
Example
A KL3044 (0 - 20 mA) is plugged in as input and a KL4424 (4 - 20 mA) as
output. As the limit, e.g., 7 - 17 is entered. Because of the different
ranges of the terminals, 4 mA suggests itself as an output offset to start.
The output slope is normally set at 1. The factor of 0.8 on the basis of the
various physical ranges [ (20-4)/(20-0) ] is determined automatically and is
not permitted to be specified as well.
Because of the fact that the values 7 and 17 still apply before the output
modification, the following limits will actually be found:
7·0.8 + 4 = 9.6 mA
17·0.8 + 4 = 17.6 mA
Conversely, in order to calculate which limits need to be specified in order
not to go outside of a particular control value range, the output offset
must be subtracted and then divided by the output slope and the given
physical factor.