PROFIBUS-DP - Parameterization in DIGSI
73
SIPROTEC PROFIBUS-DP - Communication profile
C53000-L1840-B001-03
Example Definition of the scaling for a power measurement value
In the parameter set is configured:
Nominal operation voltage of primary equipment = 12.00 kV
Nominal operating current of primary equipment = 100 A
It follows:
V
nom
* I
nom
* √3 = 2078.46 kW = 2.078 MW
In the SIPROTEC device the power measurement value is available with the following
number representation and unit (see table above), i.e. two relevant fractional digits:
0.00 ... 99.99 MW
According to this a scaling factor of 100 is meaningful for transmission of the informa-
tion as an integer value.
If the scaling factor is less than 100 then relevant fractional digits are lost.
A scaling factor of greater than 100 does not give more precision because there are
only two relevant fractional digits.
With that the "Measured value
Integer
" in the PROFIBUS-DP message has to be inter-
preted as:
+/- 32768 corresponds to +/- 327.68 MW
4.3.3 Parameterization in DIGSI
The Object properties dialog window (ref. to chap. 4.2) contains for measured
values - beside the property sheet Protocol info-Source or Protocol info-
Destination - an additional property sheet titled Measured value-Destina-
tion.
Figure 4-7 Scaling settings of a measured value
The scaling values assigned to the measured values per default are described in the
bus mapping documents of the SIPROTEC device types (ref. to page 3).
The scaling - and with that customization to the installation-specific operating values -
can be changed by selection of one Scaling index in the Object properties dialog
window of the measured value.
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