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3 Scaling and Thresholds for Transmission
3.1 Measured Value Scaling
3.1
Measured Value Scaling
Depending on the rated values of the primary equipment of the installation (Vrated, Irated), the scaling of the
measured values has to be adapted in order to ensure a correct transmission of these values in integer format
(±32767) including implicit fractional digits.
Example with rated current: 120 A
Primary current values in SIPROTEC are then displayed in A.
For transmission with implicit one fractional digit a scaling factor of 10 must be used:
120 A then is transmitted as: 120 * 10 = 1200
Example with rated current: 1500 A
Primary current values in SIPROTEC are then displayed in kA.
For transmission with implicit 3 fractional digit a scaling factor of 1000 must be used:
1.5 kA then is transmitted as: 1.5 * 1000 = 1500
In addition to the scaling factor it has to be determined whether the measured value shall be transmitted as
primary value, secondary value or percentage value (i.e. the measured value type).
NOTE
By default, only primary values are used with DNP3 IP.
For the scaling of a measured value, a scaling index in the conversion table has to be selected which is a com-
bination of scaling value, threshold value and measured value type as shown in the following table with the
default entries:
Table 3-1
Scaling Index
0
1
2
3
4
5
6
7
44
Conversion Table for Measured Values with Default Entries
Scaling Factor
Measured Value
Primary value
10
Primary value
100
Primary value
100
Primary value
1000
Primary value
100
Primary value
10
Primary value
10
Primary value
100
Threshold Value
Type
(in%)
5
3
10
5
0.1
2
2
10
SIPROTEC, Communication Module, Communication Profile
By Default Used for
AC currents
AC voltages
Power
Power factor
Frequency
DC voltages
Temperatures
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C53000-L2040-C354-1, Edition 02.2012
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