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1MRK 511 391-UUS A
3.7.2
670 series 2.2 ANSI
Communication protocol manual
In multiplicative scaling, argument four destMaxVal becomes a scale constant.
DNPvalue sourceValue destMaxVal
=
GUID-6AE38BAE-8FD6-44DD-9D53-45BE7AB121FF V1 EN-US
In divisor scaling, argument four destMaxVal becomes a scale constant.
sourceValue
DNPvalue
=
destMaxVal
GUID-35F9E774-67FF-4257-8BA1-6D2E2CB4EC57 V1 EN-US
Analog input signal scaling for DNP3 master presentation
The presentation of an analog value in a telecontrol protocol varies between the
different protocols and also with the age of the used protocol version. The range is
from a simple 8 bit integer up to a double precision floating point. Internally in the IED
many calculations are floating points.
PCM600 supports the re-scaling and the justification to the register presentation given
by the project demands.
Figure
3
presents a typical example of a signal flow in the IED from the CTs, VTs to
the DNP3 master. The CT, VT is connected to the IED by the transformer module
TRM. The SMAI function block is a preprocessor to calculate, check the signals for
further use in application function blocks of type MMXU. MMXU calculates the RMS
values for the most used analog signals like, V, I, P, Q, for example. The RMS values
are available in floating point presentation as output signals of function blocks of type
MMXU.
MMXU
or other
SMAI
application
functions
Source values
ANSI13000288 V1 EN-US
Figure 3:
PCM600: typical example of DNP3 scaling
The actual DNP3 specification defines 6 variations for the presentation of an analog
value:
Vendor-specific implementation
×
Equation mode
Reg. justification
Scaling to
DNP3
Comm.
DNP3
Interface
demands
DNP3
Register length
(Float, 32, 16, 12, 8 bit)
Section 3
(Equation 2)
(Equation 3)
GUID-CAC9E9AA-B58D-4A9E-9337-914BE52A9AB8 v5
DNP3
'DEVICE PROFILE'
Analog Input Points
DNP3
master
Destination Values
ANSI13000288-1-en.vsd
21
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