Analog Input Signal Scaling For Dnp3 Master Presentation - Hitachi Relion 670 Series Communication Protocol Manual

Section 3
Vendor-specific implementation
The ratio, multiplicative and divisor scaling methods use the first two arguments, souceMinVal and
sourceMaxVal, to define the source value range inside which the object is to be used. The complete
value range of the object is usually wanted even though the user could freely define the source range.
Arguments three and four, destMinVal and destMaxVal, define the destination value range. In ratio
scaling, arguments destMinVal and destMaxVal define the corresponding range of the scaled, reported
DNP3 value.
DNPvalue=
(sourceValue - sourceMinVal)
GUID-9F985816-2268-412A-AE24-ED90EAC44AD7 V2 EN-US
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.
DNPvalue
GUID-35F9E774-67FF-4257-8BA1-6D2E2CB4EC57 V1 EN-US
3.7.2

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
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.
18
= ×
sourceValue
=
destMaxVal
presents a typical example of a signal flow in the IED from the CTs, VTs to the DNP3 master.
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
(destMaxVal-destMinV V al)


(sourceMaxVal - sourceMinVal)
1MRK511391-UUS Rev. L

 +destMinVal

(Equation 1)
(Equation 2)
(Equation 3)
GUID-CAC9E9AA-B58D-4A9E-9337-914BE52A9AB8 v5
DNP, 670 series
Communication protocol manual