Analog Inputs - ABB RELION REF615R Manual

1MRS240048-IB C
3.2.3
REF615R
Communication Protocol Manual
For example, a DNP3 control command may be blocked through hardware or software
mechanisms; in this case, the actual status value would indicate the control failed because
of the blocking. Looping CROB actual status values as BIs has several advantages.
• The actual status of the control is included in class 0 polls.
• The status changes of the controlled point can generate events, which provide more
efficient and time-accurate method of reporting control values.
• The time stamp of the events combined can be used to calculate the delays between
the command and the status change of the controlled point.
Certain BOS points, for example, the ones related to the reset- or acknowledge points, are
not looped back as binary inputs.

Analog inputs

The following table lists analog inputs (object 30). It is important to note that 16 bit and
32 bit variations of analog inputs are transmitted through DNP3 as signed numbers.
The original DNP3 analog value is the same value as the IEC 61850 value
generated for the same point. Measurands in IEC 61850 are expressed as
floating point values while DNP3 analog values are integers. Therefore, it
may be necessary to scale the original DNP3 values in order to include
possible decimals in the DNP3 integer value.
The deadband is not configured in DNP3. It is configured at the device level. The analog
change events are therefore generated by the device functions, not DNP3. The analog
change event time stamp will inherently be accurate and consistent with the reporting of
events though other channels, for example, LHMI, WHMI and other communication
protocols.
There are four scaling options associated with analog input reporting.
• None: the reported value is the process value.
• Multiplication: the process value is multiplied by a constant. An offset is added
producing the reported value.
• Division: the process value is divided by a constant. An offset is added producing the
reported value.
• Ratio:
• Configuration-time ratio scaling: Find R for new set of {in_min, in_max,
out_min, out_max}
R = (out_max - out_min)/(in_max - in_min)
• Runtime ratio scaling: Reported value = (inval - in_min) * R + out_min
Vendor-specific implementation
Section 3
17