ProSoft Technology MVI71-DNP - Manual (Page 102)

MVI71-DNP ♦ PLC Platform Reference
DNP 3.0 Master/Slave Communication Module
Page 102 of 172 ProSoft Technology, Inc.
August 23, 2007
The 64-word block has the following structure:
Offset Variable Description
0 BTR ID Block identification code for the DNP user file to consider.
1 BTW ID Block identification code for the data request from the PLC. This
parameter has nothing to do with the user file record update.
2 to 61 Data This is the data to be written to the file.
62 to 63 Spare This value is not used.
The record number field is inserted before the data in the block. All records in a
file use the same BTR block identification code. Therefore, the record number
field is added to define where the data should be placed in the PLC. The ladder
logic must process this field and place the data in the appropriate data table.
DNP Digital Input Data
This data type stores the binary value of 1 or 0. The size of this data area is
determined from the configuration parameter Number of Binary Input Points. The
data area is partitioned into two separate areas. The first is the DNP binary input
data acquired from the PLC, and the second is the binary input data from IED
units on the DNP master port. The configuration parameter, Number of Binary
Input Points for PLC, determines the size of the PLC's data area. The remaining
portion is defined as the IED binary input data area.
PLC data are transferred to the module from the PLC using the COP command
in the ladder logic. Therefore, these data are read-only for the module and the
DNP master unit communicating with the module. When the module receives a
new block of this data from the PLC, it compares the new values to those
currently in the database. If there is a change in any of the data, the module
generates an event message for the points that change.
Data from IED units can also be placed in the DNP binary input data area.
Commands in the command list must specify the DNP database address (point
number) where the data will be placed.