ProSoft Technology InRax MVI71-DNPSNET, Руководство пользователя

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Reference MVI71-DNPSNET ♦ PLC Platform
Distributed Network Protocol Interface Module
ProSoft Technology, Inc. Page 81 of 100
September 22, 2008
The following figure displays the direction of movement of the DNP database
data between the module and the processor.
It is important to understand the relationship of the block identifications and the
data in the module. Confident data handling in the module is only accomplished if
the user defines a consistent set of parameters in the module configuration,
handles the read and write operations for the blocks in the module in the PLC
ladder logic and understands the requirements of the DNP master unit.
This manual contains forms to aid in designing your system. They can be used to
document the relationship between the point assignments, block identification
numbers and the PLC file and offset values and to define the program
configuration. Use these forms during your design phase.
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 Binary Inputs (number of words,
each containing 16 binary input points). These data are transferred to the module
from the PLC using the read operation. 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 will generate an event message for the points that change.