ProSoft Technology MVI56E-DNPNET - Manual (Page 83)

MVI56E-DNPNET ♦ ControlLogix Platform Contents
DNPNET Ethernet Client/Server Communication Module User Manual
ProSoft Technology, Inc. Page 83 of 140
February 13, 2015
DNP3 Ethernet Server Backplane Data Flow
The Server Driver Mode allows the MVI56E-DNPNET module to respond to data read and
write commands issued by a Client on the DNPNET network. The following flow chart and
associated table describe the flow of data into and out of the module.
Step Description
1 The DNPNET server driver configuration data is obtained from the DNPNET configuration
tags via ladder logic. This configuration information contains data that can be used to
offset data in the database to addresses requested in messages received from Client
units.
2 A host device (DNP3 Ethernet Client unit) issues a read or write command to the module’s
node address. The MVI56E-DNPNET port driver qualifies the message before accepting it
into the module.
3 After the module accepts the command, the data is immediately transferred to or from the
appropriate internal database in the module. If the command is a read command, the data
is read out of the database and a response message is built. If the command is a write
command, the data is written directly into the database and a response message is built.
4 After the data processing has been completed in Step 3, the response is issued to the
originating Client node.
5 Counters are available in the Status Block to permit the ladder logic program to determine
the level of activity of the Server Driver.
The response messages from the server driver include an IIN (internal indication word)
defined in the Reference section.
The server driver supports object 110 (octet string data). Four points are pre-assigned
values as defined in the following table.
Point
Number Description
0 Module Name as assigned in configuration file.