ProSoft Technology MVI56E-MNETR - Manual (Page 108)

MVI56E-MNETR ♦ ControlLogix Platform Reference
Modbus TCP/IP Interface Module with Reduced Data Block User Manual
Page 108 of 153
ProSoft Technology, Inc.
August 31, 2009
The following table describes the structure of the response block.
Offset Description Length
0 1000 to 1124 1
1 to 40 Output Data to preset in module. 40
41 Spare 1
Command Control Blocks
Command Control Blocks are special optional blocks used to request special
tasks from the module. The current version of the software supports four
command control blocks; event command control, command control, warm boot,
and cold boot.
Note: Event Commands and Command Control are not needed for normal Modbus command list
polling operations, and are needed only occasionally for special circumstances.
Event Command
Event command control blocks send Modbus TCP/IP commands directly from the
ladder logic to one of the clients on the module. The following table describes the
format of these blocks.
Offset Description Length
0 2000 1
1 to 4 IP Address 4
5 Service Port 1
6 Slave Address 1
7 Internal DB Address 1
8 Point Count 1
9 Swap Code 1
10 Modbus Function Code 1
11 Device Database Address 1
12 to 41 Spare 30
Use the parameters passed with the block to construct the command. The IP
Address for the node to reach on the network is entered in four registers (1 to 4).
Each digit of the IP address is entered in the appropriate register.
For example, to interface with node 192.168.0.100, enter the values 192, 168, 0
and 100 in registers 1 to 4. The Service Port field selects the TCP service port
on the server to connect. If the parameter is set to 502, a standard MBAP
message will be generated. All other service port values will generate a Modbus
command message encapsulated in a TCP/IP packet.