ProSoft Technology MVI56E-MNETC - Manual (Page 125)

MVI56E-MNETC ♦ ControlLogix Platform Reference
Modbus TCP/IP Client Enhanced Communication Module User Manual
ProSoft Technology, Inc. Page 125 of 183
February 3, 2013
3 Then the module goes back to where it left off on the MNET Client x
Command List and continues routine polling.
Event Command blocks send Modbus TCP/IP commands directly from controller
tags by ladder logic to the Client command priority queue on the module. Event
Commands are not placed in the module's internal database and are not part of
the MNET Client x Command List.
Block 4000 is functionally identical to Block 2000 with the addition of the Event
Command Sequence Number parameter.
Block Request from Processor to Module
Word Offset Description Length
0 4000 to4029 (last digits indicate which Client to utilize) 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 Event Command Sequence Number 1
13 to 247 Spare 235
The module will use the parameters passed in this block to construct the
command.
 The IP Address for the destination server to reach on the network is entered
in four registers (1 to 4). Each octet value (0 to 255) of the destination
server's IP address is placed in one of the four registers 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 (Modbus API for network
communications) message will be generated. All other service port values will
generate a Modbus command message encapsulated in a TCP/IP packet.
 The Slave Address is the Modbus node address for the message.
 The Internal DB Address
parameter specifies the module’s database location
to associate with the command.
 The Point Count parameter defines the number of points or registers for the
command.
 The Swap Code is used with Modbus functions 3 and 4 requests to change
the word or byte order.
 The Modbus Function Code has one of the following values 1, 2, 3, 4, 5, 6, 15
or 16.
 The Device Database Address is the Modbus register or point in the remote
server device to be associated with the command.