ProSoft Technology MVI56E-MNETC - Manual (Page 120)

Guide to the MVI56E-MNETC User Manual MVI56E-MNETC ♦ ControlLogix Platform
User Manual Modbus TCP/IP Client Enhanced Communication Module
Page 120 of 183 ProSoft Technology, Inc.
February 3, 2013
Block Request from Processor to Module
Word Offset Description Length
0 2000 to 2029 (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 to 247 Spare 236
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.
The module then places the command in the command priority queue (if the
queue is not already full; maximum capacity is 16 commands), and returns a
response block to tell the ladder logic whether or not the command has been
successfully added to the queue.