ProSoft Technology MVI69E-MBTCP - Manual (Page 73)

MVI69E-MBTCP ♦ CompactLogix Platform MVI69E-MBTCP Backplane Data Exchange
Modbus TCP/IP Enhanced Communication Module User Manual
ProSoft Technology, Inc. Page 73 of 150
May 20, 2015
Important: Take care when constructing each command in the list to ensure predictable operation
of the module. If two commands write to the same internal database address of the module, the
results are invalid. All commands containing invalid data are ignored by the module.
Client Command List
You can define up to 10 Modbus TCP/IP client connections in the MVI69E-
MBTCP. Each client connection can contain up to 16 commands each.
A valid command includes the following items:
 Command enable mode: (0) disabled, (1) continuous, or (2) conditional for
write commands only.
 Source or destination database address: The module’s database address
where data is written or read.
 Count: The number of words or bits to be transferred: up to 125 words for
Function Codes 3, 4, or 16; and up to 2000 bits for Function Codes 1, 2, or
15.
Note: 125 words is the maximum count allowed by the Modbus protocol. Some field devices may
support less than the full 125 words. Check with the device manufacturer for the maximum count
supported by the particular slave device.
 Server IP Address.
 Modbus Service Port of the server.
 Modbus Function Code: This is the type of command that is issued.
 Source or destination address in the server device.
Command Error Codes
As the list is read in from the processor and as the commands are processed, an
error value is maintained in the module for each command. The definition for
these command error codes is listed in Communication Error Codes (page 104).
You can view the command error codes through the Ethernet diagnostics port;
refer to Diagnostics and Troubleshooting (page 92). They can also be transferred
from the module’s database to the processor.
To transfer the Command Error List to the processor, set the Command Error
Offset parameter in the port configuration to a module database address that is in
the module’s Read Data area.
Note: The Command Error List must be placed in the Read Data area of the database, so it can be
transferred to the processor in the input image. Each MBTCP client must place their own
Command Error List within the Read Data area so that they do not overlap each other.