ProSoft Technology MVI69L-MBTCP - Manual (Page 74)

Backplane Data Exchange MVI69L-MBTCP ♦ CompactLogix Platform
User Manual Communication Module
Page 74 of 152 ProSoft Technology, Inc.
January 6, 2014
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 will be invalid. All commands containing invalid data are ignored by the module.
Client Command List
Up to 10 Modbus TCP/IP Client connections can be defined in the MVI69L-
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 will be 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 server.
 Server IP Address
 Modbus Service Port of the server
 Modbus Function Code: This is the type of command that will be 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 on page 103. The command error codes
can be viewed in the Diagnostics window of PCB (Page 99). They can also be
transferred from t
he 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 (Registers 0
to 239), so it can be transferred to the processor in the input image.