ProSoft Technology MVI71-MNET - Manual (Page 23)

Module Configuration MVI71-MNET ♦ PLC Platform
User Manual Modbus TCP/IP Interface Module
ProSoft Technology, Inc.
Page 23 of 109
June 23, 2009
2.5 Event Command Data
A user file containing Event Command Data is only required when event
commands are utilized in the application. This file holds the information required
for an event command. An array of these objects should be defined and hold the
event command set to be employed in the application.
2.6 Modbus Message Data
This new version of the module’s program includes the pass-through mode. In
this mode, write messages sent to a slave port are passed directly through to the
processor. It is the responsibility of the ladder logic to process the message
received using this feature. If the side-connect interface is used, this data set will
be placed in the file selected in the SC_DATA.TXT file starting at register offset
50. Ladder logic is required to parse the message or data set received and to
place the data in the correct user data file.
If the block transfer interface is utilized, the pass-through messages will be
passed from the module to the processor in special control blocks. Ladder logic
is required to handle each block received and to place the data in the correct
user data file.
This information is passed from the module to the processor using a block
identification code of 9996 if the unformatted pass-through mode (code 1) is
selected. Word two of this block contains the length of the message and the
message starts at word 3. Other controller tags are required to store the
controlled values contained in these messages. The Modbus protocol supports
control of binary output (coils - functions 5 and 15) and registers (functions 6 and
16).
Additionally, formatted message blocks can be sent from the module to the
processor when the pass-through option is selected using the format selection
(codes 2 or 3 in the MNET.CFG file). These blocks require less decoding than
the unformatted blocks. Refer to the user manual for a full discussion on utilizing
the pass-through option in an application.
2.7 ProSoft Configuration Builder
ProSoft Configuration Builder (PCB) provides a quick and easy way to manage
module configuration files customized to meet your application needs. PCB is not
only a powerful solution for new configuration files, but also allows you to import
information from previously installed (known working) configurations to new
projects.