ProSoft Technology MVI46-DFNT - Manual (Page 71)

MVI46-DFNT ♦ SLC Platform Reference
EtherNet/IP Client/Server Communication Module User Manual
ProSoft Technology, Inc. Page 71 of 177
October 12, 2010
4.2 Functional Overview
4.2.1 General Concepts
The following discussion explains several concepts that are important for
understanding module operation.
Backplane Data Transfer
The MVI46-DFNT module communicates directly over the SLC backplane. All
data for the module is contained in the module's M1 file. Data is moved between
the module and the SLC processor across the backplane using the module's M1
file. The SLC scan rate and the communication load on the module determine the
update frequency of the M1 file. The COP instruction can be used to move data
between user data files and the module's M1 file.
The following illustration shows the data transfer method used to move data
between the SLC processor, the MVI46-DFNT module, and the TCP/IP Network.
As shown in the diagram, all data transferred between the module and the
processor over the backplane is through the M1 file. Ladder logic must be written
in the SLC processor to interface the M1 file data in the module's internal
database. All data used by the module is stored in its internal database. The
following illustration shows the layout of the database:
Module’s Internal Database Structure
4000 registers for user data
M1 File
0
3999
1000 registers for command control 4000
4999
Data registers in the module above 4000 are used for command control. When
special values are written in this register set, the module performs specific
functions. The following topics define the special functions handled by the
module.