ProSoft Technology MVI71-GEC - Manual (Page 49)

MVI71-GEC ♦ PLC 5 Platform Reference
Generic ASCII Ethernet Communication Module User Manual
ProSoft Technology, Inc. Page 49 of 86
May 11, 2011
Block Transfer Backplane Data Transfer
The MVI71-GEC module communicates directly over the PLC backplane. Data is
paged between the module and the PLC processor across the backplane using
BTR and BTW operations. Data is transferred from the module to the processor
using the BTR blocks, and data is transferred from the processor to the module
using BTW blocks.
The following illustration shows the data transfer method used to move data
between the PLC processor, the MVI71-GEC module, and the Ethernet network.
All data transferred between the module and the processor over the backplane is
through the BTR and BTW blocks. Ladder logic must be written in the PLC
processor to interface the block data with user data files.
Normal Data Transfer
Normal data transfer includes the transferring of data received or to be
transmitted on the servers and the status data. These data are transferred
through read (BTR) and write (BTW) blocks. Refer to Module Configuration for
a description of the ladder logic required to perform the data movement within the
PLC processor. The structure and function of each block is discussed in the
following topics.