MVI56-PDPMV1 ♦ ControlLogix Platform
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PROFIBUS DPV1 Master
User Manual
Page 45 of 251
ProSoft Technology, Inc.
Scenario 2: The PROFIBUS data fits into two backplane blocks (different PROFIBUS data
count per block)
For this example, we will subtract one word for each I/O backplane block, using
the following backplane configuration:
For this scenario, each backplane block reserves a maximum of 99 words for
PROFIBUS I/O data. The configured PROFIBUS I/O size (100 words) will not fit
into one block, so two backplane input blocks and two backplane output blocks
will be required to transfer the entire PROFIBUS I/O data.
Note:
For this scenario, block 0 is no longer required because there are two backplane blocks with
different data.
Backplane Block Overview
Block
Number
Input/
Output
Total word count in
backplane block
PROFIBUS Data
Word Count in
backplane block
Initial PROFIBUS Data
Word Offset in
backplane block
Last PROFIBUS Data
Word Offset in
backplane block
1
Input
107
99
0
98
2
Input
107
1
99
99
1
Output
104
99
0
98
2
Output
104
1
99
99
Note:
This configuration would be inefficient and is therefore not recommended. The previous
example is a more efficient configuration that will accomplish the same thing. This example is here
solely to illustrate how changing the I/O sizes without changing the amount of PROFIBUS data to
be transferred will affect the number of I/O data blocks the module will need to transfer.
