Rockwell Automation T3831 ICS Regent Communications Package for Winterpret - Manual (Page 29)

Communications Package for W INTERPRET (T3831)
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pack the bit type variables in each Regent into word type
variables (using the Block Move instruction in ladder logic)
then we could transfer 16 bits of data in only 2 bytes of GPL
word data instead of 16 bytes of GPL bit data. In each Regent
that receives the GPL data, the word data would be unpacked
into individual shared control relays (again, using the Block
Move instruction in ladder logic). In our example above, this
type of optimization can significantly improve the GPL cycle
time and reduce the increase in application program scan
time.
For example, Table 8 shows new optimized GPL data
quantities for each Regent in our example.
Table 8. Optimized GPL Data Configuration.
Type of
Variable
Regent 1 Regent 2 Regent 3 Regent 4 Totals
Bit Data 50 100 60 320 [none]
Packed Bit
Data in
Words
4 words
(includes
14 spare
bits)
7 words
(includes
12 spare
bits)
4 words
(includes
4 spare
bits)
20 words
(no spare
bits)
35
Word Data 10 42 15 65 132
FP Data 0 0 10 20 30
With this configuration our total GPL data would be reduced
from 914 bytes to only 454 bytes. Using this new total GPL
data quantity in the graphs in Figures 12 and 13 shows that
our optimized cycle time would be 0.55 seconds and the
increase in scan time would be reduced to only 75
milliseconds.
For large amounts of bit type variables that need to be
communicated using GPL, this optimization method provides
significant performance improvements.