OMRON CHAPTER 17 – Best Practices
Release 2.0 Page 255
It is important to design the PLC program and SCADA application together. This will naturally help
create arrays of information, and optimise communications allowing CX-Server to collect data in the
most efficient manner.
Consider the examples in the following 2 figures:
Figure 1, Bad grouping example
In Figure (1) we see the PLC Programmer has arbitrarily chosen to group data by its format: Integers,
then BCD then Floats (or even worse not at all!). When the SCADA is written, this data is used by
different pages and different update rates. The different colours are to indicate that each block must
be read individually, totalling 9 communication requests, which could be for as few as 9 memory
addresses.
Inte
e
BCD
Float
PLC Memory
Inte
e
BCD
Float
Inte
e
BCD
Float
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