G
Hi all,
As an A-B eccentric, I support the developing concensus to use a PLC5-like structure. Don't forget about the S (status) section.
I'm unsure of the architecture some people have in mind, but in my mind, there is one and only one data table per physical PLC.
It seems to me that the whole issue of policing access to the data table is an unnecessary complication. There is no protection of the sort being discussed in A-B PLC's. You can write to any section of the data table from anywhere. The only (optional) protection is over access from
another PLC (e.g. via data highway). This is also a 'freedom' issue as in 'free' software - people may do things because of incompetence or
cleverness but we shouldn't assume that it must be incompetence simply because it may be contrary to personal beliefs or philosophies.
Gerry
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LinuxPLC mailing list
[email protected]
http://linuxplc.org/mailman/listinfo/linuxplc
As an A-B eccentric, I support the developing concensus to use a PLC5-like structure. Don't forget about the S (status) section.
I'm unsure of the architecture some people have in mind, but in my mind, there is one and only one data table per physical PLC.
It seems to me that the whole issue of policing access to the data table is an unnecessary complication. There is no protection of the sort being discussed in A-B PLC's. You can write to any section of the data table from anywhere. The only (optional) protection is over access from
another PLC (e.g. via data highway). This is also a 'freedom' issue as in 'free' software - people may do things because of incompetence or
cleverness but we shouldn't assume that it must be incompetence simply because it may be contrary to personal beliefs or philosophies.
Gerry
_______________________________________________
LinuxPLC mailing list
[email protected]
http://linuxplc.org/mailman/listinfo/linuxplc
