Opto22 Ethernet driver for Linux


Curt Wuollet

Hi Dave

There will be, I think. I started writing code to talk to the brain using Modbus/TCP. The brain doesn't like being repeatedly polled at even moderately high rates. Twice now I have attempted to work this out with their customer service and things stalled both times. This could be accomplished with the recently announced (on this list) modbus/TCP driver/IO process, it's much further along than my poor hacking as I stopped when the brain got recalcitrant. This new code
is done by Philip Costigan. Modbus/TCP is my preferred proto as it _should_ work with several IO products. (people like to "extend" it) By the way I forgot to thank and congratulate Phil properly which I shall have to rectify.

There is another way to talk to the Ethernet Brain that is Opto22 specific, they have a published (but not open) protocol that has
something to do with firewire, although I don't know what. I haven't been real interested as it would only work with their stuff. Although they mention firewire, It's built on top of Ethernet.
There is no reason really, I couldn't implement this proto, at least the subset we'd need for lplc, if there is sufficient interest. If you don't need high data rates the Modbus/TCP will work. They only support 5 of the Modbus operations, but they are enough for many
purposes. Look at Philip's code. There is also example Modbus/TCP code on the Modicon site. If those don't meet your need, we can talk about the private proto as I have a brain and rack that are gathering dust and they were fairly spendy.



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