Sorry I'v been out all day ...
Yes 485 or at least 485 esque is what I thought.
I don't want to go wireless the cost of TX units will far exceed the cabling cost using cat5 as all runs are in existing conduits.
What I don't know is how 485 works either the protocol or the physical layer.
My data rates will be very small, a byte from a node every few seconds would probably be overkill.
There are things that need to happen quickly, modifying throttle position to compensate fro a reduction in generator frequency for example but that can be handled locally in the node, all the coms will have to do is tell the local logic if it should be generating or not, and report status to the HMI.
I suppose what I am asking is do I start from scratch, design a protocol and then build a library to bit bang it, which I think is entirely plausible I might add, or is there some quick win, already implemented on 'standard' hardware that will do what I need.
Should I buy 'Nano' Mini or MinoPro?
If I am bit banging I guess it doesn't matter but I would be interested to know if any of those might simplify my coms implementation.
OK I get that if the project was the coms I should perhaps spend several months researching and testing but the project is the distributed logic network.
In the same way that I am buying Arduino boards and displays, so I can concentrate on the functionality not the electronics, I would like to find a quick win for my coms requirements.
If there isn't a fit then I will build a protocol, design a library to implement it and then publish but I cant help thinking that clever folk than me will have done all that already and I simply haven't found, or perhaps recognised, it yet.
Feel free to point out my failings ... it how I learn
Thanks
Al