rs485 protocals   Guidance, please

Ok, I have bee looking into this for a few days now and have found the hardware which is rather simple, but I just dont get the code.
I have posted a few times regarding the subject and I think I have better understanding of what Im looking for.

I want to hook up two ( or more) arduino’s up on a 485 network and pull datapoints from them to a computer. I can do this with with a single device now using python but I would like to expand it. distance between the devices will be 50-100ft and I would prefer a hardwired link as apposed to Rf. I imagine having a “master” hooked to the computer via usb, which recieves the requests from the computer and polls the slaves for the data

From what Ive seen thus far there isnt really any type of “library” for 485 based comms, it needs to be written from scratch. I have seen examples that people have done, with code.
Tinkering with Electronics...: Arduino and RS485 (ENGLISH VERSION) But I must confess _ Im lost on the code :-[

Perhaps Im over thinking it or it it just beyond my means currently, But Im anxious to learn, Can anyone recommend any simpler examples or maybe a different approach?


Probably the most common protocol used in industry on RS485 links is the Modbus protocol. Here is a good start on understanding the standard. Library code is avalible but I don’t know if a Arduino specific library has been contributed yet.


In the past I have used an adaptor that changes the protocol from rs232
to rs485 and back again, the units are reasonably inexpensive and simple to incorporate.