RS485 Communication help.

Hello all,

I'm pretty new, so it would be nice if any explanations would be as basic as possible. :slight_smile:
I am planning to get a Schneider Conext ComBox. It has a RS 485 connection, and they even have a Modbus map on their site ( see the GridTie Device version.

I need help reading data from a specific "registry" (as said in the modbus map). I would like to know how to read types str16,str20,uint16,uint32.

Do I need a separate shield for this? A library?


You need some thing to convert from RS485 to TTL.


You need some thing to convert from RS485 to TTL.


Something like this?

What after that?

In terms of hardware, you need a MAX485 (or, the cheaper but pin-compatible TI DS485) for TTL-to-RS485 conversion, and obviously whatever connector you want to interface with your other stuff. There are often specific shields that combine the interface IC and specific connectors for a particular application. (RS485 does not define connectors, but many protocols based on RS485 do.)

For software, there are libraries for various serial protocols. Search Google for the protocol you intend to use, like “arduino library”. (Doing this for modbus gives me this, which is maybe what you want?)

MDTech-us_MAN, did you end up getting this working?


You might not get an answer from MDTech-us_MAN.

If you check his posting history, you will find that he hasn't posted anything else in the 20 months since he started this thread