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Murray R. Van Luyn
04/05/12 11:37
Read: 1305 times
From Down Under.

#187015 - Data Link Layer for RS485?
Hi Guys,

Suppose I wanted to network some microcontrollers within close proximity, using a single master/ many slave, 4-wire multi-drop RS485 configuration, then what are my options for a standardised and very simple data link layer?

From the master, I will need to send repeated data requests to each of the slaves, and have them individually report back with some converted sensor data. The master may also need to ask certain slaves to operate outputs under their control, and have them report back when successfully done.

Now here's the fun part... Each of the slaves may end up with it's own serialised 16-bit node address, and the master will have to learn about the slave population through an initialisation-time address scanning procedure. Well, that is unless there's a better way of possibly assigning node addresses dynamically, one that I don't yet know about?

I figure there has to be some industry standard covering the ISO Data Link Layer, that lends itself toward use within a master/ slave, short request and response approach to M2M communications, so I would be very interested in a few brief pointers outlining any viable topics for further investigation.

Murray R. Van Luyn.

Disaster, they're making me code for PICs!!!

List of 5 messages in thread
Data Link Layer for RS485?      Murray R. Van Luyn      04/05/12 11:37      
   Modbus      Aubrey Kagan      04/05/12 13:13      
      Yep, Modbus Fits The Bill.      Murray R. Van Luyn      04/05/12 14:49      
         Changing the Modbus Address      Aubrey Kagan      04/05/12 17:05      
            You've been busy.      Murray R. Van Luyn      04/06/12 12:04      

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