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hello everyone,
first of all, because I couldn'st search in the forum that's why I am opening this topic .. so if it exist already, let me know and Ill delete this topic.
I am told to build communication network among controllers. Coumputers could also be included, but if then in future, so computer inclusion is not that important right now maybe next section.
can anyone write his/her experience about using CAN or RS485 or XML as communication protocol ? which one is better and why ? any practical example schematic/project must be fully explained?
regards.
<bold> i dont <deep> LIKE </deep> this forum </bold>
i go and try another and see if they can help
<bold> i now delete the toipic <bold>
Well, there really are formatting available on this forum.
You first have to decide what physical layer to use.
RS485 or CAN requires special hardware. RS232 is more readily available. Questions you first have to ask is (partial list): - simplex/duplex transfers - topology: point-to-point, bus, tree, chain, ... - maximum cable length - required bandwidth - the cost for the physical layer - use of existing cables - amount of processor load to get required bandwidth - ...
If you know what physical layer to use, it is possible to decide what protocol to use. The choice of protocol is greatly affected by the physical carrier - or you would have to spend time to tunnel the information, in case you use a physical layer that isn't suited for the selected protocol. CAN for example only transmits tiny packets.
Since XML is just a way of formatting information, you can use XML together with RS485. XML together with CAN would result in a lot of work creating the tunneling layer.
Strictly speaking, you can use ppp and tunnel TCP/IP on RS485 links too, but the required amount of code is normally too high.