CAN bus wiring

[Red_Micro]

In building a small low power CAN network (~1m, ~10 nodes) I'm thinking of how the wiring can be. It has to have four wires (CANH, CANL, Power and GND). The "master" node will power the rest of the nodes. In the attachment there's a high level block diagram and several random wiring ideas. There can be two options: a daisy-chained architecture or a central hub. Given that I have four wires maybe a hub would be more compact, but the daisy chain could give more flexibility depending on the location of the nodes. The IDC one looks good, maybe it can be modified with an smaller connector and twisted ribbon cable. The drawback is that flat ribbon takes more space. So I basically brainstorming right now. Any ideas or suggestions?

[ChristofferB]

Ribbon cable and IDC or DSUB9 connectors would be ideal, in my opinion, as you could add devices into the cable by just crimping on a new connector

[greasemonkey]

If you want to do it properly you need to daisy-chain it and terminate. The standard CAN bus cable impedance is 120Ohm but it is expensive and hard to work with. You may use UTP or STP cable but you need to terminate it with 100Ohm resistors. It will work just as well and you have enough spare wires for power.

Ribbon cable and a central hub topology will probably work too but you may have problems at higher baud rates and would be susceptible to EMI.

I would do it properly.

[dietert1]

On the hardware level CAN is simple and easy to use. USB cable with DSUB9 connectors works well. I think the bus should have no other connectors than those for the nodes. And the bus should include its terminators, so you don't have to think over the terminators again when connecting a node. The terminator fits into the plug.
I remember making a bus with 1 m segments from node to node and with 12V as supply to feed analog circuitry in the nodes.

Regards, Dieter

[Siwastaja]

Daisy chain or short (some 5-10 inches max) stubs work, use whichever is more handy. Do note that daisy chaining is a special case of stubs, just with a smaller stub length down to a few millimeters on a well laid out PCB.