CAN Network Wiring Standards?

[GoingFastTurningLeft]

I've been looking all over the internet and haven't found anything on this.

I've been asked to find out what the wiring specs for using CAN in a building is. Seems like all the info I pull up on CAN is for vehicle applications or CAN's protocol. Its cool to see the project where someone tapped the CAN line in a hybrid vehicle and interfaced it to a tablet PC to show all the data, but that doesn't help me.

The question isn't exactly how to connect it, it's things like if I run a main bus wire, how many times can I tap into it to connect it to a repeater, is there a restriction for how long this tap to repeater wire can be, is there a restriction on how far apart these taps have to be, what gauge wire, etc.

Basically, we know how to hook it up, we just want to make sure we tell the electric guys to run the right wires

[dyarker]

A single twisted pair will work well. Or, Cat-5. See:
http://en.wikipedia.org/wiki/Controller_Area_Network
for more info, and links to standards.

Cheers,

[GoingFastTurningLeft]

Of course I've already read the wikipedia article

Everything is mainly geared towards vehicle systems and the data format.

The system we're working on has just over 300 nodes in 6 different places.

On a small scale system cat 5 is fine, but probably not in this application.

Its really the information on the main 'trunk' line that i'm looking for.

I found some information on DeviceNet which is based on CAN and follows the same rules that's sort of helped.

[haklesup]

Did you find this one
http://www.interfacebus.com/Design_Connector_CAN.html
http://www.can-cia.org/

The ISO standards and the datasheets/appnotes and reference designs from the chip makers are your best sources.

http://www.linear.com/pc/productDetail. ... 0,C1,P2298

Cat5 is good for 100MHz and 100m in length when used as differential pairs. It appears the CAN bus is only 20Khz and has a termination resistor. Given the convenience and variety of RJ terminations for it, it seems like a good option.

Maybe what you want to look at is CANopen. Also check out the Open Source projects on www.sourceforge.net

[desy2820]

Do you already have the devices picked out? If so, what does the manufacturer recommend for wiring between the devices?
Best source of this info is the maker of the devices you're trying to connect.

Hope this helps!