About CAN bus and floating grounds

[minttujatapsa]

Hi,

Does anyone know would the system work if you have several nodes in CAN bus such that 1. each node is powered by isolated power supply and 2. those are connected only via CANL and CANH lines. The transciever chip used is MAXIMs --> offset may be from -80V till +80.

Thanks!

[valemike]

What applications engineers have told me is that since it is a differential pair, you may use only CANL and CANH, and things will work. They also told me that if their grounds are isolated, then you can only drift so much away from each other, and your 2-wire bus won't work reliably. Thus, if you have the extra ground pin, then you ought not to worry much about it.

So to be safe, add the ground pin. As far as the electronic theory of it, I don't know. Hopefully someone else can answer that.

-MIke