At the moment I am trying to set up my first DeviceNet system. I notice however that the DeviceNet Scanner (1769-SDN) is not supplying the other nodes with 24V dc (on the red & black lines). Is this correct? Do I need to connect an external 24V to these lines on the scanner? Thanks in advance

You have to supply the Dnet trunk line with 24VDC. the card only gets 5vdc from the backplane.

here is a link to the manual on the AB website.

http://literature.rockwellautomation.com/i...um009_-en-p.pdf

Good Luck.

he is correct each DNET Comm module draws it pwoer from the trunk line. Pay attention to the loading and voltage drop rules. Add a power supply as needed. IT can get tricky, but following the manual you should not go wrong.