CLX - more than a single 17 slot rack ?

What is the easiest way for a ControlLogix system to have more than a 17 slot local rack ?

I need to have about 29 I/O cards (and it may well be 35 when I'm done), all in the same control panel and just one cpu card.

I don't see any way to link two or more racks?

They really don't link together as an "extended local rack" like the SLC does.

I would use a 1756-CNBT in each rack, linking them together via ControlNet. I have a system with 12 racks all linked together this way.

Personally I'd have my Controllogix rack only have communication cards then use flex I/O on ControlNet as OZEE Mentioned for all the IO.

That is going to be one heck of a cabinet.

You can bridge 1756-series chassis with ControlNet or EtherNet/IP bridge modules.

A great resource for getting familiar with ControlLogix system layout is the ControlLogix Selection Guide.

http://literature.rockwellautomation.com/idc/groups/literature/documents/sg/1756-sg001_-en-p.pdf

As Ozee mentioned you can use the 1756-CNB or 1756-CN2 (newer version) and hook the chassis' together using ControlNet. ControlNet may be more than you want to tackle though.

You can also do the same thing using EtherNet/IP. The 1756-ENBT or 1756-EN2T (new higher performance version).

Either way, you add that module to your local chassis and then add a similar module in the remote chassis. As mentioned, you might go with a small chassis for the controller and comm card and then use Flex I/O for all of the remote.

** EDIT ** Ken typed faster than I did!!

OG

If it was me I would stick to ethernet/IP. I have converted all my systems over to Ethernet/IP including VFD's. It was very easy and I didn't need to buy ControlNet software!

Flex I/O works well for remote racks. I have several connected over an Esteem wireless network. (Nothing very critical!)

Kevin