Adding a remote IO rack for 1756-L61

I will be adding rack of remote IO under a 1756-L61 and I am wondering what are my options? I have a 1756-DHRIO module already in the rack with my processor using ch A for DH+ communication.

The client would prefer to use a controllogix rack for the remote IO....can I simply place a 1756-DHRIO card into the remote rack and use channel B to connect via RIO to the rack containing the PLC?

I have no more space in the rack that contains the PLC.

Thanks in advance!

Does the existing rack have any other communication modules?

ControlLogix doesn't support RIO between CLX racks.

It has an ENBT card.

You could use PointIO with an ethernet adapter, or a CLX rack with an ethernet card. You'd need RSNetworx for Ethernet to schedule.

If I had a slot available, would you suggest using a ControlNET card?

Your options for connecting 1756-series chassis to a ControlLogix controller are ControlNet and EtherNet/IP networks.

Since you already have a 1756-ENBT, the simplest mechanism would be to use another 1756-ENBT in the remote chassis. RSNetworx for EtherNet/IP is not required. If your existing 1756-ENBT is connected to your plantwide or enterprise network, you will need to be certain that your switch and network support IGMP Snooping and IGMP Querying.

Ethernet technologies and basic layout are covered in the Rockwell Automation publication "EtherNet/IP Modules in Logix 5000 Control Systems", publication number ENET-UM001.

Another option is ControlNet, which requires 1756-CNB, -CNBR, -CN2, or -CN2R modules in both chassis. RSNetworx for ControlNet software is required to create the network schedule. ControlNet has the advantage of not requiring special switches or powered elements in the network, and delivers repeatable and precise performance, but does require specific software tools and some familiarity with the technology.

ControlNet configuration in ControlLogix systems is described in the Rockwell Automation publication "ControlNet Modules in Logix 5000 Control Systems", publication number CNET-UM001.

Thank you so much! I will be using an ENBT in my remote chassis.

Ken,

can the new 1756-RIO card be used in adapter mode in a remote ControlLogix rack ?

Alan