ControlLogix RIO design questions

[williamlove]

I am designing a replacement for a SLC system. The existing SLC has two 12 slot chassis next to each other in the main panel connected by an extension cable that makes them act as one local chassis. The SLC system also has one 12 slot RIO chassis out in the field. A scanner card in the main chassis connects to that remote chassis.

Q1. The ControlLogix system will have two 16 slot chassis in the main panel (lots of spare slots). A 1756-EN2T will be installed in each of those two chassis to connect them. Is that a simple, sensible design? (Let's leave rings out of this for now, to keep it simple.)

Q2. The ControlLogix main chassis will have a second 1756-EN2T to connect to the HMI and workstation. Anything wrong there?

Q3. The remotely located SLC chassis will be replaced by a RIO panel containing Flex I/O. Do I need a second 1756-EN2T in the main chassis for this? Put another way, do you need multiple EN2T cards in the main chassis for multiple RIO panels, or is just one in the main panel enough to daisy chain(?) to multiple RIO panels?

 

[OkiePC]

1. I think so.
2. Good move. Separate network for I/O is always preferred.
3. I'd put the remote rack on the same I/O network as the 2nd rack in the main panel.

 

[williamlove]

Thanks for responding. On item 3, to do what you suggest...that means I only need one 1756-EN2T in the main chassis, for I/O right? (I'll still have the other one for HMI etc) Can I connect multiple RIO panels on the same "network" and does network just mean the same 1756-EN2T?

 

[PLCMentor]

Thanks for responding. On item 3, to do what you suggest...that means I only need one 1756-EN2T in the main chassis, for I/O right? (I'll still have the other one for HMI etc) Can I connect multiple RIO panels on the same "network" and does network just mean the same 1756-EN2T?

You're going down the right path. You can place multiple racks, drives, hmis, etc all connected to the same EN2T card. The separate cards just are for separate networks. Instead of two EN2T cards, some of the newer processors have a built in Ethernet port. The processor may be more expensive, but it is usually cheaper then the processor/comm card duo.



I generally do what you are doing. I have a EN2T card for all I/O, drives and other local network items. My PLC port connects to the SCADA network.

 

[williamlove]

Thank you!