Ethernet switch with Point I/O & 22-COM-E

Hi, I have a control system consisting of a CompactLogix L35E, Micrologix 1000 with a 1761-NET-ENI, Micrologix 1100, and a Pv + 700. I was asked to add on a point I/O and a PF 40 with a 22-COM-E Ethernet adapter. Currently the PV communicates with the two micros and the L35E. The new addition of the Point I/O and 22-com-e will be controlled from the L35E processor. The Ethernet switch that is currently in the system is unmanaged. I’m not that well experienced in Ethernet communications therefore I want to ask will I be needing a Managed switch for the add on of Point I/o and the 22-com-e.
Thank You.

Great question, and thank you for posting the diagram.

If you have v18 or higher firmware in the CompactLogix, you will be able to select "Use Unicast Connection" for the I/O connection on EtherNet/IP.

That's important because a multicast connection would mean the Net-ENI and the MicroLogix and the PanelView Plus would all have extra traffic to filter out. While they are pretty good at it compared to a device that's unaware of UDP Multicast, that's extra loading on their Ethernet ports that could affect performance.

If you can use Unicast, that problem goes away.

I like having managed switches because it makes it easy to find noise or connection problems with the Ethernet cabling, but it's not an absolute requirement. Your system has devices most of which have an EtherNet/IP object that will report errors, so you're in pretty good shape for troubleshooting if you do have cabling or noise issues.

I was introduced to this tool again at a recent class. It is remarkably effective.

EtherNet/IP Capacity Tool

We could have skipped several hours of the early part of the training, had they fired up that tool during the first hour. It is important to be able to locate information and put it together by hand, but most of us in the class were already relatively familiar with how to research and figure out how to do things like that the hard way.

I did put that in the comments for the class which was, most excellent generally......there's really too much to cover in 24 hours though.

The Ethernet Capacity tool is great once you understand how to use it. For the system described an unmanaged switch wont hurt you. What will hurt you are the number of CIP connections the L35E has or will have. That processor only supports 32 connections. The coonections come from any device which communicates to the processor and is not defined as a physical connection. You need to get on the l35 we page to see the information, it will tell you current and max seen connections.

Analog io eats these connections as each analog card requires 1 connection. I think panel views use 4, and didital io can be rack optimized for a single connection for an entire io rack. PF drive used to require 4 connections but newer firmware it's down to 1 I believe. Don't forget you need spare connections for going online to the processor as well. This will cause com issues if you don't have enough and you'll chase your tail even with a managed switch.

Verify this first, otherwise you will need to upgrade the compact logix to an L4x processor. You probably have plenty of connections available but you would need to supply complete io details of the existing system and new io.