4 posts in this topic

Posted (edited)

Hello,

A while ago I modernised a magazine gathering / filmwrapping machine. This was a fairly big project for which I used an Omron CJ2M as the main PLC, 10 Wago Ethernet/IP fieldbus couplers, a Keyence CV-X420 vision camera and an Omron NS12 HMI. 

All of these components run on the same network which contains an unmanaged switch where the HMI, PLC and the first Wago are connected. The Wago’s act as a two port switch since they are all daisy chained. At the end of the Wago chain there is also the vision cam which is connected at the last Wago coupler.

At the time I was advised against using Broadcasting instead of Multicasting with a managed switch, but I tried anyway since my networking knowlege is lacking.

Also, the only ‘bandwidth demanding data’ comes from the vision system. The Wago couplers contain only digital I/O and high speed encoder inputs run directly to the CJ2M.

I haven’t run into any trouble so far and the machine is already producing for over a year.

Now , a new project is on the way and it will need even more Ethernet couplers, 15 to be precise.

 This brings me to my question; is there a limit to the number of nodes in an Ethernet/IP network and will I possibly run in to bandwidth problems by adding more remote I/O and not using a mannaged switch? Also, I would like to get high speed input out of one of the Wago couplers.

Thanks in advance for any feedback!

Greetings from Holland

Andy 

Edited by andepand

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Your bandwidth is more dictated by the amount of information being exchanged than by the number of nodes.  It's all about the RPI.

Network Configurator will show you bandwidth usage.

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The maximum number of nodes on a LAN depends on the media type, network protocol, and (at least for the IPv4 protocol) the network address class.

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I’ve decided to just try, in my opinion not alot of information is exchanged even by the vision system. If I run into any trouble I’ll be back.

thanks,

Andy

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