Device Level Ring ?s

First Thread. Hello everyone. I was tasked to setup a device level ring. I was able to set the test project up in the shop using a 1756 L61 Control Logics Processor going out on a ENBT/A module to a unmanaged switch. From there I went to a 1783 ETap switch. I went out on Port A through 2 yaskawa drives(I had to configure them to work in 5000) into a 1734-AENTR and back into the ETap on Port B. It was succesful and it is almost time to go to the field. BUT.....

I was now informed that there are a couple other variables. The 5000 controller is communicating with the rest of the plant using control net. It has an additional control net card that communicates with a remote rack which contains the 17 motors being controlled by Yaskawa drives that need to be in the DLR with a 1734-AENTR. I was going to add a ENBT/A in an open slot in the remote rack and use the setup I used in the shop for the test. Any thoughts? Will these two forms of comms (ethernet/controlnet)work together? Any advice is appreciated. Thanks

Welcome to the Forum !

I'm very glad you asked this question before getting to the startup stage.

RSLogix 5000 will let you set this kind of network connection up, without warning you or explaining what you've done wrong. It might even work by coincidence, until it fails.

Here's why: there can be only a ControlBus backplane between the CPU and the "root bridge" for a ControlNet or EtherNet/IP network.

This is how ordinary EtherNet/IP I/O networks and ordinary ControlNet networks work. Because the networks are so flexible, RA engineers tend not to use the words "Master/Slave" or even "Scanner/Adapter" but that's the basic theme for most applications.

Your "Root Bridge" module must be in the same chassis with the CPU for the connections on its network to work properly. The CPU and the network modules will use a reliable, reserved, logically sound set of system resources to get data from the network devices to the CPU.

The "Root Bridge" module cannot be across a ControlNet or EtherNet/IP or any other network link, which is what you have described.

DLR doesn't really have anything to do with it; if that works, it will keep working, because it's entirely on the Ethernet side.

The only way to make the network you describe work properly is to run Ethernet (whether copper or fiber optic) from the chassis containing the CPU all the way to the DLR network.

Ken,
Thanks for the insight. Tonight I will install the ENBT card in the chassis which contains the controller. I think/hope I have one last available slot. Then I will give it a trial run before jumping totally in. Thanks John

Ken. Thanks again for your help. I was hoping you might have a suggestion for a new issue i am having. I just created a new thread. Any help I def appreciate. John