Posted 1 Jul 2021 I have an Ethernet/IP bus and system including Ethernet/IP devices with CPU 1756-L81ES ControlLogix. PLC is connected to the switch. Bus is built from the switch as a line. Can I connect the last device on the bus back to switch again? In thes case bus will be ring. Do I get problems with connection it this way. Switch is Stratix 2500, which is lightly managed switch. I believe it will increase the traffic in the bus. Share this post Link to post Share on other sites
Posted 1 Jul 2021 (edited) That model does not appear to support DLR (Device Level Ring). So no, do not connect the final leg back into the switch. If you need the redundancy features of DLR, you will need a Stratix 5400 series switch, or one of the Stratix 5700 series switches (certain models). This document has the various models features: https://literature.rockwellautomation.com/idc/groups/literature/documents/qr/enet-qr001_-en-e.pdf Edited 1 Jul 2021 by pturmel 1 person likes this Share this post Link to post Share on other sites
Posted 1 Jul 2021 Thanks, we are not using DLR. Should I assume that it will make bus unstable if there is traffic both directions, without DLR. Share this post Link to post Share on other sites
Posted 1 Jul 2021 15 minutes ago, Jiggadoo said: it will make bus unstable It can. In this case the 2500's spanning tree protocol might catch it. If nothing catches the multipath condition, you will have broadcast storms that crush your bandwidth. 1 person likes this Share this post Link to post Share on other sites