Hi
I have two PFC200 (750-8210) and one EtherCat Field coupler (750-354) with som IO modules on.
I am setting them up in a redundant setup and was expecting to be able to connect the ethercat FC directly to the PLC, like this
When looking at the Wago instruciton video here: https://www.wago.com/global/lp-thank-you-onlineseminar-codesys-redundancy
I see that they use a switch between the PLCs and the field coupler.
Is it possible to set this up without the switch somehow?
I do not believe this is a valid network layout. You need a switch when using multiple masters. The secondary port (OUT) on the coupler can be used for a media redundant EtherCAT link only in my experience. Here are some tutorials on the topic.
You are probably correct.
I had a look at your videos before you posted them. Great resources! I really appreciate that you an others take the time to share these things.
Regarding the single non-ethercat switch and redundant plcs, this seems more suitable for demonstration than production.
I am currently unsure how setting up a system with redundant CPUs and redundant Ethercat network would be realized without creating a single point of failure. Maybe it is not possible, but a synchronization trough the PLC redundancy link(s) to make the two CPUs “look” like one master on the ethercat network would be neat. This would allow to select a PLC1 NIC on the main ethercat link and a PLC2 NIC on the redundancy ethercat link.
For my specific case, I am replacing an existing non-wago system that had redundant CPUs and a single set of IO on the same backplane. Setting it up with ethercat switches to get redundant network to the IO will be expensive and take up to much space. I am probably better of with a Modbus TCP fieldbus coupler (750-362)?
Modbus couplers are easier to network than EtherCAT, but WAGO has discontinued the 750-882 & -885 which had dual NIC feature. This allowed for redundant Modbus Remote IO networks, which was very unique and a nice solution to the problem you are explaining. The next option is WAGO Application based controller redundancy, which uses “smart couplers”. This consists of PFC100’s running a special application that supports dual NIC and dual masters. This requires using the WAGO redundancy libraries in the controller(s). Here is more information:
Thanks for the reply!
If I understand this correctly, the application based controller redundancy, could serve as an alternative to having managed switches in my remote IO cabinets? Looks like a cost effective solution for bigger systems.
For my current project, with everything in the same enclosure, I just need a “light weight” redundant CPU installation, that is single fault tolerant until the IO.
I have not tested yet, but I believe I will be able to achieve this with my initial “network config” and a 750-362 Modbus Fieldbus Coupler.
The Ethernet Device in Codesys lets me configure network interface for both plcs. The plan is simply to monitor the the IO connection and switch over to PLC2 in case of an error.
