Ethernet through slip rings

[Steve G]

Has anyone out there used Ethernet through slip ring and if so how dependable is it.

[TimWilborne]

Never have but have you considered using something such as Banner's DX80 wireless radios?

[Steve G]

I would look into that but the equipments is being made by someone else, I thought I would ask the forum to see if anyone had done this and what problems they have had. I have ran DeviceNet, ControlNet, and RIO through rings and have had problems with all of the above, due to the machines movement. So Ethernet I am guessing would be that same, but the question is will cause more problems that the above mentioned.

[TimWilborne]

I've seen problems with Devicenet but have never been involved on a new installation were slip rings were specified for a network connection. I wouldn't think that Ethernet would be anymore robust. Even if it worked well at first I would be concerned about corrosion over time.

[Steve G]

I agree and have voices my concerns with the way they want to run the comm's through slip ring so I guess i will see when the equipment gets here and will post anything that goes wrong. I my experience like you have stated in the beginning they will work fine, but over time I think I will end up having to go to another method. The only thing I can think of, why they do not want to use a wireless solution is that the I/O attached to the system will have some AB safety rated I/O. Thanks for the input.

[BobB]

If you have to use the slip ring method I would have a look at the liguid mercury type, if still available. The mercury is in a bottle and is sealed so there are no problems with oxidisation/corrosion.

[panic mode]

i used mercury devices (Mercotac) with no issues on common fieldbuses but the limit was 8 contacts. with ethernet i would rather use wireless.

[ianbuckley]

If wireless works for your application, that is the best route. If not, definitely use a mercury rotary union. I would not trust a true slip ring with communication of any kind for very long. Mercotac is good as mentioned above. If you need more than 8 contacts, you can work with Meridian Laboratories. Meridian is more expensive, but they will customize to the application to some extent. Keep in mind though that even a mercury electrical rotary union has bearings and will therefore wear out eventually. Wireless has no such issues.

[Steve G]

Thanks for all the posts and I will post the results and any issues with the system if there are any for anyone interested.

[RussB]

Have you looked into "wireless" Ethernet?

[TimWilborne]

Yes, I'm partial to the Banner DX80s as stated above

[Emach]

Steve, I used to work on the M1 main battle tank. My company mocked up a demo where we shoved video through the slip ring and was able to get a mostly clean NTSC signal through. If my dim memory is correct that was a very fine brush based slipring; however, the tank had a fairly slow traverse speed. We also did it with CAN at a relatively high baud rate... -Emach

[Phoenix Contact USA]

Something like the DX80 would be a solution if you were transmitting I/O, however, if you wanted to communicate ethernet data, you would have to use something like an industrial WLAN radio. It is important to consider a few things prior to choosing either solution: 1. How fast must the wireless be (since a wireless solution will be slower than a wired solution)? 2. What is the distance that must be covered by the wireless network? (as this would determine what wireless technology to use) For this application in particular, Bluetooth or Ethernet could be considered. Bluetooth is usually less expensive than Ethernet and runs at the same frequency. Bluetooth is also much faster. Phoenix Contact offers either solution. For more information please visit: http://www.phoenixcontact.com/wireless or call our free tech support at 800 322-3225.