cat5 ethernet, 120V interference

[steelmtllrgst]

I have a piece of equipment that I put on embedded rails (~30ft of rail) that requires a 120V feed and two ethernet cables to operate.

I want to run the ethernet and power through a reel to keep them from getting tangled, run over by fork truck ,etc. I want to run the cables together on the same reel, but I was told that the 120V line will interfere with shielded ethernet if they are not separated.

Should interference be a concern? It chance of data corruption dependent on amount of data (very little in this case)? Any suggestions?

 

[ScottyUK]

Mixing power and data on a drum like that is asking for trouble. Use two drums and separate them.

Have you considered using wireless ethernet? The distance is short enough for it to be reliable unless you have something really awkward like an adjacent arc furnace which could overwhelm the RF signal. Wireless ethernet is pretty forgiving over short distances unless conditions are really bad.


----------------------------------

Sometimes I wake up Grumpy.
Other times I just let her sleep!

 

[steelmtllrgst]

Didn't think about this ahead of time (I know, I know - pay attention to details), but now we don't have room for two reels. We have tried wireless - it acts up from time to time. EAF is not too close to location of this equipment, but we were still cutting in and out of good signal.

I guess we will just try running on one reel, if there are problems we will simply cut a big hole in the cabinet for the unit and put another reel in there.

 

[IRstuff]

You can potentially minimize the noise problems by making sure you have adequate grounding and shielding.

TTFN

FAQ731-376

 

[boaterbill]

can you put a divider on your reel?
that might seperate the power from ethernet enough to not have problems.

 

[itsmoked]

What is the piece of equipment?? How much noise is it going to put on its power lines? 30ft is pretty short. What kind of data are you trying to transmit?

Keith Cress
Flamin Systems, Inc.-

http://www.flaminsystems.com

 

[itsmoked]

How much current does it draw?

Keith Cress
Flamin Systems, Inc.-

http://www.flaminsystems.com

 

[Compositepro]

I really don't see how this is much of a problem. If you do everything wrong, sure there will be problems. The ethernet cable is shielded and the power cable can be shielded as well with twisted wires.

 

[DaveScott]

I assume it is a ladle transfer car that you are talking about. Can you find a reel that doesn't have brushes? This would surely be the biggest problem.

I would suggest that you review the wireless system again - if you can get it to work, it would save a potential maintenance problem.

May I suggest Linksys? I haven't tested it in the EAF area, but in another (low noise) area I have managed point to point communications of more than 100m with devices that cost about $70 each. One of their routers could be located at each end.

See

http://www.linksys.com/servlet/Sate...nksys/Common/VisitorWrapper&lid=3978991233B01

 

[steelmtllrgst]

Actually we set it up like a mini-ladle car. This is for a semi-portable spectrometer that we have attached to the cart. The problem with wireless is that one little flicker of the signal causing a disconnect makes the system we have set up require resetting. We are using neoware with no monitor, so reset is by restarting (time) or remote access (computer knowledge). I just don't want called out @ 3AM a couple times per week.

We just ordered separate reels since the supplier would not even build ethernet/120V reel for us.

Thanks for all of the suggestions and help.

 

[DaveScott]

OK, please let us know how you get on.

 

[danw2]

In wireless, there is Wifi (office/consumer grade) and then there is industrial wireless ethernet.

Industrial wireless ethernet is usually freq hopping (FHSS)rather than Direct Sequencing (DSSS, Wifi technology), which is slower, because of the technology. Industrial wireless ethernet also costs 20x what Wifi costs, but industrial ethernet can be far more reliable than wifi.

If the spectrometer is only providing small amounts of data: a relatively small table of values per scan, or even a few values at whatever wavelengths, then FHSS can be viable. If it's sending full bit maps of images, then the throughput might not be adequate.

Lots of vendors like Prosoft do industrial wireless ethernet.

Dan

 

[steelmtllrgst]

Well, the unit is up and running. We ended up using two reels and doing some extra work to get them jammed into the cabinet. Next time I guess I'll just sit and think for a while before I go ordering parts and getting cabinets built.

 

[itsmoked]

Hehe.. Usually helps. The urge to just, "do something!", gets us all occasionally.

Thanks for the report.

Merry Christmas.

Keith Cress
Flamin Systems, Inc.-

http://www.flaminsystems.com