Run CAT5 in a "Noisey" Palnt with lots of motors

[DougP]

I think I should run Shielded CAT 5 cable.
What kind of HUBS or special considerations do I need to look at on the Server side as well as the PC side.
We want to use POS touch screen PC’s to run Zebra Barcode label Printers.
The PC’ are Celeron 500Mhz computers and have a 10/100 NIC built in. I don’t’ think they can accept either a PCI card or ISA. Everything is built on the Mother board.


TIA DougP, MCP

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[2ffat]

We did the same thing. But you may not like our option. At our veneer mill, we ran a fiber optic backbone. From the central concentrator we ran fiber to each hub. We could then use cat5 from each hub to our computer, printers, etc. Very little noise or data loss.

James P. Cottingham

I am the Unknown lead by the Unknowing.
I have done so much with so little
for so long that I am now qualified
to do anything with nothing.

 

[MasterRacker]

You might be able to run the cable bundle inside a well grounded metal conduit. That could end up more expensive than fiber though. :-(
Jeff
I haven't lost my mind - I know it's backed up on tape somewhere ....

 

[jimbopalmer]

I run Unsheilded Twisted pair in Mines,

http://www.bgmi.com/Overview.htm,

Large motors, Lots of welding, no real issues with professionally installed UTP (we use fiber between buildings) Do avoid actually wrapping them around the florescent lights. (There is NO ethernet specification for STP) I love everyone til they prove otherwise, sadly some prove otherwise SO quickly

 

[wybnormal]

I posted a FAQ with a link to a white paper written by the man that wrote up most of the CAT3-4-5 specs. He has very little good to say about Shielded cabling.. ranging from the difficulties to install, that you need shielded connectors AND equipment for it work right, cost and so on. Properly installed CAT5 can work in a pretty nasty EMI enviroment. Wait till you run a network cable next to a MRI imaging machine..

MikeS Find me at

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"The trouble with giving up civil rights is that you never get them back"

 

[MWM]

If your job or reputation depends upon it, of course the solution in noisy environments is fiber. Next in order of resistance to EMI is grounded conduit. If you are in a plant, you may have electricians who run this stuff in their sleep.

So, you will need a fiber-capable switch at the head end and a similar hub or switch at the other. A switch probably the better choice in noise, as the potential for corruption is diminished by reducing the cable distances travelled by the signal.

A bona-fide ground at the server end is imperative, as noise or transients are relative to the end-point ground potentials. This means a #6 or better bonding conductor to the electrical service ground in the service cabinet, bonded racks, conduit, etc. (A third-wire grounding conductor from an outlet is less than perfect when employed to provide low-voltage signal grounding (...it is there for high amperage electrical fault currents).

Yours,
Mike, RCDD

 

[wybnormal]

Just dont get caught like we did one time grounding an isolated cable run between building.. can we spell "ground loop"... it's gets pretty ugly when you ground something and sparks fly

MikeS Find me at

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"The trouble with giving up civil rights is that you never get them back"

 

[MWM]

Yes, I've measured amps of current flow in a cable shield connecting buildings. But a shield should carry this current to ground; but this shield should not be the same as the circuit shield.

Yes, there are two types of grounds: 1) low voltage circuit grounds intended primarily to stablize and control electrical properties within the cable, and 2) equipment or service grounds, intended primarily to carry fault currents and balance different ground potientials at the ends of the cable.

For example, STP is intended to provide a circuit ground path, which should be designed to be a separate ground path from an external or equipment ground path, such as conduit or telephone cable shielding.

Telephone cable shielding is not a circuit ground means, though it is constructionally the same as shielding on a data STP cable. In data circuits, the STP shield is also part of the circuit electrical definition and contributes to its controlled impedances, etc.

So an STP data cable really has its application in very high speed circuits, and, in my opinion, not for seriouis noise protection; so it is a less desirable choice than EMT conduit in rough environments.

Best,
Mike, RCDD

 

[wybnormal]

I recall a installation of Thicknet( 7,000 feet plus) back in DC and we ended up hanging the cable from trays isolated from the buildings and an earth ground was made by drilling through the floor and sinking a rod several feet into the dirt with some salt packed around it. This was per the cable designers spec for the min amount of EMI ( TEMPEST) It was also grounded on ONE end, not both.

I used to see the grounding sparks when running two sets of RADAR equipment on different generators and then connecting the two sets together. Not always.. just on occasion.

MikeS Find me at

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"The trouble with giving up civil rights is that you never get them back"

 

[FredWagner]

The grounding problem happened to me in a large high-rise, where the halves of the building were on different power grids. I had an S/36, with Twinax to the workstations - one PC didn't work - with Twinax disconnected, there were several VOLTS of a AC between the shields. I got some Twinax to Twisted pair baluns, put those and a piece of RJ11 cable between them, and solved the problem. But if I put the same balun/Twisted pair combination on any other workstation on the network, it LOST connectivity. I agree with the earlier suggestion, go with as much fiber as possible - even disable the onboard 10/100 NICs and install separate fiber NICs if need be.

Fred Wagner
frwagne@ci.long-beach.ca.us