Fiber Optical Cable to replace CAT 5 Ethernet Cable
Fiber Optical Cable to replace CAT 5 Ethernet Cable
(OP)
On an offshore platform, we have a run that is about 110 meter to connect a various PLC equipment in a machinery area with a master workstation and assorted items in another area. The communication exists with copper cable running 10 MHz Ethernet. We would prefer to run 100 MHz. However, large motor and generator switchgear equipment exists on the machinery end. The technicians had some difficulty with the communication at 10 MHz. This will carry control communication between industrial control systems and requires reliability. The interconnectin will be between Ethernet switches.
Before we begin running this equipment, I decided that fiber optical cable would eliminate the electrical noise issue and improve the distance issue. I know about nothing about fiber optical cable. I intend to use the existing conduit that connects the areas for the fiber optical cable. I need some input about the cable selection and issues such as pulling tension and bending radius in conduit. I have read that the appropriate communication method would be single mode using 62.5 micron.
I am interested in a recommendation for the appropriate cable and accessories for this application. Presumably the Ethernet switches will have about 12 RJ style Ethernet connectors and a fiber optical connector. I need to know something about the connectors, the cable diameter, pulling strength and bending radius to determine if we can use existing or replace conduit, etc. Also I need to buy the gear.
Comments??
John
Before we begin running this equipment, I decided that fiber optical cable would eliminate the electrical noise issue and improve the distance issue. I know about nothing about fiber optical cable. I intend to use the existing conduit that connects the areas for the fiber optical cable. I need some input about the cable selection and issues such as pulling tension and bending radius in conduit. I have read that the appropriate communication method would be single mode using 62.5 micron.
I am interested in a recommendation for the appropriate cable and accessories for this application. Presumably the Ethernet switches will have about 12 RJ style Ethernet connectors and a fiber optical connector. I need to know something about the connectors, the cable diameter, pulling strength and bending radius to determine if we can use existing or replace conduit, etc. Also I need to buy the gear.
Comments??
John





RE: Fiber Optical Cable to replace CAT 5 Ethernet Cable
As for conduit, each manufacturer will list the specs on their cable. I would call an electrical supplier in the area (on shore) and request the specs on a multi-strand multimode fiber. You can also visit http://bwccat.belden.com, and get some info there on different fiber cables and bend radius. They have a contact number on the site as well. An electrician I spoke with, recommended a long bed radius on the conduit (12”-24” min for multi-strand fiber cable), and no sharp transitions like found in a standard “LB” fitting. There are fiber cable made for harsh environments, with a messenger wire built onto the cable. Can you run the cable outside of conduit in a tray?
The two most common connectors on LAN equipment will be “ST” or “SC” type, see http://www.fiberoptics4sale.com/fiber-optics-connectors.asp?source=overture&keyword=fiber-connector for more info. I think that the “ST” type might work best in the corrosive atmosphere of an offshore platform.
As for the switches, try www.alliedtelesyn.com, they have some good equipment, priced right. Also look at www.netgear.com. For lower cost devices, I have found these two the most reliable. You could use a standard copper switch, and use a media converter, (copper to fiber), to change over to the fiber cable. If you want a higher end switch, you can go with someone like Cisco. You can get a used switched with multimode interfaces for a pretty good price. EBAY is a great place to look for used equipment. I would buy from a reseller to ensure you get some sort of warranty. One word of caution on used equipment, sometimes there may still be passwords set on the devices, so make sure you find some documentation to show you how to get around the password. Cisco has online documentation on how to get into their switches if the passwords are set and you do not know them.
I hope this helps.
RE: Fiber Optical Cable to replace CAT 5 Ethernet Cable
I agree that multimode fibre should be more than adequate for 110m at 100MHz, and termination equipment will be cheaper. By the way 62.5micron is multimode (singlemode is 9micron). In terms of transmission, you can get switches/hubs etc. with fibre connectivity, most major manufacturers will have something in their range. If you already have equipment with only electrical ports, you can by media convertors or repeaters from somewhere like Black Box will will allow you to cheaply use existing equipment.
Industrial fibre cables will usually have GRP or Kevlar central members for which you will get good pulling tension capability. Bear in mind that in commercial telecommunications applications, they may pull cables over 2km in buried subducts (albeit smooth bore ducts, with plenty lubricant). Nonetheless, I wouldn't expect you'll have problem over 110m. Regarding bend radii, if you can install power/multicore cables (presumably armoured) through your ducts, you'll be OK with fibre.
RE: Fiber Optical Cable to replace CAT 5 Ethernet Cable
What I would rather suggest is try to avoid getting material from different providers, if you are not used to do so and understand very well what you're doing. The best I can suggest in providing most materials you would need is Phoenix Contact. Had used them for years, a bit pricy, but rugged and very reliable, and aimed to Industrial Automation. You can check about them at: http://www.ethernetrail.com/
You better forget about hardcore IT stuff, like Cisco line, since they are not build to endure the rugged conditions of industrial applications, they don't behave very well in environments with heavy vibration.
One word of warning, as the application is in an offshore platform, I would suggest make sure the FO cable is sealed tight (don't know if jelly-filled cable would be the right seal) and will not allow the migration of gases in it.
RA
RE: Fiber Optical Cable to replace CAT 5 Ethernet Cable
Don
RE: Fiber Optical Cable to replace CAT 5 Ethernet Cable
Fiber is not too difficult, if you follow the general guidelines and recommendations from the manufacturer.
RE: Fiber Optical Cable to replace CAT 5 Ethernet Cable
As a rule of thumb, the minimum bending radius for the cable is about 10 times the outside diameter of the cable. This is for structural integrity of the cable. There is another (much smaller) minimum bending radius that will cause excess attenuation in the fiber that should not be an issue if the cable remains structurally intact.
Other things to think about:
Any fire rating requirements on the cable? Will it be exposed to water? Oil? There are various cable types that will be suitable for any of these applications.
In a previous life, I used to work for Corning. Here's a phone number for Corning Cable Systems that should provide some good info: 1-800-743-2671. Ask for the duty engineer. You'll probably have to purchase through a distributor like Anixter or Graybar. May be better pricing from other manufacturers - fiber is pretty much a commidity these days.
Hope that helps...
RE: Fiber Optical Cable to replace CAT 5 Ethernet Cable
Also, consider hiring a licenced, insured professional to see it through for you. An RCDD or PE with experience in industrial automation in the coastal oil industry could hit the ground running for you. You'll always look good and be amazed at what you didn't realize. This might not be a place to save money by substituting marketing/sales experience instead of genuine wisdom.
Best of luck.
RE: Fiber Optical Cable to replace CAT 5 Ethernet Cable
You may be able to run it in your cable tray.
I use it at my facility in the process areas for phone/data.
Your distance(110m) is at the theoretical limit of ethernet over utp but I've pushed it farther many times.
pfry
RE: Fiber Optical Cable to replace CAT 5 Ethernet Cable
John