Fiber optic termination

cdenk · Post by **cdenk** » Fri Sep 22, 2006 5:05 pm

I would like to terminate in "ST" both ends (2 fibers) of a 62.5/125 fiber optic cable. Looking for relatively inexpensive ($100 including some trial and error material is OK) and moderate skill. Cable length is 200 feet and speed would probably not be more than 9600 Baud. Suggestions??

Chris Smith · Post by **Chris Smith** » Fri Sep 22, 2006 5:24 pm

What do you mean by terminate?

Block and stop, or accept all the separate signals and process them?

You can purchase both types of equipment, or build your own if your good with your hands.

End caps, repeaters, diverters, recievers, splitters, lasers, etc?

Externet · Post by **Externet** » Fri Sep 22, 2006 8:07 pm

Hi.
The terminals alone are around $8 each :

http://www.twacomm.com/catalog/jmp_Sutt ... id_364.htm

If you want the whole link, $100 sounds about right:

http://www.computercablesource.com/detail.aspx?ID=261

What does not sound right at all is using such capability for mere 9600 baud .

Miguel

Chris Smith · Post by **Chris Smith** » Fri Sep 22, 2006 9:11 pm

There are still many relevant questions to be answered
[even for AT&T] ..... from the web...

"We terminate fiber optic cable two ways -

.....with connectors that can mate two fibers to create a temporary joint and/or connect the fiber to a piece of network gear or with splices which create a permanent joint between the two fibers.

These terminations must be of the right style, installed in a manner that makes them have little light loss and protected against dirt or damage in use. No area of fiber optics has been given greater attention than termination.

Manufacturers have come up with over 80 styles of connectors and and about a dozen ways to install them"

And you can make the whole assembly on your own.

rshayes · Post by **rshayes** » Sat Sep 23, 2006 2:36 am

You won't find fiber optic connectors at Radio Shack. Most of the major electronic distributors have catalogs on their web sites. Digikey and Newark list a few "ST" connetors in their catalogs. This will give you a couple of manufacturer's names. The manufacturers' web sites will probably have ap notes on installing their connectors, what installation kit is required, and a more extensive list of their distributors. The web sites of these distributors may give you more manufacturers names.

It looks like two connectors will be about $20. Since you are starting from scratch, plan on making a couple of mistakes. Most of the manufacturers sell tools (for stripping, cleaving, and polishing) and installation kits for installing their connectors. For only two connectors, this will probably be most of your cost. The tools required may cost far more than the connectors.

cdenk · Post by **cdenk** » Sat Sep 23, 2006 7:15 am

Thanks for the replies.

1: The application is, we have a natural gas well that is adequate to serve the house. Pressure is regulated from the up to 50psi. well head pressure to residential pressure around 5 inch of water. Currently there is an 1/8" nylon tubing in 3/4" plastic electric conduit (200' house to well) along with 120 volt wires going to well head heat (maybe 30 watts). Want eliminate tubing (safety). Friend gave me 250' of fiber optic cable left on reel from big job. Plan to pull out tubing and wires, and pull wires and fiber optic back in. Will use a PIC to read 2 pressure and one temperature sensor, and send over the fiber optic to house, where will convert to RS-385 and displayed and used to select fuel for tri-fuel standby generator, depending what is available. So the data will amount to a dozen or so bytes, and even if transmitted once a minute, that would be adequte. The 9600 is picked since the fiber/RS-485 comes setup that way, and for the PIC that's a common rate. But always ready to listen to ideas.

2: On connectors and tools. have done some research, there's a wide variety out there, and some prices get up there! If someone could coming up with a shopping list (I'm starting from nothing) (manufacturer and part numbers) of tools, supplies, and connectors, that would be good. I am quite handy and can do some precision work, like probably I could make a polishing puck to hold the connector perpendicular to the polishing surface.

Thanks again.

philba · Post by **philba** » Sat Sep 23, 2006 2:17 pm

I assume by safety, you are concerned about a spark? I think you can pretty much ensure that won't happen through the use of opto isolators and low voltages. If you burry the cable, it should be pretty immune to lightning strikes. it just seems like a lot of effort and cost for a minimal safety gain. how are you getting power to the PIC in the first place?

cdenk · Post by **cdenk** » Sat Sep 23, 2006 5:04 pm

The safety concern is the nylon tubing leaking (breaking) and the natural gas accumulating in the basement and a spark or flame from furnace, hot water tank or clothes dryer setting it off. If the well area would catch fire, no big thing, worst would be a little grass burnt and repair the well, probably a new enclosure and pressure regulator.

The Pic would be powered off the 120 VAC that is used to heat the well enclosure (a well insulated box 2' x 2' x 5' that has heat trace and a underdesk type heater. The natural gas has a dew point of water vapor just below freezing and has frosted over the inside the gas pipe or regulator, which is the need for heat. The 120 volt plastic conduit that would also have the fiber cable is buried.

Have thought about a radio link, but at 200' thought that might not be as reliable as the fiber optic. Also have thought about power line modems including X-10, but thought the fiber would be most reliable, and I have the cable, just a matter of pulling it in the conduit and adding connectors.

cdenk · Post by **cdenk** » Sat Sep 23, 2006 5:09 pm

The safety concern is the nylon tubing leaking (breaking) and the natural gas accumulating in the basement and a spark or flame from furnace, hot water tank or clothes dryer setting it off. If the well area would catch fire, no big thing, worst would be a little grass burnt and repair the well, probably a new enclosure and pressure regulator.

The Pic would be powered off the 120 VAC that is used to heat the well enclosure (a well insulated box 2' x 2' x 5' that has heat trace and a underdesk type heater. The natural gas has a dew point of water vapor just below freezing and has frosted over the inside the gas pipe or regulator, which is the need for heat. The 120 volt plastic conduit that would also have the fiber cable is buried.

Have thought about a radio link, but at 200' thought that might not be as reliable as the fiber optic. Also have thought about power line modems including X-10, but thought the fiber would be most reliable, and I have the cable, just a matter of pulling it in the conduit and adding connectors.

And about the lightening, the 120 circuit has a GFCI breaker in the panel box. Once in a while after a good electrical storm, we find the breaker open. The PLC that processes the PIC output would E-mail someone if communication was lost for a period of time.

Chris Smith · Post by **Chris Smith** » Sat Sep 23, 2006 5:18 pm

If you dont need the 120 volt, dont use it.

PICs are low voltage devices [5v] so do your high voltage in other places and run a low volt line to the danger zones?

philba · Post by **philba** » Sat Sep 23, 2006 5:29 pm

I don't think there is an option for getting rid of the 120VAC since it is used to heat the structure.

What i am suggesting is to use something like RS485 and copper wire. You should be able to pull the copper cable in the conduit. The cost of the tools and connectors for fiber will be significantly more than the cable. Your PIC and wired communications won't add any hazard.

That's kind of cool, having your own NG well.

cdenk · Post by **cdenk** » Sat Sep 23, 2006 5:36 pm

The 120 is needed for heat. I need to communicate the enclosure temperature (to call someone if it's too cold), and well head pressure (the natural gas(no cost) is one of the fuels that a 12.5KW standby generator uses. The PLC manages the generator (along with other alarms like freezer temperature and sump pump levels) and will select the fuel depending what is available (in very cold windy weather, the well pressure can go temprarily to near zero). The PIC would be powered from a wall wart at the well 120 volt outlet. The fiber optic would provide the isolation, would not be affected by lightining or much anything else. If the PIC would get zapped, no big thing would have a couple of spares that anyone (even daughter) could quickly change out. In the house the fiber optic would terminate at a fiber/RS-485 convertor, and the PLC has a RS-485 port.

All I need at this point is direction to head in buying stuff to put "ST" connectors on the fibers, or maybe find nearest contractor (maybe local cable guys) and hire someone.

cdenk · Post by **cdenk** » Sat Sep 23, 2006 5:37 pm

The 120 is needed for heat. I need to communicate the enclosure temperature (to call someone if it's too cold), and well head pressure (the natural gas(no cost) is one of the fuels that a 12.5KW standby generator uses. The PLC manages the generator (along with other alarms like freezer temperature and sump pump levels) and will select the fuel depending what is available (in very cold windy weather, the well pressure can go temprarily to near zero). The PIC would be powered from a wall wart at the well 120 volt outlet. The fiber optic would provide the isolation, would not be affected by lightining or much anything else. If the PIC would get zapped, no big thing would have a couple of spares that anyone (even daughter) could quickly change out. In the house the fiber optic would terminate at a fiber/RS-485 convertor, and the PLC has a RS-485 port.

All I need at this point is direction to head in buying stuff to put "ST" connectors on the fibers, or maybe find nearest contractor (maybe local cable guys) and hire someone.

cdenk · Post by **cdenk** » Sat Sep 23, 2006 5:44 pm

Re: the well:
Cost $8000 to drill, 30 years ago. Once in a while in winter need maybe $25 in supplelemental electric heat. It's 1000' deep, 120' 8" casing below fresh water, 60' 6" casing below salt water, and bare hole rest of way. House is 2400 sq.ft., all gas including a little greenhouse and 3 car heated garage.

Likely the RS-485 copper next to the 120 in the 200' conduit will have crosstalk problems. even with shielded cable. No question the fiber will not be a problem.

cdenk · Post by **cdenk** » Sat Sep 23, 2006 5:48 pm

Re: the well:
Cost $8000 to drill, 30 years ago. Once in a while in winter need maybe $25 in supplemental electric heat. It's 1000' deep, 120' 8" casing below fresh water, 60' 6" casing below salt water, and bare hole rest of way. House is 2400 sq.ft., all gas including a little greenhouse and 3 car heated garage.

Likely the RS-485 copper next to the 120 in the 200' conduit will have crosstalk problems. even with shielded cable. No question the fiber will not be a problem.

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Fiber optic termination

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