Fiber Optic Cable

To start to answer your question, at the very least you would have to tell us the brand (and probably) model number of the PLC that you want to convert to fiber optic.

And, is the link intended to be used for communication between two PLCs,between a PLC and an HMI device, between a PLC and remote I/O devices, between a PLC and a supervisory computer, or something else?

Hi All

Both PLC are A.B, we need this two plc to interconnect using optic cable to monitor the process variable on both location.

Regards

So, I would first contact AB (although I guess it is now (and still) Rockwell Automation--do I remember that right). See what they have to offer--I'm pretty sure they will have something. I would expect there is a sales office somewhere near you, or responsible for your geographic area. Call them, ask to talk to an application engineer.

If AB doesn't have a fiber optic link suitable for the PLCs you have, or you think it is too expensive, you might look for alternatives. But, in general, that often creates a lot more problems for you as the end user--you (or your maintenance staff) would need a high degree of technical competency to deal with a 3rd party supplier for the fiber optic link. (Less so if you buy the interfaces from AB/Rockwell and just supply and install fiber optic cable from a 3rd party supplier.)

You can get fiber optic cables in pretty much any lenth that you want. Just call your local electronics supplier and ask them what they have in stock. I commonly purchase off the shelf cables in lenths of 1m, 3m, 10m, and 20m. You can also ask your supplier to order you a custom length cable if you request one. Be sure to purchase a 2-strand fiber optic cable for use with AB ethernet devices.

All you need to convert from CAT5 ethernet cable to fiber and back is two off-the-shelf industrial Ethernet switches with fiber ports on them like this one from Overstock.com:

You can specify Ethernet switches with any "standard" type of fiber optic end such as SC, ST, LC, or FDDI. I suggest that you purchase whatever your local supplier carries the on the shelf. Make sure that the ends on the fiber optic cable that you purchase match the plugs on your Ethernet switches.

Disclaimer: AB recommends using "managed" industrial Ethernet switches particularly if you are using EtherNet I/O, but an unmanaged switch will usually work just fine if all you have networked together are two PLCs.

Here is a filterable link of companies that make fiber optic cable. You have to register with globalspec (free) to view it:

http://www.globalspec.com/SpecSearch/Suppliers/optics_optical_components/fiber_optics/fiber_optic_cable?RegEvent=login