E-stop fiber optic

A bit off topic, but this forum has a wealth of knowledge and hopefully can help. We recently put E-stops in our control room to shut down equipment in the feild about 1/4 to 3/4 miles away. The design used a normal E-stop pushbutton, they took that to a copper to fiber converter, using some existing fiber routs the fiber was converted back to copper near the equipment to be shut off. The system works fine, but the fiber to copper / copper to fiber are not fail safe. We already had one occurance when we tested the ciruit it did not work, the failed part was the converter. Looking for something that is failsafe or other suggestions. As always any help is greatly appreciated.

http://as-interface.net/EN/System/Safety/Description

ASI doesn't get enough recognition in the US IMO.

I use some American Fibertek products at work, mostly in audio / video applications. Over the past 10 years, all of the failures were attributed to water damage only. I have not had a single piece of American Fibertek equipment fail for any other reason. I don't know enough about e-stops and the requirements for using fiber in a safety circuit but I assume that whatever you are doing it is not safety rated. How else would the fiber link have failed and the machine not stopped? This seems like it would be a more reliable fiber converter http://americanfibertek.com/fiber_site/products/G-Contact Closure/1-Eight Contact/88 SERIES.pdf

Shawn

CroCop said:

http://as-interface.net/EN/System/Safety/Description

ASI doesn't get enough recognition in the US IMO.

Click to expand...

i have not used this product. however apon reading on them, when refering to safety, this seems the way to go. that way if the converters fail or the fiberoptic cable failes the machine shuts off as well.

I think that the maximum AS-I network distance with repeaters and extension plugs will be about 600 meters. For an open air application, this is not the best solution. You need to install repeaters and PS every 200m.

Its a bit more costly, but Pilz Safetybus P works over fiber, I have used it before. Good for Cat 4 or Sil 3. There is also Pilz safetynet, which is a safety rated Ethernet.
Profisafe may also have a fibre link.

Otherwise, very thick wires with good quality fusing.