Compactlogix and Ethernet

[Guest New Guy Here]

Hello! I am trying to establish communication between a compactlogix L35 and a FlexI/O ethernet adapter. Communication is fine at close distance but the install of the FlexI/O is approximately 500' away. I am pretty new to networking. What is the best approach for running Cat6 cable that distance and still maintain communication. Thanks!

[TConnolly 13]

You should not have a problem at 500' Use non-metallic conduit. Metallic conduit will attenuate the signal in a run that long. Alternatively you could go fiber. I recommend that you install a switch in the network. A good high quality industrail switch with a redundant power feed. The purpose of the switch is to give you an ethernet programming port. The compactlogix multicasts, so use a switch instead of a hub - otherwise network performance will suffer. The switch does not have to be halfway down the line, you can place it near the PLC or convenient for programming access. I use these switches: http://www.n-tron.com They also have switches that handle both copper and fiber optic and the conversion between media. Edited 19 Nov 2005 by Alaric

[gravitar 3]

I don't claim for one minute to be an expert on ethernet, but isn't the guideline 100m (approx. 300') maximum for UTP?

[TimWilborne 108]

100 meters(328 ft) is the safe limit on copper. We do have one line running around 425 feet according to the ethernet tester. We have never had a problem with it but I wouldn't recommend it. Definitely use a shielded cable. Though many still argue about it, most people say you can enclose the shielded wire in metallic conduit and it will not attenuate the signal. We use a belden cable. I can't remember the part number but I can post it monday. And use an industial switch. The Ntrons are very good

[Ken Roach 194]

My understanding of Ethernet cabling has always been that about 300 feet is the absolute maximum for any solid-wire twisted pair cable at any speed. I'd select a spot in the middle of your cable run to put a small switch, or to run fiber optics. You can run ordinary 62.5/125 multimode fiber well over a mile with typical transcievers.