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Joined: Nov 2007
Posts: 20
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The world is full of smart asses!!
I am not so worried about voltage drop or current carrying capacity. We use CAT5 at the moment for the same application. But it is not ethernet. We use 2 cores for 24V 2 for GND, the rest carry the RS422 data.
The bit I am concerned about is putting ethernet and power through the same cable, and ideally through the same connectors at the end.
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Joined: Aug 2007
Posts: 61
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I would not advise it. If the 24v is AC it may interfere with the ethernet too much and just cause collisions between your nodes. Cisco makes switches that have power over ethernet, which use all 4 pairs for data and power, but I believe it is DC power. I would say, if the data is critical, I wouldnt even attempt it.
~Matt
I would rather beg for forgiveness then beg for permission.
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Joined: Nov 2007
Posts: 20
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Matt,
It is 24V DC. I cannot see it causing too many problems for the data. Anyhow, isnt that the beauty of TCPIP, if messages get corrupted they are noted and retransmitted. It is such a wonderful, fast communication method, but we would prefer not to have to run seperate cables for power. It is a process control, factory application.
Has no adventurous soul tried this, or got a clever solution. I would even consider 2 connections at the end of the cables, one the ehternet RJ45, the second for 24V annd GND.
Michael.
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Joined: Aug 2007
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DC shouldnt cause too many issues - if any. If data gets corrupted, it isnt due to TCP/IP, it is really CSMA/CD Carrier Sense Multiple Access/Collision Detection. CSMA/CD is a layer 2 protocol in the OSI model, where TCP is Layer 3, and IP is layer 2. Anyway - I got off subject. Your goal is to keep collisions and data corruption to a minimum to keep traffic down.
I have used 1 cat5 cable to transmit 2 phone lines and 100bT connection and it is stable.
I would say youre probably OK using one cable, just make sure you keep track of your pairs! I would build a custom breakout cable / box and make note of what pairs are what. You dont want 24v being sent to your data circuit.
Good luck!
~Matt
I would rather beg for forgiveness then beg for permission.
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Joined: May 2005
Posts: 247
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Somebody has been reading the BOFH stories..
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Joined: Oct 2007
Posts: 56
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(TOOL_5150) ..."If data gets corrupted, it isnt due to TCP/IP, it is really CSMA/CD Carrier Sense Multiple Access/Collision Detection. CSMA/CD is a layer 2 protocol in the OSI model, where TCP is Layer 3, and IP is layer 2."
Wow.
The more I learn, the less I know.
Shawn.
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Joined: Apr 2004
Posts: 812
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Is there anyone on board who knows how to fly a plane?
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Posts: 57
Joined: August 2003
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