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Running all the cords


Thebug

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I have run data and extension cords together forever without any problems.  When I'm wiring my display, I usually  run all my data cords first then extension cords land on top of them.  In some spots they all run together in a bundle...ziptied.

Your results may vary.

Bri

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1 hour ago, Thebug said:

As I come put of my garage with power and data cables how far apart should i run them so I don't get interference?

I'm going to give a longer answer than you are expecting.  Every time two wires get close to each other, there is interference from one to the other.  How much interference there is and how much it affects one or the other varies greatly.  The RS-485 spec allows for quite a bit of both cable length and number of devices on the network.  Most of us are not running anywhere near as much of either.  The spec also calls for 120 ohm termination on both ends of the cable run, but very few LOR users do that.  Because our cable runs are far shorter than the max for the spec (4,000 feet), and having fewer devices than the max spec (32 devices), and are for the most part running at fairly low speed, we can get away with a lot of crappy wiring (that includes no terminations) and interference.  This depends A LOT on how long your cable network is, and how fast your network is operating.  In other words, what might work with 300 feet of cable running at 56K may not work with 3,000 feet of cable running at 1000K speed.

The summary is that is no magic answer that will always work.  Minimize the places where power and data run parallel to each other.  As several people have stated, they "got away" with a poor wiring in their situation.  That does not mean that you will.  It also does not mean that you won't "get away" with it.  Every installation is different.

In my case, I have LOR networking running in the same conduit as telephone, computer network, and in a couple case small amounts of 12V DC power.  However none of my three LOR networks have very many devices on them, and only one is running at 500K speed, and all are properly terminated.

 

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K6ccc

 

Tell me what is a proper termination exactly please. I haven't heard that one before.

 

Thanks, Keith

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120 ohms at each end is the standard for rs485. the question is: Does the LOR dongles have a 120 resistor (since it is at one of the ends)?

I have a few RJ45s with 120ohm 1/2w (only because the lead size is bigger than the smaller wattage)  crimped on pins 4 - 5.

I suggested running the data in grounded EMT if you have to run in tight parallel proximity. a magnetic shield

DC is not so much an issue unless it has high current swings (fast changing EM field). 

I tend to be conservative with my electronic designs(EX Navy ET, retired R&D tech)

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Doing this hobby with LOR coming up on 12 years now...

I have, since the beginning, run my power/extension cords with my data cords side by side, zip-tied together (you name it) and haven't had any issues since the beginning.

I will add, I haven't dealt with alot of recent pixels/nodes and such (if that matters or makes a difference) but have no problems with RGB floods/strips and LED light strings.

Just my experience.

Tom

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4 hours ago, ericm said:

i have run them together with no issues.  Data cord zip tied to 50+ extension cords and no issues at all.

Sounds like my logs (extension cords) running across my sidewalk during Christmas. 2 Bundles 

JR

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2 hours ago, TheDucks said:

120 ohms at each end is the standard for rs485. the question is: Does the LOR dongles have a 120 resistor (since it is at one of the ends)?

No, they do not.

 

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I'm glad to hear it doesn't matter that much. The reason I asked is because back when I was in college and working construction the blueprints would always call for the Cat 5 or 6 at least a foot away from all the electrical wiring in the buildings. And only cross the Romex Smurf or EnT at right angles. But then again I was also running stuff for call centers some insurance places and a few other commercial applications

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7 hours ago, k6ccc said:

No, they do not.

 

Oh!  Thanks

I guess they figured a Y feed, where both END points were terminated.

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Actually what I originally did for the termination at the USB end of the cable is to build up a very short cable with a male RJ-45 on one end and a female RJ-45 keystone jack at the other end. In the keystone jack I added the resistor. The cable was as short as I could build it - total length of the jack, cable, and plug was less than two inches. That worked but was hard to build. When I did some wiring changes in my data cabinet, I changed that. For the second method, I installed a female RJ-45 jack of the type that screw terminals rather than IDC type connections - commonly called a biscuit jack. The resistor is easily installed on th screw terminals in addition to the wires from the cable going out into the yard. Then I run a six inch Cat-5 patch cable from the biscuit  jack to the RJ-45 connector on the USB adapter. Much easier to do. For the “far” end of the network, I built up RJ-45 plugs that have a 120 ohm 1/8 watt resistor across pins 4 & 5.  I also installed a second resistor across pins 1 & 2 for two purposes. The obvious one is that if I ever do anything with DMX (which uses pins 1 & 2), I can use the same terminations. The terminating plug is installed in the second network jack on the last LOR controller on the network. The second purpose for the termination on pins 1 & 2 is that in all LOR controllers, pins 1 & 2 pass through the controller PC board. That means that at the data cabinet end of the cable, I can detect the termination resistor at the far end. The purpose is that if someone disconnects a controller, an alarm can go off. I have not implemented this yet, but it’s on the plan. 

 

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1 hour ago, k6ccc said:

 The second purpose for the termination on pins 1 & 2 is that in all LOR controllers, pins 1 & 2 pass through the controller PC board. That means that at the data cabinet end of the cable, I can detect the termination resistor at the far end. The purpose is that if someone disconnects a controller, an alarm can go off. I have not implemented this yet, but it’s on the plan. 

Very good explanation Jim. This was talked about many years ago and I myself haven't implemented it but want to do this as well. I feel running cat cable through some display props so if someone wants to steal a prop, the connection has to be broken there by sounding an alarm.

Edited by Santas Helper
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21 minutes ago, Santas Helper said:

This was talked about many years ago

Correct.  Not my original idea.  I don't know who came up with it.

 

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Seems like running the data cables with extension cords works for most of you.  But what about running an audio cable near extension cords?   There's about a 4-foot section in front of our house where the audio cable from the miniDirector to the outdoor speaker will run parallel to 16 - 24 extension cords.   Will the sound coming out of the speaker be affected by having the audio cable next to so many ext cords?

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51 minutes ago, Speedster said:

Seems like running the data cables with extension cords works for most of you.  But what about running an audio cable near extension cords?   There's about a 4-foot section in front of our house where the audio cable from the miniDirector to the outdoor speaker will run parallel to 16 - 24 extension cords.   Will the sound coming out of the speaker be affected by having the audio cable next to so many ext cords?

I would avoid it if possible. But if not, give it a try. There's one way to find out for your situation. 4 feet might not be a factor. Or it might.

Edited by Santas Helper
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12 minutes ago, Santas Helper said:

I would avoid it if possible. But if not, give it a try. There's one way to find out for your situation. 4 feet might not be a factor. Or it might.

Do you think running the audio cable through conduit or EMT would help shield it from potential interference from the extension cords?   One of the data cables may also have to travel that same 4-foot path with the ext cords, so I might play it safe and run the data cable & audio cable through 1/2" conduit or EMT in that section.

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