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CTB16PC Random Channel Blinking


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Hello

I had to unplug my controller last night due to random channel blinking.  First it was channel 1 and 2, and when I unplugged the lights to those, channels 3 and 4 started blinking.  There are Cat 5's in and out of this controller, but it is not hooked up to my show computer currently.  Anyone else ever had this issue?

Thanks

Mike

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Unterminated cables are a great way to introduce noise.  Unplug the Cat-5 cables and I would expect the problem to go away.  Or connect to your normal LOR network so there is at least a termination at one end (both ends if your LOR network has a terminator on the far end).

 

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7 minutes ago, k6ccc said:

Unterminated cables are a great way to introduce noise.  Unplug the Cat-5 cables and I would expect the problem to go away.  Or connect to your normal LOR network so there is at least a termination at one end (both ends if your LOR network has a terminator on the far end).

 

Ok the cat5 cables do go to my other controllers so you are saying that if I put a termination at the end of the line, that should solve it?

I never thought to unhook the cat5 cables.  It was 3 am when the flashing woke me up so unplugging was the quickest route.

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Your original post said that it was not connected to the show computer, so I apparently misread that to mean it was not hooked to anything (just cables to nothing).  The official answer is that the RS-485 spec requires a 120 ohm termination at both ends of the circuit.  The LOR USB to RS-485 adapter provides termination at that end (if it's hooked up).  That means that you should provide a termination at the far end of the circuit.  With that said, many (or most) lighting people do not terminate the far end of the circuit and get away with it.  There are three major factors to that: distance, number of controllers, and data speed.  The spec allows up to 4,000 feet for the entire network.  Most of us are not running anywhere close to that total length which helps. As for the number of controllers, the spec allows up to 32 devices.  Again, most of us are not running 31 controllers on a single circuit.  The faster the data, the more picky it will be.  In other words, if you are running the data network at 19.2 K, it will be far more tolerant of noise than if you are running it at 1,000 K speed.

From a practical point, the largest source of noise is your AC power cords.  Keep them away from the data cables as much as possible.  For example, running your AC power cord and the data cable in the same 500 foot conduit would not only be a good way to introduce noise into the data cable, it would also violate the National Electrical Code.  If they need to run from the same two points, keep the power and data cables a couple feet apart.  Using my yard as an example, I have six arches.  There is a CCP controller for every two arches, so I have three controllers spaced about every 12 feet.  I have a power cord with taps for each CCP controller that runs behind the controllers, and the data cables come forward (between the overlap of the arches) and then in front of the arches.  That puts the power and data cables about 2 feet apart.  No, you can't see the cables in the photo...

2014_2_arches.jpg

 

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i had this issue last year, my main issue was I was at 37 controllers... I split them into 2 networks and it fixed the problem... I asked a few of the people that have a lot of controllers and 25-30 is the area where you start seeing this.  I also got the  rs485 booster and splitter...

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