Tracy West Posted October 9, 2012 Share Posted October 9, 2012 Well... I have resolved my dmx flickering issue! Thank you all for assisting with that! How simple was a terminator. DUH!!! For all you newbies to the dmx rgb world. They don't tell you about a terminator in any of your beginning tutorials. It is almost like they want to make this DYI journey a rite of passage or something! Now... new problem.One of my 4 RGB strands on the roof is firing off pink when it should be red. The other 3 are firing red when they are suppose to.The weird part is, the strand fires red perfectly in the test mode.I have gone back into my sequence and even darkened the red on this channel and it still fires PINK.Is it a nearly bad strand and needs to be replaced?Is it in my dmx controller?Or is it in my sequence?I am going to hate to have to pull that strand off the roof if that is not the problem. Link to comment Share on other sites More sharing options...
ShaggySS Posted October 9, 2012 Share Posted October 9, 2012 explain this terminator thingy? I very curious Link to comment Share on other sites More sharing options...
Tracy West Posted October 9, 2012 Author Share Posted October 9, 2012 The dmx terminator terminates the dmx signal at the end of the daisy chain to prevent it from continuing to try to send data down the line.If you are using dmx stage lighting there is a 3 or 5 pin dmx terminator that just plugs into the last output port of your stage light.If you are using CAT5 cabling then you have to make a terminator with a 220 ohm resistor and push it in data 1 and 2 of a CAT5 connector. It works great!Dang... I sound like a pro! BAHAHAHAHAHAHAHA! Link to comment Share on other sites More sharing options...
Ken Benedict Posted October 9, 2012 Share Posted October 9, 2012 Pink is sometimes the result of the last strip not getting enough power.Check your voltage runs. Link to comment Share on other sites More sharing options...
Tracy West Posted October 9, 2012 Author Share Posted October 9, 2012 Can't be that.Each strip has it's own power supply. I did not use injector down the CAT5 line.. I just connected a power supply to each one. Link to comment Share on other sites More sharing options...
Tracy West Posted October 10, 2012 Author Share Posted October 10, 2012 I figured out my issue with this RGB strip...I had a duplicate dmx address with the unit right below it and it was causing the strip to mis-fire! At least it was not the strip and I don't have to go back onto the roof to replace the dang thing! Link to comment Share on other sites More sharing options...
edvas69 Posted October 10, 2012 Share Posted October 10, 2012 (edited) The dmx terminator terminates the dmx signal at the end of the daisy chain to prevent it from continuing to try to send data down the line.If you are using dmx stage lighting there is a 3 or 5 pin dmx terminator that just plugs into the last output port of your stage light.If you are using CAT5 cabling then you have to make a terminator with a 220 ohm resistor and push it in data 1 and 2 of a CAT5 connector. It works great!Dang... I sound like a pro! BAHAHAHAHAHAHAHA! Nearly, its a 120 Ohm resistor and not a 220ohm resistor Edited October 10, 2012 by edvas69 Link to comment Share on other sites More sharing options...
Tracy West Posted October 10, 2012 Author Share Posted October 10, 2012 Nearly, its a 120 Ohm resistor and not a 220ohm resistorNope..The guy from Holiday Coro instructed to make the terminator with a 220 Ohm.I did and it works great! Link to comment Share on other sites More sharing options...
edvas69 Posted October 10, 2012 Share Posted October 10, 2012 Nope..The guy from Holiday Coro instructed to make the terminator with a 220 Ohm.I did and it works great!mmm, the DMX standard says a 120ohm resistor so I wonder if David got it wrong. But the main thing is that it works. Link to comment Share on other sites More sharing options...
CLD Kevin Posted October 10, 2012 Share Posted October 10, 2012 mmm, the DMX standard says a 120ohm resistor so I wonder if David got it wrong. But the main thing is that it works.I agree....everything I read and used has been 120ohm. Link to comment Share on other sites More sharing options...
Tracy West Posted October 10, 2012 Author Share Posted October 10, 2012 I agree....everything I read and used has been 120ohm.See... that is where us dmx virgins are easily lead a stray! I just watched David's tutorial on how to build a terminator and he clearly states 220 Ohm.So.... I ran to RS and got me some 220 Ohm... and put the little thing together and it works. I have no more RGB Flickering.So... is my stuff going to blow up! Link to comment Share on other sites More sharing options...
ShaggySS Posted October 10, 2012 Share Posted October 10, 2012 HHHMMMM....what to use 120 or 220? I will give you all a week or so to duke this one out while I wait for my DMX dongle. Link to comment Share on other sites More sharing options...
BillyT Posted October 10, 2012 Share Posted October 10, 2012 (edited) 220, 221... whatever it takes! Seriously though, I would listen to Eddie, he spoke about the DMX standard. For the cost of a resistor, it doesn't make sense to risk anything. Edited October 10, 2012 by BillyTRichVa Link to comment Share on other sites More sharing options...
edvas69 Posted October 10, 2012 Share Posted October 10, 2012 (edited) HHHMMMM....what to use 120 or 220? I will give you all a week or so to duke this one out while I wait for my DMX dongle.The issue with putting in a higher value resistor like the 220 ohm resistor is that it can actually weaken the signal and cause issues, The fact that it works with a 220 ohm resistor is more luck than good design. It wont cause any damage, but if your going to make a terminator then use a 120 ohm 1/4 watt resistor as this is the designed specificationThe reason why a 120 Ohm resistor is used is due to characteristics of the DMX cables where they have a nominal characteristic impedance of around 120 Ohms. CAT5 has been approved for use by ESTA to use for DMX signals, CAT5 actually has a nominal characteristic impedance of around 100 Ohms. So using a 220 Ohm resistor as a DMX terminator with CAT5 does not match the nominal characteristic impedance of the cable used. So in reality using a 100Ohm resistor with CAT5 may actually be a better option, but generally to save confusion and the fact that ESTA has tested and approved CAT5 for use with DMX using a 120Ohm resistor then i see no real benifit with using a 100Ohm resistor. Edited October 10, 2012 by edvas69 Link to comment Share on other sites More sharing options...
ShaggySS Posted October 10, 2012 Share Posted October 10, 2012 The issue with putting in a higher value resistor like the 220 ohm reistor is that it can actually weaken the signal and cause issues, The fact that it works with a 220 ohm resistor is more luck than good design. It wont cause any damage, but if your going to make a terminator then use a 120 ohm 1/4 watt resistor as this is the designed specificationThe reason why a 120 Ohm resistor is used is due to chararacteristics of the DMX cables where they have a nominal characteristic impedance of around 120 Ohms. CAT5 has been approved for use by ESTA to use for DMX signals, CAT5 actually has a nominal characteristic impedance of around 100 Ohms. So using a 220 Ohm resistor as a DMX terminator with CAT5 does not match the nominal characteristic impedance of the cable used. So in reality using a 100Ohm resistor with CAT5 may actually be a better option, but generally to save confusion and the fact that ESTA has tested and approved CAT5 for use with DMX using a 120Ohm resistor then i see no real benifit with using a 100Ohm resistor.Forgive me but I understood about 50% of that. But what I get out of that is 120 is the way to go but technically I could get away with 100 but too high could cause issues which is why 220 might be something to stay away from though it may work. Thank you! Link to comment Share on other sites More sharing options...
edvas69 Posted October 10, 2012 Share Posted October 10, 2012 Forgive me but I understood about 50% of that. But what I get out of that is 120 is the way to go but technically I could get away with 100 but too high could cause issues which is why 220 might be something to stay away from though it may work. Thank you!You got it Sorry for getting a bit techinical but I thought others may be interested in knowing why a 120ohm resistor is used as a terminator. Link to comment Share on other sites More sharing options...
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