Channels misaligned....

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Channels misaligned....

Postby daba » 02 April 2019, 08:39

I posted this at the end of another post that appeared to be relevant, but I want a wider audience if possible....

Copied from my previous post.....

I am having troubles assigning my fixture channels...

Please bear with me as I am new to all this, so still on the nursery slopes of the learning curve.

My LED Par Can fixtures have channel 1 as a "master" dimmer for the RGBW channels that follow, thus.

Channel 1 : master dimmer
Channel 2 : Red
Channel 3 : Green
Channel 4 : Blue
Channel 5 : White
Channel 6 : Function
Channel 7 : Function Speed

I create my fixture exactly as per that list, but when I go to Steps and choose the fixture, I see seven "channels", but channel 2 operates as the dimmer, channel 3 as Red, 4 as Green etc.

So I'm thinking that the software is assigning channel 1 as a "Master" dimmer, then channel 2 becomes the first channel of my fixture. So I thought I would add the fixture dimmer as channel 2, effectively and hopingly shifting the RGBW channels to their correct places. So that seems to work, but the leftmost channel in "Steps" has no effect, my light brightness is only controlled by channel 2, which I added as a Color Dimmer. The fixture editor shows Channel 1 (Master Dimmer) as DMX channel 1, and My color dimmer as DMX channel 2, which of course is not correct for the fixtures themselves.

Can anyone please explain what I am doing wrong here, and please keep it simple so that I can understand....

TIA


Sorry, forgot to mention it is Chauvet ShowXpress 9.1.15 Windows 7, 64-bit
daba
 
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Re: Channels misaligned....

Postby daba » 02 April 2019, 09:25

Ahh ! I 'think' the penny has dropped....

I used my oscilloscope to look at the data being received by the fixture, and it is low going high (positive pulses). I could clearly see that the correct bytes of the data were being changed in response to my sliders.

I then looked at the signal from my hardware controller, and it is inverted, high going low.

Seems to me that the data coming out of the USB/DMX cable is being "mis-read" by the receiver in the fixture at the start of the data block, due to the signal inversion.

There is a switch on the hardware controller to invert the DMX signal, so it seems my fixtures require inverted signals, which the USB/DMX interface cable cannot provide (unless someone can tell me how).

If this really is the cause of the problems, then I would advise people NOT to purchase the cheap fixtures that hail from the far-east, as there is no guarantee they will work on the cable interface.

Next step I suppose is to open up the fixture and see if there's a link or switch to re-invert, or normalise, the signal
daba
 
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Re: Channels misaligned....

Postby daba » 02 April 2019, 09:51

And here is what I found....

[image]
[image]

... the only conclusion I can make of that "switcheroo" graphic, is that you can invert the signal polarity by turning the plug on CN1 round by 180 degrees.
daba
 
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Re: Channels misaligned....

Postby daba » 02 April 2019, 12:09

Going forward with this, I can now confirm that rotating that plug on CN1 does NOT invert the polarity of the signal at all.

What they have in these LED lights is ...
DMX pin 1 : RED wire : GND : connected to CN1 "G"
DMX pin 2 : WHT wire : D- : connected to CN1 "-"
DMX pin 3 : BLK wire : D+ : connected to CN1 "+"

All of that looks good....

Rotating the plug puts ...
DMX pin 1 : RED wire : GND : connects to CN1 "+"
DMX pin 2 remains the same
DMX pin 3 : BLK wire : D+ : connects to CN1 "G"

This will effectively ground the DMX D+ signal, so it shouldn't work, and guess what, I tried it, and it doesn't.

What I think I need to do is swap over the D+ and D- connections, that's the WHT and BLK wires, DMX pins 2 and 3.

Tried it, and got nothing working, so back to square 1 !!

Anyone got any ideas ? ....help !!
daba
 
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Re: Channels misaligned....

Postby LightWorx » 04 April 2019, 01:10

Data 1+ and - are often swapped over. The most commonly encountered pinout is given first.
Pin 1 Ground
Pin 2 Data 1- or 1+ (Primary Data Link)
Pin 3 Data 1+ or 1- (Primary Data Link)
LightWorx
 
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Re: Channels misaligned....

Postby marco » 04 April 2019, 04:34

How do u set the adress on the par?, by dipswitch or display
We dont know what light u have, maybe try setting the par 1 adress down, so instead of say channel 10 set it to channel 9

It can be that if its set bij dipswitch that somethings wrong.
marco
 
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Re: Channels misaligned.... RESOLVED

Postby daba » 07 April 2019, 06:38

All is resolved....

It turns out to be an issue with the LED Par Can itself, nothing to do with the software, or the USB/DMX interface.

The light woks perfectly well driven from my hardware controller (U'King), but not from the USB/DMX interface.

To be honest, it is a different model to the ones I have at the venue, and in desperation I ordered another of the same type and that works fine on the USB/DMX interface. So this light is going back....
daba
 
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