Mysterious null pixels

[bobschm]

I have a weird effect going on. At a transition between universe 10 channel 504 and universe 11 channel 1, the sequences insert two dead pixels putting everything down line off by two pixel positions.

I've already verified that this is not a control board issue since the test patterns are perfect. It's not a pixel string issue since swapping strings doesn't move the problem. I've checked my prop setups and all the numbers seem perfect.  There are no conflicts reported by the prop viewer. Icicle 89 is indeed in univ 10 and ends at channel 504. Icicle 90 is in univ 11 and starts at channel 1. Yet icicle 90 starts lighting at the third pixel instead of the first.

I do notice that the test patterns work over very long data lines, but the data from PE looked a mess until I shortened the data line to only 6 feet. Could it still need a null pixel boost over that short a distance?!

Any thoughts what else it could be?

[Dennis Laff]

Do you have max channels set to 510 not 512

[Little_b]

When you say "your Prop Setup" are you talking in in PE or on the Controller set up?  It may be how you have things set on the controller outputs.  Are Pixels 89 and 90 on different outputs from the controller?  If they are, did you adjust the settings on the controller to tell it how many pixels are on each output?  If they are on the same output, it makes sense to have two pixels dark as U10 Channels 505- 510 is two pixels worth of channels. 

[bobschm]

On 11/6/2016 at 0:00 PM, Dennis Laff said:

Do you have max channels set to 510 not 512

I would actually love to set max channels per universe to 510, but I don't see anywhere that I can do that. Holidaycoro says I need to do it in my application. But I don't see any way to tell PE what to do with universe size. PE just talks to whatever channels I set up in my prop.

Simplify this way: If I have a prop with just 3 pixels. PE will talk to 3 pixels. If I put a second prop of 3 pixels on the same output, PE will try and talk to 3 pixels in U1 and 3 pixels in U2. I can tell the controller there are only 3 pixels in U1 and 3 pixels in U2 and it will STILL pop two blank pixels into the start of U2.  Everybody assumes universes are 512 pixels and I can't figure out how to change that.

[Dennis Laff]

When you create  new prop in pe upper right corner ask for max circuit

[k6ccc]

What is the hardware configuration?  You mention Holiday Coro, so I assume you are using an AlphaPix controller.  I can't give any specific advise on that controller as I don't have any.  However I think I may have an idea anyway.  Is this universe transition on a single output from the controller?

My suspicion is that the problem is that the last channel you are using in universe 10 is 504.  The next pixel is universe 11 channel 1.  If that is the same physical string connected to one port of the controller, the controller has no way of knowing that channels 505 - 510 (or 512 depending on controller settings) are not used.  The fact that LOR is not using those channels is beside the point.  LOR is going to send all zeros for those channels if they are not used (that's what the E1.31 spec tells it to do).  The controller will take the E1.31 data for channels 505 - 510 (or 512)) and spit it out the SPI data line to the pixels.

Again, I don't know the AlphaPix controllers, but unless you can tell the AlphaPix that the last channel in a universe is channel 504, but the string continues on universe 11 channel 1, there is no way that will work.  I know on the SanDevices controllers, you can't do that.  The SanDevices controllers will happily have a single output cross universe boundries, but it does assume that all 510 channels (170 pixels) are used in the first universe.  Before someone brings it up, Firmware version 5.xxx for the SanDevices (still in beta) controllers do allow using all 512 channels if using RGBW pixels.

 

[bobschm]

Wow! You nailed it. That is exactly what's happening. You can only run more than one universe per output if the universe is completely populated. I switched to one universe per output and it worked fine. Ordered a second board so I should be running soon. 

[k6ccc]

Just now, bobschm said:

Wow! You nailed it. That is exactly what's happening.

Glad I got you pointed in the right direction.