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DMX fading response


Greg Young
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I have setup my LOR IDMX-1000 controller without any issues..

I am starting off incorporating DMX with the use of Chauvet colorstrips (they are light bars with red, green and blue LEDs).

Once setup, I used LOR to control the DMX values affecting the RGB section of the color strips. This section specifies these 3 colors and allows fading from 100% to zero (and vice versa).

I have noticed when fading I will get a flash of another color, at odd times. This doesn't occur with every fade, but with some - primarily when blue is faded, but on occasion green as well. It almost never happens when fading red.

It happens whether the fade is controlled by the sequence editor, or manually using the hardware editor.

My firmware is current.

I tried the other 2 lightstrips, and it occurs with them as well, so I know it is not the Chauvet fixtures.

Any ideas from those of you with some DMX knowledge?

Thanks,

Greg

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are you using a DMX terminator? sounds like you might be getting a reflection.

What type of cable are you using? is it DMX cable?

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Dr. Jones wrote:

are you using a DMX terminator? sounds like you might be getting a reflection.

What type of cable are you using? is it DMX cable?


I am using DMX cable, with a 120 ohm terminator. I tried with terminator plugged into the colorstrip, and without it. That made no difference (but I didn't think it would on a short cable length). I should mention I am only using a 3 foot cable to connect to the LOR IDMX controller for testing purposes, but it is DMX rated cable all the way..

I thought about reflections as a possibility, but don't know that much about DMX yet to arrive at any sound conclusions.

Speaking of terminating reistsors, it just dawned on me (duh!) that the LOR IDMX has internal terminating resistors on both the input, and output lines.

Would removal of either of these (especially the output side) affect reflections, etc?

Thanks,

Greg
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Will Sanders wrote:

It may be the colorstips themselves. If you watch the product video, you will notice on some of the fades that they do flicker, so it may not be LOR, it just may be the way the fixtures work themselves.

http://www.chauvetlighting.com/flash/colorstripfinal.html

Will Sanders


Thanks Will. I see the flickering you are mentioning, but mine looks different. It is more flashes of other colors, so I don't think it is a unit problem, as it is intermittent, and not consistent...

Greg
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no

the reflection is generally a factor at the end of the line

How many channels does the colorstrip use?

After looking at the video posted by Will - i may have to concur that it could be a factor with the strips themselves

If you have a device that spits out DMX natively, I'd give that a shot

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Charles Belcher

Greg,

It will be the strips themselves causing what you see. If it occurs at the 20% level above blackout, I would cut the fade off; ie, fade it from 100% to 0%, but cut the last 22% or so off. You will have to play with it. That will not be a termination problem.

Charles

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Thanks Dr Jones, and Charles.

I will play with it a bit more...

It would be a shame to think these somewhat pricey colorstrips can't do smooth fades... It still puzzles me that the flashes are intermittent, and not consistent..

Greg

Charles - the flashes of green that occur when fading the blue LEDs sometimes happen at about 20% of intensity during a fade, other times 42%, etc.. I can't find a spot that they occur with any consistency...

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Charles Belcher

Greg Young wrote:

Thanks Dr Jones, and Charles.

I will play with it a bit more...

It would be a shame to think these somewhat pricey colorstrips can't do smooth fades... It still puzzles me that the flashes are intermittent, and not consistent..

Greg

Charles - the flashes of green that occur when fading the blue LEDs sometimes happen at about 20% of intensity during a fade, other times 42%, etc.. I can't find a spot that they occur with any consistency...

Greg,

Give me a little more information. Are you fading pure blue or green when this occurs or is it a combination of two or more colors that flash as you fade?

Charles
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Charles Belcher

Greg,

One more thought. Set channel # 1 to a value between 210 and 219 which is 83-86 in LOR percents. Then control channel # 3 independently and see if it fades correctly. Do the same with channel # 4.

Edit: You are in DMX mode aren't you and not in a "program" mode?

Let me know.

Charles

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Charles Belcher wrote:

Greg Young wrote:
Thanks Dr Jones, and Charles.

I will play with it a bit more...

It would be a shame to think these somewhat pricey colorstrips can't do smooth fades... It still puzzles me that the flashes are intermittent, and not consistent..

Greg

Charles - the flashes of green that occur when fading the blue LEDs sometimes happen at about 20% of intensity during a fade, other times 42%, etc.. I can't find a spot that they occur with any consistency...

Greg,

Give me a little more information. Are you fading pure blue or green when this occurs or is it a combination of two or more colors that flash as you fade?

Charles


Hi Charles:

I am fading a pure color (red, blue or green) when this happens. The reds fade fine. The green fades almost always fine, but have an ocasional flash of a color, the blues fade fine, but more frequently (every 4 or 5 fades or so) have flashes of the green LEDs as they (the blue) fade.

Using the HWU I have the DMX value of channel one to be 214 (RGB range for these colorstick units are 210-219), which corresponds to a LOR value of 84% (range 83 - 86%).

Channel 2 then controls the red, channel 3 the green, and 4 the blue. They cover fading from 100 - 0%.

I get the same results running sequences, as I do using the HWU (channels in sequences defined as E0.1, E0.2, E0.3, and E0.4 respectively).

Finally, late last night as another test I eliminated all fades in my sequence, replacing them with simple full color on and full color off. I found that I get (although not as much) these same momentary flashes of another color when one color goes off and another one comes on.

That would seem to suggest it is not purely a fading issue.

Is it possible with a 3 foot cable (again using a good quality DMX cable) that I am getting some noise from the IDMX1000, or pc, because the units are too close??

Greg
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Charles Belcher wrote:

Greg,

One more thought. Set channel # 1 to a value between 210 and 219 which is 83-86 in LOR percents. Then control channel # 3 independently and see if it fades correctly. Do the same with channel # 4.

Edit: You are in DMX mode aren't you and not in a "program" mode?

Let me know.

Charles


Charles:

Yes, I am in the DMX mode....

Greg
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Charles Belcher

Greg Young wrote:

Charles Belcher wrote:
Greg Young wrote:
Thanks Dr Jones, and Charles.

I will play with it a bit more...

It would be a shame to think these somewhat pricey colorstrips can't do smooth fades... It still puzzles me that the flashes are intermittent, and not consistent..

Greg

Charles - the flashes of green that occur when fading the blue LEDs sometimes happen at about 20% of intensity during a fade, other times 42%, etc.. I can't find a spot that they occur with any consistency...

Greg,

Give me a little more information. Are you fading pure blue or green when this occurs or is it a combination of two or more colors that flash as you fade?

Charles




Finally, late last night as another test I eliminated all fades in my sequence, replacing them with simple full color on and full color off. I found that I get (although not as much) these same momentary flashes of another color when one color goes off and another one comes on.

That would seem to suggest it is not purely a fading issue.

Is it possible with a 3 foot cable (again using a good quality DMX cable) that I am getting some noise from the IDMX1000, or pc, because the units are too close??

Greg

Greg,

At this point anything is possible, but my guess is that it is not the cable. You could be using a 100' mic cable, not intended for DMX use and it wouldn't cause this. I will email my Chavet rep this morning and see what he says about it. I will let you know what he says.

Are we talking about this product?
http://www.chauvetlighting.com/fixtures/colorstrip_fix.shtml

Charles
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OT
Greg,
How are you be using the Chauvet colorstrips in your Display?

Jerry Plak

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Charles

I was having a similar flash when fading a gen 1 Colorblast (yes the one with 278 leds) off of a Lil DMXter. It went away when I switched to a console. I wonder if the output signal of the iDMX is wavering and adding an additional start command or if ocassionally it is sending 513 addresses.

Might just be time to put an iDMX on a scope and see what the signal looks like.:?

Greg -

how are you running the iDMX - is it from a usb->LOR or a DB9(serial)->LOR Is the usb port a version2 or 1? -if it applies

do the flashing colors flash at full intensity?

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Charles Belcher

Dr. Jones wrote:

Charles

I was having a similar flash when fading a gen 1 Colorblast (yes the one with 278 leds) off of a Lil DMXter. It went away when I switched to a console. I wonder if the output signal of the iDMX is wavering and adding an additional start command or if ocassionally it is sending 513 addresses.

Might just be time to put an iDMX on a scope and see what the signal looks like.

Dr. Jones,

That is a good point. I emailed my Chauvet rep to see what he thinks, but he hasn't anwered me yet. After he replies we can put our heads together and try to get to the bottom of it.

I doubt Greg has a hard console he can connect to.

Charles
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J_Plak wrote:

OT
Greg,
How are you be using the Chauvet colorstrips in your Display?

Jerry Plak


Jerry:

I was hoping to use them as a colorwash on the front of the house, to match the diamonds I have on the outside of windows (which are solid colors of red, blue and green LEDs)

Greg
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Dr. Jones wrote:

Charles

I was having a similar flash when fading a gen 1 Colorblast (yes the one with 278 leds) off of a Lil DMXter. It went away when I switched to a console. I wonder if the output signal of the iDMX is wavering and adding an additional start command or if ocassionally it is sending 513 addresses.

Might just be time to put an iDMX on a scope and see what the signal looks like.:?

Greg -

how are you running the iDMX - is it from a usb->LOR or a DB9(serial)->LOR Is the usb port a version2 or 1? -if it applies

do the flashing colors flash at full intensity?


Hi Dr Jones:

I forgot to mention earlier these strips only use 4 channels.

I am using a LOR 4858 USB unit from my winXP pc..

Yes the colors that flash seem to do it at full intensity, but they are so brief it is hard to be sure.

I talked to our AV guy in town today (at the local high school), who has one of the same Chauvet colorstrips! He said them dim fine using standard DMX consoles, and thinks my issue is coming from the software/DMX interface unit....

Greg
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Charles Belcher wrote:

Dr. Jones wrote:
Charles

I was having a similar flash when fading a gen 1 Colorblast (yes the one with 278 leds) off of a Lil DMXter. It went away when I switched to a console. I wonder if the output signal of the iDMX is wavering and adding an additional start command or if ocassionally it is sending 513 addresses.

Might just be time to put an iDMX on a scope and see what the signal looks like.

Dr. Jones,

That is a good point. I emailed my Chauvet rep to see what he thinks, but he hasn't anwered me yet. After he replies we can put our heads together and try to get to the bottom of it.

I doubt Greg has a hard console he can connect to.

Charles


The school has a console, but they can't get at it until the fall semester starts.

Based on what the AV guy told me, his strip dims fine. If mine do on his console, that would rule the strips out.

Having 3 strips I really doubt it is an issue with all 3 of them, which brings me back to an issue with the interface at some level (pc/software/IDMX 1000)..

Greg
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Charles Belcher

Greg Young wrote:

Charles Belcher wrote:
Dr. Jones wrote:
Charles

I was having a similar flash when fading a gen 1 Colorblast (yes the one with 278 leds) off of a Lil DMXter. It went away when I switched to a console. I wonder if the output signal of the iDMX is wavering and adding an additional start command or if ocassionally it is sending 513 addresses.

Might just be time to put an iDMX on a scope and see what the signal looks like.

Dr. Jones,

That is a good point. I emailed my Chauvet rep to see what he thinks, but he hasn't anwered me yet. After he replies we can put our heads together and try to get to the bottom of it.

I doubt Greg has a hard console he can connect to.

Charles


The school has a console, but they can't get at it until the fall semester starts.

Based on what the AV guy told me, his strip dims fine. If mine do on his console, that would rule the strips out.

Having 3 strips I really doubt it is an issue with all 3 of them, which brings me back to an issue with the interface at some level (pc/software/IDMX 1000)..

Greg

Greg,

Here is the response from Chauvet.


"Charles,

Dwight is out of town, but I have looked at your e-mail and have the following questions –

What kind of console is your friend using?
Are the fixtures sharing DMX channels?
If is a fader board, can he try changing the DMX channels to see if the problem moves with the channels or if it’s a problem with the fader
If he is using a computer console – is the DMX line terminated?

It almost sounds like a DMX reflection problem or a bad data line. Can he change the line from the controller to the first fixture?

If none of these suggestions work, please give me a shout.

Thanks,
Michael Graham - Sales Support Manager"
____________________________________________________________________
Greg,
Can you get your hands on a dmx console to check this out? If not, then I would call Dan or John at LOR and see what they think.

Please keep us in the loop on this.

Charles
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Charles Belcher wrote:

...............
Greg,

Here is the response from Chauvet.


"Charles,

Dwight is out of town, but I have looked at your e-mail and have the following questions –

What kind of console is your friend using?
LOR IDMX 1000

Are the fixtures sharing DMX channels?
No, I am only using one for testing

If is a fader board, can he try changing the DMX channels to see if the problem moves with the channels or if it’s a problem with the fader
If he is using a computer console – is the DMX line terminated?
Yes, it's terminated with a 120 ohm 1/4 watt resistor between the data pins (2 and 3)


It almost sounds like a DMX reflection problem or a bad data line.
That was my initial thought also
Can he change the line from the controller to the first fixture?
I could make up another brand new line, but I made this one myself, and know it is good.


If none of these suggestions work, please give me a shout.

Thanks,
Michael Graham - Sales Support Manager"
____________________________________________________________________
Greg,
Can you get your hands on a dmx console to check this out?
I can, but not until September, once school is back in session!
If not, then I would call Dan or John at LOR and see what they think.
Dan/John - have you either of guys been reading this thread?


Please keep us in the loop on this.
Will do, as I expect others may run into this problem along the way as well, which is why I posted it.


Charles
Thanks for following through on this Charles!
Greg







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Charles Belcher

Greg,

I emailed your answers and some further comments to Mike at Chauvet. I will let you know what he says.

My guess is that everything will work correctly with a hard console. I had some similar problems when I was programming my DMX Demo for the Texas Workshop. They weren't exactly what you are experiencing, but wierdness in general that went away when I hooked up a DMX console. I never did isolate the problems, I just danced around them.

Charles

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Charles Belcher

Dr. Jones wrote:

Charles

I
Might just be time to put an iDMX on a scope and see what the signal looks like.:?


Dr. Jones,

I am going to have my bench tech put a iDMX-1000 on the scope next week. He has some advanced DMX testing equipment so hopefully we can see what is going on. I will post the results when I get them.

Charles
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Charles Belcher

Greg,

Here is the latest response from Chauvet.

"
From: tech3
Sent: Friday, August 15, 2008 4:22 PM
To: mike
Subject: RE: LED strips

Check if there is a polarity switch on the converter box or check if the converter is receiving or sending dmx.


From: mike
Sent: Friday, August 15, 2008 3:35 PM
To: Charles Belcher
Cc: tech3
Subject: RE: LED strips

I will forward this on to the technical department. I have not seen this before and I want to make sure that we can help you out.
Thanks,
Michael Graham - Sales Support Manager"
____________________________________________________________________


I am sure you have done this but I have to make sure we are covering all the bases.

Have you tried switching the polarity switch to both positions? The "normal" position is towards the center of the iDMX. I haven't answered this email yet.

Charles

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