DMX Scans Won't Hold the Scene

[catchthebuzz]

OK...before you say you get what you pay for, perhaps you can offer some advice.

 

The following is a list of the gear in question:

• four Chauvet Intimidator 1.0s (mirror scans)
  
• two Chauvet DMX4 Dimmer Packs
  
• one Chauvet DMX55 Light Controller
  

The scans are addressed at 1 - 17 - 33 - 49 and my two dimmers I have set both to 65. The way my board works is that it assumes that each fixture has 16 channels of DMX

 

When I choose my fixtures and set my scenes to memory, everything looks fine. I can create some nice scenes; however, when I go back to that scene, one or more of the scans lighting beams has shifted position and the scene falls apart. I then toggle everything back and set it to memory, but when I bring the scene back again, the scans are either a little off or a lot off.

 

My board, scans, and dimmers only take a three pin XLR, and I am using regular mic XLR. Can this cause the problem I am describing? Is there a special 3-pin DMX cable that I should be using? Help!!!!

[Ike]

Sorry to say it but it's defiantly a case of you get what you pay for!

 

The scans have a lack of decent feedback, after a bit of movement they all drift from each other causing your scenes to "start falling apart". A full service might reduce the drift but won't get rid of it completely.

[paulears]

if the fixtures work fine when programming, then the DMX connection is fine - lack of repeatability will not be anything to do with this. There are two possibilities, one is electronic - the controller is either not storing or recalling the data properly, or it could be something as basic as stiff stepper motors, that just can't respond fast enough. I have one mirror scan that is always the one that misses the mark - sometimes close, sometimes just never makes it. The test of this would be to put the controller into manual and see if a certain position on the joystick always generates the correct position - but if I remember these controlls correctly, the joystick is just a left right, up down switch, not a pot- is that correct? Unless it moves in real time - this won't work. If the controller is faulty, then I'd have expected not just position to be dodgy, but gobo and colour too?

 

When the scanner fail to go to the position you recorded, do they always go to the same 'wrong' position?

 

What do you think?

[LampieManPro]

Are you storing the scenes correctly? in program mode?

 

I have used the controller you mention with the intimidator 1 scans on a few low budget disco rigs and installs and never had a problem, they have always behaved and possitioned themselves perfectly.

 

I would say its a fault on the controller, have you tried using a different make of scan on the controller, and do the dimmer packs replay scenes correctly as stored/programed?

 

In general chauvet products tend to be ok when it comes to quality and performance

 

vince

[catchthebuzz]

<<Are you storing the scenes correctly? in program mode?

 

Yes, I hold the program button down til it blinks, set the midi record button and apply it to a scene

 

<<Do the dimmer packs replay scenes correctly as stored/programed?

 

The dimmer pack scenes with the par cans behave correctly every time.

 

<<When the scanner fail to go to the position you recorded, do they always go to the same 'wrong' position?

 

No, not the same position. Color and gobos do not suffer same problem

 

<<A full service might reduce the drift but won't get rid of it completely.

 

All equipment is new out of the box and only on second show.

[Ike]

Presumably if you reset the scans then immediately recall a scene it recalls correctly, then if you ran them a bit and tried to recall it again things would be out?

[catchthebuzz]

Presumably if you reset the scans then immediately recall a scene it recalls correctly, then if you ran them a bit and tried to recall it again things would be out?

 

Correct

[johnhuson]

It's sounds like a problem which sometimes occurs with budget units and their lack of feedback on the movement. Essentially what a feedback circuit does is check that the unit is actually in the position that the DMX value says it should be. Thats why if you knock a MAC for example while it's on it will go back to where it was.

 

Many budget fixtures leave feedback circuits out as a cost cutting measure, however it generally means the position creeps out over time rather than the dramatic difference you are seeing. Is this just happen with one unit or all of them, if it's just one I would sense that there is a problem specific to that fixture.

 

A quick and easy way to find out if they have a feedback circuit is to move the mirror once it's set in a position, if it doesn't move back then no feedback!

 

With regard to your 3-pin XLR cables, in an ideal world you should be using proper DMX cable rather than mic cable but that doesn't seem to be the problem in your case. Reasons behind using proper DMX cable have been covered here before I'm sure so have a search.

[MarcT]

If it was a DMX data corruption (cabling) issue, I would expect the scans to "twitch" rather than just miss the mark. However, do ensure you've got a DMX terminator on the end of the line.

 

As others have said its either the controller outputting the wrong scene data, or the scans loosing their position if they don't have positional feedback.

Try a slow(er) fade into position rather than a snap. You might get more reliable results if this is the case.

 

Try another desk / controller.

 

Something is amiss - they shouldn't be that bad.

 

Marc

[paulears]

Just a thought - if the control is off, as in no DMX - do the units auto sync up to the first one? If so, then you can see if they all track together and actually work. If they all do the same, then it's a control issue.