Controlling the datamoon dish - continuous rotation

[djgraham]

Hi,

Have had a search around the forums and can't see this answered anywhere. - The problem is making the datamoon do a continuous slow rotation for those slow-dance type situations.

In a nutshell - I've got a pair of NDJ Datamoons, and one of the DMX channels (Channel 0 I think) is the "dish rotation" channel - basically DMX 0 - 0 degrees, and 255 = about 359 degrees.

When changing this value the dish takes the shortest route to reach its new position so if you were to go from 250 to 0 in one snap, the dish would move only a small amount (if you look at it from a dmx channel point of view, it would go 250, 251,252, 253.254.255, 0 .

Is it possible to create a continuous rotation using the sequencer ? I basically want to go from 0 to 255 and then flip back to 0 again then carry on counting up (Dish would then just rotate in that one direction).

I've tried to create a sequence - with dmx value of 0 on the first step and 255 on the second step - and just set to a slow fade time - however the step time minimum is 100ms - so the dish stops and then "jerks" back to its closest position.

So any ideas of what I can try - without having to resort to using my NDJ Datacon hand controller for a continuous rotation?

Thanks for any pointers!

Cheers,

David
--
DJ David Graham
w: http://www.djgraham.co.uk
f: http://facebook.com/djdavidgraham

[Mavi]

You can create a sequence with 4 steps:
step 1: DMX 85, Fade Time = Scene Time, Channel set to Fade
step 2: DMX 170, Fade Time = Scene Time, Channel set to Fade
step 3: DMX 255, Fade Time = Scene Time, Channel set to Fade
step 4: DMX 0, Scene Time = 100, Channel set to Snap

The first 3 steps will fade from 0 to 255. If you always use the same Scene Time the fade will be with the same speed trough all steps. Using the 170 as second step makes sure the fixture will not use the shortest way from 0 to 255 - wich would be only one step. The fourth step is resetting the DMX from 255 to 0. Setting the channel to snap ensures to do the reset as fast as possible - the Scene Time of 100 (what means 100ms) is thos fastes time. In fact the rotaion will stop for a very short moment. But try it and see if this effect is what you want. I do not have any other idea at the moment

[djgraham]

The 100ms stop looks "wrong" though it stops and then carries on.... Perhaps there's some argument for having a 0ms step somewhere?

[Mavi]

I was afraid the short stop will look wrong. But 100ms is the shortest amount you can set up as scene time. On the other hand you can not fade from 255 to 0 because then you would have all those values between as DMX output then.

Currently I have only the idea to set up a sequence with 255 steps, but I think that is not realy a good idea I shortly thought of setting up three values, (85, 170, 255) with snap on. The fixture will always take the shortest way. So it will go from 255 to 85 in the same direction as from 85 to 170 and from 170 to 255. But then I considderd that with snap values you have a very fast rotation from one value to the other and you will have a stop at the points.

I also thought about using 3 other values: 0, 127 and 255, all with Fade on. Run the sequence over and over again. But internal FS will fade down from 255 to 0 then.

Perhaps you can play around with this ideas and perhaps you have to do some adjustments to the values and run into a solution wich works good for you. But I think the problem is to get down from 255 to 0 instantly and I do not have any solution for this. Or we have to get rid of this minimum scene time of 100ms. I will think about and post if I get a new idea. And perhaps we are luky and someone else here in the forum has a solution


By the way: the behavior of the channel you mention sounds more like a gobo indexing channel then a gobo rotation channel. Normaly for gobo rotation you set up the rotating speed with the DMX value you select.

[djgraham]

I setup a two-step sequence for this-

Step 1: Dish: 0, SNAP - (Step: 0.1s / Fade: 0.5s)
Step 2: Dish: 255, FADE - (Step: 30.000s / Fade: 30.500s)


It seems to work fairly OK - so basically its at 2 RPM. 30.5s fade seemed better for some reason rather than a 30s fade....

I guess to make the intermediate step (100ms) faster I could go to 60s step and a 60.5 fade), and increase the cue speed to 200% - giving a 50ms "stop" as it were... Now if only we could reduce the 100ms to as little as possible.


It is a dish control channel. There are 4 DMX channels in the datamoon, Channel 1: Rotation (Should be called dish angle I guess?), Channel2: Not used, Channel 3: Gobo, Channel 4: Lamp Control (0 = lamp totally off, 1- 230 Lamp On, 232+ Lamp on, but blacked out).

If you want to do "strobing" with the datamoon, you need to setup a sequence for that as well.... 100ms on, 200ms off and speed it up a touch...

Cheers,

David