Scan Modes?

[DanielArkley]

When I assisted with Barnum at school, in the after show party I got to play with some Mac250s. I was a bit cheesed off when I found that they wouldn't move where I moved the faders too, which indicated to me that they were set up to move at the speed set on the faders in the directions they corresponded to. i.e. If I set the X and Y faders to 5, the light's didnt move.

 

When I set up my scans for the talent show (if all goes well), can I set them to move to the point I specify, and not the speed I specify i.e. If I set the X and Y faders to 5, the lights are halfway across the axes.

 

Hope this is clear ;)

 

Thanks!

Daniel

[peter]

What you may have had with the Mac250s is that they have a speed channel, which affects the speed at which they move from their old position to the new one. If the speed channel is at 255 (100%) then the head "track" - they move at the speed you move the channel.

 

If you go for fairly basic scans, they won't have the speed channel and thus you shouldn't get this problem. Once you know what model scans you'll be getting, let us know and someone will be able to tell you exactly what features it has, and how to control aspects of it you might not expect (eg the speed channel)

 

Hope this is helpful

 

 

Peter

 

PS: You can download the Mac 250 user manual from the martin website (www.martin.dk)

[gareth]

Peter's almost right, but not quite - to make pan & tilt track the desk output, rather than follow the speed control channels, set the control channels to zero (or use the fixture in mode 2, which doesn't have the speed channels). But my guess is that he's right in thinking that this is your problem. Either that, or you were moving the fine channels rather than the coarse channels - in which case the heads would move, but only by a very small amount which you probably wouldn't see.

[DanielArkley]

We will (hopefully again) be using Pro918s.

[peter]

Roboscan Pro918 channel allocation: Mode4 (most common mode)

 

1) Shutter

2) Dimmer

3) Colour Wheel 1

4) Colour Wheel 2

5) Gobo Wheel 1 - Indexing or Rotating

6) Index Control

7) Gobo Wheel 2 - Static or Shaking

8) Focus

9) Iris (+ Iris Macros)

10) Prism

11) Pan

12) Pan Fine

13) Tilt

14) Tilt Fine

15) Pan & Tilt Speed

16) Effects Speed

 

In order to get the scan to "track" to the crossfade of the lighting desk, channel 15 must be set to a value between 0 and 4, or 246 and 251 (all in DMX values - roughly 0 - 2% or 97%)

 

As Gareth suggested, you could use the scans in "mode2" which eliminates the pan and tilt speed and effects speed.

 

For full details of the functions, Click here

[DanielArkley]

Perhaps I am misunderstanding something here. What is "tracking"?

 

Lets say I have two faders on my contoller, one labeled X, one labeled Y (as there was). When I set these two faders to 5/10 50% 127DMX etc... the lights stopped moving, no matter where they were. If I then set the faders to 0, the lights would proceed to move to their home point. If I then put them back to 5 they would stop somewhere else !

 

Lets say the mirror could move 10cms (just for simplicity so I can explain - im new!) on either axis. I want to have the fixtures set up so if I set the faders to 7/10 for example, the mirror would move to 7cms. If I set the faders to 2/10, the mirror should move to 2/10 etc...

 

Hope this makes things clearer.

[Tom Baldwin]

What is "tracking"?

Tracking is where the fixture does exactly what the desk tells it, immediately (or as close to immediately as it can, bearing in mind moving heads can't move from one end of their travel to the other as fast as you can move the fader on the desk!).

 

Sounds like the only way you'd want it to work, surely?

 

Most of the time, maybe:

Let's say you want the fixtures to pan from one side of the stage to the other, and to take 10s to do it. You could set up two cues on the desk, one with the fixtures pointing to one side of the stage, the other with them pointing at the opposite corned, and have the desk cross fade between these cues in 10s. Over the 10s the cue is running, the desk will constanly be giving the scans new positions - after 1s has elapsed, it should be telling them to point 10% of the way along the path from cue 1 to cue 2; after 3.5s, 35% and so on. That's tracking mode in action.

 

But there's another way of working too:

You could tell the scans: "this is where you start" (pointing at one side of the stage), and then tell them: "move to point over here (the other side of the stage), but take 10s to do it". Now the scans know where they're going, and how long they've got to do it.

 

Doing it the first way can make the scan move more jerkily (it doesn't know the big plan, just this tiny instruction, "move as fast as you can from the last intermediate position to this next intermediate position"), and puts more processing load on the desk (it has to continuously calculate all the intermediate positions and output them).

Doing it the second way means the scan knows the whole plan from the outset, and the desk just needs to issue two commands: "start here", and "go there", and then doesn't need to worry about the rest of it.

 

So which do you choose?

 

The first one is simpler for the programmer to think about, as with the second one you need to keep the speed channel under control (always setting it to the right speed for the cue you're about to do), but the second one can allow you to do more with the desk on really big shows, and can result in smoother moves.

 

It's always choices, choices, choices, isn't it ;)

 

Hope this helped,

 

Tom

 

Random footnote. When Vari*Lites are running their own native control protocol (not DMX), it downloads cues to the fixtures, which then execute those cues - effectively the fixtures are given a list of jobs, told when to "go", and left to get on with it - like the board op in a well-called theatrical show.

[DanielArkley]

That's great advice, thanks Tom. I want the scans to run in the first mode simply because I like to be able to position them manually - if I change my mind whilst moving the scans manually, they are always where I want them (plus, being scans, I guess they can move pretty damn quick!).

 

What would I need to do to the Pro918s (if we get them) to allow them to be moved like this?

 

Thanks!

Daniel

[Tom Baldwin]

(plus, being scans, I guess they can move pretty damn quick!)

They can, although you can still outrun them if you're fast enough on the flash buttons... How flexible is the software you're using as regards assigning flash buttons to the keyboard? reason I ask is, that if you put your scans pointing roughly centre, and set four focuses (up, down, left, right) to four flash buttons, you can get some rough and ready movement effects by hitting those flash buttons very very briefly. It's rough, it's cheap, it's nasty, but it's a "flash and trash" technique that can work quite well for really noisy bands!

 

What would I need to do to the Pro918s (if we get them) to allow them to be moved like this?

Short answer, put them in Mode 2. I suggest you download the manual from the Martin website. It's buried under SPEC/ TRAC/ MOdE on the menu.

 

 

Tom

[gareth]

What would I need to do to the Pro918s (if we get them) to allow them to be moved like this?

First of all, read and absorb the following chart :

Pro918 DMX table

Then decide which mode you want to run the scans in and allocate the relevant number of channels for each unit (12 channels for mode 1, 14 channels for modes 2 or 3, 16 channels for mode 4). Address the scans accordingly (eg. for mode 4 set the start addresses as 1, 17, 33, 49, 65, etc.).

 

Assuming you're using a manual desk with fader-per-channel (sounds like you are), make sure it's patched 1-to-1, and label each fader up accordingly. If you are using this kind of desk, might be best to think about using mode 1 - takes up much less space on the desk, at the expense of the fine pan/tilt controls and the speed controls.

 

You want to use tracking mode (i.e. the heads respond to movement of desk channels in 'real time', and not governed by a timing channel), so if you are using modes 3 or 4 you need to make sure that the last two control channels for each head are set to zero.

 

For each head, set channel 1 to around 15% and channel 2 to full in order to get some light out of the front. Then by moving the pan and tilt channels (or pan coarse and tilt coarse if you're in modes 2 or 4) you should see the mirror move about according to where the fader is at any one time.

 

I really can't break it down any more simply than this - if you're still having trouble it's likely that you've got something set up wrongly.

[DanielArkley]

(plus, being scans, I guess they can move pretty damn quick!)

They can, although you can still outrun them if you're fast enough on the flash buttons... How flexible is the software you're using as regards assigning flash buttons to the keyboard? reason I ask is, that if you put your scans pointing roughly centre, and set four focuses (up, down, left, right) to four flash buttons, you can get some rough and ready movement effects by hitting those flash buttons very very briefly. It's rough, it's cheap, it's nasty, but it's a "flash and trash" technique that can work quite well for really noisy bands!

 

What would I need to do to the Pro918s (if we get them) to allow them to be moved like this?

Short answer, put them in Mode 2. I suggest you download the manual from the Martin website. It's buried under SPEC/ TRAC/ MOdE on the menu.

 

 

Tom

@ Tom: Unfortunatley, it doesnt support flashing from keyboard just yet, which is a shame - I will write up to ShowCAD and suggest it for future versions of Artist. As for Mode 2, here I come ;)

 

@ Gareth: The manual (or programmable) lighting desk I refer to was for Barnum, which my school put on not that long ago. A Performing Arts College from down the road bought along 2 Mac250s, 8 scrollers, and a FatFrog for controlling anything intelligent. They did have some programs on the desk for moving the Macs, but apparently they were miss behaving! For the show I hope to be getting scans in for, we will be using a piece of software called Artist which runs on Windows and connects to DMX via a USB-->DMX Adapter.

 

You can check out the ShowCAD site at www.showcad.com.

[gareth]

I'm not familiar with the software of which you speak, but I'm guessing that it has functions specifically for control of moving lights, and a fixutre library or some such thing which contains information about the control layouts of various types of moving light ...

 

In which case, it's even easier - set your Pro918's to mode 2, patch yourself the requisite quantity of the correct fixture in Artist, and away you go. But don't expect it all to be wonderful and sexy straight away. If you're new to programming moving lights, it takes a little time to get your head around it - it's a whole new ball game. Hopefully the software you have will be sufficiently advanced and well-written to make life a bit easier for you, but be prepared to spend time experimenting and getting it wrong (or at least doing it in a bizarre and unecessarily tedious way) before you get it right.

 

Good luck.

[DanielArkley]

It does contain a fixture library, and Pro918s are built into that library. It also provides something known as "Fixture Control" which allows you to move a little icon around in a square. The icon corresponds to the pool of light and the square corresponds to the area the mirror can cover. Moving the icon around updates the DMX values for the mirror. It also contains a colour pallete, gobo selector etc... ;)

 

You can get a free 30 day trial from the ShowCAD site.

[smeggie]

hmmm - sounds like a nice toy to use for touring shows.

 

sorry to showCAD but wysiwig still wins on the interface for design.

looks promising for smaller shows though.

 

yours.

smeggie

[DanielArkley]

I love it, but then again I am a "noob" ;)