I currently have 2 scanners, 2 barrel scanners and a centre light all linked up by DMX. I have the Acme DMX controller which says it can control 12 units. What would happen if we connected more than 12 units. Would anything after the 12th fixture not be controlled by DMX ?

How do people control setups with more than 12 fixtures, preferably without using software ?

Probably because Acme have skimped on the drive circuit for the DMX line. Each DMX fixture adds 'loading' to the line, the DMX512 standard says 32 fixtures can be driven from a controller meeting the standard so something's been cut back here!

I suppose Acme thought that 12 fixtures would be enough for any mobile DJ!

DMX512 runs in groups of 16. so 16 X 32 = 152 if you have more than 32 DMX units to control you have to then use what is called a second universe. Most DJ setups and even most clubs wont exceed one universe. How ever I have worked on Corporate events that have used three and more. Not all infact most DJ DMX lighting wont use anywhere near the 16 channels but you still have to address in multiples of 16.

My dimmer packs are four channel and so use 4 faders on my DMX desk so if this pack is assigned to 1 even though only four channels are used the next fixture would still be addressed to 17 then 33 Then 49 etc etc.

I guess the controller you are using has been cut back to save on price. Less switching memory etc.

Hope this helps a little.

Nik

Just had a look on the Prolight website and even their iLead controller can only handle 24 fixtures. But, the Martin Freekie can only handle 12 too and that's well over £400. Looking into getting a load of Par Cans to colour wash venues but controlling them seems to be the problem.

With LED par cans I think you can set groups of them to the same DMX address. So every Par Can on say address 1 will change at the same time. Would this help...

Have you thought about software instead...

Nik

It's important to differentiate between the number of individual fixtures that a controller can address, and the number of fixtures in total that can be driven...the two are very different. One is a DMX to fader channel issue and the other a driver loading issue.

Even if you set all DMX addresses the same, you shouldnt run more than 32 fixtures off one universe unless the controller is specifically designed to drive into this lower impedance.

The Martin Freekie is a 12-channel device, this means it has 12 channel faders and 12 fixture buttons. It does not mean it can only drive 12 fixtures, but merely address 12 fixtures of 12 channels!! It's not the same thing!!

That's what I was hoping. I could set all the Par Cans to the same 5 channels. Then the 2 Barrels to the same, the 2 scanners to another and the centre light on its own channel.

Depending on how many Cans we need to fill the venue we might need a total of about 30 fixtures of which there are 4 different types of fixture. Would that be ok to run off our controller so long as all the same fixtures used the same channels ?

I think so but I am no expert there are guys on here who know more about DMX than I... The only problem you might face is if you want the fixtures to be doing different things. Any two on the same address can only do the same. For example if you had two moving heads on one address you could not make one go left and the other go right or one be green and the other blue... With Par cans this is not so bad as you usually run them in banks of four. So if you had 8 Par Cans then that would be two on each address or 16 Par Cans would be four on each address and so on.

But like I say some one with more knowledge than me should be consulted before you try this.

Nik

Just looked at the PDF file for the Martin Freekie controller. It says it can control 12 fixtures or fixture groups. The fixture groups must be similar or identical units all addressed to the same channels. It also said it can handle a maximum of 32 units without amplification. And each fixture or group occupies channels in multiples of 12. Mine does what you said Nik and occupies 16 channels.

We should be fine to control everything we planned to now. Thanks !

I guess you're convinced yourself !!