Adjusting dimmer curve, for full power with soft patch

[0059099]

Hi all,

 

Has any1 experience in setting up a dimmer curve to give 100% ouput, regardless of DMX input?

Or is using a "dimmer scene memory" better for providing continuous power on a channel?

 

Also, I seem to find different responses in using dimmable sockets as fixed power sockets for supplying moving heads, beamers etc. with power, but since this is concerning a softpatch only grid, this seems to be the best solution?

[woody74]

I'll say it:

 

What's the dimming? What's the console? Are you talking about setting a dimmer as a relay? What is the application? Are you putting motors on a circuit (read: scary)?

 

-w

[Jivemaster]

Hard power is best from a hard power source, with appropriate switches and safety.

 

Many dimmers only offer 98 or 99%power out anyway.

 

Several things dont like the waveform of a triac/scr dimmer. Some will malfunction, some will die, and some things will kill dimmers. There are safety issues with using dimmers for things they were not intended for, also.

 

Some establishments use 15a sockets for dimmed power and 16a for hard power.

[0059099]

Pardon my English, I am not a native speaker.

 

I'll try to explain another way.

I need fixed power in a soft patch grid. So every socket in the grid is connected to a dimmer, I cannot connect it to hard power.

 

To supply device in the grid, (e.g. a beamer, moving head, smoke machine etc. etc.) with power, I need a solution.

 

To use the board to give full power is a little to scary for me, since the faders (and GM) can move around.

 

The dimmers can be programmed in 2 ways to supply full power to the sockets, regardless of the DMX signal.

 

1) Set a user curve which gives out 100% output, regardless of DMX input

2) Store a memory with dimmer channels set to 100% output (using HTP combined with DMX input)

 

@jivemaster

If I understand it correctly the triac doesn't give a nice +230 -230 sinus? ( If I look at the UPS logs of my server I see power drops to almost 210V ) You state this could give problems with some "things". Is there a way of telling which "things" will malfunction and which won't ?

[paulears]

you are right - although you can set many desks to output a full on, or full off DMX value, you cannot run moving heads or other kit off a dimmer - even on full. The chopped waveform isn't remotely like a real sine wave - I'm assuming the dimmers are not state-of-the-art. Plugging a moving head into one often destroys the switch mode power supplies - some people have got away with it - but it is pure luck - don't try it. You can get switch packs instead of dimmers - they will do what you want - but I assume you don't want to buy more equipment. The best solution would be to get an electrician to break into the wiring where it emerges from the dimmers and fit some kind of external patch - but this could be rather expensive and not that easy to do.

Paul

[Jivemaster]

The zero-crossing circuits in dimmers turn the devices on after the zero crossing, likely between 10 and 25 volts so there is a significant time of no power for switch-mode psu and a significant waveshape anomaly each loop.

 

Mirror ball motors are a major culprit for killing dimmers as they -though small- are a highly inductive load. Mains voltage fluctuation is a further matter for your thought.

[Shaggy]

Although even some switch packs when connected to a moving light or whatever will kill it.

[0059099]

Ok, thanks. I'll try to get some hard power in, but this is probably difficult since the yesterday most of the cable's were already installed. (they started planning the theatre part while already building :wacko: )

[Bryson]

Am I right in thinking this is still in construction? Then by all means you must get this sorted right now, before they do anything else.

 

What dimmers are you using? In some models you may be able to swap "modules" to replace dimmers with relays.

[Jivemaster]

Supplying hard power may cost! But likely less than killed dimmers or movinglights. Also you can get hard power in with commercial haste, but don't find killed electronics til just before curtain up when you have to replot on the fly round dead circuits.

[0059099]

Sadly, the "cable-pullers" are done in the auditorium :blink:. The front, which will have 4 MH's in it are supplied with only 1 16A fixed power (which should be enough, since the MH's are only 250 each, but I would rather have them divided in at least 2 groups (preferable 4). The stage grid doesn't have any fixed power :(. I already thought of a solution though, which looks to me ok. We still have the old harting multicable system in storage, and there is a CEE 32A at the back of the stage for guest use. I can make a power divider including a little fusebox, dividing the CEE 32A into 6x 16A harting multicable (does any1 know were if these are commercialy avaible? )and using the harting multicable and breakoutbox to have 6x 16A groups.

 

Any suggestions?

[Tomo]

Depending on the dimmers, you may be able to swap modules out for either switchpacks or fixed hard power.

 

One venue I've worked in had large install racks of ETC dimmers with fixed hardpatch just like you're describing.

The moving lights were all powered through this system, but the dimmer modules for these circuits had been replaced by empty tripswitch modules.

In some cases this had been done by the local technicians by pulling the boards out of a module, which were kept as spares for dimmer module failures.