Control/Dimming Silly basic question/Understanding hot power

[ngmouse]

Hey all, I have a kind of silly question that I feel I should already understand but don't.

For fixtures that require hot power (in this case LEDs using powercon), how exactly do I go about powering them? From the hot power in the touring dimmer rack and control them via DMX? And then how do I deal with patching them in the board?

 

[EdSavoie]

If I understand correctly there's a few things you're asking.

First, powering the LED fixtures:
It's been debated long and hard if you should be powering LED fixtures off of a theatrical dimmer, and there's no consensus either way.

Technicians at the National Arts Centre in Canada have been powering moving heads off with their AVAB DDII dimmers parked at full with no I'll effect that they can tell. So YMMV.

As for controlling them, this is largely dependent on the fixture, but at the very least you will need to use a DMX / Ethernet cable going into the first fixture, and using either DMX, Ethernet, or some proprietary power + data cable to link them together.

Patching is largely dependent on the board, so we'll need more details.

 

[icewolf08]

Hey all, I have a kind of silly question that I feel I should already understand but don't.

For fixtures that require hot power (in this case LEDs using powercon), how exactly do I go about powering them? From the hot power in the touring dimmer rack and control them via DMX? And then how do I deal with patching them in the board?

There are many ways you can power non-dim fixtures. Usually the one requirement people try to fill is that you can control the power from the ground and not have to touch the fixtures once they are hung. This could be accomplished by using relay modules in a dimmer rack, connecting your fixtures to a PD that you can power down after the show, or even just having them plugged in somewhere that you can unplug them at the end of the night. "The best" soluition is going to be the one that allows you the most convenient safe control of your fixture power.

In situations where I use relay modules, I usually patch my relays into channels that correspond to the channels of the fixtures, so if my ML were channel 101, I might put it's power relay in channel 1101. If you connect your fixtures to a PD, you don't have to worry about any patching.

If I understand correctly there's a few things you're asking.

First, powering the LED fixtures:
It's been debated long and hard if you should be powering LED fixtures off of a theatrical dimmer, and there's no consensus either way.

Technicians at the National Arts Centre in Canada have been powering moving heads off with their AVAB DDII dimmers parked at full with no I'll effect that they can tell. So YMMV.

As for controlling them, this is largely dependent on the fixture, but at the very least you will need to use a DMX cable going into the first fixture, and using either DMX, Ethernet, or etherCON to link them together.

I would argue that there is pretty good consensus that powering fixtures with electronics, unless they are designed to be powered from dimmers, should not be powered by dimmers. The reason being that standard SCR/SSR dimmers still "chop" the waveform, even when parked at full. While it may work, it is one of those things that could also just stop working and then damage your electronics when it decides to stop working. Also, the "chopping" action of a dimmer can mess with any electronics that use the electrical frequency for any internal timing.

 

[ChrisB_SanDiego]

Since you mention a touring dimmer rack, then I would just plug it into a constant-on relay on that rack and just ignore trying to patch power. You can either go straight powercon to the distro if it has one, or use an edison to powercon. these by nature on distro's are relays.

You can also go stagepin to powercon although I would highly recommend NOT going this route simply for the sake that stagepin is notorious for loose connections.

If you are linking power by using the through powercon than judge your amperage limit based on the first powercon out amperage usaully 15amps versus the 20amps at the distro.

I would highly recommend keeping the power at the distro and not patching it. This way you don't have to worry about either parking the relay, or having power cut to the LEDs when you hit blackout, or having it programmed off in a random cue or someone else using the board and randomly applying an effect to everything on the board... it happens.

If you don't have a relay than a lot of newer road distros have settings that you can turn a dimmer into a constant on if you need it.

I do not believe that chopping is really as much of an issue as it used to be, especially with name brand fixtures. Most fixtures I deal with that were created in the last 5 years tend to be rated for variable voltage. And newer distros no longer have the 'chopping' effect because the internal circuitry accounting for this fault when changed at the distro setting. If your not sure or want a little more reassurance, check the manual or contact the manufacturer of your LEDs

ex. ETC Selador Manual "The Selador series fixture operates on AC power, 100 to 240VAC/50-60Hz. You may use a circuit powered through an SCR dimmer, as long as the dimmer is set to unregulated non-dim (switched) operation."

That being said, use a relay if you have them, and keep your power off of the board, unless you really need to control it. Keep it simple and limit your risks.

Just turn the distro off after the show so they aren't always running up the bill

 

[soundofsparks]

I would argue that there is pretty good consensus that powering fixtures with electronics

+1 to IceWolf

I find that this explanation from ETC is very helpful in understanding best practices here.

https://www.etcconnect.com/Support/...witched-Mode---Regulated-vs--Unregulated.aspx



For the OP,

You need to be able to supply whatever voltage the unit requires over cable sufficient enough to cover the unit's maximum amperage over the distance of the run. That's your hot power run. It can come from the Hot Pockets on your rack or the outlet the bathroom as long as you know that the voltage and amperage are all kosher (note: consider what else may be using said circuit when calculating draw... if you have someone drying their hair in the aforementioned bathroom on the same circuit, that might be less than ideal)

You also need to send control signal to the unit (usually via DMX cable). When the unit is powered on (or before if it has an analog addressing system like a dipswitch), you choose it's starting address.

Depending on what type of control console, you patch that starting address and then assign a profile that matches the units parameters to the control keys on the console. If your console doesn't do profiles, you'll have to know which offset address does which function and patch them separately.

For example:

Maybe the fixture's channels are:

1 - Intensity Master
2 - Red
3 - Green
4 - Blue

So if the starting address is 101, you could patch 101 to channel 1 in the console, 102 to channel 2, etc. and then you can control the light using those four channels.

 

[RickR]

Many touring racks contain a few "hot power" outlets besides the usual dimmer/relay cards. If you only have a few fixtures and you won't pop the 'hot' breakers (read up on in-rush) then yes that works well. If you need more then relay cards/modules are the way to go.

I strongly suggest that you read the manual for your fixtures. That will tell you how to control them.

 

[TJCornish]

If you don't have a relay than a lot of newer road distros have settings that you can turn a dimmer into a constant on if you need it.

I do not believe that chopping is really as much of an issue as it used to be, especially with name brand fixtures. Most fixtures I deal with that were created in the last 5 years tend to be rated for variable voltage. And newer distros no longer have the 'chopping' effect because the internal circuitry accounting for this fault when changed at the distro setting.

Please explain this, giving specific examples. Other than the ETC full Sinewave dimmers which certainly don't make up the vast majority of touring systems out there, I'm not aware of any touring racks that don't affect power, even in "constant" mode. Normally "constant" is just a software setting that prevents that channel from being dimmed by DMX. A fixture being rated for variable voltage does not necessarily mean it's stable on something other than a full waveform - this creates lots of ugly power harmonics that the power supply of the LED/Mover/whatever fixture probably wasn't designed for (a few specific ETC fixtures excepted).

If they are your fixtures, feel free to tempt fate and power them with whatever garbage power you have access to. If they are rental fixtures, you may want to check with the rental house on their policy. If you're renting from me, you will not be powering my gear from dimmed power.

 

[JD]

"The Selador series fixture operates on AC power, 100 to 240VAC/50-60Hz. You may use a circuit powered through an SCR dimmer, as long as the dimmer is set to unregulated non-dim (switched) operation."
------
Although a big proponent of directly powering fixtures, I want to point out a key phrase: "set to unregulated" Why? Regulated sound so much nicer BUT dimmers achieve "regulation" at 100% by dimming down the power if it goes above the regulated set point. So, lets say your regulated set point is 115 volts, the dimmer is at 100% and the line voltage is 128 volts .... The dimmer actually drops back to 90% to achieve regulation putting a big sawtooth into the AC feeding the light.
One other note: It isn't the voltage variations that damage electronics. The above fixture can handle variation between 100 and 240 volts. It is the waveform a non-sine (phase chop) dimmer produces. With the many thousands of dollars a good mover costs, why risk the fixture on a setting being set right?

 

[Jay Ashworth]

Well, in our house, our movers are powered from a pagoda box plugged into our 100A-3ph company switch; that's where we put other flown-non-dim stuff, too, but if we went whole hog on flown LED Fill (for example), it's likely we'd either rewire the battens or put in some non-dim modules in the rack.

 

[RickR]

For bypass dimmers, I'm only aware of the ETC "thru-power" modules. They have 3 modes; dimmer, relay, constant. Relay and constant modes actually bypass the SCR so you have a full waveform.

Anybody else make something similar?