DMX Relay Question

[Stan Longhofer]

I have a Chauvet Pro D6 dimmer pack on which the channels can be configured to work as dimmers or relays, and I can configure the "no dmx signal" to blackout. I know that many dmx devices require a constant AC power source (not a dimmer running at 100%).

My question is this: Properly configured, can I use this dimmer pack as a true relay to shut off power to my other dmx devices when I shut down my console, or does configuring this device in "relay mode" simply provide the same power as it would in dimmer mode with the channel set at 100%?

Thanks in advance for any wisdom.

 

[JChenault]

In general any dimmer that can be configured to be a dimmer or a relay only treat the “Relay” as turn on the dimmer to 100%.

IE not a good idea.

 

[seanandkate]

+1 for what John said. Dimmer doesn't = relay.

 

[BillConnerFASTC]

+1 but this has gotten more complicated and simpler in world with ThruPower Modules and Power Through Dimmer Modules.

 

[Stan Longhofer]

+1 but this has gotten more complicated and simpler in world with ThruPower Modules and Power Through Dimmer Modules.

That was the reason for my question. The user manual specifically states that it can be configured as a dimmer or as a switch/relay. What isn’t clear is whether the nature of the power provided is different when it’s set up as a relay. As I understand, there is some difference in the wave form of the current of a dimmer set at Full versus a constant power circuit, but that’s reaching the edge of my knowledge.

 

[BillConnerFASTC]

This issue id does the power still go through the SSR or whatever solid state device they are using when in relay mode. I suspect it does - as I think both John and Sean do - but I do not know that particular product. @Ford should. I can't tell what device (ssr, triac, mosfet, ???) or how its configured or much about it from online sources.

 

[RonHebbard]

That was the reason for my question. The user manual specifically states that it can be configured as a dimmer or as a switch/relay. What isn’t clear is whether the nature of the power provided is different when it’s set up as a relay. As I understand, there is some difference in the wave form of the current of a dimmer set at Full versus a constant power circuit, but that’s reaching the edge of my knowledge.

@Stan Longhofer I'll attempt to summarize this two ways:
1; If your dimmers cost $100.00 or less for four, they'll likely be incapable of operating as real relays.
2; If the dimmers within your packs or modules contain ONLY dual SCR's, TRIAC's or IGBT's and do NOT also include mechanical contactors or relays, they are incapable of operating as real relays.
Addendum: Some manufacturers refer to genuine relays as mechanical, or "air gap" relays or contactors.
Autotransformer / "Variac" mechanical / magnetic dimmers when parked at 100% are likely safe to use to power most electronic devices and mechanical "On / Off" switches on those same magnetic / inductive dimmers are normally safe to power and switch off most electronic devices so long as the "Variacs" are parked at 100%.
Mechanically parking a "Variac" at 100% is NOT to be misconstrued with "parking" an electronic / dual SCR / TRIAC / IGBT dimmer at 100%. I think I've covered this and made it clear as mud but I'm sure someone will be along shortly to poke holes in my summary.
EDIT: Edited to 'cross a few I's' and 'dot a few T's' in my summery summaries.
Toodleoo!
Ron Hebbard

 

[Mac Hosehead]

I own a similar Chauvet portable dimmer pack that you can put outputs into "switched" mode. There are no relays in this unit and it just drives the triacs to full.

 

[BillConnerFASTC]

Thanks to Mac for confirming my assumption.

If the dimmers within your packs or modules contain dual SCR's, TRIAC's or IGBT's they are incapable of operating as real relays.

That's the hard part because both ETCs ThruPower Module and Strands PowerThrough Module contain SCRs or such but both are capable of operating as a real relay or constant power source.

 

[RonHebbard]

Thanks to Mac for confirming my assumption.



That's the hard part because both ETCs ThruPower Module and Strands PowerThrough Module contain SCRs or such but both are capable of operating as a real relay or constant power source.

@BillConnerFASTC That's only possible when they ALSO contain mechanical contactors (butch relays) in addition to their SCR's, TRIACS's, IGBT's, MOSFET's, etcetera.
Toodleoo!
Ron Hebbard

 

[BillConnerFASTC]

@BillConnerFASTC That's only possible when they ALSO contain mechanical contactors (butch relays) in addition to their SCR's, TRIACS's, IGBT's, MOSFET's, etcetera.
Toodleoo!
Ron Hebbard

True. But the noted modules meet your criteria in your no. 2 yet they are fine for power supplies. It was the basis of the o.p. - did his dimmers include this feature, which allows bypassing the scr or whatever .

 

[Stan Longhofer]

I just got a confirmation from Chauvet Tech Support: This unit (Chauvet DJ Pro-D6) CANNOT be used as a true relay, just as a dimmer or a switch. What I expected, but it was worth a shot since I already had this in house.

Does anyone have suggestions for an inexpensive dmx relay? I have a dmx controlled dowser mounted on a data projector dropped down from a catwalk lighting position. I'd rather power this off remotely than to have to climb up to the catwalk to unplug the device. Is the ETC ColorSource Relay my best bet?

 

[BillConnerFASTC]

Fro $250 plus a couple of cords, seems hard to beat.

If this is "permanent" you could look the ETC Foundry relay. All terminals - no plugs - but mounts in a standard knockout. $225 at same place I found CS relay for $250. Plus it gives two relays. Just not plug and play.

 

[digital1]

I have a Chauvet Pro D6 dimmer pack on which the channels can be configured to work as dimmers or relays, and I can configure the "no dmx signal" to blackout. I know that many dmx devices require a constant AC power source (not a dimmer running at 100%).

My question is this: Properly configured, can I use this dimmer pack as a true relay to shut off power to my other dmx devices when I shut down my console, or does configuring this device in "relay mode" simply provide the same power as it would in dimmer mode with the channel set at 100%?

Thanks in advance for any wisdom.

 

[digital1]

A Triac dimmer, which is like what the Chauvet unit has, will be able to provide 120 VAC full ON ( 99% of voltage ) or Full OFF ( still with minimum voltage created by snubbers and depending on the Load ) . There is no mechanical open gap switch to isolate completely the 120 VAC from the load. Triacs are electronic switches which still allow a minimal leakage current.
It could be used to turn ON and OFF lighting products which are not transformers or inductive loads ( motors) unless the dimmer is designed to handle these loads too.

 

[coolsvens]

As others have mentioned. You want to make sure you have an actual relay module and not a dimmer set to 100% or switched mode. Something like the ThruPower module has both a dimmer and a relay in it like others have mentioned. You can set it from the front panel of the module or via a console or even a phone app to be a dimmer (lots of copper coils) or a relay (Actual air gap). It's the ideal way to have a super flexible power system in your space. See pics below from one of the modules in our racks.

 

[taneglaus]

I want to play devils advocate here. I'm an electronics engineer. I've studied how SCR, TRI-AC, & Varistors work. I understand how these chop up the duty cycle to dim the light, or create a variable speed drill, motor, etc. But this ? Seems to come up now and then, can a dimmer at 100% be used to run electronic devices?

Does anyone have a strong engineering explanation why an SCR dimmer running @ 100% cannot run other devices?

My thought is that an SCR dimmer ckt @ 100% is passing a full sine wave...or virtually the full sine wave, both voltage & current. As long as the ckt can handle the power & associate heat, why not?

I've herd the "you can't do that" statement, but I want a technical description as to why not. With today's electronics, other than lamps & motors, electronic devices have power supplies that will filter or compensate or minor abnormalities in the sine wave. So with those power supplies, why not?

I'd appreciate waveforms describing the issue.

 

[coolsvens]

Taneglaus,

This get a bit in-depth, and there are a few good articles I read about this. The non-technical explanation is that yes an electronic device will power up if you put a dimmer at 100%, but what you are doing is degrading the internal electronics because any SCR dimmer is indeed going to have a "clipped" sine wave. And in regards to voltage, you are likely running in a regulated voltage mode on a dimmer, when unregulated is what you want. In short, the best way I've been explained it: Running a dimmer at full in regulated mode is like hitting an electronics board with a hammer every 60hz because of the chopped sign wave and it's frequency rate. Yes it works, but if you just bough some expensive new LED lights, you probably want to power them correctly.

There are a few postings about this that I think get into some better details.

https://www.ledsmagazine.com/articl...-issues-to-ensure-compatibility-magazine.html

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

http://www.etcconnect.com/Support/A...and-Moving-Lights-Powered-by-ETC-Dimmers.aspx

I want to play devils advocate here. I'm an electronics engineer. I've studied how SCR, TRI-AC, & Varistors work. I understand how these chop up the duty cycle to dim the light, or create a variable speed drill, motor, etc. But this ? Seems to come up now and then, can a dimmer at 100% be used to run electronic devices?

Does anyone have a strong engineering explanation why an SCR dimmer running @ 100% cannot run other devices?

My thought is that an SCR dimmer ckt @ 100% is passing a full sine wave...or virtually the full sine wave, both voltage & current. As long as the ckt can handle the power & associate heat, why not?

I've herd the "you can't do that" statement, but I want a technical description as to why not. With today's electronics, other than lamps & motors, electronic devices have power supplies that will filter or compensate or minor abnormalities in the sine wave. So with those power supplies, why not?

I'd appreciate waveforms describing the issue.

 

[derekleffew]

View attachment 16651

Hate to be pedantic here, but highlighted in red are two choke, torodial . The "dimmers", SSRs actually, are on the left side of the module.

 

[Chris Pflieger]

Does anyone have a strong engineering explanation why an SCR dimmer running @ 100% cannot run other devices?

This issue pops up about every six months on CB. I'm guilty of starting it up a year or two ago - I really never got a detailed answer that satisfied me.

I've designed several commercial dimmers, but I'm not a power engineer (EE w/ embedded focus), so... no, I can't give you a clear reason why it won't work. In theory, with a triac (SSR) or IGBT continuously biased it should work flawlessly. And if it's zero-crossing turn on, you'd think it'd work better than a non-zero-cross relay since these power supplies tend to have a big inrush current. I've always been at small companies, so I never have had the time, money, resources or need to investigate it further. I do know that these new LED dimmable line voltage lamps are a bitch to dim right, but that's for another thread.

Some dimmers try and compensate for excess input voltage by reducing the output a bit. That's a problem. (and it's 120 Hz, not 60 Hz) And if the dimmer attempts a soft start, i.e. ramping up phase over one second, that's a bigger problem. Other than that, I can't tell you why. Perhaps a current lag issue from the chokes... I don't know.

The fixture manufacturer says don't do it, the "big boys" making dimmers w/ EE's smarter than me (at least when it comes to power engr.) say don't do it, the grey beards here on CB say don't do it, so it's not worth the risk, IMHO.