Control/Dimming Help With Various DMX Issues

CameronLD

Member
Hey all,

I am a young LD designing for a production of Grease this summer in a very small space. As such, I have decided I would like to use some of the scrollers the theatre company I am working with owns, as well as rent/buy some gobo rotators (http://www.stagelightingstore.com/core/media/media.nl/id.42197/c.689066/.f?h=a863686d204ef7435cd3), LED Pars (http://www.stagelightingstore.com/core/media/media.nl/id.42197/c.689066/.f?h=a863686d204ef7435cd3), and I-Cues, in order to compensate for a relative deficit of dimmers and conventional fixtures.

Can you all check my plans to make sure I'm not making some dangerous mistake or missing something obvious?
I'm planning to operate 4 Chroma-Q Scrollers and 2 I-Cues off a 4-pin cable run from a Chroma-Q PSU we own. The cables would go from the PSU, to 2 scrollers, then to the 2 I-Cues, then to the last 2 scrollers, and back to the PSU to complete the connection. Then I would run a 5-pin DMX from the PSU to the board.
Then, I would need to make a seperate run with 3pin cable to connect my LEDs, as well as a run of extension cords to give them power. The last LED would be connected to the board via a 3-pin to 5-pin DMX connector.
Finally, I would plug the gobo rotators into a dimmer near the fixture they are on to give them power.

Hope this all makes sense and should work. My only concern at this point is how to connect both DMX runs to the board (an ETC Express), since there is only one open DMX input, as the other one is being taken up by the DMX run to the dimmers. Any ideas on how to get both runs to the board in this situation?

Thanks very much in advance!
- Cameron
 

dreamist

Member
I'm planning to operate 4 Chroma-Q Scrollers and 2 I-Cues off a 4-pin cable run from a Chroma-Q PSU we own. The cables would go from the PSU, to 2 scrollers, then to the 2 I-Cues, then to the last 2 scrollers, and back to the PSU to complete the connection.
This sounds okay, though others who know the equipment better can jump in. I'm pretty sure the return cable is optional, but recommended. You didn't mention which specific PSU, so I don't know if it can support all the devices here.. Might want to check the manual for it to make sure you aren't going over power..

Then I would run a 5-pin DMX from the PSU to the board.
Then, I would need to make a seperate run with 3pin cable to connect my LEDs, as well as a run of extension cords to give them power. The last LED would be connected to the board via a 3-pin to 5-pin DMX connector.
Finally, I would plug the gobo rotators into a dimmer near the fixture they are on to give them power.

Hope this all makes sense and should work. My only concern at this point is how to connect both DMX runs to the board (an ETC Express), since there is only one open DMX input, as the other one is being taken up by the DMX run to the dimmers. Any ideas on how to get both runs to the board in this situation?

In order to hook it up as you describe, you'll need some sort of a DMX repeater. A cheap option that I have used to good effect is the ENTTEC D-Split. http://www.enttec.com/index.php?main_menu=Products&pn=70572

I've seen them online for $99 or so..

You could instead try daisy chaining off the PSU DMX Out port.. use your 5-to-3 converter on the out port and then send the cabling to the LEDs via the 3 pin cable..
 

SteveB

Well-Known Member
Hey all,

Hope this all makes sense and should work. My only concern at this point is how to connect both DMX runs to the board (an ETC Express), since there is only one open DMX input, as the other one is being taken up by the DMX run to the dimmers. Any ideas on how to get both runs to the board in this situation?

Thanks very much in advance!
- Cameron

Only option I see is to use the pass-thru DMX port on the scroller PSU (if there is one) to the rotators. Hopefully it's an easy run. Obvious "correct" solution is to use a DMX splitter, if you have or can get one. That could be placed wherever it's convenient, or maybe right at the console as they need A.C. power.
 
I'm planning to operate 4 Chroma-Q Scrollers and 2 I-Cues off a 4-pin cable run from a Chroma-Q PSU we own. The cables would go from the PSU, to 2 scrollers, then to the 2 I-Cues, then to the last 2 scrollers, and back to the PSU to complete the connection.

I would make sure the power output from the power supply is the correct voltage for the I-Cues, and that you are not over drawing power for the output. Also make sure you are not exceeding the recommended 200 ft maximum cable length.

Then I would run a 5-pin DMX from the PSU to the board.
Then, I would need to make a seperate run with 3pin cable to connect my LEDs, as well as a run of extension cords to give them power. The last LED would be connected to the board via a 3-pin to 5-pin DMX connector.

Is the separate run needed because of location? a plot would be helpful to look at cable runs. You could pass through the power supply with 5-pin DMX to get to your LEDs if they are close enough. Also you want to make sure you use 3-pin DMX and not mic cable.

If you can't do this then you are going to need a DMX splitter for your multiple runs of DMX, Unless the dimmer rack is close to the LEDs and you have room in the first universe. You could then come out of the Dimmer rack into your LEDs


Finally, I would plug the gobo rotators into a dimmer near the fixture they are on to give them power.

I would be hesitant to put them on a dimmer unless you have the relayed dimmer packs for constant power. A cheap solution would be running the power off of a power strip in the booth and manually turning them on and off.

These are all my best guesses based on the information provided if you could show me a plot I could give you more concise answers and solutions to your DMX problems.
 

microstar

Well-Known Member
....since there is only one open DMX input, as the other one is being taken up by the DMX run to the dimmers. Any ideas on how to get both runs to the board in this situation?

Terminology: you are using the console's DMX output, not input. It is sending DMX to the inputs of your various devices.
 

CameronLD

Member
All,

Thanks for the replies.

Here is the power supply unit I will be using: http://www.chroma-q.com/products/ps08-power-supply.asp
And the scrollers: http://www.chroma-q.com/products/plus-colour-changer.asp
And the I-Cues: http://www.rosco.com/lighting/icue.cfm


Here are all my thoughts after reading your comments, I apologize for its slightly jumbled nature:

I'm not totally sure how to determine if the power needs of the I-Cues and Scollers would be more than what the PSU can provide (I've almost exclusively worked with just conventional fixtures until recently). How do I do that?

I was planning to do 2 separate runs mostly because the LEDs use 3 pin while the I-cues and Scrollers are 4 pin, but maybe I'm wrong about how that would all work. They're also in slightly different locations, but there is a cable run already established between the two locations, so that isn't a huge issue.

In regards to sending the run from the PSU through the LEDs, am I correct in understanding that the suggestion is to do the loop for the scrollers/I-Cues, then run the 5pin to 3pin adaptor from the input of the PSU to the first LED, daisy chain the four of them together, and then use a 3 to 5 pin adaptor to go from the last LED to the output on the board? If thats possible that sounds like a super simple solution.

The dimmer rack is fairly close to the LEDs (the rack is just to the right of the electric labeled B1 on the plot). If necessary, how would I go about patching the LEDs directly into the ETC Sensor Dimmer rack?


I've attached the plot with the fixtures in question below.

Thanks for any more help you can give!
Cameron
 

Attachments

  • Screen Shot 2016-07-01 at 2.50.09 AM.png
    Screen Shot 2016-07-01 at 2.50.09 AM.png
    34.4 KB · Views: 182
I'm not totally sure how to determine if the power needs of the I-Cues and Scollers would be more than what the PSU can provide (I've almost exclusively worked with just conventional fixtures until recently). How do I do that?

After doing some digging from everything I've found it looks like this will work. All of this information is usually in the manuals so I would always start there when working with new fixtures.

I was planning to do 2 separate runs mostly because the LEDs use 3 pin while the I-cues and Scrollers are 4 pin, but maybe I'm wrong about how that would all work. They're also in slightly different locations, but there is a cable run already established between the two locations, so that isn't a huge issue.

In regards to sending the run from the PSU through the LEDs, am I correct in understanding that the suggestion is to do the loop for the scrollers/I-Cues, then run the 5pin to 3pin adaptor from the input of the PSU to the first LED, daisy chain the four of them together, and then use a 3 to 5 pin adaptor to go from the last LED to the output on the board? If thats possible that sounds like a super simple solution.

I have attached a layout that is one solution to the dmx problem without needing to buy any other equipment.

The dimmer rack is fairly close to the LEDs (the rack is just to the right of the electric labeled B1 on the plot). If necessary, how would I go about patching the LEDs directly into the ETC Sensor Dimmer rack?

If you use the DMX out on the dimmer rack you will just have to start the addresses for the LEDs above the address of the last dimmer
 

Attachments

  • Cable Layout.pdf
    49.2 KB · Views: 170

CameronLD

Member
Wow, that is awesome. Thank you very, very much.

I'm going to be in the space tonight and I'll see if there is anything else I have questions on about this, but that is very helpful.

Thanks!!
Cameron
 

CameronLD

Member
After checking out the dimmers in person and looking through the Sensor manual, I'm not so sure that they have outputs. Are there definitsly outputs on the dimmer rack, and if so where would said outputs be located?

Alternatively, could it be possible to just do a single run from the console, through the LEDs, to the PSU, and then to the scrollers and I-Cues (that last bit with the scrollers and icues in two separate runs)? That would seemingly make things much simpler, but I just am not knowledgeable enough to know if power and control can be Daisy chained like that.

Thanks again.
 
Last edited:

SteveB

Well-Known Member
If it's an installed Sensor rack, as opposed to a portable, there's no DMX output port on the rack.

Not uncommon though for the design to have called for a port somewhere on stage that picks up the DMX that goes to or from the dimmer rack. Never hurts to check around for a DMX female jack somewhere.

As answer to the 2nd question is yes you can daisy up to 32 devices on a single DMX run, in theory, but it doesn't sound like you have that many so should be good to daisy the whole setup. There's no power on the 5 pin DMX stuff, only on the 4 pin scroller and PSU units.

It sounds like you want DMX off the 2nd (or 1st) console port, to the PSU (which sends data to the scroller via the 4 pin cable, and the I-Cue if using the scroller PSU for power), then adapt to 3 pin to get data to the LED's.
 
...I'm not totally sure how to determine if the power needs of the I-Cues and Scollers would be more than what the PSU can provide (I've almost exclusively worked with just conventional fixtures until recently). How do I do that?...

The PS-08 can handle 8 Chroma-Q units safely. Your setup seems to have 6, but in my experience the I-Cues draw just a bit more than the Chroma-Q units. You're still fine.

You may notice some lag if you are running live changes, if you make a single loop with your 4-pin lines. If you can, run two lines (The PS-08 has two sends and two returns) to split them up, which should minimize lag, if necessary. It doesn't matter much which units go where. Just so you know, the PSU sends DMX to the units on the first three pins and 24VDC(ish) on pin 4. The return line is optional, but helps that DC circuit feed power to units near the end of the line to help reduce later-units-in-line lag.

If you're short on 4-pin cables, you may find that two separate runs without returns work better than a single run with a return, but that will depend on your particular situation. You may notice no difference at all, or it may make it worse, depending on the runs.
 

GreyWyvern

Well-Known Member
Just so you know, the PSU sends DMX to the units on the first three pins and 24VDC(ish) on pin 4.
DMX only uses 2 pins/wires. What do you think the third is? The pin out* is- pin 1: -VDC(or common or ground, whatever you want to call it), pin 2: -data, pin 3: +data, and pin 4: +24VDC. There has to be a connection other than the +24VDC for it to work. For instance, you can't make something like a flashlight work by only connecting the + side of the battery. There has to be a loop for the power to flow.
The return line is optional, but helps that DC circuit feed power to units near the end of the line to help reduce later-units-in-line lag.
That is the right idea. Having the return line essentially feeds power from both directions so the isn't really an "end of the line" or "later units in line". The result is a much more constant voltage across the line and units. The other big, possibly bigger, thing is that it terminates the data.

*Note that this is for most common 24VDC power supplies. There are exceptions, the main ones being Morpheus PSUs and Wybron Coloram PSUs. Plugging accessories that use the aforementioned pin out into those supplies may cause damage to the accessories.
 

kicknargel

Well-Known Member
For thinking in terms of DMX data chain, you should consider the PSU and any devices it's driving (scrolers, I-cue) as a single device. So your DMX data chain can run from the console through the PSU and any LEDs in any order that's convenient. The 4-pin run from the PSU to those devices is a sub-branch of the DMX chain.
 

GreyWyvern

Well-Known Member
For thinking in terms of DMX data chain, you should consider the PSU and any devices it's driving (scrolers, I-cue) as a single device. So your DMX data chain can run from the console through the PSU and any LEDs in any order that's convenient. The 4-pin run from the PSU to those devices is a sub-branch of the DMX chain.
Each 4-pin accessory counts as one device towards the limit of 32 devices per DMX line. Where those devices get counted isn't always clear though. If there is not an opto-isolator inside of the PSU, all the 4-pin devices on that PSU need to be counted as devices on the DMX line. The PSU may need to be counted as a device as well. The safe bet is to count the PSU and each device, unless you know for sure that the 4-pin outputs are isolated, such as is the case with Apollo's Smart Power 200 and 400 supplies.
 
DMX only uses 2 pins/wires. What do you think the third is? The pin out* is- pin 1: -VDC(or common or ground, whatever you want to call it), pin 2: -data, pin 3: +data, and pin 4: +24VDC.

...Having the return line essentially feeds power from both directions ... The other big, possibly bigger, thing is that it terminates the data.

From what I've read, pin 1 is a shared common, or ground reference, for both the 24V circuit and Data Common for the DMX. Without that reference, data transmission is flakey at best, so you definitely need that third (first?) pin.

I hadn't been aware of the data termination on the return. Good to know!
 

GreyWyvern

Well-Known Member
From what I've read, pin 1 is a shared common, or ground reference, for both the 24V circuit and Data Common for the DMX. Without that reference, data transmission is flakey at best, so you definitely need that third (first?) pin.

I hadn't been aware of the data termination on the return. Good to know!
4-pin cable has four wires: 2-14AWG for power and a 22AWG twisted pair for data. 5-pin cable also has four wires: 2-22AWG twisted pairs. The shield of the cable gets put on pin 1. I think that is where your confusion is coming from. I don't think that the shield should ever be tied to ground.
 
...The shield of the cable gets put on pin 1. I think that is where your confusion is coming from. I don't think that the shield should ever be tied to ground.

There is an important difference between a ground reference for differential signals like DMX and the earth ground typically used in electrical systems. The two should not be confused. From the sounds of things, the Apollo systems (and possibly others) might rely on an implied ground reference for the data on 4-pin cabling (which uses only two wires), but on a standard DMX512-A run, this reference is provided on the shield, on pin 1.

And you're right: Connecting the shield (ground reference) directly to chassis (earth ground) should not be done, as anybody touching two items with different ground potentials could be seriously hurt, or worse.
 

CameronLD

Member
Thanks for all the responses.

Im attaching a rough sketch of what is hopefully my final plan for this all.

My last concern is about the icues. I am renting the two of them from a local company that has kitted a PSU-50 with them. I'm confused as to white the extra power unit would be necessary, and if they are necessary, how they'd fit into my runs. Any help?

Thanks!
 

Attachments

  • 1467915959692-1474670619.jpg
    1467915959692-1474670619.jpg
    104 KB · Views: 151
This is maybe a little late, but:

It's common practice for some production companies to provide supplemental gear which would be necessary for the operation of the rental gear supplied - if for no other reasons than 1) they should know their gear works, and 2) If -you- decide not to use it, and it doesn't work as planned, they then don't then have to deal with a crisis, or potential loss of rental income.

That said, your PS-08 should work just fine by itself, for everything in your setup, above.

If you decide to use the provided, extra power supply as well, it's treated as just another DMX unit in your line. If it has a DMX thru, plug it in wherever is convenient, and continue along with your previous configuration. If it doesn't, it goes at the end of your data line. Addressing should not change. Of course, it'll also need plugged in to a non-dim power source. If you're feeling nervous about the setup, you could always park it right beside the PS-08 and use it if it's needed. But it's just a peace-of-mind thing. I doubt it's necessary (The PSU, not your peace of mind).

Hope it goes/has gone well.
 

JChenault

Well-Known Member
Each 4-pin accessory counts as one device towards the limit of 32 devices per DMX line. Where those devices get counted isn't always clear though. If there is not an opto-isolator inside of the PSU, all the 4-pin devices on that PSU need to be counted as devices on the DMX line. The PSU may need to be counted as a device as well. The safe bet is to count the PSU and each device, unless you know for sure that the 4-pin outputs are isolated, such as is the case with Apollo's Smart Power 200 and 400 supplies.

I want to make sure I am reading this correctly

If I am using the Apollo 200 or 400 PSU, I count the PSU and all connected Scrollers as a single device on the 32 device chain. Is that correct?

And just for grins, if I have a Right Atm with a scroller and Iris is it one device or three?
 

Users who are viewing this thread