Number of DMX channels

[Heptagon]

Greetings - I have a question about a DMX channel mapping in an all-LED lighting setup.

We are hiring a theatre, and having to supplement the standard lighting with our own - but there is a shortage of DMX channels.

Does anyone know why the Selecon PL Profile, and Selecon PL Fresnel units are taking 15 channels each?

The tech details show them as 5 channels. - or do we have older Mk1 units?

 

Thank you in advance.

[david.elsbury]

A quick google for the manual shows me that you can run them in 3 channel mode if you want. The 15 channel mode just offers the most control of the unit.

 

You will need to change the mode on each unit. And then quite likely put it back once you are done so that the theatres usual control system still works properly

[Shez]

Do you know for sure that they're actually occupying 15 channels or have the addresses just been selected for ease of numbering?

e.g. if a fixture uses 17 channels, it's sometimes easier to just patch them as 1, 21, 41, 61 rather than 1, 18, 35, 52.

Or they may be in a lower channel mode but addressed to allow expansion to the widest mode.

[timmeh2]

Hi

 

Have they really only got one universe available? If it's a single output desk I doubt they are using them in 16-bit dimming mode. What desk have they got?

 

All the best

Timmeh

[beware]

Isn't the standard way to do this to run your supplements on one universe, and then the existing lighting on another?

[Heptagon]

Thank you for these replies - I have been lighting for more years than I care to remember, but I'm new to LED.

David - I could only find reference to a 5 channel mode on these lamps. The theatre specs show no of channels for the other lighting (e.g. EK EProfile FC is shown as 9ch), but the PL profiles and fresnels are shown as 16 bit (but without number of channels) - is this significant?

Shez - I suspect this might be the case - 5 channels used, and 10 left spare. I will try to confirm. (The documentation supplied shows DMX starting address only - not the full range).

Timmeh2 - There is a second universe, but not with cabling connected. It is a Hog4.

"Beware" - I am not familiar with LED conventions - is this something we should observe?

Thanks again

[Don Allen]

PLPROFILE1 3 channel mode is Ch1 intensity, Ch2 preset colour selection, Ch3 is timing. There are 25 preset colours and 6 custom colours, so you will need to make your own colours in the 6 custom presets. user manual.

[DrV]

Thank you for these replies - I have been lighting for more years than I care to remember, but I'm new to LED.

David - I could only find reference to a 5 channel mode on these lamps. The theatre specs show no of channels for the other lighting (e.g. EK EProfile FC is shown as 9ch), but the PL profiles and fresnels are shown as 16 bit (but without number of channels) - is this significant?

Shez - I suspect this might be the case - 5 channels used, and 10 left spare. I will try to confirm. (The documentation supplied shows DMX starting address only - not the full range).

Timmeh2 - There is a second universe, but not with cabling connected. It is a Hog4.

"Beware" - I am not familiar with LED conventions - is this something we should observe?

Thanks again

If they are in 16 bit mode then this implies that they are using 15 channels. Each DMX channel is 8bits wide giving you 256 levels. To get higher resolution 2 channels are used together providing 65536 levels. The PLPROFILE and PLFRESNEL have 4LEDs. If you put the fixtures into 8bit, 5channel mode the 5 channels are Red Green Blue White and Intensity. In 15 channel mode these 5 are doubled up to make 10 and then there are a few other functions on the remaining 5 channels (timing etc).

Dave (a different one)

[vinntec]

Actually the Philips Selecon PLPROFILE1 and PLFRESNEL1 can run in 3, 9 and 15 channel modes. The manual linked already tells you what you get in each case. You have to change both the lantern and the desk profile at the same time. We use both and run them in 15 channel mode in a single universe with everything else - but we are a tiny 77 seat theatre.

 

 

What desk does the theatre use? Assuming it can handle more than one DMX universe, if there is no wiring possible to take DMX to your lanterns as a second universe you might consider hiring wireless DMX to use instead, something like ShowBaby? The theatre people should know what is possible and what has been done before to supplement their normal fit (as wifi might not work well in that venue).

 

I would only consider changing their standard rig when it is absolutely essential and the theatre itself is comfortable for it to be done. Almost certainly you will have to put it back how it was in the early hours of your getout. We have taken our LEDs to hired venues this year, and they all advised us how to complement what they had with our stuff. In one case, they didn't care what we did with their kit as they didn't have a standard rig. In another, the standard rig was holy cow status but they provided infrastructure to run our stuff on a dedicated DMX universe.

So I would speak to the resident technician at the hired space to discuss the problem from your point of view. They should know what would be easiest for both of you and any options available.

[Heptagon]

Again, thanks for the quick and useful replies.

 

I see the error in my ways - looking at the brochures rather than the manual. Now I understand the 15 channels.

 

I think we will probably go down the "alternate universe" worm hole.

 

I must say I like this forum - masses of useful info - congrats to the regular posters.