Zero 88 Fat Frog - 'setting a permanent level on a DMX channel'

[Andrew H]

I have a Zero 88 Fat Frog controlling the lighting in a theatre which controls a series of rack mounted dimmers with 'dimmable sockets' on the trusses.  Very conventional set-up.

I have six Martin Mac 250 washes on the trusses, with the control coming from the Fat Frog.

The power for the Martin Mac's comes from the 'dimmable sockets' and this has been done by not assigning the six sockets to channel 512 (the opposite end of the desk's working range) and then manually setting the outputs on the dimmer packs to maximum.  We put an oscilloscope on the outputs first to be sure that the output from the dimmers was "pure".

This works perfectly.

The disadvantage is that every time the dimmers are switched on, each of the six channels that power a Mac have to be manually set to maximum, pushing a button for each channel to increment the output.

A very neat solution would be to have channel 512 set to maximum (and each of the dimmer channels are set to 512).

However, this needs to be set so that the Grand Master doesn't vary the output level to channel 512 as it would do if, say, slider 48 was manually patched to 512.

Does anyone know any way of doing this?

[sunray]

If they are truly being classed as permanent would is not make more sense to do a physical rewire?

Otherwise assign them to channel 48 and use the fader.

Edited June 20, 2022 by sunray

[Andrew H]

Hi Sunray, in answer, yes, it makes sense to have additional sockets put on the trusses which are permanently live 230v ac.  This is currently being costed.

My understanding is that if I assigned slider 48 to DMX channel 512, whilst I can set slider 48 to maximum, when the Grand Master is used (for all the parcans in use), then this will vary the output on DMX channel 512, unless it is logically separated.

I am not sure how to do this, or whether it is even possible.

[david.elsbury]

This is usually referred to as “parking” channels- it’s been years since I used a Frog, can you see if that’s an option?

[sunray]

3 minutes ago, Andrew H said:

Hi Sunray, in answer, yes, it makes sense to have additional sockets put on the trusses which are permanently live 230v ac.  This is currently being costed.

It may be quite easy to simply move one wire for each circuit within the dimmer rack, to bypass the dimmer.

5 minutes ago, Andrew H said:

My understanding is that if I assigned slider 48 to DMX channel 512, whilst I can set slider 48 to maximum, when the Grand Master is used (for all the parcans in use), then this will vary the output on DMX channel 512, unless it is logically separated.

I am not sure how to do this, or whether it is even possible.

Of course, I hadn't considered the master..

Is there any form of 'auxilliary channel' on the desk? On desk of this ilk: https://gavshop.co.uk/24-channel-dimmer-console-DMX-lighting-controller---DMX-24-6002-p.asp  there are often additional channels (top right of desk) for things such as smoke machines which are not usually on the masters.

[sunray]

What dimmers do you have?

[sleah]

19 minutes ago, sunray said:

It may be quite easy to simply move one wire for each circuit within the dimmer rack, to bypass the dimmer.

 

I was thinking similar.

Or if the dimmer has analog inputs, lash the analog input for said channel to 10v.... pretty easy if the DIN has 10v out. I'm certain analog will take priority over DMX?

[timsabre]

This sort of arrangement powering fixtures from a dimmer which isn't locked into switching mode always makes me anxious. It is too easy to accidentally feed dimmed power to the fixture, maybe Mac250's will stand being fed dimmed power but a lot of fixtures will suffer power supply module failure if the channel accidentally gets dimmed.

If the racks have hot (mains side) patching then it is much better to arrange a local set of permanently live outputs to patch into. Or hardwire the dimmers as suggested. Leaving it up to the desk op is risky in my opinion...

[Tregilibob]

I have a set up where I only have dimmer power, however for running fixtures that require mains I have them plugged in to the rig, then next to the patch bay there are 15amp to 13amp convertors, so they run on mains sockets which are close to the dimmers. Pretty easy to set up, just flip the switches as part of your setting up routine, and no accidental power surges.

As far as I am aware, the Fat Frog (also still in use!) doesn't have the ability to 'park' channels.

[Jivemaster]

With the cost of six replacement Macs the cost of a hard power circuit seems trivial.

[kgallen]

Fat Frog doesn't have Parking and the Grand Master rules all.

Channel 48 is a vanilla "generic" channel on Fat Frog so you can't override it with for example a custom fixture definition that has Intensity default @FUL.

Echo others that are nervous about a triac dimmer channel being used to provide hot power. Even at full I believe there will be some waveform distortion and I don't suppose the output circuit will be overly happy with the lamp strike of the mover.

[Edward- Z88]

Hi @Andrew H

3 hours ago, Andrew H said:

The power for the Martin Mac's comes from the 'dimmable sockets' and this has been done by not assigning the six sockets to channel 512 (the opposite end of the desk's working range) and then manually setting the outputs on the dimmer packs to maximum.

As others have mentioned, powering non-dimmable loads from dimmers set @ full is certainly not ideal. If the dimmers are being set at full from the console, it is always possible for that level to be dimmed, even if the parameter is hidden away on the console.

If you do wish to proceed with setting your dimmers @ full to provide power, you could do this by using the fixture file attached...

Power Non-Dim.ift

This fixture file features a single parameter under the "Beamshape" parameter, that is defaulted at full. Therefore once this fixture is patched and the console is powered, this channel will be taken to full. As it is a Beamshape parameter, it will not be inhibited by the Grand Master.

2 hours ago, david.elsbury said:

This is usually referred to as “parking” channels- it’s been years since I used a Frog, can you see if that’s an option?

Frog consoles cannot "Park" fixtures/channels.

Hope this helps,

Edward

[Andrew H]

Edward,

Thank you very much indeed.  First, let me confirm I understand how to use the profile you provided:

This is loaded into the desk and assigned as, say, moving light 12.  In the manual patch, I would assign moving light 12 to be DMX 512.  As the characteristic is Beamshape, it is unaffected by the Grand Master.

I understood enough to recognise that there was a solution of this nature, but I don't have your experience or knowledge.

I realise the potential risks of this approach - providing power to a fixture with a power supply in it that will be damaged if it is subjected to a leading-edge dimmed supply.

The context is that the lighting trusses are fed by one of three phases of a three phase supply and the nearest 'normal sockets' are something like 15m below on a different phase, so there's no option to take power up to the trusses from that source.  The installation needs to be modified by a qualified electrical contractor, and it will be.  The work is currently being costed and will then be commissioned.

[Edward- Z88]

Hi Andrew,

4 minutes ago, Andrew H said:

Thank you very much indeed.  First, let me confirm I understand how to use the profile you provided:

This is loaded into the desk and assigned as, say, moving light 12.  In the manual patch, I would assign moving light 12 to be DMX 512.  As the characteristic is Beamshape, it is unaffected by the Grand Master.

Yes - you've got it.

Please see the link below for information on loading in fixture files from a disk...

https://zero88.com/storage/downloads/24230203-252a-4a5a-b578-43c498bd6721/Frog-Range-Manual.pdf#page=55

Edward

[sunray]

For what it may or may not be worth there is one of these in a local village hall:and matching patch panel. when permanent power was required a botch with 13A 4ways and 13A to 15A adapters was plugged into the ring final. Seeing the 2 blanking plates I suggested filling them with MCB's and additional 15A sockets beside the patch panel.