Controlling LED fixtures - HTP or LTP?

[Shez]

This should be really obvious but my brain's having a holiday at the moment...

 

I can't get the desk & fixture together until next Wednesday to try, hence my asking now whilst digging out personalities...

 

Pearl 2000, Showtec LED PAR64. If I use the LTP personality, presumably bringing down a playback / master won't fade it out? Will it fade if I use the HTP personality?

 

The fixtures use 3 channels for CMY plus a couple more for other functions - no master dimmer type channel. I've only ever used fixtures with a dimmer channel before, so not having one confused me slightly.

 

It's definitely Friday afternoon; any help much appreciated <_<

 

Sheriton

[tokm]

My advice would be to go for the HTP profile.. Tried both versions only last week on a pearl 2004 with the same LED cans and felt I had better control over the fixtures.

 

Think it has something to do with the fact that the HTP profile has some channels that aren't all HTP. Such as strobe/global on or off of light (same as a shutter in a moving head) which is designated a LTP channel.

 

10 1 H 1 100 1N B 1 "Red" 0 255 0
10 61 H 2 100 1N C 1 "Green" 0 255 0
9 61 H 3 100 1N D 1 "Blue" 0 0 229
8 61 I 4 100 1N 0 1 "Colour Macro" 0 0 0
9 1 L 5 100 1N O 1 "Strobe" 0 0 0
8 1 I 6 100 1N 0 1 "Control" 0 0 0

 

According to the profile legend.. 3rd column means type of channel. H is HTP, L is LTP and I is instant LTP.

 

When pulling down the fader yes, the led's did dim. When I tried playing with the thing using the LTP channel version, it was like how you said, they didn't go off until I pushed up a sub that had the colour channels at 0. As you'd expect from LTP, didn't change till you gave it another 'command' to go to a level.

 

HTH.

 

Tom

[Ynot]

Pearl 2000, Showtec LED PAR64. If I use the LTP personality, presumably bringing down a playback / master won't fade it out? Will it fade if I use the HTP personality?

 

The fixtures use 3 channels for CMY plus a couple more for other functions - no master dimmer type channel. I've only ever used fixtures with a dimmer channel before, so not having one confused me slightly.

I can only comment on my findings using a dozen Showtec Par 56 LED lanterns and our Strand 300.

I created a fixture personality for the LED's with the RGB (Are you sure yours are CMY???) attributs, one for strobe, another for effect and whatever the other att was.

The problem I have with this is that because there's no overall dimming option, you can't set levels for the LED's on a submaster, and some of the fades on the memory playback can be a little harsh and quick.

The only way I can see to make the transitions better is to utilise a DMX channel for each colour attrib, though that could tend to take up a LOT of channels if they're all to be set to different addresses!

[niclights]

If I use the LTP personality, presumably bringing down a playback / master won't fade it out?

 

Correct

 

Will it fade if I use the HTP personality?

 

Yes. And is most definitely the way to go where these fixtures don't have a dimmer or the desk does not have a 'virtual' dimmer option (D4/Hog do)

 

Personally I don't use the Avo personalities at all. I found the Macro and Control channels unimportant and wanted HTP control of the strobe channel.

Using a personality with the 'CMY' attributes defined as HTP gives the option of using colour shapes and HTP palettes for building chases (as opposed to the nightmare of all dimmers and the handles that requires). I use ChromafixHTP which is a basic 3 channel HTP on CMY attribute personality. The disadvantage of this is you must manually bump up DMX addresses as you patch, since ChromaFix is 3 channel but the units are 6.

I then patch the strobe channels of each LED fixture all overlayed on one handle. I could see no advantage to having individual fixture control of the strobe function. It's quite handy to just 'add in' a strobe effect over all your fixtures by one preset fader.

 

Bear in mind that the Pearl (2000/2004) has a maximum number of HTP channels which, IIRC, is 240 (an overlayed dimmer handle = 1 channel) and the more that are patched the slower the desk response/max chase speed. This can become a significant problem towards the top end.

[Shez]

Thanks for all the input. HTP it is then. And yes, they are of course RGB - brain really wasn't working that day!

Thanks for the tip about the max number of HTP channels niclights, shouldn't be a problem in this case but useful to know.