Question concerning soft patch & Dimmer per Circuit

[wemeck]

I am trying to sharpen my understanding of lighting systems. I was pretty good with are old Kliegl Performer III series with dimmer per circuit. Then I went to college and had 88 8.8Kw Varie-Lite dimmers with a patch panel that reminded me of an old Graham Bell patch panel. But we did have an ETC Expression board, and the good thing is once you learn one ETC board all other ETC consoles are pretty self-evident.

My Questions:
1.)Soft patch can only exist in a dimmer per circuit environment. Correct?
2.)In a dimmer per circuit environment you can not overload a dimmer unless you have a 5Kw Fresnel plugged into a 2.4Kw dimmer, or you have two-fered two lights that exceed the wattage on the lamp? Because every light uses its own specific dimmer. Correct?

 

[DMXtools]

Hi Michael!
1.) Soft patch exists (or not) in the controller, regardless of how the dimmers or effects themselves are wired. It's a way of telling the controller "Fader 1 should transmit on DMX channel 1, Fader 2 on DMX channel 7, Fader 3 on DMX channel 2, Fader 4 on DMX channel 8, fader 5 on DMX channels 3 and 9, Fader 6 on channels 4 and 10, fader 7 on channels 5 and 11 and fader 8 on channels 6 and 12." This is, by the way, a real-life setup I use for a pair of scanners - faders 1 and 2 control pan on the left and right scanners respectively, faders 3 and 4 control tilt, so movement is independent. Faders 5-8 control color, gobo, pan/tilt speed and shutter on both scanners in unison. One of the best uses of soft patch is in conserving fader channels on a small board.

2.) Most dimmer packs have multiple dimmers in one package - and two load ratings, one for the individual channels and one for the package as a whole. A common pack has four dimmers, each rated at 1200 watts... but the package rating is 2400 watts. You can easily exceed the package rating without even coming close to the channel rating. You have to make sure that when you add the wattage of all the lamps on a single dimmer, it doesn't exceed the per-channel rating AND that when you add the wattage of all the lamps on all channels it doesn't exceed the package rating.

I hope that helps.

John

 

[wemeck]

2.) Most dimmer packs have multiple dimmers in one package - and two load ratings, one for the individual channels and one for the package as a whole. A common pack has four dimmers, each rated at 1200 watts... but the package rating is 2400 watts. You can easily exceed the package rating without even coming close to the channel rating. You have to make sure that when you add the wattage of all the lamps on a single dimmer, it doesn't exceed the per-channel rating AND that when you add the wattage of all the lamps on all channels it doesn't exceed the package rating.

So if everything is fine and dandy when you have the board set to a default 1:1 patch, then I can not overload a dimmer by playing with the soft patch in the console? Like it coulkd with the Alexander Graham bell system in college.

 

[DMXtools]

So if everything is fine and dandy when you have the board set to a default 1:1 patch, then I can not overload a dimmer by playing with the soft patch in the console?

Correct!
Soft patch won't change the load per dimmer, it simply changes where the dimmer's control signal comes from. However, it can get confusing when the dimmers and faders aren't mapped one-to-one, so keep a record of what patches you make. Even more confusion can come if you map one dimmer to two or more faders. Some controllers may not be prepared for this and operate very strangely. Some handle it pretty gracefully, setting the dimmer to follow the last fader moved. I can't imagine a situation where you'd want to use this configuration, but if you think you might need to, study your controller's soft-patch documentation very carefully first.

John