Design Controlling House Curtain Via DMX

[Clifford]

If you have intercom, plus someone with arms and a little common sense then automating a curtain is relatively easy...

 

[SanTai]

If you belive that the curtain can hurt people and thats the reason you do not want it to be on DMX, you should not have the controls in the booth, even if it is not DMX. Not in any venue I have worked I would be comfortable with running pyro from the booth postion since you do not have the view for proper safety. SO if not using DMX is because of safety, in my book i should not be controlled from the booth, it might be cued from there, via intercom or an control system that uses a dead mans grip at the stage level.

 

[n1ist]

In addition to all that was said, you can't just pull any random cable for this control circuit. What's the voltage? the current? insulation requirements (supply class)? Are you licensed to do the work? Get these wrong and you may end up with a fire or shock hazard, or have the place shut down by the inspector. There are very few cases where running cat5 from the stage to the booth will work for motor control.
/mike

 

[creamers]

I measured everything electrical wise yesterday. The circuit is 120vac. With 34 Miliamps. It has a 1.5 amps fuse built into the line. The Ethernet is 24 gauge coming out of the control box. According to American Wire Gauge table and AWG Electrical Current Load Limits with skin depth frequencies 24 Gauge will handle up to half an amp. I can swap the intercom system to an Ethernet line and take back the old wiring if needed. It would be a box with mushroom buttons like mentioned with an open and close. I can not figure out how to get the stop button to work. When shorting the two terminals that the button connects nothing happens.

 

[AEGProduction]

I measured everything electrical wise yesterday. The circuit is 120vac. With 34 Miliamps. It has a 1.5 amps fuse built into the line. .

The circuit draws 34 Miliamps? How did you get this reading? If the line is fused at 1.5A and the wiring can only support 0.5A, that fuse isn't doing you much good either.

 

[creamers]

The circuit draws 34 Miliamps? How did you get this reading? If the line is fused at 1.5A and the wiring can only support 0.5A, that fuse isn't doing you much good either.

The connection that the push button connects is 34 milliamperes. It's a one touch button that shorts it temporarily.

 

[Morte615]

Just curious was the 34mA measured at load or rest? If it was measured while the system was running then I would guess (without having seen the system) that what you have is just a dry contact switch that goes to a separate circuit (most likely in the motor controller) that operates the system. If it was measured while nothing was happening that could be the stand-by voltage.

Here is where it starts getting dangerous, anytime you work with electric circuits (even small amperage ones, and this IS a line VOLTAGE system) you run the danger of electrocution. If everything works correctly but you hit a bare wire you will probably just get a small zap. But if something is wrong in the system you could get a full charge right through your heart. This is not something to undertake lightly, and not at all if you don't know what you are doing.
*safety rant over*

 

[n1ist]

cat5 cable's insulation isn't rated for 110VAC. Despite it being 34mA (not sure if that's leakage current or holding current; sounds too low for pull-in on a contactor), it is still a class-1 circuit and MUST be wired using class-1 wiring methods.

At this point, I VERY STRONGLY recommend that you stop even considering doing anything with this system. You are not licensed to work on it and from your posts, you don't have the knowledge to do it safely and to code. It is not worth risking fines, losing insurance coverage, or risking burning down the theater or killing someone.

If you have cat5 currently wired to the motor control (or something other than THHN in conduit or MC), you need to call a licensed electrician in right away to have it rewired safely.

Safety MUST be the number one priority here.

/mike

 

[Chris15]

I'm sorry, but the questions you are asking tell us you are in way over your head.

This is mains voltage, even an amp can cause SERIOUS damage to your heart (like frying it - literally).

At this stage you need to close back up whatever you have opened until you have someone competent around to help you explore things...