automated scenery platforms

[techie_stg]

How do the automated systems that move scenery wagons on and off stage work?
thanks

 

[ship]

Good question and I don't know if it's beyond a light board like controller which controls movement of various winches etc. Probably something written up in TCI, or on the various manufacturer websites.

Anyone use such a thing or see them at USITT?

 

[ledieu]

Howdie, we have for side stage wagons and one rear stage wagon that are radio controlled. They each have 2 modems on board - a 900Mhz and a 2.4Ghz to transmit and receive ethernet and enable signals. They are all part of a global emergency system (which is linked to the enable signal). There is a dedicated motor controller card on board eac wagon. It receives instructions from a master computer suite then sends those instruncions to the Variable speed drive (VSD) which is also onboard each wagon. The VSD translates a +/-10vdc into power to the motors. They are a bit weird because they are powered by big battery banks so everything is in DC. Its not a simple subject but very interesting.

 

[ledieu]

Forgot to mention that we are about to convert them to a trailing cable system because maintaining and replacing the batteries is way tooooo expensive. So its back to AC power with PLC I/O modules onboard talking to an intelligent VSD to control the motors.

 

[Peter]

You mentioned "Global Emergency system" in there, but how do these tie into it and what happens with them in an emergency? Sorry if this seems like an obvious question, but I have never worked with equipment like this before and I am curious thanks!

 

[ledieu]

The global 'Estop' system in automated systems stops motion for all machines until the reason the 'Estop' was hit (by an operator) is cleared. For example if an actor walks under a piece being flown in anyone in the venue can hit an estop button to prevent an accident. Once the actor is clear the estop can be released and the move completed. The estop system generally removes power to the variable speed drive so no power goes to the motor or the breaks. There are dozens of layers of safety in the systems - the estop is a last resort final safety device. hope this helps.

 

[Peter]

hmm ok, that kinda sounds like what we have in all our science rooms @ school. There's at least 1 big red button in each room that when hit turns off the power supplies to the lab benches and cuts the gas line to all the gas outlets at the benches. They also do some strange stuff to the flame hoods to basicly rip all the air out of them in an attempt to put out any fires inside. All kinda alarms go off too. but ya, I can see how a system like that would be nice in a theator, obviously with a few differences. (add another thing to to the list of things my auditorium doesnt have )