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Author Topic: Exhaust system automation James Skinner Film Handler Posts: 22 From: Wolfville, Nova Scotia, Canada Registered: Dec 2012 posted 02-14-2014 04:44 PM                     We currently have a Christie CP200-M projector with a manual wall switched exhaust system. I would like to automate this so that when ever the projector is running the exhaust system turns it self on. There is a GPIO port on the CP200-M that I am hoping can send the necessary signal? I assume I needs to be some type of relay connected to the GPIO port to control the exhaust system power. I'm hoping some of you have some recommendations on how to do this properly?  |  IP: Logged Mark Gulbrandsen Resident Trollmaster Posts: 16657 From: Music City Registered: Jun 99 posted 02-14-2014 08:18 PM                     It's a more involved thing to do with the GPIO but it is easy as cake with an automation unit. You will need an appropriate sized contactor for the fan possibly with a low voltage coil in it (leave the manual switch in there too!). Then you will need a lower voltage relay capable of interfacing to the GPIO that will in turn drve the larger contactor coil. There may also be large contactors that are capable if interfacing directly to GPIO logic levels however, I never use GPIO so you'll have to research that part. I suggest you contact an industrial controls company if no one else here chimes in.  |  IP: Logged Steve Guttag We forgot the crackers Gromit!!! Posts: 12814 From: Annapolis, MD Registered: Dec 1999 posted 02-14-2014 10:36 PM                     The problem with the GPIO method is that it is format specific, not mode specific. While you can track the lamp on/off with GPIO, normally this isn't sufficient since a Christie won't let you light the lamp with the exhaust off...for the CP2000-M...you are in luck because it doesn't have an air flow switch. The GPIO is just an optoisolated output so whatever you hook to better be low-current. I slicker method would be to use an automation that monitors serial...when the projector is in the "on" state (via the PWR status), turn the exhaust on. When the PWR changes state so the lamp is off...wait x-minutes and then turn the exhaust off.  |  IP: Logged Dave Macaulay Film God Posts: 2321 From: Toronto, Canada Registered: Apr 2001 posted 02-15-2014 09:40 AM                     You could control the fan directly with a simple SSR (solid state relay) from the GPIO. I'm not sure if the GPIO is default programmed to indicate lamp on - but it's not difficult to set it up for that, if not. I would add a "delay on off" relay as well to run the exhaust a few minutes after shutoff. I'm with Mark in that I've never used the GPIO for anything (except 3D sync) because we almost always install a Jnior and in my opinion the - probably minimal - risk of blowing a GPIO output on the projector or server (both will be on $$$$ parts) is a consideration. The Jnior uses a relay output rather than the somewhat delicate open collector output from the GPIO.  |  IP: Logged Harold Hallikainen Jedi Master Film Handler Posts: 906 From: Denver, CO, USA Registered: Aug 2009 posted 02-15-2014 09:56 AM                        I wonder if there is some more direct way of knowing that the exhaust fans should be on. I thiught of a thermostat, but you probably want the fans on before the temperature rise. Air flow or pressure in the exhaust seems like it would get confused by the flow caused by the exhaust fan. So, how about a current sense relay on the projector power? When the projector is drawing a certain amount of current, the fan comes on. Harold  |  IP: Logged Sam D. Chavez Film God Posts: 2153 From: Martinez, CA USA Registered: Aug 2003 posted 02-15-2014 10:36 AM                       I did Harold's method of a current sensing relay that only turns the fan on after the lamp is struck and it senses the increase in the input current. There is a delay that lets the projector cool before turn off. This installation is inside a planetarium where it's only on occasionally and a noise issue. The staff electrician found the device so I don't recall the model #.  |  IP: Logged Steve Guttag We forgot the crackers Gromit!!! Posts: 12814 From: Annapolis, MD Registered: Dec 1999 posted 02-15-2014 12:48 PM                     Again, with Christie, if the exhaust isn't running before the lamp is struck, it won't let you strike the lamp (except the small footprint Christies).  |  IP: Logged Brad Miller Administrator Posts: 17775 From: Plano, TX (36.2 miles NW of Rockwall) Registered: May 99 posted 02-15-2014 01:06 PM                     Which is exactly how they should ALL be.  |  IP: Logged Steve Guttag We forgot the crackers Gromit!!! Posts: 12814 From: Annapolis, MD Registered: Dec 1999 posted 02-15-2014 03:29 PM                     Bull. The projector shouldn't make the decision to can a show...the exhibitor should...it is fine for the projector to yell and scream that the exhaust isn't on. It isn't okay for it to shut the lamp off because the exhaust isn't on. It has thermal sensors to determine if it is in danger.  |  IP: Logged Sam D. Chavez Film God Posts: 2153 From: Martinez, CA USA Registered: Aug 2003 posted 02-15-2014 03:36 PM                       The install I mentioned was a Barco so no issue. Christie did have lots of issues with sail switches back in film days that could shut down shows for no particularly good reason. There was someone around back then to resolve the issue. Now, no way.  |  IP: Logged Brad Miller Administrator Posts: 17775 From: Plano, TX (36.2 miles NW of Rockwall) Registered: May 99 posted 02-15-2014 03:48 PM                     Bull to you Steveo. With the ever-declining quality of projectionists these days, many won't pay ANY attention to that silly tail light. As always I'm sure the people you work for are super intelligent and would never ignore a warning, but the rest of us work in the real world. I've heard of this happening a few times in 2013 where a projectionist didn't bother paying any attention to the red light on a Barco and it got so hot the lamphouse got welded into place requiring a tech to go chisel it out and replace parts as the theater enjoyed a down screen for a day or two. It is NOT acceptable for a machine to "just run". Those Barcos just kept going and going and going without any care in the world that they were committing suicide. If they were at least smart enough to shut down when it reached critical failure I wouldn't argue it so much with you, but that has proven to not be the way they work. I'll take a featherswitch ANY day over that nonsense. Plus it kills the lamp life. (Amazingly in the above example the bulbs didn't blow to my knowledge.) It's MUCH better for the show to not start forcing someone to turn their brain on for a few minutes and deal with the issue, then start the show a few minutes late. (I would be ok with a check of airflow in order to ignite the lamp, bu then NOT kill it should the airflow die mid-show though.) Let's turn this around into something we CAN agree on. It isn't acceptable for a show to stop just because the projector foolishly thinks marriage has been broken when nobody has even been in the booth. I'm getting real tired of seeing THAT happen. Fortunately it isn't widespread.  |  IP: Logged Carsten Kurz Film God Posts: 4340 From: Cologne, NRW, Germany Registered: Aug 2009 posted 02-15-2014 06:02 PM                     +1 These systems can not run without the exhaust blower if installed that way. Where is the sense to favor an electronic temp sensor when a (properly designed) airflow sensor catches the problem right at the start? Also, how much sense does it make to start a show without the blower, when it will be interrupted anyway after some time due to overheating? A 'show doesn't start' is the better indicator for a problem than a tail light in an unmanned booth. 200 impatient patrons make an excellent fault sensor. - Carsten  |  IP: Logged Marco Giustini Film God Posts: 2713 From: Reading, UK Registered: Nov 2007 posted 02-15-2014 06:34 PM                     I agree. The real world is, unfortunately, going into that direction and red light means nothing today, manned or unmanned booth.  |  IP: Logged Steve Guttag We forgot the crackers Gromit!!! Posts: 12814 From: Annapolis, MD Registered: Dec 1999 posted 02-15-2014 06:50 PM                     A red tail light should shut a show down...a yellow shouldn't With your NOC Brad, are you saying you all don't notice that the exhaust isn't running? The projector is kicking out SNMP so no need to depend on the "projectionist." I've had Christies drop the lamp due to the odd down-draft that caused the sail to bobble...Christie also won't restrike once the air has been satisfied. In the film days, Christie would restrike the lamp since the sail was merely in line with the contactor on the rectifier (when we called them that). In the digital world...one bobble...you are playing to a dark screen. I live in the real world too...I don't like losing shows. It should be the exhibitor's decision as to if they are going to can a show over a sail switch. I'm not against a sail switch...in fact, I'm in favor of them. I would have less of an issue with the Christie implementation if it had some intelligence behind it. Whey can't it have a "bobble delay" If the exhaust is really off...it will be off 5 seconds later too.  |  IP: Logged Mike Blakesley Film God Posts: 12767 From: Forsyth, Montana Registered: Jun 99 posted 02-15-2014 07:42 PM                        These things ought to be designed to "recover" automatically when something tiny and quick like a short air drop or a quickie power failure (1 or 2 seconds) happens. The fact that a tiny little "blip" can bring down a machine that's designed to present entertainment to the paying public is an insult to the people who bought tickets and the exhibitor who bought the equipment. You wouldn't see this kind of crap at, say, Disney World. Of course those people are paying $90 a ticket, so...  |  IP: Logged

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