Why do all automation controllers seem to have a maximum of 16 relay contact closures

[Bruce Cloutier]

In the beginning Kodak used I think 4 relays to simulate projector cues. I guess they had their pre-show system looking like a projector to some equipment. So we had designed it to insure that you could change multiple relays simultaneously and time their contact closures to the millisecond. The JNIOR still has that capability with the internal relays. The 312 came along after Kodak. They were happy with the 8 relay outputs back then.

[Steve Guttag]

It really depends on the system as to what constitutes enough relays. With 4 relays, you've really just covered conventional light presets. If the theatre has masking (and there shouldn't be an "if" there but...here we are), then 4 is insufficient. And then it really all depends what the cinema system is supposed to control (and what voltages/current it might need to control).

[Justin d'Entremont]

I run a 3 screen complex without any contact closures whatsoever. We don't have masking, and both audio and lightning are done via ethernet.

Just boggles my mind that anyone would want to control lighting any other way in this day and age. I can control any lighting circuit in the complex, set a custom brightness if I want, and a fade time. Example, when the credits start, I can have it jump quickly (3 seconds or so) to around 30% brightness, and then set a custom fade time that by the time the credit roll comes up, the lights are just hitting 100% brightness. For auditoriums with more than 1 circuit (think main lights, accent lights on the walls, track lights on the floor, and high power cleaning lights) you can do some fun automations with. Lutron is the pretty much the defacto lighting control system used in most high end commercial and residential builds in North America. We use a RadioRa2 system as we're quite small, but most commercial places would use XPS, LCP, or Energi Savr Node. Can all be controlled over Telnet or RS-232.

I got our Ra2 system on eBay for pretty much pennies. The controller/main repeater was around $400 (they go for $200 now), and each dimmer - which is just the size of a standard lightswitch - was around $30 (they go for about $75 now).

All the info to integrate to a server is available in here: https://www.ideadigitalcontent.com/f...RINS/84212.pdf

If I wasn't using this, I'd definitely recommend a DMX based system.

[Steve Guttag]

Justin...consider this...you are converting an existing theatre like we did from 2008 through 2015ish, and they already have a dimmer and lights. In the USA, by FAR, the most popular type lighting system was some form of triac based (Kelmar, Xetron, ASH, SPECO, EPRAD...etc.) that had contact closure control because, well, that is how film automations worked. You have 4-hours to swap a film system over to digital. You could redo the dimmer system and lighting and rewire all of that...or... put in an automation system like the eCNA or JNIOR, that you would have pre-configured for the server/lighting system that was in place and put it in within a couple of minutes and moved on. You don't even need to reset the light levels...they were exactly where they were.

We often changed the sound processor but I'd say most or a lot of people didn't do that...they put in a box like the DAX602 and kept the sound the same for the same reason...the sound is all calibrated and most film sound processors had some form of aux 6-channel input...and again, you have 4-6 hours from start to finish on each film to digital conversion (including alignment/calibration).

As for dimmers today on new builds...I've seen it all. Everything from a DMX style on down to a conventional triac based dimmer controlling either dimmable lamps (least reliable/consistent) to LED drivers designed to take a chopped signal and drive specific LEDS...with everything between.

We are taking to Eprad's LED dimming system. We already use their automation so the controller part is built in (but it will take contact closure from JNIOR or others). It uses their lamps but they dim to zero without flicker and, like you say, you have control over the level and rate, up to 16 zones and while you only have 4 presets (scenes) plus off, you can also set up offsets (e.g. go to Mid-1 level and then offset that down a percentage for this particular cue.

Below are just 2 out of 16 channels that can be configured. Note, one can have up to 16 zones or 16 channels, in any combination up to 16. Most cinemas 1-4 zones will suffice but, in the case of the theatre below, there are several overhead lights with some being more decorative so more than one channel was needed and their levels are not necessarily the same.

Screen Shot 2022-05-14 at 11.01.26 AM.png

So far, the Eprad LED dimmers have been a winner for us. All of the problems of conventional dimmers with "dimmable LEDs" are gone. We even went through a nightmare at one site where the client supplied their own LED lamps that mount on the T-BARS and their own LED drivers...of which things didn't work. At least with a system like DMX or the Eprad one, it is a holistic system where controller/dimmer/fixture are all part of the system designed to worked together. And, you don't have to worry about batch-to-batch problems when a manufacturer of "dimmable" LED lamps doesn't dim like the other batch or isn't compatible with your particular dimmer.

Back to the relay thing. As mentioned, we use the relays for all sorts of things and probably more than most. There is nothing wrong with not using any relays, as you just indicated. But, if you had maskings, curtains, old style dimmers, a lamp exhaust, a sound rack, perhaps the projector and server...you just might want a gaggle of relays at your access to control all fo those things.

[Marcel Birgelen]

Technically, you could implement a lot of this stuff using ZWave too, as long as I'm not on the call list if shit goes haywire, I'm perfectly fine with that. :P

[Bruce Cloutier]

You might be able to command the automation through Ethernet but at some point you're possibly toggling a relay (dry contact or solid state) anyway.

[Justin d'Entremont]

You might be able to command the automation through Ethernet but at some point you're possibly toggling a relay (dry contact or solid state) anyway.

Technically, yes, through the relay would be inside the actual switch/dimmer. These dimmers have the same form factor as a run of the mill light switch, and communicate with the controller wirelessly.

maestroleddimmer.png 41k2H-NtKRL._AC_.jpg

[Gordon McLeod]

One issue is that in most locations houselight must tie into the fire alarm system and most wall box dimmers dont do that nicely and a contactor accross them often causes a DVDT spike that damages them

[Mark Gulbrandsen]

Never had an issue with tying a digital booths automation into the fire alarm system. The Eprad automations do it easily and they can be networked so that if one theater has an issue the rest of the the theater(s) follow suit and all are evacuated from the building. In older film installations, we used the cue detector drop arms through what ever automation was installed. Always used Kelmar or Eprad dimmers. Emergency lighting happened at the same time the fire alarm activated. In addition a line back to the booth from the main fire alarm box shut down the show and brought house lights up. So we basically had a backup for the emergency lights. All this was inspected by the Fire Marshall before a new site could open.

[Jesse Crooks]

I am not a fan of using Lutron systems in auditoriums. Lutron is fine for general purpose lighting but occasionally fails, either due to random glitching or due to the wifi repeaters losing power. I've had strip lights fail to turn on, spotlights freeze up and become unresponsive, overhead lights get stuck on when a touch panel dies, etc. I have also found that LEDs that the manufacturer claims to be dimmable to zero are actually only dimmable down to 5-7% using Lutron dimmers. When you're dealing with safety lighting in an auditorium that last few percentage can be critical, since they make everything so damn bright these days. We spent thousands of dollars on step lights that I have to leave off because they can't be dimmed down to a functional level.

The traditional Kelmar dimmers we have in most auditoriums have been rock solid. I only recall replacing one board ever. We have not found a way to get them to place nice with LEDs, though. The new Eprad LED dimmer that Steve mentioned (we have an LCS-320WxC) has also been working very well for us so far. I would definitely recommend that for new installations.

[Mark Gulbrandsen]

I agree on the use of Lutron, it is sketchy at best. It's really home type dimming gear, not commercial. Aside from servicing movie theaters, for about the first five years after moving to Utah I was the Strand Lighting and Colortran tech in a five State area, Colortran was bought out by Leviton and then Lee. Even those mega expensive systems had their own problems, plus the older dimming racks all need to have new computers installed so they can even function on DMX. Kelmar dimmers do get wonky when they get old. The dimming functions depend on electrolytic capacitors for the up down dimming and fade rate function. So as the capacitors age, things can get really strange. Anyway, just replace ALL of the capacitors, or send it to Tom at Kelmar. They can also send you a loaner board while yours is in getting repaired. I have only seen this with just a handful of their dimmers out of many hundreds I encountered over the years. The Eprad stuff is great!!.

[Dave Macaulay]

Kelmar dimmers have been good with certain "dimmable" LED lamps and hopeless with others. Kelmar sent me a list of LED bulbs they recommended and I had good results with them. No LED bulb on a dimmer will dim up from or down to off completely. The best ones go down to very dim before they just go off and on dim up start fairly dim (rather than flashin on around 50% bright).
LED fixtures are another story. These may be available dimmable... but reading spec sheets the dimmable ones want AC power constantly and a 0-10VDC control voltage. You can get that control voltage in a Kelmar dimmer and it works great. But if you have lighting retrofitted with LED fixtures that you hope to use AC dimming on, expect trouble. The standard recessed or hanging fixtures are unlikely to be dimmable unless you found ones that work on a dimmer and specified that exact model.
Personally I like fixtures that use replaceable bulbs. With fixtures that have non-replaceable LEDs, the LEDs will burn out eventually and the lamp will probably be out of production by then.

[Steve Guttag]

One of the features of the Eprad LED Dimming system is you get to keep your existing fixtures and wiring. You merely put there dimmer in place of your existing one OR they make a module that will adapt your dimmer to their lamps (takes your Traic based PWM dimming and turns it into a DC output for their lamps). The key there is that you HAVE to use their lamps (they are low-voltage but will screw into the standard "medium" base (they have A19 and PAR38 lamps). So you do retain the ability to change light bulbs.

[Brad Miller]

For what it's worth, these actually dim flawlessly with a standard Kelmar dimmer:
https://www.amazon.com/gp/product/B01N95BH3E

You set the color temperature you want, screw the converter cable into your existing can light fixture, then connect the other end of the converter cable to the fixture and push it up into the existing housing. Other than that, just adjust the speed and levels a touch and you're done. It impressively dims all the way off smoothly and doesn't have a "burst on" when trying to fade back up.

This second link below is another company's offering where you need to pre-select the color temperature you want, but it has a gimbal head to direct the light a bit instead of the lamp aiming "straight down". For that gimbal feature you will pay about 3 times as much as the first link above, but these do dim as good as the first link I posted above with a Kelmar dimmer.
https://www.amazon.com/gp/product/B093PSTZSG