CINEMA AUTOMATION, Review of KMTronic Web Relay

[Mark Gulbrandsen]

" I think this is the problem that NEC has...in order to leave that slot powered up, it also has to run enough air across that slot to ensure it is cooled."

You would want the AC On, and the Power On fans running in that case. AC on cools the card cage power supply, and Power On cools the card cage itself. Both are behind tje front panel filters. Those are large 8" fans, but NEC could have put in two speed fan controlers so they idle when the projector is in "Standby"...

[Bruce Cloutier]

You kind of run into a problem when look for the thing that is the "automation device". It is actually a process and components throughout the system contribute to the automated operations. The subject relay device is a good thing because at least you are not relying on the DIO pins provided by your expensive media system where, when smoke is eventually emitted, you are destroying a very expensive component.

The argument as to whether it is better to centralize your control (e.g. IBM 360) or distribute it (e.g. DEC PDP-8) has gone on for a while. When you finally have a functional system doing everything you need (as if that ever happens) you will find that it is distributed in some way even if that is minor.

This relay box has a processor of some kind ahead of the relays. I wonder what happens when you want to monitor it (polling the hell out of it) from one place while wanting to control it from another? The question really is that if the box fails in a few years can you still get that unit or will you have to learn to use something else?

Let's face it, the technical complexity these days continues to increase (relates to Entropy in some way I think - 2nd law of thermodynamics) and you are less and less likely to successfully get "any idiot" to do anything successfully (if you would even want to risk it). We would all be better off if we kept things simple.

[Dave Macaulay]

I have nothing against the relay box in question. Seems like a good unit for what it is.
The relays worry me. A 15A relay contact often has trouble switching low current loads, most of what we control is dimmers and cinema processors with very low current draw.
We do use Jnior automation pretty much exclusively and I've only had one intermittent no-closure issue with one relay on one unit over the 10+ years and hundreds we've installed. These are low power relays and handle small loads well.
Also the need to issue close and open commands plus have a wait time for each cue (assuming your device needs a pulse, not "on") is a pain IMO.

We see sites where either a mystery relay unit from some unrecognizable supplier, or one made in house or by a local electronics wizard, is used. While it works, all is well. If it fails... what then? With Integ or Eprad you get good support and can get a replacement for a really dead one pretty quickly. I have had some really poor experiences with custom made interface systems where the person that made it is unreachable and there are no schematics or software available.

[Stefan Scholz]

It is an IP controlled relay box. These things do what they're supposed to do, they operate a switch contact when receiving a message. And they do it reliably and well.
In most cases all you needed to do, is a momentary closure to control curtains, maskings and old fashioned "push button" light dimmers. Not really complex. Just like a GPO on the IMS, which only offers a limited number.
Sound equipment can be directly interfaced via network. Even older processors like a 15 year old USL JSD 80 has a network interface.
I wouldn't trust those China relays to switch 10 A or 220 V, but they do 5V logic to ground really well, normally a problem for high amp relays. I suppose they do a motor load from a movie projector only a fistful of times, before the contacts weld.
The JNIOR does a lot more, most of which I have never needed. But I sometimes needed interfacing for contacts that controlled curtains or dimmers, fed from 220 V, something requiring another interface relay.