Thread: DMX Dimmer Pack with Relay (Help Needed) !

Tweet

I read somewhere that instead of using a DMX Relay board ($120+-) you could just use a standard DMX Dimmer Pack ($50+-) and buy some 120v relays at radio shack (item 275-217).

So I got a few of these radio shack relays and wired them up and tested them by just plugging them in the wall. I was able to complete the (dry contact) circuit i wanted with this set up.

I am now using my newly purchased DMX Dimmer Pack and I got the pack to work just fine with a light but not the relay.

I set it up in VSA as a DMX Relay and going from 0-254 (as a relay, not dimmer) the light turns on and off just as it should. Now when I plug the relay in place of the light, the relay never turns all the way off?

I tested the volts and when the dimmer pack is turned on (via VSA) the radioshack relay gets 119+- volts (as it should) and the relay completes the circuit, but when the dimmer pack is turned off (via VSA), the relay is still getting like 50+- volts? So the relay buzzes and hummes and stays connect so the circuit never disconnects?

I have unplugged the relay and plugged a light in and again everything works fine, its just the pack is send to many volts to the radioshack relay when it should be off.

Here is my setup. Im using the relays to control a hacked universal remote. The remote is used to play 4 different videos on a dvd player (thats why 4 relays). The setup works perfect when Im just plugging and unplugging into the wall, just not the dimmer pack.

I also found that if I have a light bulb and the relay plugged into on channel on the dimmer (so the light and relay both go at the same time) that the relay works Perfect? is the light bulb eating up some left over volts or something?

Any of you dmx guys using relays? I'm sure there's a simple fix I'm over looking?

I'm in need of using dry contact relays in other parts of my haunt and I was hoping to use this setup. Should I have just bought the Bluepoint board?

try a small rocker switch between the remote and the dmx or if you want the creepy look use a small Frankenstein switch to cut the circuit

Thank you for replying but I think you mis understood my objective. This will all be behind the scene running off a computer. Everything must be automated so I don't think a switch will solve my problem but again thank you for your input.

Anyone have a solution or do I need to plug a light bulb into the second Edison plug on each channel of the dimmer pack?

Please help

I haven't attached relays to my dimmer pack, but my best guess is...
1. You might be using the wrong event type pulse vs linear bar in VSA
2. You are not sending the correct command to trun it off??? 0-254 to tun on 254-0 to turn off???

here is an older link that I posted to explain in better detail
DMX/ VSA programing problems

I know this is kinda alot to read but please do if you think you can help.


Im not sure what the difference between linear and pulse is but I did try it both ways.

I set up the dmx channel first as a "dmx relay" in VSA settings and I have the values set as min 0 default 0 max 254). So when I create an event it automatically goes from min to max and holds max tll the event is over and then to min. So if I drag a two second event bar in vsa the light simply turns on (to max 254 the whole time) and when the event is over back to 0.

I then tried setting up the channel as a "dmx dimmer" and then did a really short event 0-254 and then a second or two later another short event of 254-0.

I can get a standard light bulb i plug in to do exactly what I want with both methods. The VSA setting "dmx relay" is a little simpler because I only have to draw one event, versus an "on" event and then an "off" event. Ether way would be fine with me but as soon as I replace the light bulb with the relay is when I have the problem.

I tried both methods as pulse and then a linear and tested the volt the radio shack relay is getting and its the same ether way on either method. The relay gets 120+- volts when it should and then when it shouldn't it still gets 50+- volts.

Also to again clarify what I was doing in the video is that if I plug the light bulb in and run the vsa everything works. I plug both the light bulb and the radio shack relay into the same channel on the dimmer (two edison plugs per channel) and everything works. I unplug the light bulb so its just the relay plugged in and I then have the problem. Its like there is left over volts in the line or something and the little relay cant use them up to get back to 0 volts, and when I have the light bulb plugged in also, the light bulb uses the little bit of volts and drops it back to 0. I dont know if thats true, just a guess. Im not an electronic guy so maybe someone knows of a resistor or capacitor or something I need to put inline. who knows?

I guess I can get around this by plugging in a light bulb to the second plug on every channel but that seems like a "Duct Tape" type of solution.

Thanks!

indeva,

Have you debugged this using a normal lamp yet, to make sure the dimming is occurring as you'd expect? One thing that I wonder about is whether dimmer packs reallly go down to 'zero'. I used to work for Bose doing the home theater dog and pony show, and we used some rack mounted dimmers. These *never* went all the way to zero. When they were 'off', there was still a faint glow from the lamps. From what I understand, this 'preglow' helps the lamps live longer (when you jump to 100%, they're already warm, so there's less thermal shock on the filament).

The 50VAC you're measuring when VSA tells the pack 'Relay OFF' reinforces my suspicion that your DMX dimmer pack may be doing the same thing. Just for grins, you might try hooking the light back up to one of the outputs, and verifying that when the light is 'out', you're getting the same voltage on the output as when the relay is supposed to be 'off'.

I think I've read about others trying this method. Maybe they were using different relays than you are, which require more current (higher average voltage) to switch on.

- Hook

Thanks Hook for your comments. It seems that I am having the same problem you described at Bose, but only when the relay is plugged I alone. Not sure if you read my post #7 (we both posted pretty close to the same time) but I did try it with a lamp only and the lamp does take the volts down to 0.

Guess I might need some new relays?

ahh the answer to this problem has gotten buried in one of my threads somewhere..
these packs use triacs for the dimming on the circuit, triacs leak a small amount of current even when not energized, with an incandescent light this is drained and is not enough of a current to operate the bulb. however it is enough of a current to keep the relay energized. what I did is to attach a small load to each of the free outlets on the channels. IE a small c7 light bulb or a short string of the 20 mini christmas lights. this puts enough of a load on the circuit to make the relay function properly and can be easily hidden with the pack.

ps. great hack on the remote, I love these kind of hacked uses of standard controls.