Thanks and need advice

[Franchise]

First of all I have been meaning to say thanks for over a year. I asked a couple questions last year at this time. I ended up doing a real small 8 channel display for Halloween and another small 12 channel display for Xmas. Yes, both displays were small but it was a lot of fun and I appreciate the help I got from this forum.

Now I have a small problem and I want to get some advice from this forum. I added another dimmer pack to bring me up to 16 channels (still small but still fun.) At one point in my sequence, I am turning a total of 6 channels on for 50ms and then off for 50 ms. I noticed that it is just working intermitently. The way I see it the problem could be many things:

1.) My old computer
2.) The Open Enttec Dongle (instead of the PRO)
3.) I am not doing any termination (and the problem channels are the last 4), could that be the problem?
4.) I read that the lastest version of Vixen has some problems, could that be causing it?

Any advice on where I should look?

Thanks!

[WWNF911]

Are you set up for real or just the adjustable preview? Did you have issues last year?

[scorpia]

not sure if im going to be much help but if your using the enttec open check the vixen forums and grab the beta 3 version that frostyn has linked. it works much better for me with the open.

[Franchise]

Thanks for the quick replies.

The flashing lights work fine in the adjustable preview, but only work part of the time for real. Last year (with the only 8 and 12 channels) everything worked perfectly. Is it the new dimmer box? The Vixen bug? My computer getting older? Do I need the terminator?

I searched the forums before I posted and saw the link to the Beta 3. I downloaded it but have not installed it yet. If it worked for you, I'll try it. I had some other problems with Vixen that I never had last year so I definitely want to try this older version. Thanks for the advice.

[DynamoBen]

There has been mixed results at 50ms, personally I've not had any problems. Try removing the new dimmer pack (set things up like last year) and see if things get better. Also be sure to terminate. Finally what type of cable are you using and what are the lengths?

[awhaley]

I'd try slowing your timing and see if you have any OTHER DMX related problems. A good test for a data problem might be to turn your last 4 channels on full and leave them on while flashing OTHER channels at 50ms. If your last 4 flicker, then they might be having dmx data problems... and if they stay steady then you're probably not. The problem with operating the opendmx on short timing has been detailed pretty thoroughly elsewhere, but I'll hit the basics one more time - the driver for the open dongle tries its best to meet the DMX standard, which asks for a complete data packet sent ever 25ms... but it doesn't always manage this perfectly... and if it mangles one packet and lags another, they may not get the on signal till they should be getting the off signal.

As for terminators... always use them with DMX... it COULD be your problem here too. Why terminate:

What's a capacitor? A device to store charge. How do you make one? You put two pieces of metal together and separate them with an insulator.... which sounds a lot like the recipe for a data wire too, right?

It is. You get capacitance between the two conductors your data's travelling on, which means instead of very clean square highs and lows, they start to get all sawtoothy when you look at them on the scope. At a certain point, the receiver (and different receivers are better or worse at it...) can't tell the highs from the lows and it starts mangling your dmx packets. Since there's no error checking, , dmx is very prone to just USING the bad data, so for 25ms you get radically wrong values. This could easily mean a flicker, or failure to respond to a very short (like 50ms) instruction. The terminator lets the stored charge discharge rapidly between the conductors, cleaning the data back up.

Hope this helps!

Art

[Franchise]

Thanks again for the quick replies. That is two votes for using a terminator. I'll go buy one. I looked online and saw they were pretty cheap.

I had a bunch of problems with Vixen and lights not lighting, but after I rebooted, everything seemed great, except with the last 4 channels not flicking on and off at 50ms. Everything else seemed fine.

In terms of cables, I bought six 6 foot OSP DMX cables. I hook three of them together to get from the computer to the garage. While we are on the subject, here is a question I have on the cables. I have my 4 dimmer boxes sitting right next to each other and they are connected together each with a 6 foot DMX cable all coiled up. Could that be a problem?

[awhaley]

If this double posts, I'd love for someone to PM me to delete it.....

Glad to hear you found a cheap source of terminators. If you want to try it out without waiting for the shipping... all a terminator does is put a 120ohm resistor across pins 2 and 3... so you can go to Radio Shack, grab the resistor 5 pack, and just bend the leads so you can gently push it into pins 2 and 3 of the last dimmer's DMX OUT jack. I'd still spend a few dollars to have it put into a nice connector (sometimes buying a terminator is cheaper than buying the connector to solder it yourself (No idea why this is... lol. I also just bought 3 to 5 pin adapters of both genders for cheaper than I've ever seen the 5 pin connectors alone....) but pushing the resistor in there will tell you if a terminator will solve your problem.

After reading the thread again, I WOULD make sure you're using the beta 3 version of vixen 2, as well. I also had OpenDMX problems till I switched from the main distribution to the beta.

And your cable setup sounds fine to me... I've run a lot more dmx equipment off of a lot less ideal situation. IDEALLY (as in the next time you buy dimmers and so have more need for short DMX cables) I'd replace the three you're using to get out of the garage with one of sufficient length, since every connection is a POSSIBLE point of failure, and there is actually (according to sound guy friends) a certain amount of signal lost per connection. But DMX allows up to 32 devices connected in series, which means up to 32 connections in the chain, so your six shouldn't be a problem at all. And coiling DMX cables up at the dimmers won't give you any trouble under normal circumstances. I suppose you could put a giant magnet in the center of the coil and jerk it up and down enough to make the data corrupt... maybe? But it's very common to connect short jumps of dmx with long cables and leave it coiled up. Now if you start coiling your very high current power cables, we need to start talking a little about induction and a LOT about heat dissipation...

Again, hope all that helps.

Art

[Franchise]

Thanks again for all the help. I went back to Vixen 2 Beta 3 and the first time through it messed up only about 35% of the time instead of 70% of the time. So it was a big improvement. I let the sond play a couple more times and it seemed to get better every time? Does that even make sense?

Anyway, the bottom line is that going back to the old version was a huge improvement. It might not be perfect now, but it look a lot better. Hopefully when my terminator gets here in 2-9 days, that will help even more.

[DynamoBen]

Thanks again for all the help. I went back to Vixen 2 Beta 3 and the first time through it messed up only about 35% of the time instead of 70% of the time. So it was a big improvement. I let the sound play a couple more times and it seemed to get better every time? Does that even make sense?


There is a chance that a couple of threads are trampling the data, I will touch base with the Vixen developer to see what thoughts he has. Thanks for the news.

[awhaley]

Glad to hear it's working better!

Just in case you missed it earlier in the thread, if you want to see if a terminator will fix your problem, a trip to radio shack to buy 120ohm or 150ohm resistors (5 for 99c) will give you a quick check.

You just carefully stick the ends of the resistor in the sockets for pins 2 and 3 on the dmx output of the last device in the chain (not the AC output... I guess I should say explicitly.. just to be safe... lol.) this does the same thing a terminator will do without the pretty package. That will tell you if your problem will be solved when your terminator arrives or not...

Art

[Franchise]

Thanks for the idea of using a resistor as a terminator. I had already ordered a terminator, so I'll just wait until it comes.

I have been busy the past couple nights so I haven't tested anything out in the past couple days. I'll be sure to post if anything interesting happens. Thanks again for all the help. Discussing issues on this forum has helped make this a fun hobby.

[Franchise]

My terminator came yesterday. At first, things were not working well, but then I turned off the preview window in Vixen and I did not see it mess up once. So between using the older version of Vixen and using the terminator, I think the problem has been fixed. I'll keep an eye on it and let you guys know if things change.

Thanks again for all the help. It has been fun posting on this forum and I'll probably go ahead and post more questions soon. Thanks!

[Franchise]

I know this is several months late, but I never got a chance to say thanks again. I was having problems with my Halloween display. The advice to buy a terminator and go back to an older version of Vixen worked for the rest for the Halloween dispaly and for all of Christmas. Thanks again.

Currently I am just using dimmer packs that I bought off of Ebay. Now that I have time, I'd actually like to build my own. Any advice on what kits and where I could get one?

[DynamoBen]

If you intend on using higher current loads, multiple flood lights per circuit, the packs you have are a good way to go (thats what I use). For lower current loads, a single 100W flood, any of the DIY DMX project here should work. Check out the coops for up coming group buys and the DMX projects thread here.

[Franchise]

You use packs also? My biggest problem with them right now is the weatherproofing issue. (I did a search thinking that there would be a good article on how to put them outside but I could not find one.) I have all mine in the garage and then I run a bunch of extension coords outside. This keeps me from really increasing my display. Any advice?

Also, I see between this site and DIYlightanimation that there are a ton of DIY projects/kits out there. I Get a bit overwhelmed by the number. Any advice on which one to chose?

[dmcole]

Also, I see between this site and DIYlightanimation that there are a ton of DIY projects/kits out there. I Get a bit overwhelmed by the number. Any advice on which one to chose?

I really like RJ's SSR4/DMX ... it's a four-channel, self-contained DMX dimmer (http://www.diylightanimation.com/wiki/index.php?title=Manual_SSR4). I'm on a tight budget (and who isn't?) and it allows me to build out controllers slowly. I only did 64 channels last year and expect to do no more than 100 channels this year, so I don't really need a big device. Further, I like having the controller close to the actual light, cutting down on the number of extension cords needed.

YMMV.

\dmc

[DynamoBen]

I typically put my packs in a safe place and run extension cords. For me its less expensive and simpler to maintain when the dimming is all in one place. This could be due to the fact that I did professional lighting for a number of years and was used to setting up "Dimmer Beach" for my shows.

As far as managing cables you might want to consider making your own multichannel extension cords with SO cable. SO has multiple conductors so one cable could contain 3 or 4 connectors on each end.

In regards to weatherizing packs you may want to consider buying plastic storage containers or even just throwing them in plastic bags. Typically packs don't generate a lot of heat so using these methods should keep them dry.

As far as DIYAnimation that site and many of its projects are made by a user from this forum. His projects are DIY; I don't believe they are Open Source. So if you are interested in learning and tinkering that might not be the direction you want to go. However if you want to build your dimmers and never worry about them, then what is there might be a good fit.

I haven't built my own dimmers because I'm determined to design them myself. I want something that is open source and can scale to higher wattage loads, and can adapt to new technologies and protocols. At present its on my project list but hasn't gotten a lot of time.

[Franchise]

Thanks for the responses. I am pretty incompetent when it comes to fixing or building things, so a kit is probably the best for me. I'll have to check out that SSR4/DMX.

Sorry to keep asking questions, what do you mean by building extensions cords with SO cables? I did a search on these forums and on google and only found a little on SO cables.

[DynamoBen]

Sorry I meant SOOW (said "s.o."). It can be purchase in spools and is multi-conductor. A typical heavy gauge extension cord would be 12/3 SOOW. However you can buy cable with more conductors like 12/5 or 16/6. By going this route you would have 1 ground, 1 neutral, and the rest are separate hots, all in one cable. So instead of one dimmed channel per cable you can have multiple.

NOTE: You have to be sure that your neutral is sized correctly for the loads you will be attaching. If you only use 1 wire in the 16/6 cable for neutral then the max total load for all the hots can not exceed 8 amps; 2 neutrals would give you 16 amps.

http://www.grainger.com/Grainger/items/1UGV9?cm_mmc=Google%20Base-_-Electrical-_-Wire%20and%20Cable-_-1UGV9

http://www.grainger.com/Grainger/items/1YPU4