DiyLightAnimation

Hardware => Lynx MR16 / 16 CH DC Controller => Topic started by: claytor1999 on May 06, 2009,

Title: Hardware DMX
Post by: claytor1999 on May 06, 2009,
OK... so I came across a You Tube video of a guy controlling his LOR lights with a hardware DMX controller (looks like an audio mixing board with sliders). That seemed like a good idea for controlling my Wirekat MR16s on the top of my bookshelf. My wife isn't about to turn on the living room computer, pull up vixen, etc... to get a little mood light going.

So instead of asking first if this would work I made the assumption it would work and bought a cheap board. The board arrived yesterday so... after making an XLR to RJ-45 cord with my poor soldering skills I plugged it in and... flicker. I've made sure all my connections are correct, the Lynx MR16 controller is terminated, etc... but still a lot of flicker.

Before I pack this thing up and return it does anyone have an ideas... DMX cord length, grounding, etc...? I like having an option for turning on mood lighting quick but not sure I'd use it that often (unless I start putting on plays or concerts in my living room - not sure that's going to happen at my age). I need to learn to leave well enough alone.

Thanks,
Robb
Title: Re: Hardware DMX
Post by: RJ on May 06, 2009,
Not controlled just flickering or is it controllable and just flickers ?

If the first he may use the reversed DMX connections. Some stuff has the DMX wires switched from the standard.

RJ
Title: Re: Hardware DMX
Post by: claytor1999 on May 06, 2009,
Hi RJ - it's controllable, just flickers. I have 3 MR16s hooked up to 3 channels and they flicker in tandem (at least appears that way). The flickering is random but constant. I've tried changing the wires on the pins but get the same thing.

Thanks,
Robb
Title: Re: Hardware DMX
Post by: rrowan on May 06, 2009,
Hi Robb

First I am assuming that you have the Lynx MR-16 start address set to 1. Figure the board is starting there.

With a volt meter:
RS485 - Pin #5 = ground - Pin #8 = 5v, Pin #1 = Output

Pin 5 & 8 should be around 5 volts

Move the slider to full on and take some readings at the rs-485
Take a reading on Pins 5 and 1

Move the slider to off
Take a reading on Pins 5 and 1 (should be slightly less then above)

If above is good then test the output on the Lynx MR-16

Move the slider around and put your meter on the channel one outputs and see if the voltage changes. Should go from zero to about 12 volts (assuming your power supply to Lynx MR-16 is 12 volts)

Rick R.
Title: Re: Hardware DMX
Post by: dr. jones on May 06, 2009,
are you giving the mr16 board dc current or ac? led's will flicker on ac current
Title: Re: Hardware DMX
Post by: claytor1999 on May 06, 2009,
Hi Rick,

Not sure I'm following you on the pin assignments. On the DMX hardware the pin assignments are:

Pin 1 = Ground
Pin 2 = - Data Signal
Pin 3 = + Data Signal

On the RJ45 side (Lynx MR16) I'm assuming:

Pin 1 = + Data Signal
Pin 2 = - Data Signal

So maybe the problem is my cable is configured wrong?

Checking the output of the channel on the Lynx MR16 gave some interesting results:

With the software setup (Vixen --> Enttec Pro --> MR16) the voltage was stable once I stopped moving the slider (maybe a little jump once but stable)

With the hardware setup (Hardware Board --> MR16) the voltage kept on dancing around once I stopped moving the fader.

Let me know if I have the pinout configuration completely messed up - might be the answer.

Thanks!
Robb
Title: Re: Hardware DMX
Post by: claytor1999 on May 06, 2009,
Hi Dr. Jones,

The hardware runs off of a wall wart - DC 9V - 12V 500mA. Since the software setup (Vixen --> Enttec Pro --> MR16) works fine I assume that my power supply running the MR16 is OK.

Thanks,
Robb
Title: Re: Hardware DMX
Post by: rrowan on May 06, 2009,
Robb

See the wiki for the pin out of the cable. http://diylightanimation.com/wiki/index.php?title=Light-O-Rama_Controllers (should give you the correct info)

I was talking about the a chip on the MR-16 controller ( 8 pin chip in a socket next to the crystal)

Rick R.
Title: Re: Hardware DMX
Post by: smartcontrols on May 06, 2009,
Just a long shot for you to try, but I had a similar situation with my lighting board. It worked fine if I did not of my controller terminated but would not work if the terminating resister was on. I know it sounds backwards. Just something that worked for me.

Jeff
Title: Re: Hardware DMX
Post by: RJ on May 06, 2009,
If the units uses swapped DMX lines this is waht it will do. Try hooking up the lines reverse to the unit.

RJ
Title: Re: Hardware DMX
Post by: claytor1999 on May 07, 2009,
Thanks for all the input gentleman!

Jeff - you hit a 3-pointer from half court. :o Without the MR16 terminated the lights are flicker free.

RJ - by swapped DMX lines do you mean reverse polarity? I'd like to keep the terminator on so if I switch back and forth from Vixen to the lighting board I don't forget to put back on the terminator. Would an RJ-45 terminator for the DMX Out work instead of taking off the terminator pins? Maybe I need to just keep my mouth shut and enjoy the flicker free LED light coming off my MR16 board minus a terminator.  ;D

Rick - good weather right around the corner on the Atlantic seaboard!  :) Thanks for the input - glad I got a chance to use my multimeter for something.

Have a good day guys!
Robb
Title: Re: Hardware DMX
Post by: Murl on May 08, 2009,
Hi Robb,

Have you tried swapping the + and - like RJ said?  That's a pretty common issue with RS-485.

If so, then just out of curiosity, I'd shut everything down and then check the resistance between the data+ and data- signals coming from the hardware board.  Since it's working for you without the terminating resistor on the MR16 side, then there's a good chance that it's either not properly terminated on the transmitting end, or there's a cable issue.

If it's properly terminated, you should read around 120 ohms between the signal wires.  (If you can manage to check it with the cables connected and both ends terminated, it should read around 60 ohms since the resistors are in parallel).

One other question just out of curiosity...  You wouldn't happen to be using a really short DMX cable, would you?  Generally speaking, for RS-485 they recommend at least a 3m cable to minimize reflections.  I've used shorter cables without issue, but it's something to throw out there since its working better for you without the resistor.

Thanks for sharing with us!

-Murl
Title: Re: Hardware DMX
Post by: claytor1999 on May 08, 2009,
Hi Murl,

I'll take some readings tonight and see what I get. I have swapped the + and - with no luck.

The cord appears to be around 10ft long so maybe I need to try something a little longer. I've got a longer one I can try - I'll let you know the results.

Thanks for the input Murl - appreciated.

Robb
Title: Re: Hardware DMX
Post by: Murl on May 08, 2009,
Robb,

If your cable is around 10ft, that should be plenty long enough.  I was thinking you might possibly have this set up on a bench with a really short adapter cable for testing. 

It wouldn't hurt to try a different one, though, since a bad cable can cause issues like your seeing.

-Murl
Title: Re: Hardware DMX
Post by: rrowan on May 08, 2009,
Hi Robb

Just curious, what controller did you get?

Thanks

Rick R.
Title: Re: Hardware DMX
Post by: claytor1999 on May 09, 2009,
Hi Rick,

It's a Chauvet "Obey 40". I wanted to get a simple 6 channel dimmer made by another company but it cost $60. For $30 more you get 192 channels and, even though I won't use that many, it seemed stupid not to cough up the $30. Plus, if I ever win that contest to have ZZ Top play in my living room I'll be set.  ;D

I don't like all the buttons (around 30?) but my wife only has to push one when she wants to use it so I can put a smiley face next to it and she's good to go. Part of the reason for buying this is for her to see something practical come out of this hobby. She doesn't mind the money but my desk is in the living room so it's a bit of an eye sore.

Take care,
Robb
Title: Re: Hardware DMX
Post by: Murl on May 23, 2009,
Hi Robb,

Just curious: did you ever figure out what the problem was - or did you just leave the terminating resistor off?  Did that fix it?

Thanks for sharing!

-Murl
Title: Re: Hardware DMX
Post by: claytor1999 on May 24, 2009,
Hi Murl,

So far I've kept the resistor off but only because I got sidetracked with another part of the puzzle and wanted to keep variables to a minimum. I'm new to electronics, Lynx, and Vixen so the learning curve is steep no matter how simple the issue. : )

I'll let you know when I add the longer cord - thanks for asking!

Robb