Open DMX to control RGB LED lights

[rsprik]

For a demonstration I would like to control RGB LED lights through DMX.

I have an Open DMX compatible USB2DMX cable (made by JMS but similar to ENTTEC) based on a FTDI interface.

All necessary drivers are available and everything works with e.g. Freestyler.

Labview can communicate with the FTDI interface using the Labview examples provided by FTDI, but the DMX control is not working.

Has anyone experience with Open DMX and USB2DMX communication under Labview ?

Best,

Rudolf Sprik 

[ninlmartijn · Accepted solution]

Dear Rudolf,

thank you so much for your post on our webforum. Did you configure the device in MAX? Please see the following KB about this subject. I don't have any experience with this hardware, but if you post the driver and an example I can have a look. In the end it is trouble shooting a serial device. This is a little bit more complicated since I don't have such a device, but I hope I can give you some valuable  tips.

Best regards,

[rsprik]

Dear Martijn,

thanks for your suggestion.

Indeed defining it as a COM port using the drivers on the FTDI page worked!

Enclosed a simple VI that sets all channels of the DMX controller to the same value (between 0 and 255).

I.e. 513 Bytes of data with a '0' for a startcode.

The COM port is set at 250000 baud, 8N2 and no flow control.

Best regards,

Rudolf Sprik

[mom]

please send me this vi in labview 8.2.1

Regards

manasi

[ninlmartijn]

Dear Manasi,

here you are,

best regards,

[kuenzif]

Hi,

Does anybody find how to make it work? I'm trying to communicate between labview and dmx, it doesn't work. 

Thank you to revival this subject with me.

best regards 

Florian Künzi

Engineering school in Geneva

[Serdj]

Hello,

I have an Open USB2DMX Controller with the tipical FTDI 232 Chip. This contoller is connected to an 24 DMX-LED controller. I want to controll the LED lights over LabVIEW via DMX. Now here is the sad thing - this program works sometimes, and sometimes not. It is very strange. I change the slide, run the program and sometimes the lights change and sometimes not 😞

This things have to be completed in order to make it run:

1. Install FTDI drivers - u must have in your hardware manager under "connections" somthing like "USB serial port (COM 5)". In my case it is COM 5!

2. U must configure this "USB serial port (COM x)" in the syszem manager - just double klick it and go to options. There you put the Baud rate to 230400 nad 2 stop bits.

3. U run the attached program in this thread.

But as I said, sometimes it works and sometimes not. Dont know why yet. I am also just a beginner. When I get more information, I will write again. However, it would be nice, if the thread-opener would put more basic information on this thread. So far, thx for the attached pgoram - at least the lights are changing 🙂

[ninlmartijn]

Dear Serdj,

did you put the same settings on the Visa Configure serial.vi? When it fails is the return count write indicator indicating the number of bytes you are trying to write? Please make also sure that no other application is writing to the same port when using Labview.

Best regards,

[Serdj]

Dear Martin,

thx for your support. I tried to work with the FTDI VI-functions from their homepage - they work with the ftd2xx.dll. 

I explain again my hardware: I have a 24-channel LED DMX controller. The whole device has the start adress 1. My first LED-stripe is green and this is also my adress 1. The next LED-stripe is a red one and it´s adress is therefor 2. The next is a blue one and has the adress 3. Then again green with the adress 4. Ando so on, till my last blue LED-stripe with the adress 24. When I use the FTDI functions, I am able to turn the lights on - for example all 24 lights get the value 255 for 100% on (I send 512 bytes with a value of 255). Or I can send a lower value like 19 , then they are shining very little (like almoust turned off). But here is the thing, I can do it only once. Then I have to do a cold restart (electrical power off and then on). After the cold restart I can send a value again and the lights turn on according to the value. Then I decidad to send only 1 byte with a value of 255 (after a cold restart again). This byte controlls my first green LED-stripe and it got turned 100% on. After that I decided to send again only 1 byte (this time without restart) with a lower value (f.e. 19). Insted of lowering the lights on the green LED-stripe, my second LED-stripe (the first red one) got turned on according to the low value of 19. The next byte turned the third LED-stripe (or the first blue one) on. So basecally, my DMX controller is adding the bytes internally instead of changing it. I dont know why yet. I tried to read something out of the connection, but the read buffer is empty - I also dont need any information of the LED controller, since it should only pass the value to the LEDs.

Can you help me out? Thx for any response!!!

[Serdj]

Update: I connected an oscilloscope to my DMX cable, in order to see the bits. This is what I founf out - my FTDI VI´s dont send the BREAK signal ( LOW for at least 88µs - see this link http://www.circuitcellar.com/archives/viewable/217-Ernst/2.html ). I dont know why?!? I choosed the DMX communication settings (8 databits, no parity, 2 stop bits, no flow control). Did I forgot to activate some special setting? Pls help!!!!