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I am currently working on a small project as an engineering trainee, where i am to continue on the development of a DMX tool to help with the testing of intelligent light fixtures at my workplace.

The project is written in C# and uses the managed FTD2XX_NET.dll wrapper available from Ftdichip website as well as using the Enttec DMX USB PRO Mk2 as interface between the PC and light fixture.

The whole point of the DMX Tool is to be able to send DMX packets with different parameters e.g. sending DMX with a user setable start code or packet size, as well as customizable port settings e.g. different baud rates, to see how a given light fixture will run with non-standard settings for testing purposes.

I have partly succeeded in implementing the above features, and I have now hit a brick wall...

The DMX Tool is required to be able to run with two different modes:

Continuous mode and Single Packet Mode.

As stated earlier, I am able to successfully send the given DMX packet, but only continuously. I have searched the deepest and darkest corners of the web to find a explanation as to how the Enttec DMX USB PRO Mk2 actually works internally and how to stop this seemingly continuous data transmission, but have gotten nowhere.

And this leads to the real questions:

How does the Enttec DMX USB PRO Mk2 handle the USB-RS232 serial connection? Is it possible to programatically bypass this continuous data transmission to be able to send a single DMX data packet and if so, how?

JasonMArcher
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Mose
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1 Answers1

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I can't see any useful datasheets, but you might want to try using a tool like RealTerm to monitor the virtual COM port FTDI uses while using the standard software.

If you haven't seen the DMX box sending single packets at all, it may be worthwhile opening it up to see if there's a jumper or DIP switch that needs changing.

Sorry I can't be more help than that.

RoadieRich
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  • Thank you for your answer RoadieRich. Thats right, there is a major lack of datasheets for this. However, I will try to take a look at the software you linked to and see if that can help me on my way. If it yield any good results i will be back and post it here. Otherwise i will try to take your advice and open the Enttec DMX USB PRO Mk2. Cheers – Mose Apr 08 '15 at 07:52
  • It's also possible that the Enttec just doesn't support single packet DMX transmission. While DMX fixtures are *supposed* to hold state when they're not receiving packets, constant transmission is one way to guarantee your fixtures are always where you last left them. – RoadieRich Apr 08 '15 at 18:13
  • If that's the case, you might want to look into a homebuild solution. I've heard pretty good things about the Arduino DMX Host shield, and looked into using one myself - but we decided not to use it for unrelated reasons. – RoadieRich Apr 08 '15 at 18:14
  • I tried using the RealTerm software you suggested RoadieRich, but it didnt work for some reason. I did however find [Device Monitoring Studio](http://www.hhdsoftware.com/device-monitoring-studio) which yielded the suspected result; that the Enttec USB DMX PRO Mk2 does indeed only support continuously packet transmissions. Guess i will have to go with your way and look for a homebuild solution. I accept your answer as the solution. Thank you for the help. – Mose Apr 11 '15 at 11:56