Hi All,
I have been playing with the DMX output option and think I have a decent grasp in using it. To make it easier for anyone interested I have put together a page with information I learned.
Note that it is a works in progress and I`m not a WLED or DMX expert. Let me know if there is anything I can add, correct or explain better…
Hi packetbob,
I’m trying to get the DMX out going mostly based on your website - but no luck.
I tried different ESP8266 and an ESP32, pre-compiled and self-compiled binaries.
I tried different MAX485 - with automatic flow control and without.
I’m trying to control single RGBW-spotlights (Cameo Q-SPOT 40 RGBW | Spotlights | Cameo).
I think wiring the MAX485 is the most unclear to me - there is a lot of different reports on how to wire it up: which voltage to use, DE/RE connected at all, or to Gnd/Vcc. I also switched wiring A+ and B- on the XLR plug.
I don’t have a XLR terminator though - the cable is 15cm and I read it’s not really a must.
The only thing I manage to get is on Reboot of WLED the Spot switches to Red color.
Since I don’t own an oscilloscope I run out of ideas to find the issue.
Any idea what to try and check else?
many thanks in advance!
donnerstein
Ok, problem solved. I misunderstood the DMX proxy universe option and set it to 1 everywhere.
Now it works!
donnerstein
Hi,
What RS-485 interface are you using?
Send a picture if possible…
For a single device on a short cable you probably don’t need a terminator but it can depend on how you have the RS-405 interface wired…
Bob
The RS-485 standard says termination is required for the endpoints of the RS-485 bus.
Endpoints typically mean the first device and last device on the daisy-chained bus.
Can you get away without one on “short runs”?
Maybe, it depends on many factors including the data transfer rate you’re trying to maintain over the link.
With LED data, you’re effectively in the MHZ range so there’s very little incentive to not include the termination resistors on the 1st and last device as per the RS-485 spec.
I found two problems: the misread DMX option and the length of the cable. One was 15cm and the other like 10cm long. The long one didn’t work. I shortened it and voila, works as well.
If I encounter stability issues I’ll order some XLR terminators and hope that fixes it.
Thanks all for the help…
donnerstein
All you need for termination is a 120Ohm 1/4 watt resistor across the A+ B- wires at the point of connection (start and end of the wire run). Many RS-485 boards have the termination option on board, you just have to enable it.
You should easily be able to use wire lengths in 10’s of meters with properly installed RS-485.
Centimeter lengths should be no problem at all.