DE FX5 DMX does not wok correctly

[Codehunter]

Hello!

At first, I'm Cody and very new to QLC+. Formerly I've used DMX Control but I'm away from lightshows for a long time. It was only a hobby but unfortunately 5 years ago, most of my equipment was killed by a high water flooding. Only my fixtures which was hang on a truss had survived. After then, I had no money and no time to work with lightshows.

Today I'm tried to go back into my beloved hobby. Since my old controller PC is gone, I've lost all of my old DMX Control projects and my knowledge are a little bit rusty

Okay, now to my problem. I have two interfaces: An very cheap chinese USB to RS485 converter with a manually soldered XLR plug. And second, a more valuable FX5 DMX from Digital Enlightenment. Both are connected to my new control PC which is driven by Linux Mint 19.2 64-Bit. QLC+ has ad-hoc detected both (very cool that's so easy! I'm remember that DMX Control on Windows was very hard to configure to do the same.). For testing purposes, I've attached an Showtec XB-Wave. It is a 4-channel flower with rotation and strobo.

Using the cheap USB interface, the XB works perfectly and QLC+ let control it very easy. But using the FX5, it does weird things. It seems that channel 1 (RGB color) does work fine. But the other channels makes nonsense. The LEDs does flash with 5 secs pause instad of permanent light-on. The rotor plays fast ping-pong instead of value-controlled angle. Changing the channel values results in random effects without a senseful scheme.

Looks like the FX5 does permanently set and reset the bus. Does anybody know how i can make the FX5 working or knows typical tweaks for this interface? Many thanks!

Greets from Germany
Cody

[GGGss]

Lower the DMX frequency of the FX5. You most surely have timing issues...

[mcallegari]

Lower the DMX frequency of the FX5. You most surely have timing issues...

FX5 is not mapped by USB DMX. It is a HID device. (check here https://www.qlcplus.org/features.html)

@Cody, can you please try to raise channel 511 in Simple Desk and see if it makes any difference. This action forces the output plugin to send an entire Universe instead of partial buffers.

[Codehunter]

Hello again and please escuse the late answer.

I've tried following: Device start address set to 1. All channels in simple desk set to 0. Saved the project. Closed QLC+. Disconnected both interfaces from USB. Connected the FX5. Restarted QLC+. Turned on the output checkbox on the HID interface. In simple desk channel 511 set to 255 and channel 1 to 25. The fan in the XB runs faster but no light on. Same if channel 1 is set to 45 or 65.

25, 45 and 65 should be static light red, green and blue without rotation or shutter.

I've done the same again but now with the chinese adapter instead of FX5. Static red, green and blue light works fine at 25, 45 and 65.

In summary: Raising ch. 511 does not make any difference

Greets
Cody

[Codehunter]

No ideas?

[Codehunter]

Hello again! I have some new insights:

I've downloaded the (Windows based) test programs from http://www.digital-enlightenment.de/prusbdmx.php3. The Test.exe shows an EStringListError when clicking on "Get connected Devices". I could solve this according a tip in this Forum: https://forum.dmxcontrol-projects.org/i ... #post75578 (German). In Summary: Find the HID device id via Windows Device Manager, then go to HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Enum\USB\<HID Device Class>\<HID Device ID>\Device Parameters and change EnhancedPowerManagementEnabled from 1 to 0. Then dis- and reconnect the USB to apply this setting to the device. Restarted Test.exe and "Get connected Devices" works properly now.

An click on "Version" tells me that the Interface Firmware version is "1.10".

Now i've plugged an loopback test into the FX5, choosed Mode 6 from the dropdown, click on "Open Link" and played with the value sliders. Voila: The FX5 sends properly and Test.exe receives the data through the DMX Loop.

Now the decisive test: Connected the Showtec flower. Click on "Close Link" -> Mode 2 -> "Open Link" and raised the most left slider to 14 (hex). And... The Showtec works fine! Goes to Red light on. I'm able to control all functions properly and absolutely no glitches.

This tells me: The FX5 hardware is not defect and the connection is ok. It's only a software problem. Neither QLC+ nor DMX-Control works properly with this device.

[Codehunter]

I've found the cause why the FX5 doesnt work properly after a very long search. It is very sensitive regarding to the DMX bus termination. It doesnt work without termination, even not with a single fixture and a short XLR cable. And the magic bug in my setup was: A wrong resistor in the termination plug! I bought this plug from a professional shop and never believed that they have soldered a wrong resistor. It should be 110 ohms but 1,2 k ohms have. My cheap china interface has worked fine with 1,2k termination but not the FX5. I've soldered 110 ohms resistor myself to the termination plug and voila: The FX5 runs perfectly. Unbelievable...

[GGGss]

I'd suspect a very cheap RS-485 chip in place. So it can't work with reflections in place?
Strange...
Do you possess 100m+ of DMX cable? I'd be very interested to see, with this cable in place, what happens when you connect your fixture behind 100m+ of cable...

and wait a minute ... what cables do you use? DMX states that cables with an impedance of 120 Ohm should be used. A micro cable has an other impedance and gets in conflict with the interface... Now a days this shouldn't be a problem but since you are talking about chinese fixtures I was getting suspicious...

[Codehunter]

The other way around! The cheap china device (an FTDxxx) had never any problems with my cabling. Only the FX5 seems to be very sensitive about bus impedance. Weird: A cheap FTD as the workhorse, the expensive FX5 as a diva.

I have no long cables because I'm not an stage professional. You're right, its microphone cable. But I think in a universe with 7 fixtures and total of 25 m cable it does not matter. Maybe more in the future but not now.

Is dedicated DMX cable really so much better than mic cable? Years ago I had buyed a expensive DMX cable but it was really similar to mic cable. So I was thinking, its snake oil. Simply a mic cable with different label for more benefit like shielded optical fibers for allegedly less interference.

[GGGss]

Is dedicated DMX cable really so much better than mic cable? Years ago I had buyed a expensive DMX cable but it was really similar to mic cable. So I was thinking, its snake oil. Simply a mic cable with different label for more benefit like shielded optical fibers for allegedly less interference.

There you are wrong - DMX cable has a substantial bigger core in its wires and has an impedance of 120 Ohm. Moreover it has a low capacitance.
With the mic cable (higher capacitance on long runs) you are creating a R/C filter which limits the frequency that can pass.

[Codehunter]

There you are wrong - DMX cable has a substantial bigger core in its wires and has an impedance of 120 Ohm. Moreover it has a low capacitance.
With the mic cable (higher capacitance on long runs) you are creating a R/C filter which limits the frequency that can pass.

The dedicated DMX cable I've bought ago had the same wires and shields like cordial mic cables for a 3x higher price. Maybe I just had bad luck with the seller. At Thomann I've found a description about mic and DMX cables:

https://www.thomann.de/de/onlineexpert_ ... arten.html

It seems that DMX cables are similar to CatX network cables with twisted pair solid wires. My dedicated DMX cable was definitely not twisted and had no solid but stranded wires. Therefore i was thinking about snake oil. But its also been 10 to 15 years. Maybe there are better DMX cables now.

[GGGss]

Have a look:

(blue caps clearly tell me: DMX)

[Codehunter]

After some time i will report my conclusion on this issue with the FX5. For a while it has worked fine, then it falls back to senseless output. All time in a fix installation without movement of cables or fixtures. At a point i would drop it into my trashcan. But then I think when it is scrap, I can open it and look inside. It would not make any difference because the warranty for the FX5 is over for a long time.

And then I found it out. The one and only cause for the issue: There was some bad soldered pads on the PCB and a broken pin on the USB connector! So I have re-soldered all the pads and replaced the connector with a used one from a old flatbed scanner. And voila: The FX5 works very well since them. Not a single transmission fail for months.

I think the broken USB pin was happen when the FX5 was manufactured because it has never worked correctly until my overhauling. Maybe the powering was insufficient for a good DMX signal since the broken pin was the +5V in the USB connector. The fracture had caused a higher resistance between the 5V from the host and the FX5 PCB. Sometimes the fracture was pressed more by the USB cable, sometimes less. Here in germany we call such fractures "Wackelkontakt".

I like the FX5 now It is really a good USB-DMX-Interface and works on very long distances (more than 300 meters tested). Thanks to all who has tried to help me but it was never a software or cabling issue.