F8-PB DMX, refresher

[Livermore-Dad]

I am about to hook up my DMX stuff (last year was my first time). And I've got a cable here I created, RJ45 broken out so that I guess I get 2 ports out of it. But I've got what appears to be a single ground wire coming from the RJ45 to a F8-PB pixel connector (3 pin, connected far left (should be ground).     Does the DMX need a ground, is that why I have this dongle created? Looks like I've got wht/brn and brn broken out of the RJ45 and tied to the ground and each RJ45 connector at the end has either the brn/white or brn wire, which is gnd for it's 3rd pin.

Luckily I have a spare sitting here, so I can take an image of it..

DMX cable, F8-PB

RJ45 has 2 ports broken out for 2 DMX devices (yes I realize I can chain DMX devices . But in reality, I only use the one low lying fog machine.

Yes I can plug it in and . "see if it works", but I was wondering why I did this. I really can't find documentation for the boards, otherwise I wouldn't ask, or I would stop asking. I can hack my way through most things, but sometimes a reality check is not a bad thing!

[dkulp]

Technically, the rs485 differential data does not need a ground.  That is why the differential receivers work.   There is no ground connecting through the cat5 to the differential receivers.   

However, the DMX connectors all put a ground line in as it's generally a good thing to do to increase distance and reduce some noise.   I don't think it's required (my two DMX test things in my office don't require it), but, again, nice to have.

[algerdes]

I have several DMX devices (American DJ/Chauvet) that won't work correctly without the third wire.  Not all of them, but a few.  Any chance you are plugging into something that does need it?

[trikidiki]

If you check out bigclivedotcom's Youtube channel, he has a video showing how to construct a simple DMX test dongle.

I have used it and can see DMX data going to the device from a USB DMX dongle but cannot see any data from my F8-B controller.

[dkulp]

I know the DMX stuff is "working" as I have 3 F8-B's running DMX stuff running in my halloween show right now.  All three have two outputs of DMX.  2 of the outputs are going to 12V 10W DMX floods.   The other 4 are off to DM-103 based controllers/props (https://www.aliexpress.com/item/2012430551.html?spm=a2g0o.productlist.0.0.3879234f9mZhcj ) .  

Do you have any differential pixel receivers to at least test if the differential chips are working?   

Try turning on debug log for "Channel Outputs", restart FPPD, and make sure it's picking up the right information for the DMX outputs.

Finally, login via the command line (ssh,   username fpp, password falcon ) and make sure the /tmp dir contains a FalconSerial.bin, FalconPRUSerial.i, and SerialPinConfiguration.hp files.