Hardware Concept - PoE Ethernet Duet 3

TLAS

Hello Everyone,

So I just finished putting in Cat8 Ethernet in my house (future proofing) and it got me thinking - why haven’t we seen any Power over Ethernet (PoE) in the Duet space? Now I know you’re probably thinking ‘not powerful enough for heaters!’ but hear me out.

The new Cat8 lines I put in were super beefy - 22 AWG, shielded, twisted pairs with a shielded outer braid. The stuff is rated up to 40 Mbs with POE+ certification.

I believe you can transfer 10 amps over a 22 AWG wire - if you use 2 pairs at 24V, that’s 480W while also leaving 2 other shielded pairs for data. If you designed the system at 48V that’s almost 1000W. Now this doesn’t say anything about distances or insulation temperature, but I don’t think that’d be too hard to design around.

From a product standpoint I was thinking:

Duet main board inlet continues with screw ring connectors.
PoE motor adapters (Ethernet jack to JST motor female connector). Maybe (or maybe not) make a ‘motor tool board’ with embedded drivers?
PoE CAN bus for toolboards - maybe combine this with a tool distribution board.
PoE smart effector with single-cable design
PoE filament sensors
(maybe) PoE end stop board with connections for the most common types of endstops

Here’s a relatively simple PoE injection schematic:

https://4.bp.blogspot.com/-qXsn6YVknb8/XAUyj7Z_dfI/AAAAAAAAHVg/iUZQ1ikOwHY1zTRSKfHC5SuhF5l4jFE9QCLcBGAs/s1600/48V%2BPoE%2BInjector%2BDIY.jpg

Maybe I’m dreaming but it’d make for an amazing printer electronics design to just plug everything in with standard (ok top end) Ethernet cables.

TLAS

And if you can’t tell - I hate making cables. lol

Michael Hathaway

Did you hear about that new Cat9 coming out? ... just kidding

elmoret

10 amps over 22awg?! You could use the cable for bed heating!

TLAS

@elmoret

https://www.is-rayfast.com/news/wire-cable/temperature-rise-by-current/

7.4 amps for 30C rise, 10 amps around 40. Yeah, it’ll get warm, but doesn’t sound too bad if you have good materials. Most cables are rated about that high. But yes, you could probably wrap it around the bed if you really wanted to.

Derating cable between 0.66 and 0.5 for multi core still leaves a pretty good amount of power.

elmoret

You need to derate by 0.5, leaving you with 3.5 amps. A far cry from the originally promised 10!