Duet 2/3 POE (power over ethernet)
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@bearer I think power handling should be ok for what I have. I have 4 of these poe switches:
https://www.amazon.ca/gp/product/B07TX5CX37/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1They are good for 30 watts per port. now, if I can just harness it!
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@LeckieTech said in Duet 2/3 POE (power over ethernet):
if I can just harness it!
thats where the problem lies, the cheap-ish PoE power adatpers can negotiate any power level and if you exceed what the adapter told the switch the switch will kill the power as its reasonable to assume the device failed.
you can usually change the power classification with a simple resistor in the cheaper adapters, I had lots of problem with some Chinesium adapters off eBay until I put the correct classification resistors in them.
so do some reasarch or get some name brand stuff is all I'm saying; you don't want your switch to kill the print if you exceed the power budget for the active link.
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@bearer Im not looking for cheap, I am looking for reliable though. They make a shield for the raspi. I wonder if this can be used?
It appears to have a buck converter builtin, I would imagine removing the jumper on the duet SBC header and allowing this shield to back feed on the 5-volt rail of the Duet3 would work? I might have to hardwire the signal wires over from the RJ45 housing?
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@LeckieTech I replied in the other thread but if the switch and the PoE hat you linked can really provide the quoted 5A then it should be able to power both the Pi and Duet3. You'd have to consider any USB powered devices attached to the Pi in the power budget though. The ribbon cable alone is just fine for powering the Duet. It has 2 5V conductors and several grounds.
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@gtj0 I don't think we're going to run the raspi with the new setup. well were undecided. I set up a few printers with wifi2 boards and everyone seems to be happy here with the web interface from DUET and all the other features we need can be done in G code. But anyway, I did find a board that seems like it could power both if we wanted to go that way. Im confident that both the raspi and duet will never use more than 4 amps since the onboard AOZ1284 of the duet is only able to do 4amps continuous and nobody seems to be complaining about power supply issues with this.
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looks like there is a 4pin comms header that I can wire to the Duet3 with a small pig tail RJ45 jack. Does anybody know if there is a header for the RJ45 comms on the D3?
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@LeckieTech said in Duet 2/3 POE (power over ethernet):
looks like there is a 4pin comms header that I can wire to the Duet3 with a small pig tail RJ45 jack. Does anybody know if there is a header for the RJ45 comms on the D3?
not sure what the plan is, but if you're gonne use the Duet3 with the raspberry pi then you won't be using the Ethernet on the Duet3.
run 5v from the Pi PoE shield either through the ribbon cable and set the 5v -> SBC + SBC -> 5v jumper or run 5v from the Pi PoE shield and to the Duet 3 5v ext, but thats just extra wiring when you already have the ribbon cable that can carry the 5v if you set the jumper.
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@LeckieTech And are you sure those 4 pins aren't the transformer taps? If they are, they've got 48V+ on them.
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@gtj0 Yea, youre right, they will be powered! I can always run the raspi. But if I did want to access the Duet web control, can I do that through the raspi? Or would I have to cable up to the ethernet on the D3?
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@LeckieTech said in Duet 2/3 POE (power over ethernet):
But if I did want to access the Duet web control, can I do that through the raspi?
When used with the Raspberry Pi, Duet Web Control is run as part of the Duet Software Framework on the Pi, and it communicates with the Duet over the SPI bus / ribbon cable, ethernet is not in use on the Duet at all.
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@bearer Ok, right on! Thats good to know in helping me weigh the setup options. Im assuming the pi would be running something other than octoprint to do that?
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How long is your intended cable run. To get the required wattage you may need to run 24v or 48v over PoE and step it back down to the correct voltage at the far end. The resistance of 26/28 gauge Ethernet cable adds up really fast.
FYI, even at 10 feet of cable you will lose around 25% of your voltage if you run 5v. https://www.calculator.net/voltage-drop-calculator.html
48V at 2A will still have line loss of nearly 3 volts but just might get you the required wattage before turning Ethernet cable into a fuse. (AKA fire)
You will need higher voltage or thicker wire. Home running extension cords for AC power supplies would be much better.
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All the 802.3 at/af PoE stuff use 48v, is just the cheapo passive "PoE" stuff that suffer from voltage drop issues (interoperability/safety issues and should be avoided at all cost imho)
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@bearer I've had some updates to this project. As mentioned, we've been testing the Duet2 Wifi on a few printers. We actually found that these boards are exceptionally slow for uploading files. I'm not sure if it's our access point or what, I've tried a lot of things but nothing seems to get the Duet2 Wifi up to network speeds of a Raspi. We have a single gigabit network AP over the center of a 13' print rack that is just for our print room with 24 printers running 22 RasPi 3B+ W/ Octoprint servers and 2 Duet2 boards. To combat the slow upload speeds and try out the new POE idea I added via USB - RasPi 4's to the Duet2 wifi boards. A 50mb file would take the duet2 wifi sometimes 4-5 minutes to upload vs the Raspi 4 wired RJ45 w/ POE hat 1-2 seconds to upload the same file. So my question now, using the guide you linked earlier (https://duet3d.dozuki.com/Wiki/Getting_Started_With_Duet_3#Section_Duet_Software_Framework_on_Raspberry_Pi) will this framework work with USB to the Duet2 Wifi boards? I really have gotten use to the Duet Web Control and how convenient making operating changes is that I don't think I will be able to go back to octoprint!
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@mwwhited Missed your comment earlier. I've experienced no issues so far with 20' cables powering a raspi 4 and duet2 wifi. I've been running 2 printers for about a month. Power delivery is flawless so far! I check our printer rack daily with a thermal imager for traveling bed heating wires that are about to break (they always get hot in the spot where the break is going to happen) and I've never seen a network cable on the radar!
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Yes the current Duet 2 will work with DSF as of RRF3.2 (you can compile a beta from github and test it today). Caveat is it requires custom wiring for the Ethernet, and soldering or pogo-pins for the Wifi (my own) preliminary testing is indicating that it may be possible to skip desoldering the Wifi module to use DSF, but no official word on that yet.
There are two recent threads dealing with this showing how to do it.
As far as hot cables go, then its not a problem with real PoE, there the voltage is sufficiently high to have low currents. But running 5v through passive PoE will be a different story even if the cable doesn't get hot, you won't have 5v at the output.
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https://forum.duet3d.com/topic/17203/duet-2-ethernet-and-sbc
https://forum.duet3d.com/topic/17241/quest-duet2wifi-sbc-without-espectomy-possible-yes
think the credit is better aimed towards dc42 and wilriker ; i'm just a happy (ab)user:) -
@bearer This is really great stuff! Thanks man!