Duet 2 wifi 12v in 24v bed

Hi everybody, i am a 3d printer lover, i work as CNC operator so i can resolve mechanical troubles without big problems but my knowledge lack a lot in electronical parts, i am buillding a machine (few pics in the topic) and i want to add a 24v bed ø400mm 300W, on my machine right now i have a 12v 200W ø220mm heatbed, the machine isnt new i bought from a guy that built it and i am using it as start for my project.



The machine mount: Duet 2 WIFI - duet smart effector - magballs ecc running on a 12v 30A PS but as i said, i want a bigger printing volume so i got a different bed running 24V, so my question is wich is best way to make everything work without problems? Changing the PS or add something between duet 2 and bed?

Thank you everybody for your help

Two easy options:

1. Convert the whole machine to 24V and use just a 24V PSU. You will need to replace the heater cartridge and fans with 24V versions, also don't forget to remove the 12V/24V jumper on the Smart Effector.

2. Use 2 PSUs and run just the bed at 24V. To do this, connect the negative output of the 24V PSU to VIN ground side (along with the negative output of the 12V PSU), positive output of the 24v PSU to one wire of the bed heater, and the other wire of the bed heater to BED- on the Duet bed heater output terminal block. Leave the VIN side of the bed heater terminal block not connected.

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Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].

Okey so the 2nd option seems to be the best since it doenst need to change a lot of parts, is there any draw somewhere for this cabling? and as 2nd PSU wich one should i go for?

Thank you a lot

Since you seem to be opting to do this...

Buy a 24V supply large enough to power everything. Since the bed is the largest power drain, you probably already are.

The things that are V||in supply dependant are in 3 groups: the bed, the hot-end and fans. The above wiring converts just the bed. For the same investment in parts (the power supply) you can convert it in a better way.

Connect Vin to the 24V supply, and do as was described above for the hot-end. (Connect the negative of both PSUs together at the VIN terminals, but connect the 12V positive to the hot-end(s) heaters. Also connect the 12V positive supply to the V_Fan jumper (Where you can select 5V or Vin for fan voltage.

The advantage is that running the stepper drivers at 24V will allow them to potentially run faster. Current through the motors will have the same selected limit, but they will run nicer. I believe that they will also run more quietly, but I don't know that I'd count on that. 24V will also allow the Duet to run its power failure state save.

Upgrade hot-end heaters to 24V later. Once you do that, you can swap out the 12V supply for something of much lower power output for the V_Fan jumper. You shouldn't need more than 1A, easily available from a buck-boost converter for the fans. (A V1.4 board comes with a 1A fuse anyway.) Personally, I see no advantage to 24V fans, and enough advantage to the 12V ones (Selection and availability) to make it worth getting the 12V buck-boost converter. Of course feel free to use the 12V PSU you already have.

Edited 1 time(s). Last edit at 01/02/2019 03:33PM by SupraGuy.

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MBot3D Printer
MakerBot clone Kit from Amazon
Added heated bed.

Leadscrew self-built printer (in progress)
Duet Wifi, Precision Piezo parts

As @SupraGuy says, using 24V VIN will potentially give you higher travel speeds, and is essential IMO if you use 0.9deg motors. Personally I use 24V for everything; however some users prefer Noctua fans because they are quiet, and those are not available in 24V. So a good solution is to use 24V for everything except the fans, and to use a 12V buck converter for the fans. If the hot end on your printer uses a cartridge heater (as almost all do) then it should be easy to replace it by a 24V cartridge.

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Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].

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dc42
As @SupraGuy says, using 24V VIN will potentially give you higher travel speeds, and is essential IMO if you use 0.9deg motors. Personally I use 24V for everything; however some users prefer Noctua fans because they are quiet, and those are not available in 24V. So a good solution is to use 24V for everything except the fans, and to use a 12V buck converter for the fans. If the hot end on your printer uses a cartridge heater (as almost all do) then it should be easy to replace it by a 24V cartridge.

Indeed, a buck converter is what I use too. So damn cheap and not that much choice in 24V fans
I use these:[www.banggood.com]
They have a good trim pot.

Edited 1 time(s). Last edit at 01/03/2019 11:22AM by MKSA.

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"A comical prototype doesn't mean a dumb idea is possible" (Thunderf00t)