I also do lots of other DIY electronics.

For audio amplifiers, and circuits where ground loops can cause some very undesirable things, particularly since there are a lot of places that can cause ground loops in audio equipment, it seems to be pretty standard practice to have an isolator between the DC ground and actual earth.

I have built a bunch of circuits from Eliott Sound Productions, pre-amplifiers, signal processors, and audio amplifiers. I made quite the sound system with his circuits.

In this schematic, you can see in the bottom, the parts used for the loop isolator. D1, D2, R1 and C1 are all in parallel providing a nominal break between earth and the DC ground. This one is for a dual amplifier supply, but shows that the AC earth should have at least a modicum of isolation from the DC ground. This is also true for single-rail supplies. Failing to do this can result in audible noise in audio circuits.

If you omit D1 and D2, this will still work as an isolator, however should a large potential build up, you might end up burning R1, which would normally be a 0.25W device. The diodes protect R1 by acting as a dead short for voltages above the Vf of the diode, typically a bit under a half volt.

The Meanwell diagram seems to only use C1. This is probably adequate if there is no electrical fault elsewhere, but we're doing this in case there IS a fault elsewhere.

Re-sizable controls. I might want a fairly control dense screen on my RPi 480X320 screen with a trackball, or I might want only a few key buttons if I'm using the same in a 5" touchscreen. Kind of different if I'm displaying on a 4k monitor.

I commonly use an RPi with a 1280X720 7" screen, my phone (5" 1080X1920 or 1920X1080 screen) or my media PC (40" 4k screen) with DWC now.

The phone is the most maddening, but the one that I am most likely to use for babystepping adjustments.

For me thought the biggest thing that I'd like to see is user levels. One level where you can print pre-stored files, one level where you can upload macros and files, and one where you can update firmware, and main configuration. (Let the kids print another object, daily use, and admin privs.) Yeah, I'm aware that with "Gcode everywhere" uploading a Gcode file can do whatever mucking with the configuration files can do, but at least it can be reset with a power down. (I'm a network admin for my day job. Proper user sandboxing is something that I like.)

No way I'm granting Internet access to any device that doesn't need it.

My Duet can talk to my LAN, but cannot talk to the Internet. Even if you can somehow convince something else on my LAN to talk to the Duet for you, the Duet isn't going to talk to the Internet. My Raspberry Pi running its RetroPi distro can't talk to the Internet directly. I download images and updates to a more secure server on the LAN, then download to the Pi from there.

I don't need access to my 3D printer from the Internet. I don't think I'd even leave it powered on while I'm not there. Maybe (but probably not) if I were leaving the house to go somewhere and finish a 3D model which I wanted to start printing before I come home... But then what to do if the first layer messes up? I suppose that I can put a webcam on the printer to see, and abort the print, but it's not like I can scrape off the ruined layer, re-prepare the bed and start again. It would be a one-shot "works or doesn't" attempt, and something rare enough that I can't see setting up for it. Besides, there are plenty of secure enough ways to remote control a PC with reasonable security, which will then be able to access other machines on the LAN.

I figured that it's only a matter of time before things like this become hacker targets.

I'm not concerned about someone stealing my gcode files, and I believe that I have reasonable enough safeguards in place to keep someone from starting a fire with my 3D printer.

Test that the wires go where you think that they do. Test for continuity with it disconnected from the Duet. You should have continuity between the black and red wires, and between the blue and green wires, but not between any other pairs.

Check that you have the jumpers on the second Z motor connector. If that is open, your motor will not move.

You have the choice of Vin (Whatever your main power supply is) or 5V as selected by a jumper on-board. Alternately, if you have another power supply voltage (Say, your Vin is 24V, and you have a 12V converter) you can connect that to the jumper instead and power your fans that way.

Most people select fans to match their main power supply.

I've moved all of my stuff (Except for some half-baked things that weren't any good) onto Prusaprinters.org myself. Probably moves some of the crap over, too, honestly.

I've recently become a little more serious about my CAD development, so hopefully better things coming.

Okay, so looking at your printer, it appears that the bed moves in the Y axis.

Since you have a Bowden extruder, the X axis is going to be much lighter than the heavier bed, so increasing the moving mass in the Y axis is going to slow down your printing, in that you will need to use lower values for accel in the Y axis with the heavier mass, all else equal.

However, if you are upgrading from 12V to 24V, you might find that your motors will deal with it better overall, though there will still be some ringing, just as a part of the nature of the drive belts. Well, any drive system, really.

I added a couple of pieces of aluminum bar to my Y axis as a part of getting my Piezo Andromeda sensors set up. Maybe a couple hundred grams, I didn't weigh them specifically. It didn't seem to make a noticeable difference in the ringing that I get in the Y axis, but I also print somewhat slowly, since the leadscrew drive configuration that I use doesn't lend itself to very high speed moves. I hardly ever have anything above about 75mm/s, and perimeters are never over about 50mm/s.

How much does your mirror weigh? If you can print without it on the aluminum, that's probably a better solution anyway. Glass is terrible for thermal properties. I use it myself because I like the super-smooth first layer, but I'm looking at solutions to print without it, since almost everything that I print can tolerate a slightly rougher surface texture, and even the 2mm glass that I'm using has its weight to consider.

In your position, I would probably use the 5mm plate, and do away with the glass. Use a PEI sheet or similar instead, and you'll have more even heating, and probably better adhesion with most prints. It's likely that you'll be much happier with the overall result, even if you have to slow down your Y accel by a few percentage points.

From your post, I'm assuming that you have 2 Z stepper motors, and that the printer worked, but you (temporarily) removed one motor, and when you reinstalled it, you're getting inconsistent results.

Is it consistent? Is it always the same motor that is lower at the end of the print, or does it go back and forth?

I'm sure that you checked, but I'll ask for completeness. Are you certain that you didn't get anything stuck in the motor mount, like plastic debris, or bits of leftover plastic skirt/brim? Are all the screws tight? Are the Z screw couplers tight and have you checked them for play?

I'd think that the most likely cuplrit would be a set screw that is allowing the motor to turn inside the coupler, or the coupler to turn without turning the screw. A very small amount would add up, particularly if you have fine-pitched screws. It's unlikely to be the control electronics, or the motor itself. I would think that a mechanical issue is the highest probability. (I just replaced my Z couplers, and had an issue where the threaded rod on one side would MOSTLY turn with the motor, buton high speed moves, or with sudden reversals like a short lift motion could get out of sync with the motor.)

I'd go over all of the screws, from motor mounts to couplers and make sure that they're tight. I'd go with both sides, just to be sure. Make sure that you can't turn the screws without the motors turning. With them powered on, you shouldn't be able to turn the screws at all.

@t3p3tony Sorry 'bout that. I "report to moderator" when I see one of those (But only once, even when there are 20.) On a forum this active, I'm probably not the only one, but the "I thought someone else would do it" factor applies, too. (I've been a forum moderator for other places before, I know how this sometimes works.)

Every once in a while the bots manage to sneak one past the mechanisms meant to keep them out. Sometimes the bot software gets better, sometimes they just get lucky. Whenever they do, it's always a fight like this. I'm almost certain that it's almost always SEO crap (Something like this one, where it seemed to be a website URL over and over again is almost certainly SEO.) and sometimes it's regular spam, trying to get users' attention.

Thanks for taking care if it!

You can specify a minimum of say -110mm and a maximum of 110mm (for example) in order to have the bed center be 0,0. Some people do this so that the same gcode will operate on multiple printers with different geometries or mechanisms.

I personally do not do this, since I use different materials and nozzle sizes, so I need to re-slice for different printers regardless.

In my case, I set it up so that 0,0 is the front right hand corner of the printable area, even though the printer mechanics can move the print head further. If memory serves, my minimums are -11mm X and -9mm Y. (Might be the other way around. My pause.g parks the print head at -5,-5.)

@siam Thanks for the confirmation. Yeah, fuses were the first thing I checked.

The more I probe at this cloned board, the more I appreciate the build quality of the originals.

Edit, looking at where U3 is located, I don't think I can repair this myself, so I'll use an external 5V supply, until I can source a genuine replacement... Or I retire one of my printers.

So I was cutting a CNC job, when the Duet just stopped. Bang, no power to motors, no response on the network, nothing.

No LED lights for 5V or 3V3, just the Vin light, so it was getting 12V power, but no logic power.

Full disclosure, this is my one knock-off. I have 3 other Duet 2 Wifi boards, all genuine, but I wanted one more, and the official supplier out here was out of stock. Still is, it turns out. Looks like they only have the Diet 3 boards now. (I want one for my CoreXY printer, which needs 6 drivers, but that has to wait for now.)

Anyway, I pulled the Duet from the CNC, and decided to see how bad it cooked. As opposed to th e last time (I let a hotend run over the cabling ) when I cooked a bunch of stuff, this time, it didn't seem so bad. The SD card at least wasn't dead. So I plugged it into USB. Hmmm. Recognised device, so turn on the serial monitor, and it connected to the wifi. DWC works.

12V power... nope.

So I suspect that the knock-off 5V regulator has comitted seppuku. It appears not to have taken the wifi module or the MCU with it. The status of the motor drivers is unknown because I have not had both USB and Vin connected at the same time, but I might try that with a USB power brick (I don't know that I want anything that I care about connected to the USB when there's a suspect regulator between 5V and 12V, though I suppose that if it were that bad it would have damaged more stuff on board.)

The moral of the story is one that I've told often enough... The cost of cheap equipment is the cost of the cheap equipment, plus the cost of the expensive equipment to replace it, plus the time and trouble to troubleshoot and replace.

I might give some SMT soldering a try to replace this regulator though. No stock on replacement boards.

Guess I better figure out which is the 5V regulator...

I've moved all of my stuff (Except for some half-baked things that weren't any good) onto Prusaprinters.org myself. Probably moves some of the crap over, too, honestly.

I've recently become a little more serious about my CAD development, so hopefully better things coming.

@code7 It will somewhat depend on your laser, it might need a 3V3 connection (100% PWM) or it might have an "on" button on it, so it only needs the 12V connection.

I went ahead and ordered the PWM modules that will output the 5V PWM from the Heater 3 pin. Turns out that I got 15 of them because minimum orders, so depending on where you are in the world, I could probably mail you one for pretty cheap. (I didn't get the wire headers for the 12V/GND in, and the 12V/GND/PWM out because they didn't seem to be in stock anywhere.) I don't like using the PWM on the full 12V, but some people have had good results from that.

I'm in a similar boat, though I don't have the Duex5.

The PWM on the Duet triggers the negative, so you can sort of use it. You can power the laser from the heater circuit, or at least the trigger. You can use a separate 12V supply for the positive side, and use the PWM management for the negative, or you can use something like this circuit to switch the PWM input from the laser, with a separate 12V supply. (I just got a few boards made for that circuit, which can be (apparently) plugged into the expansion header on the Duet2.)

Looks like if you want a native PWM manager, you need the Duet 3.

For the 12V version, you may need an external MOSFET, you just feed the 12V from a separate supply, tie the ground together with your 24V supply, and supply the ground through the MOSFET to the laser. The laser then stays at 100% and the heater circuit will manage PWM. It should work OK, but the fan will also be PWM controlled to match the laser.

Very timely, as I was just looking for this information myself to drive a PWM laser from a Duet 2 Wifi.

I ended up purchasing boards from JLCPCB.com, and they appear to have a minimum order quantity of 5 (And for some reason, it's cheaper to buy 15.) ... So I have 15 on the way, populated with the SMT components C1 and U2. It was a bit unclear as to which side H1 connected to. It looks like it should go on the bottom of the board, though I'm not sure which header it connects to. If it's on the expansion board, that could be a problem for me, and I might need to figure some other stuff out, but it appears to occupy pins 1-8 of the 50 pin expansion header.

Anyway, I've got the boards on the way, and 8 pin headers coming separately. I'll probably just solder wire to the board for the DC in and laser out, since neither JLCPCB nor Digikey seemed to have appropriate connectors in stock when I looked.

For what the extra cost, maybe I should have just bought a Duet 3 6HC instead.

First off, hi everyone! It's been a while!

Okay, so I'm setting up a new machine, replacing an SKR board running Marlin.

I'm setting up my fourth Duet2 Wifi, (3rd currently in use) to take its place, because I'm tired of sneakernet file management. I've just got it set up on RRF3.3 (Sticking with stable releases) and realized that there's one feature that I had on Marlin that I'm not sure of how to implement in RRF.

For an axis with multiple drives, setting up the multiple stops is straightforward enough, but I don't have those stops as perfectly aligned as I'd like. Marlin let me set an offset to the first endstop, so when I home it, it just bumps the one end away from the stop a little, and everything is nicely levelled (M666) used for dual endstops, slightly different from the Delta calibration usage.

Physical adjustment of the endstops is a bit of a pain, and getting the desired precision is troublesome. It wouldn't be so bad if it were Z, because I could use the Z probe to level it to the bed, but it's Y, and aside from measure and adjust, there's no guaranteed way to force it to be perpendicular to X. (The whole reason I really love this printer is because I can have X and Y absolutely perpendicular, and adjust as the printer frame ages, something that I've been unable to do with other printers.

The approach that I've been mucking with is the old one of "uncouple the Y axis into U and V axes, then make a tiny adjustment to U, then recouple the Y axis to both drives." My hope is that there's an easier way.

If you use G92 to set Z to zero, make sure that you allow the Z axis to go negative by more than you will need to cut, or set it to the minimum depth. The firmware by default won't allow the axis to go negative, so you will get an error "out of limits" and your gcode will abort when you try to plunge into the work.

You'll also want to allow negative movement in the X and Y axes as well, since most CAM software sets the 0,0 point as the outside of whatever shape you're cutting and will want to go negative by at least 1/2 your tool diameter at some point.

@weed2all True... However if the DWC were fully adequate, I'd have never got started down this path, since what I started with when I installed the Duet on the CNC was a 7" tablet which I had a browser connected to the DWC. Some things with that were annoying me, so I stopmed off upstairs to grab the PanelDue from my 3D printer and plugged it into the CNC instead. (Mostly on the printer I use it to set temperatures before I start to print stuff, MAYBE adjust babystepping.)

I see the reasons why things are how they are in the DWC, but for what I need when I'm standing in front of the machine, it's just enough different. So far, I've programmed a set of macros that do most of the functions that I want, and I can call them from the PanelDue, but the interface is kind of ugly that way.

In short, this is a project that was born of frustration with the existing set of tools, and I'm still learning what things I actually want/need when I'm standing at the machine, so I was planning to adjust it over time.

@phaedrux I'm seeing that. I've set up the build environment and have been getting familiar with the setup for the firmware.

Some things don't seem too difficult.

It looks like I might be just building a replacement using a Raspberry Pi and a touchscreen.