@GillesDB when you have the XY motors connected to drivers 0.2 and 0.3, and you have motors connected to those outputs, after commanding them to move (and failing to see movement) does M122 ever report short-to-ground for those drivers?

If it does, and it's a version 1.01 board, then it might be caused by a quality control issue on some boards manufactured in 2020, in which case we would definitely replace the board under warranty. Please report the serial number, which is the one starting WD on the paper label on top of the main processor. This thread https://forum.duet3d.com/topic/18011/duet-3-6hc-short-to-ground-issue contains more details.

Which country are you in?

@Ballador No, just make sure the SBC supports ARMv7 instructions and that it has a relatively new Linux kernel. If you run Armbian on the ODROID M1, you should be able to install DSF. See also https://docs.duet3d.com/en/User_manual/Machine_configuration/DSF_Other

@Phaedrux Excellent explanations and exactly what I was not grasping, that make perfect sense now!! As you could tell I was fixated on the bed changing height since I had to deal with that compensation manually without the probe. probe to nozzle offset does not change other than the heat of the nozzle vs cold.
It is little details like that that those main instructions are missing. They are more quick reference to get you going but not detailed on "how it works" which I do understand since there are lots of different probes and printers.
Thanks again, I have to find some time to get back to the printer and spend a few hours to get it finished.

@T3P3Tony Thanks. I had a more accessable ground going to my filament runout sensor so I ended up using that.

Why try using a DC motor as an extruder? It goes back to the recent (ish) discussions on print artifacts that are potentially caused by extruders.
https://forum.duet3d.com/topic/23502/vertical-lines-vs-geared-extruders/89
https://www.bondtech.se/2023/01/26/how-we-improved-our-plastic-main-gear/
https://www.bondtech.se/2023/03/09/turning-lemons-into-lemonade-chapter-two/
https://www.youtube.com/watch?v=c6JmCdovE0U
https://www.youtube.com/watch?v=UWuSsYKI-YM

I've always been fairly happy with the print quality I get out of my two BMG extruders, however I've been impressed with the surface quality of prints done by my Stratasys Dimension BST 1200es (excluding 'ringing' artifacts on direction changes). Inspired by the DuePrint project posted here and on Hackaday, I pulled the extruder off the Stratasys printhead, and worked to get it integrated onto my DIY IDEX machine.

Prior to that though - about a year ago I started looking into designing my own extruder - inspired by all innovations of the LGX, Orbiter, Sherpa, etc. I was using these extremely slim Nema17 motors (PKP242D23A2) that are similar in stature to the popular pancake motors used on the newer generation of extruders (chief difference being the larger shaft diameter). As I played around with designs, it felt like I was reinventing the wheel - why not use a small stepper with an integrated gearbox (aside from price... right?). Starting looking at 15:1 Nema11 motors from Oriental Motor (PKP223D15A-CS15), but then the extruder project fell to the wayside. This past October I came across a nifty Nema8 with a 16:1 gearbox, and have been using that in a few different extruder combinations.

Based on the DuePrint project, I figured integrating the DC motor into the existing design would be easy enough - and after working past some Beta2 bugs, it was!

58f07574-fdf6-42f6-abbc-378ab6955402-image.png
https://www.youtube.com/watch?v=vvajxcZIf6M

Unfortunately, my lack of knowledge starts to creep in. With the Geckodrive G320x, I'm getting excessive motor thermal rise (at extreme conditions, the controller/encoder has either faulted out, or I disengaged the motor based on concerns of it failing) within 15 minutes or so. I'm seeing at least a 35°C thermal rise, and if my chamber sits at 62°C, that is not good. The twist is (detailed temperature measurements pending) that the Dimension series chamber temperatures settle at 75°C, and the motors operate comfortably at that temperature.

The Maxon P/N on the motor and gearhead don't lead anywhere (nor have I directly asked them, assume its 'proprietary' to Stratasys), but I'm pretty sure they're the similar to the following:

RE 25 Motor - P/N 118743, 12V nominal voltage, 2.18ohm terminal resistance, 1.25A nominal current GP 32 Planetary Gearhead - P/N 166167, 86:1 (with the 8mm shaft option) 1000 CPT MR Encoder - P/N 225780

At slow speeds, I have to turn the current pot on the G320x to ~2.5A, and in normal printing conditions, I have to bring it closer to 4A. If I've identified a similar motor, that is much too high!

From the uPrint (very similar print head to the 1200es) service manual:

The 5 VDC and 12 VDC are used by the controller board, single board computer, and hard drive. The 12 VDC also powers the filament motors. • The 24 VDC powers the stepper motors, solenoids, fans, and chamber lights. • The 120 VDC circuit powers the model heater and a separate 120 VDC supply powers the support heater.

Block diagram of the uPrint/1200es - of note is the L298P Dual Full Bridge for the extruder motor.
2ac09183-a753-4fbb-b5ce-4b00635388f7-image.png

This means then for the DuePrint implementation... we're using the G320x to signal to the PDB, and in turn the L298P?
78917a25-2a7d-4236-8561-0dbdba83371b-image.png

Still doing some learning and digging around.

EDIT - Next Day Update:
Trying to use my brain here - my motor current estimates were based on how far I turned the current trimpot on the G320x (starting from 'off'). As one could expect, there is a bit of slop in the trimpot. For the setup with my DIY printer - Making the assumption that V.controller_in * I.controller_in = U.motor * I.motor, I finally hooked a meter in line with the motor controller input (24v supply). Testing at standstill (dithering) and slow 5mm/s feedrates, I'm sitting at roughly 24v * .4A = 9.6W. This took minuscule adjustments to the trimpot, closely monitoring the meter reading. I'm at a steady thermal condition, with ambient (chamber/bed is off) at 22°C, and the motor casement at 57°C (35°C rise, but may be wise to imagine the true range is 30°C - 40°C to include some error with the readings). Separate thermal testing inside the Stratasys is ongoing now.

@3Dream thanks. I've done a temporary build of the EXP1HCL firmware that supports an SPI-connected accelerometer when a magnetic encoder is not connected, with the INT pin of the accelerometer connected to io1.in. I haven't had time to test it yet.

The alternative would be to connect the accelerometer I2C pins IO1 and fit the bypass jumper, but then you would need to solder the INT wire to the PA20 pad on the underside of the PCB. That may be a better option going forwards, if we add the PA20 pin to the IO connector in the next board revision, because it would also be compatible with using a magnetic encoder.

@jay_s_uk oh thank you so much 😊 , this was the issue, as I usually test everything in cold state and work my way through all stages of testing the functionalities. As soon as I let the hotend heat up the extrusion and retraction worked without any problems.

@Phaedrux thanks for checking in on my issue, too.

@T3P3Tony, it seems to have fixed it. I’m using a revo hemera xs hotbed with the 1lc board.

@jay_s_uk said in Correct way to power 1LC?:

The 3HC v1.02 and 6HC v1.02 can accept up to 48v as an input voltage

HEY!!! Look at that.

I usually google, get to the obsolete documentation which has a link to the new documentation and sometimes that's still old.

This is good to know, thanks.

@Phaedrux
If it only has to be temporary then I will use the ribbon and bypass the cable chains I guess.
I will try to find time to do that this weekend. Then I will try to get the necessary Gcode added.

Can you post your full config.g and the results of M122 and M98 P"config.g"?

Can you check this troubleshooting step please?

https://docs.duet3d.com/User_manual/Connecting_hardware/Temperature_connecting_PT100#troubleshooting

@Phaedrux I will try that and report back. Thanks.

@jjem I worked with the dev team and struggled with poor closed loop behaviour, from memory axis jitters and choppy motion.

Based on the latest dev work I guess there were some issues with commutation and an on axis encoder that is "loosely coupled" with the motor hence the need for a motor shaft encoder as well as an axis feedback encoder.

I abandoned on axis closed loop, in favour of just motor closed loop and the team said they'd look into it some more. I guess the latest dev activity is the result of further thinking.

I've been out of the loop for quite a while so it's great to see the duet team have continued with development.

All the best
Barry M

for low voltage high current dc powered bed you can also use external high power mosfet with a heatsink . usually will be cheaper then ssr .

@silveroranges said in Duet 3 Heater failed open:

the heater is a 350mmx350mm 24v heater that is 430watts

That thing draws ~18 amps - did you have to replace the 15A fuse, and if yes: with what?

I think you’ve blown the MOSFet - take a look at your board for visible damage of a chip. Can you publish a good narrow shot of the board?

@jjem said in RRF 3.5beta2/closed-loop encoder config-problems:

Is there scope for doing linear encoding (with the Renishaw LM10, for example) without also having the magnetic shaft encoder?

No. We need the magnetic encoder so that we can set the coil currents the desired angle ahead or behind the current step phase position to reasonable accuracy. In effect we are treating the stepper motor like a BLDC motor with a very high number of poles. BLDC motors that can operate over a wide range of speeds in either direction have built-in sensors for commutation.

OTOH it may in future be possible to run the stepper motor in open loop mode and use the linear encoder to monitor deviation between commanded and actual position.

Our magnetic encoder board takes up about 15mm of depth on the back of the stepper motor, including the connector.

@dc42
Between the TC input (when disconnected) and the chassis ground. I’m still scratching my head over it.

@dc42
Just a quick reply...
I replaced the mosfet with:
AOSS32334C

It was a little challenging to solder but I could replace the part and the board just works fine again.

Thanks for the support.

@gloomyandy thanks

@T3P3Tony I swapped the motor for another. unsure if it was the Wires/Connection or motor itself and it solved the problem.

@droftarts
wiring diagram
Screenshot 2023-03-05 180213.png

@mendelevium
Basically, the PS-ON pin supplies a switched negative ground. Taking a positive from the PSU 12v provides a supply of 12vdc. I use simplify 3d so I put M80 in my start script when a print is started and M81 when a print is finished after all cools down and machine returns to idle state. This can be used to trip my contactor and switches everything off. Thanks for the tip DIY-O_Sphere.

I know this is an old topic, but I'm running into exactly the same issue. Did you find a solution to this??

My bad, it turns out my coordinates for the leadscrews were way off, I honestly don't even know what I was doing!

@dc42 I was only able to get them to work together on a home by creating a second axis and hiding that axis and homing them together.