Cannot flash MKS Robin Nano 3.1 to Klipper firmware

General Discussion
1

Basic Information:

Printer Model: Custom - upgrading an old Floger FT5
MCU / Printerboard:MKS Robin Nano V3.1
klippy.log

I don’t think klippy.log is relevant because Klipper is running fine, I need to get the MCU flashed before I can take the next step.

Describe your issue:

Please note that I know there is a similar discussion from last December, I have read that thread but it went off on so many tangents it was really difficult to gain much insight from it. I’m hoping this is much more straightforward of a problem since I am trying something that should be possible and doing everything as much by the book as I can.

I’m brand new to Klipper so please don’t assume I did anything correct. I’ve had this printer for 5+ years and it is working well and seems like a really good candidate to upgrade instead of replace because much of the structure is similar to a Voron.

So I ripped out the guts which were an old MKS Gen 1.4 and a 12v power supply, added the MKS Robin Nano 3.1, a PI 3b, 24v MeanWell and a 5v MeanWell, and a solid-state relay for a new hot bed.

I got everything wired up (basically just like a Voron). I got OctoPrint with Klipper loaded on the PI just fine.

Then I went to flash the firmware on the Robin Nano and followed the instructions in the Nano config file for Klipper to a T. I set all the settings in Klipper as described in make menuconfig, then ran make, it built klipper.bin with no errors, copied that to a USB microSD card and renamed it to Robin_nano_v3.bin. I stuck that into the SD card slot on the MCU and powered it up. I can see the LED for the SD card light up on the MCU, but it doesn’t seem to do anything. I give it several minutes, power it down, pull the sd card out and power it back up and it is still running Marlin Firmware (I have a screen that came with the MKS Robin that has an about menu that shows you the firmware running).

So I thought maybe my microSD card was not actually being read because it is a 64GB card that is not formatted as FAT32. So then I tried a 32GB thumb drive that I could plug into the USB port. This time I downloaded the bin file from MKS GitHub and used their image. Same process, put in the USB drive, power up (the display screen never seems to work with a USB drive plugged in) so I give it several minutes, power down, pull out the drive, power back up and the display tells me firmware is still Marlin. Tried the same process again with 512MB USB thumb drive formatted as FAT16, same result.

I’m running out of ideas so anything someone could suggest would be really helpful.

Thanks,
Greg.

2

Hi @ArchitekGreg

I have a Robin Nano V3 on one of my printers and I’ve never had any problems loading Klipper using a USB thumb drive. I’m a little confused with your description of the “USB microSD” card and then using USB thumb drives.

Are these the instructions that you are following (you said you’re following the instructions in the nano config file):

When I update the Klipper firmware, I use a 16GB Thumb Drive formatted with FAT32 and the only thing on them is the “Robin_nano_v3.bin”. Normally I do a full format before loading the file.

Can you describe how you set up the SD Card and USB Thumb Drives with the Klipper firmware? Is there anything else on the cards and did you do a format before saving the “Robin_nano_v3.bin” file on them? Did you get any messages when you tried storing the “Robin_nano_v3.bin” on the devices?

I’m guessing that the SD Card/USB Thumb Drivers are not getting set up correctly but the other thing could be that the board isn’t getting completely powered down - do you have anything plugged into the other USB port on the board?

3

20230228_204459_resized
20230228_204459_resized1920×1080 315 KB

So I attached a pic of my Robin Nano (hope that is visible). At the top you can see the USB cable from the PI plugged into the regular USB port. Just to the left of that is the micro SD slot. My first try was with the micro SD card and when I tried that, I just left the PI plugged in. When I used the thumb drives I obviously had to unplug the PI to plug in the thumb drives.

Those are the instructions I was following to build the bin file. The file I built was 2KB smaller than the MKS file. Since neither one is working, I don’t think that’s a factor.

I did not actually reformat the thumb drives. I did delete everything off of them so the bin file is the only file on the drive. Copying the file onto the drive was straightforward, no errors. I will try reformatting the drive to be sure it is clean.

Is there anything you should see when it is successfully flashing? A particular light pattern or anything?

Really appreciate the help.
Greg.

4

No specialized lights.

The one thing that jumps out at me is the WiFi module plugged into the board. I don’t have one and I wonder what would happen if you pulled that and then tried to reflash the board?

5

Ok, really appreciate your help. I got it figured out.
I did reformat the drive as you suggested. I have both a Mac and a PC and when I looked at it on the PC I could see some hidden files there that were not showing on the Mac.

But that actually wasn’t the problem(or at least not the whole problem). When I went to flash it again, it really started to bug me that the display would not come on if I unplugged the USB cable from the PI. So then I noticed that when the USB cable was plugged in, the red light on the Robin Nano was solid on and when it was unplugged, the red light would flash. On a whim I put my volt meter on the MeanWell and the output was about a whopping 2v!! So I disconnected the MCU, powered up the MeanWell and played with the potentiometer until I got the voltage up to 20.78v. That was as high as I could get it to go but when I hooked it all back up, the red light on the Robin Nano would stay lit even without the USB. Then I powered it all down, put in the thumb drive and when it powered back up the display showed that it was updating and gave me a progress bar (it actually updates in just a few seconds FYI).

I was able to ssh to the PI, list the USB port and update the printer.cfg file. Running status in the terminal window of klipper now reports back ready so I think I’m over this hurdle and will proceed with the configuration checks.

As long as I have your attention though, I have a couple of quick questions:
This printer has 2 Z steppers and 2 Y steppers. Currently they are plugged into the MCU as just one stepper and have a Y connector to split the wiring and go to two motors. I noticed that the Robin Nano has 2 connections for Z motors even though it only has one stepper driver. There is also a second stepper driver for an extruder that I’m not using. So potentially I cloud wire each motor to its own driver. Is that worth the effort or should I just leave the wiring as it is?

Second question: do you think the 20.78v that the MeanWell is putting out will be sufficient or should I just replace it?

Thanks,
Greg.

1 Like
6

Great news - I’m glad you got the Robin programmed. It sounds right that it just takes a few seconds.

The Floger FT-5 looks like a Cartesian printer (I can’t find a good picture or description of it) with 2x Y Axis steppers and 2x Z Axis steppers. Personally, I would connect the two Y Axis steppers to the paired “Z” connectors on the Robin and drive each of the Z Axis steppers with it’s own driver - the Z Axis steppers will have more weight on them, so give each of them their own driver for more power and you can add Z-Tilt (if it’s applicable for the printer).

That was good analysis of the power supply problem and I’m glad you figured it out. I’m guessing it’s a 24V supply (an LRS-200-24 or LRS-350-24)? If you have to crank it up like that with no load then something’s seriously wrong with it and I’d recommend buying a replacement (from the way you’re talking, it sounds like it’s out of warranty).

I hope you do some interesting things with your printer and I look forward to hearing how you make out.