Another file transfer issue

  • Hi,

    I'm new to Duet and it's whole infrastructure. I want to replace my existing controller with the Duet but am running into some functional issues.

    I have udated to all the latest ( I think files ), all the pertinent files from It all shows as installed. I also updated to Duetwebcontrol-sd-2.04

    First problem I run into is Web Control may or may not start properly. Some times all I get is a blank page, sometimes reloading will bring it up, in all cases, it take a very long time.

    Once it is up, if I do an update through web control, it will complete but the file transfers take a long time, though it seems to display 10 - 15 MB/S at times, it is taking longer than that.

    The real issue is when trying to upload a gcode file, with DWC 2.04 or what ever version was on the SD card contents zip file I have, both fail immediately ( I see 6% tranfered, then it stops ). A few moments after that I get a network failure message ( don't see a failure in the logs ).

    I looked at the various file transfer issues on the forum and can't find and answer. I have tried two SD cards, an 8GB and an 16GB, both were formatted FAT32 64KB block size.

    Many of the Machine pertinent settings are complete, but I don't think that should affect this bench testing.

    I attached a dump of some actions, I did a M122 before trying a file transfer and again after.

    Any thoughts?


  • I'm not very experienced in diagnosing Duet problems but that sounds like a network issue.
    What's the wifi signal strength where your printer is?
    Can you reset the Wifi router?
    Could you try a continuous ping? The response should be consistent without any timeouts.

  • I don't believe it's networking, no other issues. Signal strength is -65dBm, not the best but not horrible. Uploading updates does not seem to be an issue, albeit slow. I also tried turning off my firewall to see if it was doing something, but no change. Can't seem to send a gcode file.

  • Moderator

    I’d say it was signal strength. See

    Run M122 from either the web interface (if you can reconnect) or from USB. In the Network diagnostics, check the WiFi signal strength, also called RSSI. Values in the range -30 to -50 are good, -50 to -60 is OK, -60 to -70 is marginal. Anything below -70 is weak and likely be unreliable.

    See rest of that page for troubleshooting tips.


  • OK seems signal strength was part of it, you were both right. Still curious why only uploading a gcode file was an issue and not updates. I have a feeling the WiFi module on the board is not very good. My router is only about 30 feet from the Duet. I put a repeater in about 2 feet from the duet and the signal strength is -35dBm. Web control comes up reasonably fast but file transfers are still slow. a 10MB file starts at about 800KB/S and drops to about 400KB/S. I tried the same card plugged into a card reader on my computer and it transfers in less that a second, so I don't think it's the SD card ( Sandisk ). I don't recall the exact number, but when I do file transfers from my laptop ( wireless ) to my NAS using the same WiFi, it's pretty fast also.

    I did try another SD card ( no name ) and it's the same.

    Thanks so far, I am going to remove the existing WiFi module and replace it with one that uses a standard WiFi antenna and see if that resolves at least the WiFi connection part of it.

    Thanks for the suggestions so far.

  • Moderator

    @Joel said in Another file transfer issue:

    a 10MB file starts at about 800KB/S and drops to about 400KB/S

    That's normal speed. There are other bottlenecks beyond just the wireless link. The Duet doesn't have a lot of ram available to use as a buffer, so everything has to be paced so that it can be written to the SD card.

  • The SD card can be written to a whole lot faster than that. I recall in another thread the expectation is many MB/S. Now that the WiFi issue is sort of resolved, I'll go search again. if this is truly as good as it gets, I'll live with it.

  • OK, I just went and found the other threads. I guess this is expected speeds to the SD card.
    So far I'm liking what I see with the flexibility of this setup. Once I get the new WiFi module installed, I will work on swapping controllers.

    Thanks everyone.

  • administrators

    @Joel, you can use M122 P104 to test how fast the Duet can write to the SD card. This is useful to test whether a faster SD card will help.

    With good WiFi signal strength and a good SD card, upload speeds for files of 10 to 100Mb should be around 800kbytes/sec.

    The antenna on the WiFi module is small. Depending on how you have mounted the Duet, is may also be in the wrong orientation to get the best signal strength, or shielded by metal parts of the printer.

  • @DC42, Thanks, I suspect the antenna is an issue. I expect that part of it will be much better with the new module and external antenna.

    I ran the test and it gave me 3+MB/S which is more of what I expect. When I upload a gcode file through Web Control, also around 10MB, I start around 800KB/S but taper down.

    From what I'm reading, I guess everything is OK.

    Now I will work on the implementation for my printer.
    For my usage model, I will likely see if there is a way to transfer the file directly to the Duet via explorer and start the job at the printer.



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