Duet Wifi Print status Error



  • It seems that for some reason my DUET is estimating the wrong print time.
    On my CoreXY and being almost 1minute to finish the print, progress shown on both Webcontrol and Screen is about 58% done and not 99%.
    Plus print started with estimation really close to slic3rPE but finished it almost 2,5 hours later.
    Could someone tell me what am i doint wrong?
    0_1563815227382_6bf9ee23-8deb-4bf1-9e64-b8fe340498f2-image.png



  • I would say you're looking at it from the wrong point of view.

    Your slic3rPE estimate is wrong because it doesn't have enough information or correct information about things like acceleration, jerk, retraction etc.



  • Slicer, any slicer, estimates are almost always radically wrong. For the exact reasons bearer stated. The slicer really doesn't know enough to calculate it correctly.

    IF you set the slicer acceleration, jerk, and many other things to match the printer, they'd get a lot closer. I've never found it worthwhile.

    Regarding the estimates that Duet produces, they are simple math from scanning the file and finding:

    1. How many bytes are in the file. When printing, it is "duration so far" * "bytes remaining" / "bytes total". This is probably the least accurate of the three, because the actual duration to execute a command that takes, say 10 bytes, can be very short or very long. Also, many prints have top skins that are different from the walls or supports or etc, so past time/byte is not a good indicator of the last big handful of time/byte.

    2. Same thing for filament. Duration * filament used / filament total. This can be fairly accurate, the big kicker being there is no industry standard for looking at a G-Code file and finding "filament total". Duet scans the file and attempts to find the E extruder commands and sum them... and/or looks for a comment that some slicers leave at the end of file with the total. So... this can be fairly accurate, or it can be WAY off because the number used for total can be way off.

    3. Layer time. Scan the file for every Z change. Count these. And/or look for max Z and divide by the layer height (which you have to get by scanning for Z changes). Again Duration * Layers so far / Layers total. Again, can be close, or WAY off, depending on the accuracy of the total. And, as mentioned above, the top few layers may be quite different than what came before.

    So... Duet does its best with very limited information. You need to learn from experience which of the four (slicer, Duet File, Duet Filament, Duet Layer) is most accurate for you. Personally, I regard the slicer as "order of magnitude", and regard all three Duet estimates as meaningless until at least 1/3 of the way through the print. As the print progresses, I find that filament becomes the most accurate.

    YMMV.



  • SliderPE and PrusaSlicer, when set to Marlin gcode flavour, will let you set the accel and speed and jerk values for the printer, which it then uses for time estimates using the actual Marlin motion planner code, so the estimates can be very accurate indeed.

    This entire tab only shows up when using Marlin gcode flavour, so if you've had it set to reprap, it won't be displayed.

    However, even the basic estimation isn't too far off in my experience. Certainly not several hours. Can you post a .3mf file from slicer with the model and print settings that you're seeing this with?

    If you run a print simulation for that gcode, how far is it from the prusa estimate and the actual print time?

    Also can you include your config.g so we can see what your settings are?



  • Thank you guys for all your valid replies, but at the moment my issue is not the Slic3R estimate compared with the actual print time, but the estimate of the duet and the fact that while the progress bar shows 58% the file had actualy less than a minute to finish, on the last second of the print, it showed progress as 59.2% (if i recall correct). This is my first "problem"
    As about the slic3R i had taken all machine "info" out for now and will try to tune it in a way to have a proper estimate.
    On all my other printers, original prusa or not, print time from slic3r has been tuned to a close 3 minutes almost, but simply this seemed strange to me.
    I most likely stated my info wrong, but if you check the picture in detail you will see the "issue"



  • @tonygr The web interface displays 3 time estimates. One based on filament usage, another based on file usage and yet another based on layer time. Are all 3 estimates "wrong" or just one of them?

    The best way to get an accurate estimate of how long a print will take is to run it in simulation mode first (right click on the file).


 

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