7 ms·

If all Octoprint provided was the ability to print directly from Cura it would be worth it. Luckily it does much more than that. The only downside I've found i

If all Octoprint provided was the ability to print directly from Cura it would be worth it. Luckily it does much more than that. The only downside I've found is I've lost the Ender 3 Pro's resume ability if the power goes out.

blisterpeanuts 6y ago
I put my Prusa on a UPS, and was delighted to watch it just keep right on printing during a 10 minute power outage a week ago.
- walrus01 6y ago
  Out of curiosity, did you measure the prusa's load on a kill-a-watt or similar while printing, before you put it on the UPS? I wonder what the load during printing is.
  - abstract_put 6y ago
    IIRC it's around 120W printing something like PLA. Obviously higher when heating (pretty much maxes out the PSU), and higher steady state when printing other polymers.
    - justinclift 6y ago
      Is that a measured amount, or a guess based upon the heating element? Asking because if it's a guess, then the electronics + stepper motors need to be factored in too. :)
      - sgtnoodle 6y ago
        Can't you just look at the power supply ratings? For example, 20A*12V would be 240W. Assume 80% efficiency, so 300W on the 120V side. Seems reasonable for an UPS designed to power a desktop.
        walrus01 6y ago
        You can if you want an absolute maximum of what the thing can draw as a load, it'll be labeled, but very often the real world use of a thing with an AC to DC power supply is a very different wattage figure from what the power supply is theoretically capable of. Such as having an ATX midtower size 'gaming' desktop PC with an 850W power supply, that might be measured at 350W at the wall under full CPU+GPU benchmark load.
        sgtnoodle 6y ago
        Right, so if your max rated load is below your UPS's capability, it should work with plenty of margin and you can stop worrying about it. If your max rated load is higher than your UPS's capability, then you can either analyze the actual load more to see if it still works, or just buy a beefier UPS.
        abstract_put 6y ago
        There's a dramatic difference between max draw and how much energy it takes to keep everything at a given temperature. Particularly so if heating the bed to a high temperature for ABS or PC or whatever. Looking at the power supply rating you could easily be 2-3 times the average real power consumption, which is a big deal if you're trying to use battery back up.
        sgtnoodle 6y ago
        Yes I agree with you? You need to size your battery supply to meet both peak power and overall energy needs. Generally when folk express concern about running random equipment on an UPS, they are concerned about peak power rather than energy capacity. I'll also make the claim that most hobby grade 3D printers come with power supplies that are barely adequately rated for the printer's peak power, so using the supply's rating is probably in the right ballpark. Edit: ah, I interpreted the thread a bit differently. Ignoring the UPS rating aspect, yeah the average power draw will likely be a fraction of the peak. My guess would be around 100W total for most Prusa style printers printing PLA. The stepper motor draw would be highly dependent on the speed of the print and the shape of the part, since power draw will be highest when accelerating at higher speeds.
      - abstract_put 6y ago
        It was a measured amount at the outlet with a Kill a Watt style device, so including electronics, stepper motors, and PSU inefficiency. That said, I did it a year ago so I could easily be misremembering. I'm pretty confident it was < 150W printing PLA ~215°C with a 60°C bed.
        a254613e 6y ago
        Yup, that's pretty consistent with my measurements. 210/60 temperatures: https://i.imgur.com/i1L5rwo.png https://i.imgur.com/i1L5rwo.png Prusa MK3S, with enclosure.
        justinclift 6y ago
        Cool, that's good info then. :)
  - mdorazio 6y ago
    I measured this previously on a Kill-a-Watt with a Prusa clona (Monoprice Maker Select v2). Heat-up sequence draws between 120-130W (heating both bed and hotend at the same time). Once at temp for PLA, it only draws around 80-90 average depending how many steppers are moving.
jcims 6y ago
I tried it with the Ender 3 V2 and there is some kind of bandwidth issue that kept it from printing successfully. Exact same gcode worked great from sdcard, failed miserably via octoprint. I’m guessing it has to do with the available ports?
- xuki 6y ago
  I’m using the same exact setup, works fine for me. My OctoPrint is running on an old Mac mini.
- sokoloff 6y ago
  You might be having too many very small moves, which will hurt print quality as well from micro start/stops. Watch 30-ish seconds starting at 2:57 here: https://youtu.be/Hvw3DrVAeTA https://youtu.be/Hvw3DrVAeTA
- willis936 6y ago
  I have prints fail over serial on my CR-10S Pro (both stock and TM3D firmware). Maybe it’s a Creality design flaw, maybe it’s a Marlin firmware issue. Also, the micro SD card slot has never worked well. For a while I had to be very gentle when inserting micro SD cards to have them stay in after the click. Now micro SD cards never stay in. I haven’t found any references to this issue with 3D printers online, but from what I can gather it is an issue seen on faulty micro SD card slots in other equipment. My fix has been to buy a micro SD card extender (flexible PCB), duct tape it in place, and pray it doesn’t come loose. It survived a 3 day print so far.
- luminiferous 6y ago
  It might have to do with the USB buffer on the Ender. If the buffer is too small (e.g. 4 gcode commands or so) then when the buffer is filled with commands that execute very quickly, its possible for the printer to empty the buffer before new commands come down the pipeline from Octoprint. This causes the printer to stop the printhead sharply, which can cause quality issues on prints, or maybe even print failure if the sudden stop causes the print to detach from the bed. [You can fix this if you're using Marlin](https://www.reddit.com/r/ender3/comments/btjk22/octoprint_issues_increasing_usbserial_buffer_size/ https://www.reddit.com/r/ender3/comments/btjk22/octoprint_is...), since Marlin allows you to configure the buffer size. Generally more buffer is better, but do be aware that increasing the buffer size will cause the printer to be less responsive to the "stop print" command on octoprint (since the printer will continue executing the commands that have been buffered).

blisterpeanuts 6y ago

I put my Prusa on a UPS, and was delighted to watch it just keep right on printing during a 10 minute power outage a week ago.

walrus01 6y ago
Out of curiosity, did you measure the prusa's load on a kill-a-watt or similar while printing, before you put it on the UPS? I wonder what the load during printing is.
- abstract_put 6y ago
  IIRC it's around 120W printing something like PLA. Obviously higher when heating (pretty much maxes out the PSU), and higher steady state when printing other polymers.
  - justinclift 6y ago
    Is that a measured amount, or a guess based upon the heating element? Asking because if it's a guess, then the electronics + stepper motors need to be factored in too. :)
    - sgtnoodle 6y ago
      Can't you just look at the power supply ratings? For example, 20A*12V would be 240W. Assume 80% efficiency, so 300W on the 120V side. Seems reasonable for an UPS designed to power a desktop.
      - walrus01 6y ago
        You can if you want an absolute maximum of what the thing can draw as a load, it'll be labeled, but very often the real world use of a thing with an AC to DC power supply is a very different wattage figure from what the power supply is theoretically capable of. Such as having an ATX midtower size 'gaming' desktop PC with an 850W power supply, that might be measured at 350W at the wall under full CPU+GPU benchmark load.
        sgtnoodle 6y ago
        Right, so if your max rated load is below your UPS's capability, it should work with plenty of margin and you can stop worrying about it. If your max rated load is higher than your UPS's capability, then you can either analyze the actual load more to see if it still works, or just buy a beefier UPS.
      - abstract_put 6y ago
        There's a dramatic difference between max draw and how much energy it takes to keep everything at a given temperature. Particularly so if heating the bed to a high temperature for ABS or PC or whatever. Looking at the power supply rating you could easily be 2-3 times the average real power consumption, which is a big deal if you're trying to use battery back up.
        sgtnoodle 6y ago
        Yes I agree with you? You need to size your battery supply to meet both peak power and overall energy needs. Generally when folk express concern about running random equipment on an UPS, they are concerned about peak power rather than energy capacity. I'll also make the claim that most hobby grade 3D printers come with power supplies that are barely adequately rated for the printer's peak power, so using the supply's rating is probably in the right ballpark. Edit: ah, I interpreted the thread a bit differently. Ignoring the UPS rating aspect, yeah the average power draw will likely be a fraction of the peak. My guess would be around 100W total for most Prusa style printers printing PLA. The stepper motor draw would be highly dependent on the speed of the print and the shape of the part, since power draw will be highest when accelerating at higher speeds.
    - abstract_put 6y ago
      It was a measured amount at the outlet with a Kill a Watt style device, so including electronics, stepper motors, and PSU inefficiency. That said, I did it a year ago so I could easily be misremembering. I'm pretty confident it was < 150W printing PLA ~215°C with a 60°C bed.
      - a254613e 6y ago
        Yup, that's pretty consistent with my measurements. 210/60 temperatures: https://i.imgur.com/i1L5rwo.png https://i.imgur.com/i1L5rwo.png Prusa MK3S, with enclosure.
      - justinclift 6y ago
        Cool, that's good info then. :)
- mdorazio 6y ago
  I measured this previously on a Kill-a-Watt with a Prusa clona (Monoprice Maker Select v2). Heat-up sequence draws between 120-130W (heating both bed and hotend at the same time). Once at temp for PLA, it only draws around 80-90 average depending how many steppers are moving.

jcims 6y ago

I tried it with the Ender 3 V2 and there is some kind of bandwidth issue that kept it from printing successfully. Exact same gcode worked great from sdcard, failed miserably via octoprint. I’m guessing it has to do with the available ports?

xuki 6y ago
I’m using the same exact setup, works fine for me. My OctoPrint is running on an old Mac mini.
sokoloff 6y ago
You might be having too many very small moves, which will hurt print quality as well from micro start/stops. Watch 30-ish seconds starting at 2:57 here: https://youtu.be/Hvw3DrVAeTA https://youtu.be/Hvw3DrVAeTA
willis936 6y ago
I have prints fail over serial on my CR-10S Pro (both stock and TM3D firmware). Maybe it’s a Creality design flaw, maybe it’s a Marlin firmware issue. Also, the micro SD card slot has never worked well. For a while I had to be very gentle when inserting micro SD cards to have them stay in after the click. Now micro SD cards never stay in. I haven’t found any references to this issue with 3D printers online, but from what I can gather it is an issue seen on faulty micro SD card slots in other equipment. My fix has been to buy a micro SD card extender (flexible PCB), duct tape it in place, and pray it doesn’t come loose. It survived a 3 day print so far.
luminiferous 6y ago
It might have to do with the USB buffer on the Ender. If the buffer is too small (e.g. 4 gcode commands or so) then when the buffer is filled with commands that execute very quickly, its possible for the printer to empty the buffer before new commands come down the pipeline from Octoprint. This causes the printer to stop the printhead sharply, which can cause quality issues on prints, or maybe even print failure if the sudden stop causes the print to detach from the bed. [You can fix this if you're using Marlin](https://www.reddit.com/r/ender3/comments/btjk22/octoprint_issues_increasing_usbserial_buffer_size/ https://www.reddit.com/r/ender3/comments/btjk22/octoprint_is...), since Marlin allows you to configure the buffer size. Generally more buffer is better, but do be aware that increasing the buffer size will cause the printer to be less responsive to the "stop print" command on octoprint (since the printer will continue executing the commands that have been buffered).