Printing over USB  

Re: Printing over USB

It is not recommended. I don’t know why.

Re: Printing over USB

When you print over USB (which I do), you can't send the entire body of G-code to the printer all at once. It doesn't have enough memory to hold even the code for a tiny print. So you use a program like Prusa Control or Repetier or Pronterface or any of several other programs that reside on your computer and send lines of G-code using a "handshake" protocol so that the printer indicates it's ready for the next line of code. A few lines are "buffered" in the printer, but not many. I guess if you have a very configurable terminal emulator you could make it work that way, but the dedicated programs give you huge advantages in being able to "see" the state of the printer, the print's progress, and exert some control - even during the print.

Many people use a RPi running Octoprint; the RPi can handle large G-code files. I don't have this system, but I think it actually uses the USB port on the printer's board to send G-code to the printer; the RPi just releases your computer from any responsibility during the print.

By the way, the USB port on most 3D printers is configured to be used like a serial COM port.

Also, you can copy your G-code file to an SD memory card and plug that into your printer; that doesn't use the USB port.

Re: Printing over USB

also thing like update notices from microsoft will interrupt a print session as will things like screen savers and other OS interrupts they shut down the print if your computer sleeps. I ran my big delta printer this way when I first built it 4 years ago... I quickly decided that the SD card system was a better one but I keep meaning to looking into the Toshiba FlashAir SD wifi thing.

Re: Printing over USB

Windows problems? I guess it depends on some settings. I have Windows updates set to "inform me but don't install until I say so" and Windows "sleep" is not turned on. The screen is set to go to black (no screen saver) after an hour. With these settings, I have completed a 28 hour print with no computer-generated problems. I love my USB connection for the control it gives me.

RE: Printing over USB

If that is not possible: my SD card (that was in the kit) seems to be write protected (for whatever reason) so I cannot write the gcode on it.
Anything ideas how to make it work without having to go out and buy a new SD-card (have only 64Gb card....)?
And why can't you upload a file to the SD-card using a USB cable - shoud be the least (and not very hard to implement) in my opinion

RE: Printing over USB

Posted by: @pawiegersma

If that is not possible: my SD card (that was in the kit) seems to be write protected (for whatever reason) so I cannot write the gcode on it.
Anything ideas how to make it work without having to go out and buy a new SD-card (have only 64Gb card....)?

Unfortunately, cards can just go bad and there's no reliable fix. The good news is that replacement cards with much more capacity than you'll ever need are inexpensive. Just reformat it as FAT format. 

And why can't you upload a file to the SD-card using a USB cable - shoud be the least (and not very hard to implement) in my opinion

Unfortunately, the actual interface between the printer and USB is very slow at serial speeds. There is no fast method of accessing the SD card. This is why you can't quickly copy files over the air from your computer to Octoprint to the SD card. It "works" but can take hours for a large file.

RE: Printing over USB

Thanks for the explanation. It is clear now. And I'll suffer in silence 😊

RE: Printing over USB

Posted by: @pawiegersma

If that is not possible: my SD card (that was in the kit) seems to be write protected (for whatever reason) so I cannot write the gcode on it.
Anything ideas how to make it work without having to go out and buy a new SD-card (have only 64Gb card....)?

Have you checked the write-protect slide switch on the side of the SD card?  I have a couple really old cards I just tossed because the slides were completely loose.  The side labeled "Lock" will make the card read-only until switched.

But on this thread, I was just wondering the same thing for different reasons.  I hate full OS distros just to run a program...so I threw together an OctoPrint install script for Buster and have been playing with it in my spare time.  I love watching the camera on my VPN, but not a huge fan of the software as I don't have a use for remote control.  I really wish I could use it to simply upload a file to SD Card, then use the Prusa firmware to print.  I do not understand why the ability seems to be there, but the implementation requires a handoff of control to OctoPrint.

I am new to this, so I apologize if my question has been covered somewhere!

RE: Printing over USB

@nilok

I did check the lock several times, but no joy...
I will try a format of the SD card ánd buy a new one just in case. As bobstro said - they are not that expensive....

And - seeing your technical explanation - I think I am even newer than you are 😉 (printed my second print today from the list on the SD card....)

RE: Printing over USB

Posted by: @nilok

[...] I love watching the camera on my VPN, but not a huge fan of the software as I don't have a use for remote control.  I really wish I could use it to simply upload a file to SD Card, then use the Prusa firmware to print.  I do not understand why the ability seems to be there, but the implementation requires a handoff of control to OctoPrint.

You can almost do what you want with a FlashAir SD card. I'm not a fan of these cards, mind you, as mine seem to disconnect frequently and abort transfers. However, they do allow you to copy a file from your desktop to the SD card in the printer wirelessly (assuming you've got home wifi). What they can't do is "push the button" to start a print. If you're OK with walking over to the printer to physically launch the print, they work. Otherwise, you need something like Octoprint to work in place of your button presses on the front panel. Octoprint communicates directly with the printer over USB.

RE: Printing over USB

@pawiegersma

If it was me, I'd just grab a cheap card today from walmart, bestbuy, or whatever big-box store is close. I have impulse control issues.  Can never have too many spares around.  Formatting may do it also...but to test, pop it into a PC and run a scan on it.

RE: Printing over USB

Scans:

Windows - Error Check Drive

Linux - Disk Utility

MacOS - Burn and replace with Debian

RE: Printing over USB

Posted by: @nilok

[...] MacOS - Burn and replace with Debian

Do you mean the OS or the card format? You can get the SD Card Formatter for Mac.

RE: Printing over USB

@bobstro

The OS, the hardware it was running on......the office it was sitting in.  All of it 🙂

But on a real note, I'm just trying to understand what octoprint is actually doing.  I just cant seem to figure out how it fits into the actual chain of operations.  I know there are forums and tons of topics out there, but I feel like I keep missing the most basic thing about it.  I do not understand if it is simply monitoring what the printer is doing while doing its thing and printing from the SD card.....or if it takes control of issuing the gcodes and the timing and the location of the print file.....or if it is a combination.

Not trying to steal a thread tho.....

EDIT - I have it setup and running fine on a pi3b+

RE: Printing over USB

When you have a question about the horse - check the mouth:

https://octoprint.org/#full-remote-control-and-monitoring

RE: Printing over USB

I know Bob's not a fan of the Flashair cards but I have one in my mk3 and a second in my cr10s.  I really like them.  Both printers are mapped drives in Win10 (P and S) and I basically just drag the files over to them.  I dont mind starting the print off from the lcd's though as I'm a firm believer in making sure the first layer goes down without a hitch.  If you are there checking that first layer then its not any hardship to start the print off anyway.

Both of mine have never disconnected from the network and work flawlessly (if you don't use special characters in the filenames) which webdav doesnt handle. 

What is a pain is Windows 10 but thats Windows 10 for you 🙂  Unlike Windows 7 with 10 if I turn a printer off while trying to use the computer it basically locks up anything file related as it cant find the mapped drive again once its been used.  The cards though are great once you get them set up.

RE: Printing over USB

Posted by: @nilok

[...] The OS, the hardware it was running on......the office it was sitting in.  All of it 🙂

Hah. No for me on that. MacOS isn't perfect, but I grind my teeth every time I have to deal with a problem on Windows. Ran MSDOS 2.1 to Windows 7 and finally tossed it out of my house. Replaced casual machines with Linux and anything where I need commercial apps with MacOS. Not spending any more weekends doing annual re-installs and trying to debug registry stuff!

But on a real note, I'm just trying to understand what octoprint is actually doing.  I just cant seem to figure out how it fits into the actual chain of operations.  I know there are forums and tons of topics out there, but I feel like I keep missing the most basic thing about it.  I do not understand if it is simply monitoring what the printer is doing while doing its thing and printing from the SD card.....or if it takes control of issuing the gcodes and the timing and the location of the print file.....or if it is a combination.

Simplest way to think of it in parts:

• As a server that accepts inbound gcode direct via the network API (if you use that feature) or web interface and stores the file on its own storage (usually the MicroSD card in the RPi).
• As a printer controller front-end. You can have it automatically print uploaded files, or select them individually via the web interface. It will open the gcode, begin parsing lines and sending lines to the printer one at a time. 

Octoprint actually intercepts the gcode stream, so various plugins can react to gcode and insert modified commands as desired. It sits to the side of the printer and doesn't fundamentally change anything you do on the printer itself. It just provides a way of starting prints via USB instead of files on a card.

RE: Printing over USB

@bobstro

Thanks so much for the info!!  As far as windows goes, I think of 10 like my ISP.  I hate it....but I have no other choice.  If I want gaming, autodesk, and business programs all in one place with enough affordable power to run, I have to use it. Linux flavors go everywhere else, and I consult with a lot of my clients to assist in migrating from Windows based systems to Linux.....since so many only use basic MSOffice features and browser-based everything else.  OS-as-a-Service is the only thing worse than Software-as-a-Service.

As far as Octoprint goes, thanks again!!!  I've been through their forums, adapted Gina's pi guide to correctly install and configure with the latest Buster, and I even left the weird not-install of MJPG alone so it can run in the user folder without sudo permissions. I had to modify the systemd and a few other things, but I felt like an idiot for not grasping the fundamentals of the actual program.

However, it seems like it doesn't do exactly what I wanted.  I like the HAProxy and stream features,  I like being able to write to SD Card  over network, I like being able to start a print remotely.....and stop a print in an emergency.  BUT I don't like the idea of having to run all the gcode in a timing-heavy system thru an additional processor.  I would just like a way to issue simple commands, similar to the front panel.  You saved me a TON of time.

RE: Printing over USB

Posted by: @nilok

[...] BUT I don't like the idea of having to run all the gcode in a timing-heavy system thru an additional processor. 

That's a definite limitation of Octoprint, or at least the only common alternatives considering that USB is the only external interface provided on the Prusa Mk3 printer.

I would just like a way to issue simple commands, similar to the front panel.  You saved me a TON of time.

You can do that, but again only over USB. Octoprint or something like it can be used to send commands via serial USB to the printer. You're still running into host computer limitations (though a Pi3 or 4 is pretty robust) and limited by USB. I had considered writing something on Linux to just do what you've described, but realized Octoprint has already implemented a far more sophisticated approach than anything I'm likely to cobble together. The coding's not all that hard, but you still run into the limitations of USB printing.