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MK3 coming!  

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PJR
 PJR
(@pjr)
Antient Member Moderator
Re: MK3 coming!


My Pi's stay up for months and I can't remember the last time they crashed a print

Ditto


The only problem I have with them is SD card corruption.

No, never had that one.

I brought the Pi into discussion as I believe that a lot of the Mk3 recovery "features" will only work when printing via SD; printing from a Pi will effectively disable many of them.

Peter

Please note: I do not have any affiliation with Prusa Research. Any advices given are offered in good faith. It is your responsibility to ensure that by following my advice you do not suffer or cause injury, damage…

Respondido : 28/09/2017 10:21 am
Shoey
(@shoey)
Estimable Member
Re: MK3 coming!


I brought the Pi into discussion as I believe that a lot of the Mk3 recovery "features" will only work when printing via SD; printing from a Pi will effectively disable many of them.

If the functionality was built into the Octoprint MK3 profile, it could handle the functionality. ie, on Octoprint bootup with MK3 profile, check to see if recovery is available.....code to return results and start recovery for example. Also lots of possibility of seeing Prusa developed plugins in the future.

BTW, did anyone miss no socket, though I saw in one of the videos that Pi Zero needs to be soldered on?

Respondido : 28/09/2017 12:49 pm
gz1
 gz1
(@gz1)
Estimable Member
Re: MK3 coming!


No, never had that one.

I brought the Pi into discussion as I believe that a lot of the Mk3 recovery "features" will only work when printing via SD; printing from a Pi will effectively disable many of them.

It's a known issue; some cards get it and some don't.

As far as recovery, here is how I envision it working:

1. Flashair SDCARD functionality should boot up MUCH faster than Wifi, on par with a normal SDCARD, else that might cause problems with a lot of devices. Won't know until I get one, but this is what I suspect.
2. Control board stores its current status in some sort of NVRAM, pointing to exact place in the gcode where it stopped.
3. A PWR_OK signal from the PSU to the control board tells if there's an impending power loss; the PSU still has enough power to save state and stop at a known place, especially if it immediately kills power to the bed/nozzle. My printer actually survived a few brownouts a few weeks ago and kept printing.
4. Upon power-up, the board reads NVRAM for status and seeks to the place in the gcode file from SDCARD where it left off and essentially resumes operation.

So given that, if they wanted all they would need to do is tell the Pi the file and position or something and it could choose to resume if they wanted.

Again, the Pi doesn't seem to be a first order customer of PR printers so... likely that functionality isn't ready yet.

Respondido : 28/09/2017 5:01 pm
303dips
(@303dips)
Eminent Member
Re: MK3 coming!



No, never had that one.

I brought the Pi into discussion as I believe that a lot of the Mk3 recovery "features" will only work when printing via SD; printing from a Pi will effectively disable many of them.

It's a known issue; some cards get it and some don't.

As far as recovery, here is how I envision it working:

1. Flashair SDCARD functionality should boot up MUCH faster than Wifi, on par with a normal SDCARD, else that might cause problems with a host of devices. Won't know until I get one, but this is what I suspect.
2. Control board stores its current status in some sort of NVRAM, pointing to exact place in the gcode where it stopped.
3. A PWR_OK signal from the PSU to the control board tells if there's an impending power loss; the PSU still has enough power to save state and stop at a known place, especially if it immediately kills power to the bed/nozzle. My printer actually survived a few brownouts a few weeks ago and kept printing.
4. Upon power-up, the board reads NVRAM for status and seeks to the place in the gcode file from SDCARD where it left off and essentially resumes operation.

So given that, if they wanted all they would need to do is tell the Pi the file and position or something and it could choose to resume if they wanted.

Again, the Pi doesn't seem to be a first order customer of PR printers so... likely that functionality isn't ready yet.

It would be sad if we loose those features if running from OctoPrint, not sure it they are making a fork of OctoPi or are thinking of a custom slimmed down version with OctoPrint or cooperation with Gina Häußge to make this possible.

Would be great if it's official Octopi as I'm happy with that setup.
Currently I really need the camera function for monitoring prints from the sofa or outside my home and timelapse and also integrating with my "smart home" ( home-assistant.io ) to start/stop led light in the cabinet, display start/stopped print on my phone/tv/lametric (not finished with this project yet, also thinking of changing led color depending on hotend cooled down/getting up to print temp etc etc.)

However, they explicitly said you need to solder a header, and to my knowledge the same header is on all raspberry pi's as of v2, so one might think you could just solder a header and use a flat cable to connect an RPI3 or modify the rambo case to accommodate for the larger RPI3 in the case if there is anything to gain to have a header connection, not sure how it's communicating, (serial? spi?) vs the USB cable as I have it set up now, may be power issues for the brown out function if it's supported as i think the RPI3 consumes about double with hdmi etc disabled.
Now both my MK2S and RPI3 are connected to an UPS so that function would not be critical to me but filament jam/run out would be gold as i had problems with this on MK2S with certain filaments (prusa transparent/white-ish filament I'm looking at you!)
And not sure how well OctoPi would handle that if it's "paused" all night or however long it takes to manually fix the filament issue if connected via USB in current state.

Respondido : 28/09/2017 5:53 pm
PJR
 PJR
(@pjr)
Antient Member Moderator
Re: MK3 coming!


2. Control board stores its current status in some sort of NVRAM, pointing to exact place in the gcode where it stopped.

Can't remember seeing any NVRam on the Einsy schematic; but it's been a while since I looked. Maybe uses the SD card or E^2?

Otherwise agree with the rest.

Peter

Please note: I do not have any affiliation with Prusa Research. Any advices given are offered in good faith. It is your responsibility to ensure that by following my advice you do not suffer or cause injury, damage…

Respondido : 28/09/2017 5:55 pm
gz1
 gz1
(@gz1)
Estimable Member
Re: MK3 coming!

It probably doesn't have NVRAM, that's just how I guess I theoretically would envision such a thing.

As far as soldering the Pi, it would be nicer if they had the option for pogo pins instead, that way you could just bolt and unbolt the Pi as needed. Soldering an entire row of pins is easy enough... desoldering it cleanly is where it gets annoying.

Respondido : 28/09/2017 6:14 pm
PJR
 PJR
(@pjr)
Antient Member Moderator
Re: MK3 coming!


It probably doesn't have NVRAM, that's just how I guess I theoretically would envision such a thing.

As far as soldering the Pi, it would be nicer if they had the option for pogo pins instead, that way you could just bolt and unbolt the Pi as needed. Soldering an entire row of pins is easy enough... desoldering it cleanly is where it gets annoying.

Not sure about the soldering bit; the Pi Zero needs the header pins soldering to the board, it should then simply plug onto the Einsy.

Same standard header for all Pi's I believe, so it should theoretically be possible to plug in a 2 or 3 - but that's dependant on space.

I would imagine the Pi would use pins 8 and 10 (serial comms) and simply by-pass the USB sub-systems. Plus 5V and 0V of course.

Peter

Please note: I do not have any affiliation with Prusa Research. Any advices given are offered in good faith. It is your responsibility to ensure that by following my advice you do not suffer or cause injury, damage…

Respondido : 28/09/2017 6:52 pm
gz1
 gz1
(@gz1)
Estimable Member
Re: MK3 coming!

Oh OK. Took a second look at the board. If that works, super.

Respondido : 28/09/2017 7:22 pm
Vertigo
(@vertigo)
Trusted Member
Re: MK3 coming!

With octopi, you can 'print from sd', or at least store your gcode on the sd, and run the print from there. I never use this, so Im not entirely sure how it works, but it is different, if nothing else, octopi cant estimate print time and wont do timelapse on Z change, because it doesnt know those things. So maybe, possibly, the resume features would still work if you print that way?

Personally, Im not too bothered. The last time I had a power outage was probably last century. The thing that interests me most about the MK3 is its speed. But then again, with a V6, thats only useful with really thin layers.

Respondido : 28/09/2017 11:55 pm
PJR
 PJR
(@pjr)
Antient Member Moderator
Re: MK3 coming!


With octopi, you can 'print from sd', or at least store your gcode on the sd, and run the print from there. I never use this, so Im not entirely sure how it works, but it is different, if nothing else, octopi cant estimate print time and wont do timelapse on Z change, because it doesnt know those things. So maybe, possibly, the resume features would still work if you print that way?

Personally, Im not too bothered. The last time I had a power outage was probably last century. The thing that interests me most about the MK3 is its speed. But then again, with a V6, thats only useful with really thin layers.

For me, the Octo "Save to SD" does not work, and in any event, it would be exceptionally slow (as discussed previously on here). Yes, it does allow printing from SD which it monitors to a very limited extent.

I think I mentioned earlier, these "recovery" features are not a lot of use to me; the "speed increase" remains to be tested and I am looking forward to some positive feedback on here.

Peter

Please note: I do not have any affiliation with Prusa Research. Any advices given are offered in good faith. It is your responsibility to ensure that by following my advice you do not suffer or cause injury, damage…

Respondido : 29/09/2017 9:34 am
PJR
 PJR
(@pjr)
Antient Member Moderator
Re: MK3 coming!


Oh OK. Took a second look at the board. If that works, super.

Ha. Just seen that you also need to solder a header to the Einsy. That's not good...

Peter

Please note: I do not have any affiliation with Prusa Research. Any advices given are offered in good faith. It is your responsibility to ensure that by following my advice you do not suffer or cause injury, damage…

Respondido : 29/09/2017 9:50 am
DevDoc
(@devdoc)
Estimable Member
Re: MK3 coming!


With octopi, you can 'print from sd', or at least store your gcode on the sd, and run the print from there. I never use this, so Im not entirely sure how it works, but it is different, if nothing else, octopi cant estimate print time and wont do timelapse on Z change, because it doesnt know those things. So maybe, possibly, the resume features would still work if you print that way?

Personally, Im not too bothered. The last time I had a power outage was probably last century. The thing that interests me most about the MK3 is its speed. But then again, with a V6, thats only useful with really thin layers.

I would agree with your assessment of the print from SD within Octoprint. This would seem to replicate the same behavior as manually doing it on the console. Just my .02

Respondido : 29/09/2017 7:37 pm
stahlfabrik
(@stahlfabrik)
Honorable Member
Re: MK3 coming!

Soldering a raspberry pi connector to the board should be a super easy task. And regarding the computing power of the pi zero: Of course one could also attach a Pi3 directly to the board or use a flex cable or single cables to route the necessary pins outside to external Pi3. Or use another pi zero like system which has more power - or wait for the next pi zero:-)

What I wonder about is heat development with the 24V power supply: Will it run cooler than a 12V PSU given that it only needs to produce have the Amps to achieve the same power? This would be benefical for enclosing the printer. And does the change from 12V to 24V mean that it is less likely to meld the connectors (again thinking that you need only have the current to achieve the same wattage on the bed)

Regards,
Stahlfabrik

Respondido : 01/10/2017 3:54 pm
JoanTabb
(@joantabb)
Veteran Member Moderator
Re: MK3 coming!

The power connections have changed from plugs and sockets to spade and screw connections. These should be less likely to over heat, both because 24volts needs lower current for the same power. And because the terminals are likely to provide a more secure. Lower resistance connection. At the expense of increased liklihood of reverse polarity connections

I try to make safe suggestions,You should understand the context and ensure you are happy that they are safe before attempting to apply my suggestions, what you do, is YOUR responsibility. Location Halifax UK

Respondido : 01/10/2017 5:26 pm
Ido
 Ido
(@ido)
Trusted Member
Re: MK3 coming!

I get a thermal runaway error when I have the nozzle set to 250 deg C, the bed temp to 80 deg C and using the fan on 60%, the problem goes away if I set the fan speed to 30%. The reason, the bed temp drops too much, triggering the error.

Will the new PSU be able to handle the extra current draw, needed to keep the bed at the desired temperature?

Respondido : 02/10/2017 7:45 am
stahlfabrik
(@stahlfabrik)
Honorable Member
Re: MK3 coming!


Will the new PSU be able to handle the extra current draw, needed to keep the bed at the desired temperature?

Actually, to reach the same amount of heating power the PSU will only need to deliver HALF the current, when doubling the voltage (from 12V to 24V). So my guess it that the bed will heat faster and be more stable.

P = U * I

Power = Voltage * Current

To get the same power when doubling voltage, you need to half the current

Respondido : 02/10/2017 10:11 am
JoanTabb
(@joantabb)
Veteran Member Moderator
Re: MK3 coming!

The lower current will addittionally lead to lower cabling losses. If the cabling stays the same.

At the moment some people are getting improved results by raising the psu to 12.5 volts
Regards Joan

I try to make safe suggestions,You should understand the context and ensure you are happy that they are safe before attempting to apply my suggestions, what you do, is YOUR responsibility. Location Halifax UK

Respondido : 02/10/2017 2:01 pm
richard.l
(@richard-l)
Miembro Moderator
Re: MK3 coming!


Soldering a raspberry pi connector to the board should be a super easy task. And regarding the computing power of the pi zero: Of course one could also attach a Pi3 directly to the board or use a flex cable or single cables to route the necessary pins outside to external Pi3. Or use another pi zero like system which has more power - or wait for the next pi zero:-)

I doubt the Einsy Rambo is capable of providing 2.4 amps to a Pi3. The Pi Zero W is going to max out around 0.5 amps so it is much easier to power.

Respondido : 02/10/2017 6:29 pm
stahlfabrik
(@stahlfabrik)
Honorable Member
Re: MK3 coming!

According to http://raspi.tv/2016/how-much-power-does-raspberry-pi3b-use-how-fast-is-it-compared-to-pi2b the pi3 uses something like 250mA when idle.
It needs up to 2.5A when you connect usb device to it and hdmi. You won’t on the printer I guess:-)

And of course you could not connect power to the einsy. But use a separate power supply for the pi. Or a buck converter from 24V to 5V.

We will have to wait and see. I just think you will not be limited to pi zero

Respondido : 02/10/2017 11:06 pm
Nigel
(@nigel)
Honorable Member
Re: MK3 coming!

The Pi Zero W and Pi Zero do require headers to be soldered to the boards. If you need them. Done this many times with Raspberry Pi's.

Nigel
Life is keeping interested and excited by knowledge and new things.

Respondido : 03/10/2017 4:26 am
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