Power Outage - Can I resume the print?  

RE: Power Outage - Can I resume the print?

Posted by: @malabor

Hey folks!

I had a bad storm go through over the weekend (Florida!)  and we lost power for several hours.   My print was ALMOST finished (less than 25% to go) when the power went out.    Once the power came back on, the printer reset and there's no option to RESUME.   Am I out of luck, or is there a setting / option that I'm missing?

thanks in advance for any help!

-C

The Prusa Mini does not have a power panic function. The problem is also that in the event of a longer power failure, the print bed may cool down and the printed part/s may come loose.

https://forum.prusa3d.com/forum/general-discussion-announcements-and-releases/prusa-mini-and-power-outage/

Given that the print part still sticks to the print bed, you could possibly try to edit the gcode manually so that the print resumes where it left off.

wbr,

Karl

RE: Power Outage - Can I resume the print?

And invest into an uninterrupted power supply (UPS). 

RE: Power Outage - Can I resume the print?

Another option to complete the print, depending on it's geomitry, can be to measure the height of the failed print, load the stl in slicer and cut it to that height and just print the top remaining part and glue them together.

But yes, as fuchsr wrote, if power is unreliable or not "clean" a ups should be used.

RE: Power Outage - Can I resume the print?

A good UPS is quite expensive. Furthermore, with a theoretical power consumption of 160 watts, the thing should have sufficient reserves to be able to compensate power outage for a longer time.

I would possibly think about the idea of @mrstoned.

wbr,

Karl

RE: Power Outage - Can I resume the print?

Good call with the UPS.  I may see if I can pick one up.   It's coming up on storm season here and power outages are pretty common where we live.  Thanks everyone for your help!

-C

RE: Power Outage - Can I resume the print?

Maybe some thoughts before you click "buy"... because UPS specifications (Watts or VA) can be quite deceiving.

Most consumer UPS's use single 12V battery, which can be either 7Ah or 9Ah. Let's take 9Ah as an example:
12V x 9Ah = 108W/h
That means, if printer consumes 108W, then UPS should be able to supply power for period of 1 hour -but that's the theory! In reality, UPS conversion from 12V-DC to 115V or 230V-AC introduces very big losses (next factor, which also shortens supply time, is quality of battery itself). In short, you can expect printer to run for about 30min's on UPS (also depends on filament you use).

You can decide for UPS which has two 12V batteries inside (12V+12V 9Ah =24V 9Ah = 216W/h) and so double your printing time -compared to single battery UPS.
Battery inside UPS will last for about 4-5 years and then needs to be replaced.

RE: Power Outage - Can I resume the print?

@bogdanh

this is a great point.  Most of the time, the printer is going to need more than 30 minutes or so to run and our power outages can range anywhere from seconds to hours.    What I'll probably do is just keep things the way they are and plan around the big storms.  If I know it's going to get nasty out, I'll hold off on printing anything until it clears up.  

I'm hoping that this storm season isn't as bad as they say it's going to be and I won't have to worry about it. 😀

Thanks again for all of your help and suggestions!

-C

RE: Power Outage - Can I resume the print?

Had a power failure at the middle of a 20+ hours print and just found that the MINI+ that I just recently purchased doesn't have a resume option on power loss... What a shame. Is this something that could be added in firmware update?

RE: Power Outage - Can I resume the print?

That would be best asked on the Prusa Mini Git Hub Page. 

in the mean time, 

you could measure the height of the part you have printed, edit the model to remove that height, print the remainder and glue the parts together, this is s particularly useful if you are painting the final object  

regards Joan

RE: Power Outage - Can I resume the print?

Have you considered using a UPS?  I have one, because it is more reliable than power panic... 

regards Joan

RE:

In my 2 recent failure cases, UPS won't make a difference, as I had BSOD crashes. But anyway, I had quite a few UPS units in my life and they all needed maintenence and battery replacement evey 2 years or so, which costs like a new UPS. On power panic the printer would keep printing from where it stopped, without spending a penny on a 3rd party solution. That is if the power loss wasn't too long.

RE:

 I don't recall you mentioning BSOD in the initial post. otherwise I would not have mentioned UPS. 
I believe Prusa does power panic in a different manner to other vendors.
I believe Prusa monitor the Mains, before the power supply, and if there is an interruption to the power, the prusa controller stores the program pointer information at that time, then moves the extruder off the print before the printer loses power.
I understand that other manufacturers repeatedly store the next position, before moving, in case there is a power loss situation this works the storage hard, and possibly delays data transfer.
in my understanding Power panic would not recover from a BSOD episode. 
BSOD occurs because the controller ceases controlling the printer, 
If the controller is not controlling the print progress, it will not be able to store the program controller information. 

the Mini has a Computer style 'Power Brick' which does not give the printer the opportunity to sense for power loss, 

You would need to ask the developers why they don't store the current program pointer at every step of the print

IF a power loss exists for longer than a ups can maintain printing the chances are that the heatbed will cool and release the print in which case restart will not be an option. 

there are pro's and con's for all options

regards Joan

RE: Power Outage - Can I resume the print?

Correct, I kind of mixed up between power failures and BSOD. I also read in another thread about this flaw in the 'computer style power brick' of the MINI that isn't enough to keep the printer alive for saving its position, and about the cool-down of the heated bed on long power outage scenraios. As for BSOD - coming to think of it, a crash such as this is really unexpeced fail which doesn't give a chance to save settings, like the power panic feature on supported power supplies can. But nevertheless, I think that Prusa MINI users would appreciate if there was an option to upgrade the MINI power supply to one that could keep the unit alive on power failures. That way the MINI for those who doesn't have much space will share this very same feature that its bigger sister printers have.

RE: Power Outage - Can I resume the print?

This thread brings up a very important issue for Mini owners, and while all the responses are great points and ideas, the real issue is simple: why did Prusa go to the trouble to *remove* a feature that's in the firmware base for all the other printers? This isn't a feature request, it's a "please undelete the feature that was already there" request. 🙂 I own ~10 UPS boxes, they are awesome. I just had a failure myself where I was shocked to discover this "feature deletion" on my Mini (I also have a MK3 and MK4). As it happened, I the printer was in a temporary location and didn't have the UPS--it would not have helped, we just had an 18 hour power outage. It was 90% through a lovely 2 hour print using expensive TPE filament. It would never slip off the bed! I can't glue it together, and the idea to hack the code is great but I'm unlikely to get it right after wasting an hour on it. 

All fun ideas aside, there is no reason for this feature to be deleted and missing in the Prusa Mini firmware, owners should be able to make their own decisions about hitting "resume" or not, based on the situation, filament, etc.