Resuming print

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mark_3d
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Resuming print

Postby mark_3d » Wed Mar 14, 2018 12:10 pm

It could be a nice feature that when there is a black out while printing the printer save a file in the internale memory so that you could resume the printing from the poin it has stopped.

Jetguy
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Re: Resuming print

Postby Jetguy » Wed Mar 14, 2018 1:12 pm

You just asked for a feature which is already built in.
viewtopic.php?f=2&t=3341&p=18746#p18746

mark_3d
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Re: Resuming print

Postby mark_3d » Wed Mar 14, 2018 1:49 pm

Jetguy wrote:You just asked for a feature which is already built in.
viewtopic.php?f=2&t=3341&p=18746#p18746


Great... But how to resume the print? I had a black out at night and in the morning the printer was off. I turned on and nothing happens. Should I do something?

Jetguy
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Re: Resuming print

Postby Jetguy » Wed Mar 14, 2018 2:30 pm

Define blackout? There are holes missing in this sequence.
Power was lost while the printer was printing last night. It's assumed you used Ideamaker and a standard profile to generate the print file. It's assumed the printer had been on long enough previously and had a full charge in the battery.

But here is where the the story falls apart:
"in the morning the printer was off". Wrong, If the printer suffered a power loss and power was restored the printer would then be in the ON state. The resume feature only happens when the printer boots AFTER the power loss save sequence. If you turn on the printer, tell it not to resume or restart the print, that save point is lost. If someone was by the machine when the power loss happened, and then turned the machine physically off - they may have cancelled this resume. That means when you got to the printer, you turned it on (a second time since the power loss) and no print resume is possible.

Jetguy
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Re: Resuming print

Postby Jetguy » Wed Mar 14, 2018 2:51 pm

#1 if you experience a power loss, consider the print lost. The first rule is a stable steady power source- and that may require a properly sized UPS. On the off chance the resume print works, be happy, throw a party, you just won the lottery. If you depend on this feature as part of your "business plan" for the printer, you are just asking for failure.

#2 The resume function is limited to a very narrow scope of sequence in which it works or is even viable. The battery in the LCD touch system needs to be fully charged and does discharge when the printer is off. If you turn off the printer for a week, and then just turn it on the day you need to use it, and you experience a power loss- you may find the battery had drained in the off time and resume point may not get saved if the system crashes during the power loss. The gcode print file must have the important Raise3D end of starting gcode and start of ending gcode commands added if you use a 3rd party slicing application. If the print file does not have them the save sequence does not work. The resume point is only going to come up once. If a user bypasses that screen- that is the decision point and the save is lost. Educate ALL people who may touch the machine NOT to bypass or cancel that screen. Leave the printer on and just sitting at that screen or resume the print and a second power loss would then create a new save point.

#3 Did I mention again, that print resume is a miracle if it works? Has nothing to do with the resume function, it's the entire concept of having a printer stop, cool off and be unpowered for some time, and then resume the same position it left off on- meanwhile the part did not warp or break free or a dozen other issues with power loss failure and print recovery. At a minimum, there is a chance the print will have a visible line at the point of the stop and resume. At worst case, the print will outright fail do to head strike against a warped or broken free part. In addition the extruder could jam (fans stop on power loss and filament can melt where it shouldn't). There are 1 million ways it could go wrong and only very few ways it can go right.

mark_3d
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Re: Resuming print

Postby mark_3d » Wed Mar 14, 2018 3:02 pm

I had a black out at two in the night (for example) and at the morning at 7 i saw there were no electricity. I'm thinking to buy a UPS but how does a UPS works? Will the ups give electricity to the printer only to stay turned on and then resume the print or will the printer continue to print until the up battery are empty?

Jetguy
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Re: Resuming print

Postby Jetguy » Wed Mar 14, 2018 4:24 pm

You ask a valid question as there is room for improvement. I'm not denying that, just telling you it's complicated.

A UPS battery backup simply internally switches over to it's batteries and continues to supply the printer with power but from battery. Here lies the issue. Most folks are not going to buy or afford a UPS with enough battery to run the print for hours on end. Batteries and the UPS in general are not highly efficient. Figure between 6-15 minutes of realistic time. The main idea is the nature of the power outage. If it's just a surge or couple second long power loss- the UPS is great at preventing the printer from ever seeing this. If it's a multi hour long outage- again, batteries are just not the way to power a heating device. Worse, you have power loss conversions. The DC battery power in the UPS is switched into AC, feeds a transformer to raise it to 120V or 220V (depending on the country) and the the printer PSU down converts this AC line voltage back to DC 24V required by the printer. At best, the PSU is roughly 90% efficient. The UPS is highly likely to be even less efficient and the resulting combines end to end system efficiency from battery is just a joke. That's why you get maybe 15 minutes. Another good thing about most UPS is that when it does die from the batteries, it performs a nice relatively safe power cut to the printer. This is safer for the electronics and more likely to give you a safe shutdown that invokes the save printing file function.

So here is the problem. You want good stable power to the printer. The UPS can do that for short power loss. Any longer than that, UPS becomes impractical. It's still needed for short surge protection, just does not answer long term power outage. A potential modification is that given recent firmware updates to the LCD Raise touchscreen application, and combined with open source community updates to the Marlin motion control firmware, a person could better integrate a status state from an externally connected UPS to the printer such that the printer now has some idea of the power state of both the line AC and the state of the UPS and battery in the power loss state. Basically, I'm saying the same triggered pause function of the filament detection can also give us a way to cause a pause function from external sources. Since that subsystem exists, then the idea is most UPS units can give out signals when they experience a power loss. This could trigger a pause when the outage was over a certain time period or when the UPS battery hits an lower limit and before ultimate shutdown, tells the printer to pause while there still is time left on battery. Then when the battery finally dies, the print looses power and it's own internal file save sequence is invoked. 2 ways of getting to this goal. many UPS units now have USB cables and send this power loss and battery state conditions over USB. The problem this is, we then need those drivers and that software logic in the linux image running the pcDuino that runs the Raise 3D touch user interface. Then comes what brand works and is supported, is it a certain model only and all kinds of issues. OR, the alternate way is hardware. We have open source firmware and spare inputs on the motion control board. We can build simply logic interfaces from the typical UPS to trigger a function and integrate certain brands or models that we can access such signals in.

The bottom line is that in almost every single case, adding a UPS between the wall and any printer is simply a good idea. At a minimum it conditions the power to the printer and adds a layer of security. It prevents multiple power losses from power cycling the printer multiple times in most cases. It gives a cleaner shutdown in the case of sudden power loss or surge events. You spend $2k or more on a Raise 3D printer, it deserves the best power you can feed it.

Jetguy
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Re: Resuming print

Postby Jetguy » Wed Mar 14, 2018 4:32 pm

mark_3d wrote: Will the ups give electricity to the printer only to stay turned on and then resume the print or will the printer continue to print until the up battery are empty?


The printer will continue to print until the UPS battery dies and the UPS stops making AC power.
Then, if all the conditions were met for the internal Raise 3D power loss print recovery, it should save the printing file.

mark_3d
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Re: Resuming print

Postby mark_3d » Wed Mar 14, 2018 4:53 pm

And what about connecting the Ups to the LCD battery? So that it can stay turned on for hours? Or maybe connecting a big battery to the LCD screen?

Jetguy
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Re: Resuming print

Postby Jetguy » Wed Mar 14, 2018 5:40 pm

mark_3d wrote:And what about connecting the Ups to the LCD battery? So that it can stay turned of fo hours? Or maybe connection a big battery to the ldc screen?


You are basically talking about just starting over and a new printer electronics design. Clearly, the details of this printer and architecture haven't fully sunk in. The Marlin motion board controls the actual hardware of the printer. The front panel computer is nothing more than a gcode sending system or gcode print server with a nice user interface for some manual commands.

what about connecting the Ups to the LCD battery?

Not sure what you think you solve here. The issue is, this is sending gcode to the mainboard. You need it to know when power is lost and have it save the last gcode position. It already has a battery. Again, nothing about connecting this makes any sense. It solves nothing. So what if this board stays powered? It's NOT actually controlling the motors or position of the printer. It simply sends commands and receives status.

What matters is that the motion control board that actually runs the printer can either pause, and then it needs power forever running the steppers to HOLD that position OR, in the case of normal power loss recovery, the board loses power, so it never sends the completion of the last command executed, so then that's how the front panel computer knows the last line of the print file completed when it does the save.
This board is NOT battery backed. Since it powers the heaters and fans and LEDs it's not suitable for battery backup.


Again, there are only a limited number of scenarios in 3D printing.
Current system, power loss, the motion stops, the front panel computer is battery backed and saves the last position completed. Print recovery, when the system reboots and a print loss file was saved, it gives the user the option to resume the print (start where it left off), restart the print (remove the current failed object from the build plate and start print completely over, or cancel and this bypasses print recovery.

UPS battery backed system: The power loss does not immediately impact the printer. If the power comes back in time, the printer is complete unaware anything happened. If the power loss is longer than the battery in the UPS can handle the UPS shuts down, this causes the printer to go into the above normal power loss recovery option.

Modified printer and UPS battery backed system: Power loss happens for short time- printer is none the wiser. Power loss exceeds a set threshold defined by custom electronics or settings, the printer is triggered into a pause mode by added electronics and custom firmware. The reduced power load of pause mode allows the battery backed UPS to run longer before it has to shut down. This is all in hope power comes back. If the power still does not come back in time, the UPS turns off, the printer goes into normal power loss save point mode, but this time from a paused location. Print resume is either going to happen from the paused mode (short term power loss), or from the normal recovery mode at startup after an extended power loss.

mark_3d
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Re: Resuming print

Postby mark_3d » Fri Mar 16, 2018 6:54 pm

I made a test. While printing i pull out the printer plug, and the printer turn off completely also the screen. I think that the screen should stay on.

Jetguy
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Re: Resuming print

Postby Jetguy » Fri Mar 16, 2018 8:00 pm

I think we are talking cross things here.
#1 you asked for a feature in the feature and improvements topic- except that feature already exists
#2 you may have a technical problem with your printer and that feature is not working on your printer because your battery is either not plugged in or not charging. As such, the correct action is open a help ticket. http://help.raise3d.com/support/tickets/new

mark_3d
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Re: Resuming print

Postby mark_3d » Sat Mar 17, 2018 3:42 pm

I opended a ticket support.
Returning to my request. I would be great to evolve the resume print support. Something like saving a file with the remaining part to print.

zemlin
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Re: Resuming print

Postby zemlin » Sat Mar 17, 2018 5:13 pm

I haven't messed with the resume feature. My printers run off of UPS power to insulate them from the small glitches. I question how often a resume on a print would actually work?

I have had prints fail due to apparent power glitches in the past, and normally the nozzle oozes a significant amount before cooling and also melts/distorts the material surrounding the nozzle. The magnitude of these issues will vary with the material being used, of course, but those issues combined with cooling of the build surface, the part, and the interior and the structure of the machine, surely there must be a significant band on the part where a restart occurs. If the nozzle blobs on the part a restart would likely be impossible without removing the blob - and blob removal would risk shifting the build plate i would think.

Am I being overly skeptical? Is it really a valuable feature?

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Vicky@Raise3D
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Re: Resuming print

Postby Vicky@Raise3D » Mon Mar 19, 2018 6:03 am

mark_3d wrote:I opended a ticket support.
Returning to my request. I would be great to evolve the resume print support. Something like saving a file with the remaining part to print.


Isn't it the same as the dump file which is saved after switching power supply from PSU to battery? the print status and current code line will be saved inside dump file. And next time you power on the machine, the print status record inside damp file will be took out to recover and continue the interrupted task.

frjez
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Re: Resuming print

Postby frjez » Sat May 19, 2018 7:53 pm

There is one major flaw that makes Raise3D solution unusable. At least in my experience. When a power goes off, the printer stops in a certain position. If you are lucky the extruder was moving to a new position, so was in mid-air. In this situation, you can retain yourself a very lucky person. In my case, more than just a few times (sometimes deliberately while I was trying this feature :-) ), the extruder stops on the part. While the hot end was still hot and the pressure in the hot end was still considerable, the molten filament got out and created a huge blob! Of course, this blob hardens while the Temp went down. Basically, I ended up with a blocked extruder on that spot.
Now, during the "resurrection" this blob also got hot as it was deposited around the nozzle, but not hot enough and I regularly have a broken or floating part.

And, there is no solution for this!! As it is the resume after a power outage is useless. Though would be feasible and even OK, if like in the new Prusa 3 where there is still enough power in the capacitors of the power supply, the carriage moves toward the X-Y zero location. Prusa demonstrates this feature and it proved to be reliable.
This is the only way. Even if the extruder does not reach the "0,0" the controller board "has in mind" (dump file or similar -google for more precise info) that has to go to "0,0" and resume from there.
I would really love to see that in my N2+... well actually I installed a huge UPS so no need, but still...


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