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Power failure, Print pause - Resume

Posted by selva_tvi 
Power failure, Print pause - Resume
April 20, 2017 06:31AM
I am using DUET boards. In my area frequent power failures will be there.

What is the solution for power failures? For example, when there is a power failure, the print is failed in the middle (if there is no backup). Is there any way to solve this issue?

When printing, when the power fails, the electronics can read the last line before power failure and keep it in memory, so that when the power comes automatically the print resumes? Is it possible to implement with additional electronics?

These people are claiming that even after power fails completely, the print will resume. Any idea?

[cncparts.in]

I heard Raise3d N2 also using some technology and WASP Ressurection?

Thanks
Re: Power failure, Print pause - Resume
April 20, 2017 03:32PM
This facility is on the firmware wish list for the Duet WiFi and Duet Ethernet. These boards have a power monitor to detect impending power failure. There are a few things to consider:

1. Either the head must hold position reliably when the power fails, or you must be able to home the printer with a print on the bed.

2. If you use a heated bed, the print is likely to detach if the bed cools too much while the power is down.

3. You will need to use 24V power so that the head can be moved before the voltage drops too much.

4. You may need to use a capacitor bank or SLA battery to provide power for a second or two.



Large delta printer [miscsolutions.wordpress.com], Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].
Re: Power failure, Print pause - Resume
April 22, 2017 03:53AM
For point 2, yes it is difficult to use the power failure option when printing with Heat bed on. Once cooled, the print will automatically popped up.

Can be used without heatbed filaments.

How it will be implemented in the new firmware? When the power fails, automatically the position will go into memory and when the power comes how it go to the resume point (Once the power goes, homing has to be done again, isnt it?)

Thanks
Re: Power failure, Print pause - Resume
April 22, 2017 03:09PM
Quote
selva_tvi
How it will be implemented in the new firmware? When the power fails, automatically the position will go into memory and when the power comes how it go to the resume point (Once the power goes, homing has to be done again, isnt it?)

The position will be saved automatically, and when the power comes back there will be a command to resume printing. Homing again may or may not be necessary, it depends on how well the printer maintains position with power off when the motors are parked at a full-step position.



Large delta printer [miscsolutions.wordpress.com], Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].
Re: Power failure, Print pause - Resume
April 22, 2017 07:13PM
I would think you would at least do a home on X and Y. The print shouldn't interfere with that. I would hope the printer would home first, if possible, before the power goes off.

I have one of my printers on a UPS that can keep it running for 15 minutes with the heater on. Would it be possible to have a user defined time period to wait before shutting down? In cases where it is just a momentary outage.
Re: Power failure, Print pause - Resume
April 23, 2017 05:02AM
Quote
ElmoC
I would think you would at least do a home on X and Y. The print shouldn't interfere with that. I would hope the printer would home first, if possible, before the power goes off.

Unless you have a UPS or SLA battery, there probably won't be enough power to keep the machine going for the time it takes to do slow homing moves. But I plan to have it execute a power fail script when the power goes off, and that script could be similar to pause.g, i.e. quickly move the head to the pause position.

Quote
ElmoC
I have one of my printers on a UPS that can keep it running for 15 minutes with the heater on. Would it be possible to have a user defined time period to wait before shutting down? In cases where it is just a momentary outage.

If you have a UPS then the Duet won't detect the power failure anyway. You would need to feed a power failure signal from the UPS to the Duet instead, or have a separate device to monitor the mains and generate that signal such as a simple 5V USB power supply and a couple of resistors.

Edited 1 time(s). Last edit at 04/23/2017 08:31AM by dc42.



Large delta printer [miscsolutions.wordpress.com], Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].
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