Hi Snapmakers,
whenever I hit the power switch to switch off the A350, I feel like doing something wrong, knowing that the touchscreen runs Android. Wouldn’t Android require a proper power down like e.g. a Smartphone does? Don’t I trigger a fsck each time?
I suppose I’m completely wrong - anyone with more insights?
Thanks!
Hauke
It probably does but this android device only runs one app so it’s not as bad as on a smartphone. I would have loved to see a psu control like on a pc. A physical switch in the back but also takes a dry contact closure for power on/off
Most probably the internal file system is mounted read-write but since the only App that’s running looks like it doesn’t require write access during normal use, but only when you save configuration values, the sudden shutdown while the machine is idling could not be an issue.
I agree that a soft on/off switch would have been technically better, but in my opinion we should also consider that forcing the user to completely cut the power to a machine that can reach hundreds degree Celsius, and that would be left there unattended, is way safer for everybody.
That’s different from leaving the machine on for a 20 hours print, because that way you are aware the machine is working and theoretically you should check it every now and then.
@Enne but a computer with a soft on/off controls every other aspect of our safety, from the power delivered to your house, to the monitoring of nuclear reactors, and even life sustaining medical equipment. Temperature has nothing to do with it. I design industrial heaters such as the ones used in large stores (HVAC equipment) and even ovens that cure military vehicles (process equipment) and all our digital controls have a soft on/off button and they literally control giant burners with over 3 million BTU output. It should always have a hard kill switch (just like any pc power supply does) but I see no safety issues with having a soft on/off button as long as it is done properly.
Hello Atom, that’s exactly as you said, but on our machine that would have probably required extra safety mechanisms that were actually not implemented, such as snap acting thermal protections, non-standard connectors, a stronger cable for the heating bed or a non-restartable power supply. For example the Meanwell power supply inside our Snapmaker power unit automatically restart itself in case of high current spikes and it doesn’t just power off like an ATX power supply.
So, of course it would have ben technically possible like on today appliances, but not really sure if we are talking to implement it on our “development” machine as is since it is non-standard and it’s dealing with high temperatures.
Enne,
I see what your saying, while i believe we could, modifying what we have is probably not worth the effort. I do intend on placing a smart switch between the power supply and the wall so that i can turn the printer on and off remotely (in case a project fails while i am away). but a soft On/Off would be a good improvement for the SM3.
happy making,
Atom.
Atom, I think that’s a really great idea, very useful also when a long printing end and you are away and you want to avoid the linear actuators to stay uselessly engaged for hours until you come back. 
DIY thinking, by voiding warranty and taking the necessary responsibility, since the SM2 power unit has a CAN line, it would be great to make some relay module to implement a “kill on demand” command inside the firmware, for example by programming it to cut the power to the machine after a few minutes the printing is complete.
Enne,
that is a great idea, if the power supply has an active CAN bus. however i suspect that while it uses the same cable it is not actively communicating via CAN. similar to how the linear rails only use CAN bus for the end switch. i think the best way would be to have a separate controller (pi anyone?) to control the power, then hook that up with CAN from the SM controller. so that it can turn off the unit after completion of a print. but can still be turned on remotely. just in case you leave for work and realize you forgot to start that 9 hour print. I have a friend who has done this using octoprint for his CR-10. he really enjoys the system.
@Enne @Atom For what it’s worth on this old topic, much to my frustration the M112 Kill gcode, as Marlin originally intended, is present in the firmware and is supposed to do exactly as you both describe.
It is supposed to stop all motion, turn off all heaters, and additionally shut down any power supplies.
None of that functionality works because the firmware was compiled without the necessary flags / possibly because there’s a hardware limitation in the mcu.
This is something that I brought up over here:
What I’ve done in the past is make an AC relay that everything plugs into, that self kills. I designed it to manually turn on with the push of a momentary button, it will then stay on until the firmware sends a kill command and turns it off. Anything is possible when you have the necessary firmware, programming means, and cabling, and maybe someday those will be available. I have the firmware, and a means of programming, but it would be nice to have some official cable connectors to plug in.
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