I am trying to setup a runout sensor with ramps on a Prusa i3. It is a bit surprising that runout is only handled when printing from sd card. The argument that the host dies if ramps stops accepting commands doesn’t make any sense to me. I would rather the print fail fast than continue printing for hours without extruding. Thoughts?
@Mark_Rehorst , oops yea, filament runout. There was a thread somewhere that suggested host software might get upset if the printer stops responding. I have not tested that, but it seems plausible.
Why would the printer stop responding is a better question
@Justin_Nesselrotte , the printer has a limited buffer and will stop receiving commands if paused. I don’t think there is and two way communication regarding runout pausing afaik.
@Mark_Rehorst , I don’t want the filament to run out (or snap) causing the hotend to cook the filament and jam up. These are things I worry about and it makes me anxious.
A sensible reaction from the printer when it detects a filament runout would be to signal to the host to pause printing, eg with // action:pause (or maybe a custom action command) which was thought up for exactly this type of situations and is supported in OctoPrint from 1.2.0 on, including support for custom actions through plugins, and afaik also printrun. Just to stop responding is the least sensible approach and yes, that will lead to the host assuming that the printer is on fire or otherwise dead and abort all communication attempts, reporting an error to the user.
@Mark_Rehorst optical sensor.
@foosel , good info. Maybe I will put together a patch for marlin to make it do that on runout. For all I know, it already does and the runout just needs to be tweaked.