Keep Mini on and connected, but no heat?  

RE:

As an example, could I just put use the below gcode for after a print job completes? This is the same as what Octoprint has as the default gcode script to execute after a print job is cancelled. Would this shutdown everything but the connection to Octoprint, and keep the printer in a safe state when not printing?

; disable motors

M84

;disable all heaters

{% snippet 'disable_hotends' %}

{% snippet 'disable_bed' %}

;disable fan

M106 S0

RE: Keep Mini on and connected, but no heat?

Out of curiosity, what's wrong in your mind with just shutting it off? That's what I do, shut my Minis off while leaving the Pis running. 

RE: Keep Mini on and connected, but no heat?

what's wrong in your mind with just shutting it off?

Disconnection stops updating the temperature readings so that my smart home no longer knows the temperatures. It also bothers me that Octoprint indicates the printer's state as "offline after error". There's no error! It's a small quibble, though, so mostly just interested in doing this if it's a practice that is common, acceptable, and safe.

RE: Keep Mini on and connected, but no heat?

Note - I dont have a mini but.....

When you slice a file for the mini with the default profiles then those do turn off the extruder and bed heating as well as the part fan.  So it already does what you want.  No need to add anything to octoprint, the commands are in the sliced file you are sending to the printer.
There is no need to power the printer off after a print.  On the MK3 in fact doing so is not recommended, this is because the hotend fan normally is controlled by firmware and will carry on working until it drops below a certain temperature (around 50 degrees) and then the firmware turns that off itself.  I should imagine the mini is the same.  
If you just power off immediately without letting it cool down then the heat will work its way up the extruder (in effect generating heat creep) and could cause problems on the next print as the filament would have been partially melted while sat there in an area thats normally 'cold'.

It's quite normal for a print to finish middle of the night and for it to sit there afterwards for hours before being attended to in the morning.  

RE: Keep Mini on and connected, but no heat?

I don't see any safety issue. My printers are pretty much on all the time. And I don't even have a separate smoke detector for the printer beyond the standard ones across the house. As neophyl said, standard print profiles turn hotend and bed off, and there's a safety timer in firmware that turns off heat after a period of time (eg after loading or unloading filament) 

RE: Keep Mini on and connected, but no heat?

Would there be any issue in including the above gcode scripts in Octoprint as a safeguard? I'm thinking about a scenario where I print a gcode file downloaded from Printables, without necessarily knowing whether the gcode was modified to exclude those commands?

RE: Keep Mini on and connected, but no heat?

I guess why not but then again the whole notion of downloading gcode files is not something I can condone. The only exception I can come up with is the Prusa belt tension meter because for inexcusable reasons they do not provide a 3mf or STL file. Beyond that you should always reslice for your specific printer and filament because more likely than not the downloadable  gcode is not optimized for that particular combination. If an author feels the need to communicate specific settings for a print they should do that through a 3mf file. 

RE: Keep Mini on and connected, but no heat?

Good to know. Makes sense. Thanks!