How to disable safety timer for the heatbed?  

RE: How to disable safety timer for the heatbed?

It is called safety due to reason not to heat the bed while not printing. When you print the safety timer will not switch off the heating.

So start a 12 hours print.

RE: How to disable safety timer for the heatbed?

okay, but how can I have the heated bed turned on for 12 hours without printing anything? I know how to make it print stuff. I have been printing stuff for over a year now. I just want it to heat up the bed to 80C and not do anything else. No movement of the bed, no movement of the nozzle. In my research I read that the safety timer shuts off the heated bed after 30 minutes of no activity. Is there a way to use gcode to trick it into thinking it is printing when it is actually not moving?

RE: How to disable safety timer for the heatbed?

The only way is to change the FW - change it and flash unsigned fw, provided you broke the appendix, which means loss of the warranty. It is built in safety, in normal circumstances not possible to bypass.

RE: How to disable safety timer for the heatbed?

No, you have to move it, however you don’t have to move it FAR. Even 0.1mm every 25 minutes would stop the timer kicking in. So move the extruder up 0.1, wait 25 minutes, move it down 0.1mm, wait 25 minutes, repeat as often as needed. 
I do question why you want to cause a fire hazard though. There are much easier ways to warm things up. 

RE: How to disable safety timer for the heatbed?

I have a theory and that is that I think he wants to do the same thing I'm looking to do, use the hot bed to remove moisture from filament spool cheaply since a filament dryer machine is a bit expensive in some parts of the world.

PS: Thanks for the advice, I'm going to try to interact with the printer every 25 minutes for 5 hours, to see if it works.

RE:

You can try to use a dummy print with command heating the bed 

M140: Set Bed Temperature M140 SXXX - XXX temperature in °C

followed by M25 pause or M226: G-code Initiated Pause

I guess he printer will think it is still printing, will not be in idle status so the timeout will not be active.

Never tried, sou you can be a pioneer.

RE: How to disable safety timer for the heatbed?

yea, i have a mk2.5 with latest firmware and i wanted to do this as well and kept getting the heatbead disabled by safety timer .. glad its not just me 🙂 this was helpful to understand ways around it , would be better if a Gcode could set the time out to more then 30mins , like an hour or two would be good and reset to default on a power cycle .. but my filament dryer just arrived so i perhaps wont really need to do this again, and it was only because i got a few opened rolls with another printer i bought that were a bit saturated so i thought i would speed up the process of drying 5 rolls by putting them in a box on the heatbed for an hour or so.

RE: How to disable safety timer for the heatbed?

I actually just did that today after finding your post. For what it's worth, it actually worked quite well (even if I'm going to look for alternative drying methods anyway)

Posted by: @pink_clown

You can try to use a dummy print with command heating the bed 

M140: Set Bed Temperature M140 SXXX - XXX temperature in °C

followed by M25 pause or M226: G-code Initiated Pause

I guess he printer will think it is still printing, will not be in idle status so the timeout will not be active.

Never tried, sou you can be a pioneer.

RE:

I needed to do this today to help save a print, keep the bed warm whilst I was at work. Simplest option was a two line gcode of;

M190 S60 (Set bed to 60°C and wait to get there)

G4 S18000 (Dwell for 5hours)

Easily uploaded via OctoEverywhere to my Octoprint, and printer is now happily sitting at 60°C bed temp.