M190 R Supported?

Obviously M190 S55 will set the bed temp to 55 degrees and wait until that temp is reached before continuing, but M190 R28 should set the bed temp to 28 degrees and wait until it cools down (if already heated above that). I can’t seem to get M190 R28 to work. Is it not supported?

See if M400 will hold the future commands until the temp is where you want it.

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M400 is only to wait for moves to be completed, not temperature setpoints. Thanks though.

That is incorrect. Bambu Printers can use M400 as a general wait time.

Example from the Bambu Specific G-code Thread

M400	Pause - Can be used 2 ways*
*Pause Method 1 Example/Description:
Including S# with the M400 command pauses for # seconds

M400 S30
G1 Z100
G1 X100 Y100

Explanation: Pause for 30 seconds, then start moving towards Z100, and move to X100 Y100 (regardless of whether we’ve arrived at Z100 yet or not)

Pause Method 2 Example/Description:
Use M400 by itself to pause until the next command completes

G1 Z100
G1 X100 Y100

Explanation: Pause until we arrive at Z100, then move to X100 Y100

I’ve been meaning to try that out. Bambu seem to use M190 S for cooling too: I’ve seen it (unnecessarily) wait for cooling after I replaced the smooth PEI to the cold plate between prints. And they only ever use M190 S[bed_temperature_initial_layer_single]. Please report your findings!

Sure but not temperature setpoints. Also, I am pretty sure that wiki thread is incorrect. I believe M400 pauses until already queued commands have finished - you put it after the moves you want to wait for. I really can’t picture Bambu having turned that around.

I believe that you are right.

Reading through the stock Start and and End Gcode confirms this. There are also several instances of M400 Pxxx used. I’m not sure what the “P” designator does.


I appreciate everyone taking time to respond to this. I didn’t expect a quick response. I suppose I should go ahead and describe my use-case for M190 R.

I use a bed adhesive that lasts through multiple prints as long as I let the bed cool before removing the print. So what I’m trying to do is kick on the Part Cooling Fan and Auxillary Fan until the bed cools to say, 28 degrees. Then shut everything off as usual. Doing my own research I found that M190 R28 should’ve accomplished that, but in my testing, it does not work. The fans kick on, a warning pops up on the screen about High Bed temps, the fans stay on for a couple minutes, and then they shut off and wrap up like nothing happened. The bed temp usually gets down from 55 to 45 in that amount of time.

I like the idea of just trying to use the M190 S parameter instead, as you said, it might wait for cool down using that parameter as well. I haven’t tried it yet, but will.

Me neither but M400 U1 parks toolhead at chute and pauses for user interaction - that too a Bambu thing, not in Marlin.

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That’s exactly what I want as well, and I know others too - for various reasons such as chamber evacuation or not getting burned by the hotbed after printing ABS/ASA.

Similar to something posted a while back for a user that was looking to slowly cool their bed utilizing M400.


Similar to something posted a while back for a user that was looking to slowly cool their bed utilizing M400.

I don’t wanna hack my way to it. I want to use the gcode the way it was meant to be used. lol