Best posts made by JA

I think all you need is M99
Here you have a macro using variables, if someone doesn't want variables (to use with older firmware) just replace the values.

To download: Cool_Bed.g

;[Macro Cool_Bed.g]		; Needs RRF3.3 or later because uses variables

; Change these variables to suit your printer
var BedFan = 9				; Fan number
var ThresholdTemp = 50			; ºC
var CheckEvery = 1			; Seconds


if heat.heaters[0].current > {var.ThresholdTemp}
	M108						; Cancel Heating (just in case), Breaks out of an M109 or M190
	M140 S0						; Turn off bed heater (*)
	M106 P{var.BedFan} S1.0				; Turn on BedFan
	while  true
		G4 S{var.CheckEvery} 			; Wait 1 sec, to check temperature every second
		if heat.heaters[0].current <= {var.ThresholdTemp}
  			M106 P{var.BedFan} S0.0		; Turn off BedFan
   			M99				; Return from Macro/Subprogram
		;END if
	;END while
;END if

"*" in line 11, is there anything analogous to M568 A0 for tools but for the bed??

I have the same issue and it's prior to variables, object model nodes also don't work
In standalone mode works as expected but not in SBC mode.

Example: