So I have reconfigured the whole config file with the configurator and i figured out the problem.
If you set an active temperature for the bed in m140 command of lets say 100 degree and standbye of 80 degree. But in the web interface you set the bed heater off, obviously nothing is happening, as it should. until the moment that you turn off the printer, on which the bed suddenly starts to heat the bed, with no chance to control the heating process!! then as soon as the printer started up completly, and you get back into the web interface it shuts the heating process down and raises a fault since the heater was supposed to be off.
I replicated this for a small amount of time by restarting the duet after a configuration. But i also noticed the duet needs more time after an emergency shutdown, in this case meaning more time of heating before the duet raises a fault. With the m140 command it seems like it just starts heating withoud checking if it is actually allowed to in the web interface.
My new configuration
; Configuration file for Duet WiFi (firmware version 3)
; executed by the firmware on start-up
;
; generated by RepRapFirmware Configuration Tool v3.1.4 on Fri Oct 23 2020 16:47:43 GMT+0200 (Midden-Europese zomertijd)
; General preferences
G90 ; send absolute coordinates...
M83 ; ...but relative extruder moves
M550 P"3Dennis" ; set printer name
M669 K1 ; select CoreXY mode
; Network
M552 S1 ; enable network
M586 P0 S1 ; enable HTTP
M586 P1 S0 ; disable FTP
M586 P2 S0 ; disable Telnet
; Drives
M569 P0 S0 ; physical drive 0 goes backwards
M569 P1 S1 ; physical drive 1 goes forwards
M569 P2 S0 ; physical drive 2 goes backwards
M569 P3 S1 ; physical drive 3 goes forwards
M584 X0 Y1 Z2 E3 ; set drive mapping
M350 X16 Y16 Z16 E16 I1 ; configure microstepping with interpolation
M92 X160.00 Y160.00 Z3215.00 E400.00 ; set steps per mm
M566 X1500.00 Y1500.00 Z60.00 E120.00 ; set maximum instantaneous speed changes (mm/min)
M203 X3000.00 Y3000.00 Z360.00 E1200.00 ; set maximum speeds (mm/min)
M201 X1000.00 Y1000.00 Z50.00 E250.00 ; set accelerations (mm/s^2)
M906 X1300 Y1300 Z1300 E1000 I40 ; set motor currents (mA) and motor idle factor in per cent
M84 S30 ; Set idle timeout
; Axis Limits
M208 X-8 Y-15 Z0 S1 ; set axis minima
M208 X447 Y444 Z530 S0 ; set axis maxima
; minima x as +7mm naar endstop y as +15mm naar endstop
; maxima x -8mm(-10!) tot X carriage Y -5 naar Z threaded rod
; Endstops
M574 X1 S1 P"xstop" ; configure active-high endstop for low end on X via pin xstop
M574 Y1 S1 P"ystop" ; configure active-high endstop for high end on Y via pin ystop
M574 Z1 S2 ; configure Z-probe endstop for high end on Z
; Z-Probe
M950 S0 C"exp.heater3" ; create servo pin 0 for BLTouch
M558 P9 C"^zprobe.in" H5 F100 T6000 ; set Z probe type to bltouch and the dive height + speeds
G31 P200 X-25 Y-34 Z1.7 ; set Z probe trigger value, offset and trigger height
M557 X30:410 Y30:410 S380 ; define mesh grid
; Heaters
M308 S0 P"bedtemp" Y"thermistor" T100000 B4725 C7.06e-8 ; configure sensor 0 as thermistor on pin bedtemp
M950 H0 C"bedheat" T0 ; create bed heater output on bedheat and map it to sensor 0
M307 H0 B0 S1.00 ; disable bang-bang mode for the bed heater and set PWM limit
M307 H0 A85.7 C164.4 D1.4 V24.3 B0 ; Bed with glass
;M307 H0 A133 C283 D1.1 V24.3 B0 ; Bed with glass old
M140 H0 S100 R80
M143 H0 S120 ; set temperature limit for heater 0 to 120C
M308 S1 P"e0temp" Y"thermistor" T100000 B4725 C7.06e-8 ; configure sensor 1 as thermistor on pin e0temp
M950 H1 C"e0heat" T1 ; create nozzle heater output on e0heat and map it to sensor 1
M307 H1 A445 C79.1 D1.4 V24.2 B0 ; e3d test hotend with cooling
M143 H1 S280 ; set temperature limit for heater 1 to 280C
; Fans
M950 F0 C"fan0" Q500 ; create fan 0 on pin fan0 and set its frequency
M106 P0 S0 H-1 ; set fan 0 value. Thermostatic control is turned off
M950 F1 C"fan1" Q500 ; create fan 1 on pin fan1 and set its frequency
M106 P1 S1 H1 T50 ; set fan 1 value. Thermostatic control is turned on
; Tools
M563 P0 D0 H1 F0 ; define tool 0
G10 P0 X0 Y0 Z0 ; set tool 0 axis offsets
G10 P0 R0 S0 ; set initial tool 0 active and standby temperatures to 0C
; Custom settings are not defined
; Miscellaneous
M575 P1 S1 B57600 ; enable support for PanelDue