260° heater limit - M143 does not work?

Reefwarrior

Hi all,

Info as needed:

config.g

; ===========
; : Heaters :
; ===========
M950 H0 C"bedheat" T0 ; create bed heater output on bedheat and map it to sensor 0
M307 H0 R1.343 C240.800:240.800 D4.78 S1.00 V24.2 B0 I0 ; Set heater parameters
M143 H0 S120 ; set temperature limit for heater 0 to 120C
M570 H0 T20 P20 ; configure heater fault detection
M308 S0 P"bedtemp" Y"thermistor" T100000 B4138 C0 R4700 ; configure sensor 0 as thermistor on pin bedtemp
M140 H0 ; map heated bed to heater 0

M950 H1 C"e0heat" T1 ; create nozzle heater output on e0heat and map it to sensor 1
M307 H1 R3.856 C120.212:120.212 D7.92 S1.00 V24.1 B0 I0 ; disable bang-bang mode for heater and set PWM limit
M143 H1 S290 ; Set maximum heater temperature to 290C
M570 H1 T20 P20 ; configure heater fault detection
M308 S1 P"e0temp" Y"thermistor" T116470 B3923.68 R4700 ; configure sensor 1 as thermistor on pin e0temp
M302 S180 R180

general

Board: Duet 2 WiFi (2WiFi)
Firmware: RepRapFirmware for Duet 2 WiFi/Ethernet 3.3beta2 (2021-03-10)
Duet WiFi Server Version: 1.25

Note: You can install updates on the System page.

From the above config file you can see that I have set 290 as my maximum temperature. However; as soon as I hit 260 I get an error. I have tried changing the fault detection too; but it still keeps on triggering.

Any suggestions perhaps?

Tinus

jay_s_uk

@reefwarrior

What error are you getting?

o_lampe

@reefwarrior
290° with an PT100 thermistor? Isn't it a bit too much? I had several thermistors fail at much lower temp, because the legs of the sensor weren't crimped to the wires, but only soldered and shrinkwrapped.
Maybe you get false values from the sensor above 260° for the same reason?

Reefwarrior

@jay_s_uk Just get a 'heater fault'

Reefwarrior

@o_lampe No it's not a PT100. It's one of the cheaper chinese brands; as I can't get locally.

jay_s_uk

@reefwarrior if its a heater fault, have you PID tuned your heater?
Look at M303 https://duet3d.dozuki.com/Wiki/Gcode#Section_M303_Run_heater_tuning
I suggest tuning as a tool rather than a heater

Reefwarrior

@jay_s_uk I have done PID tuning, but will do so again as a 'Tool'; any specific reason why 'Tool' vs 'Heater'?

jay_s_uk

@reefwarrior the Tool algorithm turns on the part cooling fan during the second part of the tuning to take into account the effect it has

Reefwarrior

@jay_s_uk Cool thank you I will do so!

Also; when I compare the reprap firmware vs the marlin firmware, I find that the marlin firmware, with regards to the PID tuning; and temperature reporting, seems to be more 'stable'. With the reprap I find that the temperature sometimes oscillates with as much as 3°C - is this normal?