strange message when PID tuning

nick9one1

thanks

for some reason I still get the same error when heating. Triggered at about 80C

If I clear the error it usually happens again, then on the third try It gets to temp OK.

I PID tuned next to the bed and the part cooling fan kicks in during the second half of the tune.

; Heaters
M308 S0 P"bedtemp" Y"thermistor" T101302.1408 B3950 C0 R4700 A"Bed Temp" 	; 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
M140 H0                                        								; map heated bed to heater 0
M143 H0 S100                                   								; set temperature limit for heater 0 to 100C
M307 H0 R0.278 C1408.5 D27.03 S1.00											; Set PID for bed values
M308 S1 P"e0temp" Y"thermistor" T96774.19355 B3950 C0 R4700 A"Hotend Temp"             
   ; 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
M143 H1 S265                              									; set temperature limit for heater 1
M307 H1 R3.461 C147.8:85.5 D7.80 S1.00 V23.9								; Set PID for hotend values

You can see M307 in config.g matches the tuning result in my first post.
I've run the tune 4 times, each PID was very slightly different but all trigger the Error.

droftarts

@nick9one1 You have reset the Duet since changing config.g? Send M307 H1 to check what settings are actually being used. It's possible that you have a config_override.g file that is using a different (old) value, too.

Ian

nick9one1

@droftarts said in strange message when PID tuning:

M307 H1

Yes I've reset the printer a few times since changing pids.

I dont have a config_override file..

and this is the result of M307 H1 (values look the same as the the PID tuning result)

droftarts

@nick9one1 Are you running the print cooling fan when heating up? If so, turn it off. Was the heated bed already hot when you did the M303 tuning (might have a small effect on results)? Did you tune the heater with the nozzle close to the bed (which simulates the conditions when printing)?

Ian

nick9one1

Yep I did all that. nozzle at Y0, bed was cold. part cooling fan is off when the error happens.

I wonder if the thermisistor that came with the Biqu H2 is differnt to what I have specified.

M308 S1 P"e0temp" Y"thermistor" T96774.19355 B3950 C0 R4700 A"Hotend Temp"  ; configure sensor 1 as thermistor on pin e0temp

the H2 product page doesn't list any data on the supplied thermistor
https://www.biqu.equipment/products/biqu-h2-direct-extruder-dual-driver-gear-extrusion-for-ender3-b1-3d-printer?_pos=1&_sid=10dc3ab2a&_ss=r

but they do seem to sell (what I imagine) is the the same thermistor separately
https://www.biqu.equipment/products/biqu-3d-printer-parts-1m-2m-ht-ntc100k-thermistor-temperature-sensor-for-high-temperature-filament-350-degrees?_pos=2&_sid=81f4ff1ef&_ss=r&variant=46654559299

three isn't much information other than its a HT-NTC100K

nick9one1

I've changed M308 to reflect more 'default' settings, re-tuned, but still get the same error...

M308 S1 P"e0temp" Y"thermistor" T100000 B3950 A"Hotend Temp"

Phaedrux

After doing the tuning can you try sending M500 to save the result to config-override.g. Then you don't have to manually copy anything over. As long as you have M501 at the end of config.g to load those settings it should then take effect at boot up.

nick9one1

Thanks. I'll try that

nick9one1

I had to add M501 at the end of config.g (as I dont usually use config-override.g)

; Configuration file for Duet WiFi (firmware version 3)
; executed by the firmware on start-up
;
; generated by RepRapFirmware Configuration Tool v3.1.4 on Sat Sep 05 2020 23:57:30 GMT+0100 (British Summer Time)

; General preferences
M80					       	; Turns on the ATX power supply
G90                                            	; send absolute coordinates...
M83                                            	; ...but relative extruder moves
M550 P"BLV MGN Cube"                           	; set printer name
M669 K1                                        	; select CoreXY mode

; Network
M552 S1                                        	; enable network
M587 S"your_wifi_name" P"your_password"        	; Configure access point. You can delete this line once connected
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 S1                                     	; physical drive 2 goes forwards
M569 P3 S0                                     	; physical drive 3 goes backwards
M584 X0 Y1 Z2 E3                               	; set drive mapping
M350 X16 Y16 Z16 E16 I1                        	; configure microstepping with interpolation
M92 X200.00 Y200.00 Z3200.00 E932.00            ; set steps per mm
M566 X820.00 Y820.00 Z70.00 E500.00             ; set maximum instantaneous speed changes (mm/min)
M203 X20000.00 Y20000.00 Z500.00 E2000.00      	; set maximum speeds (mm/min)
M201 X3000.00 Y3000.00 Z150.00 E5000.00        	; set accelerations (mm/s^2)
M906 X1100 Y1100 Z1100 E800 I30               	; set motor currents (mA) and motor idle factor in per cent
M84 S30                                        	; Set idle timeout

; Pressure advance
M572 D0 S0.1

; Axis Limits
M208 X-30 Y0 Z0 S1                            	; set axis minima
M208 X305 Y329 Z950 S0                        	; set axis maxima

; Endstops
M564 H0					       					; allow jog without homing
M574 X1 S1 P"xstop"                            	;
M574 Y2 S1 P"ystop"                            	;
M574 Z1 S1 P"zstop"                            	; configure Z-probe endstop for low end on Z

; Z-Probe
M558 P1 H5 C"^zprobe.in" H5 F250 T9000 R0.5 T7200	; set Z probe type to switch and the dive height + speeds
G31 P500 X0 Y25 Z1.97                      			; set Z probe trigger value, offset and trigger height
M557 X10:280 Y25:278 P5                      		; define mesh grid

; Heaters
M308 S0 P"bedtemp" Y"thermistor" T100000 B3950 C0 A"Bed Temp" 				; 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
M140 H0                                        								; map heated bed to heater 0
M143 H0 S100                                   								; set temperature limit for heater 0 to 100C
;M307 H0 A340.0 C445.4 D27.6 S1.00 V23.9 B0									; Set PID for heated bed values
M307 H0 R0.278 C1408.5 D27.03 S1.00											; Set PID for bed values
M308 S1 P"e0temp" Y"thermistor" T100000 B3950 A"Hotend Temp"  				; 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
M143 H1 S265                              									; set temperature limit for heater 1
M307 H1 R3.349 C228.7:133.4 D7.83 S1.00 V23.9								; Set PID for hotend values
		
; Fans
M950 F0 C"Fan2" Q50                        	; create fan 0 on pin 2 and set its frequency
M106 P0 S0 H-1 X204                             ; set fan 0 value. Thermostatic control is turned off
;M950 F0 C"Fan0" Q100                           ; create fan 2 on pin fan2 and set its frequency
;M106 P0 S1 H1 T45                              ; set fan 2 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

; Screen
M575 P1 B57600 S1


M501

and config-override.g

; config-override.g file generated in response to M500 at 2021-03-21 01:19
; This is a system-generated file - do not edit
; Heater model parameters
M307 H0 R0.278 C1408.500:1408.500 D27.03 S1.00 V0.0 B1
M307 H1 R3.445 C219.932:130.532 D7.80 S1.00 V23.9 B0
; Workplace coordinates
G10 L2 P1 X0.00 Y0.00 Z0.00
G10 L2 P2 X0.00 Y0.00 Z0.00
G10 L2 P3 X0.00 Y0.00 Z0.00
G10 L2 P4 X0.00 Y0.00 Z0.00
G10 L2 P5 X0.00 Y0.00 Z0.00
G10 L2 P6 X0.00 Y0.00 Z0.00
G10 L2 P7 X0.00 Y0.00 Z0.00
G10 L2 P8 X0.00 Y0.00 Z0.00
G10 L2 P9 X0.00 Y0.00 Z0.00
M486 S-1

Unfortunately I get exactly the same..

SJI

I've also been experiencing this also. Once it's at temp all is good

edit: Firmware 3.2.2 Duet 3 6HC

Phaedrux

Can we see some photos of the hotend assembly?

nick9one1

sure..

A couple of stock images, then three of my setup.
It way be worth mentioning the whole assembly is aluminium.. The block, gears, extruder housing, tensioning arm.
Its fairly similar to the E3d Hermera, although smaller and lighter.

Phaedrux

Is the heat block making contact with the cold side? Can't quite tell from the photo of the underside.

what does your heater graph look like during the tuning?

nick9one1

3mm-4mm gap between heat block and cold side.

There's quite a lot of thermal mass with the complete extruder assembly being 100% metal. My initial thoughts were this was the reason for the error. But the pid tuning should take account of this? (tuning was done from cold).

Phaedrux

Thanks for the feedback on the new algorithm. Will see if DC42 has any tuning suggestions.

nick9one1

@phaedrux

update - after making a few changes the hotend is now heating without the error.

The all metal throat is secured by two grub screws to the body/heatsink. Although properly secured, I think the throat was heating up, expanding slightly and making better contact with the heatsink, causing it to dump heat a bit quicker and triggering the error.
I've added some thermal compound to the throat/heatsink, re-tuned and can now heat from cold without any issues.