M307 "bad model parameters" please help

honeycris

@fcwilt
Any thoughts on the "bad model parameters" when trying to add more dead time?

fcwilt

@honeycris said in M307 "bad model parameters" please help:

@fcwilt
Any thoughts on the "bad model parameters" when trying to add more dead time?

I'm doing some tests now.

Will post soon.

Frederick

fcwilt

@honeycris

The largest value for D that is allowed under firmware 3.3.0 is 70.

I just tested D10, D20, D30, etc until I found the limit.

Frederick

Phaedrux

@fcwilt said in M307 "bad model parameters" please help:

The largest value for D that is allowed under firmware 3.3.0 is 70.

I think it may actually depend on what the other values are. Will have to get DC42 to answer for sure.

fcwilt

@phaedrux said in M307 "bad model parameters" please help:

I think it may actually depend on what the other values are. Will have to get DC42 to answer for sure.

That well may be but the error message the OP was getting was the same error that I got when the value for D exceeded 70.

So it seems that he should determine if that is the problem by trying lower values.

Frederick

honeycris

@fcwilt
OK cool. that makes sense. I'm a she not a he just fyi.

honeycris

@fcwilt
I tried to change D to lower numbers and here are my results:

M307 H7 D30
Error: M307: bad model parameters

M307 H7 D60
Error: M307: bad model parameters

M307 H7 D69
Error: M307: bad model parameters

M307 H7 D70
Error: M307: bad model parameters

Phaedrux

Can you share your full config.g and config-override.g files please?

Also the results of sending M122 and M98 P"config.g" may be helpful.

It probably won't help in this case, but your firmware is also out of date. Update by uploading this zip file to the system tab in DWC.

https://github.com/Duet3D/RepRapFirmware/releases/download/3.3/Duet2and3Firmware-3.3.zip

honeycris

@phaedrux

M122
=== Diagnostics ===
RepRapFirmware for Duet 2 WiFi/Ethernet version 3.3 (2021-06-15 21:44:54) running on Duet WiFi 1.02 or later + DueX5
Board ID: 0JD0M-9P6M2-NW4SJ-6J9DD-3SJ6J-KASRK
Used output buffers: 3 of 24 (16 max)
=== RTOS ===

M98 P"config.g"
HTTP is enabled on port 80
FTP is disabled
TELNET is disabledconfig-override.g config.g

fcwilt

@honeycris said in M307 "bad model parameters" please help:

@fcwilt
OK cool. that makes sense. I'm a she not a he just fyi.

That's marvelous!

fcwilt

@honeycris said in M307 "bad model parameters" please help:

@fcwilt
I tried to change D to lower numbers and here are my results:

M307 H7 D30
Error: M307: bad model parameters

M307 H7 D60
Error: M307: bad model parameters

M307 H7 D69
Error: M307: bad model parameters

M307 H7 D70
Error: M307: bad model parameters

Interesting.

I cannot test under the version of firmware you are using as all of my printers are now running 3.3.0.

At this point I suggest you upgrade and see if it makes a difference - they have the upgrade procedure mostly foolproof.

Frederick

honeycris

I upgraded the firmware and I'm getting all the same results.

M307 results:
m307 h7 d60
Error: M307: bad model parameters

Tuning results:
m303 h7 s50
Auto tuning heater 7 using target temperature 50.0°C and PWM 1.00 - do not leave printer unattended
Auto tune cancelled because temperature is not increasing

Phaedrux

Try replaving your heaters block with this, which I generated from the config tool. For some reason you have it skipped to heater7 when the next heater should be 5.

; Heaters
M308 S0 P"bedtemp" Y"thermistor" T100000 B3950              ; 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
M140 H0                                                     ; map heated bed to heater 0
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 B0 S1.00                                            ; disable bang-bang mode for heater  and set PWM limit
M143 H1 S280                                                ; set temperature limit for heater 1 to 280C
M308 S2 P"e1temp" Y"thermistor" T100000 B4725 C7.06e-8      ; configure sensor 2 as thermistor on pin e1temp
M950 H2 C"e1heat" T2                                        ; create nozzle heater output on e1heat and map it to sensor 2
M307 H2 B0 S1.00                                            ; disable bang-bang mode for heater  and set PWM limit
M143 H2 S280                                                ; set temperature limit for heater 2 to 280C
M308 S3 P"duex.e2temp" Y"thermistor" T100000 B4725 C7.06e-8 ; configure sensor 3 as thermistor on pin duex.e2temp
M950 H3 C"duex.e2heat" T3                                   ; create nozzle heater output on duex.e2heat and map it to sensor 3
M307 H3 B0 S1.00                                            ; disable bang-bang mode for heater  and set PWM limit
M143 H3 S280                                                ; set temperature limit for heater 3 to 280C
M308 S4 P"duex.e3temp" Y"thermistor" T100000 B4725 C7.06e-8 ; configure sensor 4 as thermistor on pin duex.e3temp
M950 H4 C"duex.e3heat" T4                                   ; create nozzle heater output on duex.e3heat and map it to sensor 4
M307 H4 B0 S1.00                                            ; disable bang-bang mode for heater  and set PWM limit
M143 H4 S280                                                ; set temperature limit for heater 4 to 280C
M308 S5 P"duex.e6temp" Y"thermistor" T100000 B3950          ; configure sensor 5 as thermistor on pin duex.e6temp
M950 H5 C"duex.e6heat" T5                                   ; create chamber heater output on duex.e6heat and map it to sensor 5
M307 H5 B0 S1.00                                            ; disable bang-bang mode for the chamber heater and set PWM limit
M141 H5                                                     ; map chamber to heater 5
M143 H5 S80                                                ; set temperature limit for heater 5 to 80C

honeycris

@phaedrux
This worked! I was able to tune correctly and the bad model parameters were probably that heater 7 shouldn't have existed.

Phaedrux

Glad that solved it.

honeycris

This post is deleted!

honeycris

@phaedrux

I spoke too soon. I tuned the heater with the thermistor pretty close to the heater because otherwise I kept getting the "auto tune cancelled because temperature is not increasing" error. So I moved the thermistor and was able to get it to tune, but then I moved the thermistor to above the print bed. After moving it when I tried to run the heater it would never get up to temp. So then I tried to re-tune with the better thermistor position and I got the auto tune error again and again.

I ultimately want the thermistor to be above the print bed for reasons but I cant get the heater tuned in that position.

Phaedrux

@honeycris said in M307 "bad model parameters" please help:

I ultimately want the thermistor to be above the print bed for reasons but I cant get the heater tuned in that position.

Chamber heaters are usually pretty slow to heat the entire volume, so placing the thermistor far away from the heat source makes for a very loosely coupled heater control system. It's probably a better idea to have the thermistor closer to the heater so that it can actually be controlled. You'll just have to have a delay to wait a while for the temp in the chamber to rise and equalize.

honeycris

@phaedrux

Okay that makes a lot of sense. Thanks.

dc42

@honeycris alternatively, use a small fan (one that can stand the temperature in the chamber) to circulate air, so that the heat reaches the thermistor more quickly. This should also make it viable to use PID control.