Duet3 6HC with Goliath Hotend PT1000 temperature too hot

gringo

Hello friends,

I built a VZBOT and use the Goliath hotend. I'm currently doing my first prints and have found that I have to set the temperature of the filament (Extrudr Greentec Pro) 30°C lower than on my other printers. I don't know what the problem is or whether it's just the long melting zone.

Do you have an idea?

When the printer is cold, the bed temperature and hotend are the same.
Bed 19.8°C
Hotend 20.3°C

dc42

@gringo two things:

You can calibrate the thermistor input of the 6HC as described at https://docs.duet3d.com/en/User_manual/Connecting_hardware/Temperature_connecting_thermistors_PT1000#semi-automatic-calibration. However, unless your 6HC board is very old then this should have been done during manufacturing.
You can test the accuracy of the Duet in determining temperature from a good PT1000 sensor by connecting a fixed resistor across the temperature sensor input on the Duet in place of the sensor. Use a PT1000 resistance temperature table to determine the relationship. For example, a 2K0 1% tolerance resistor should give a reading between 261C and 272C.

gringo

Thanks @dc42

Made a Calibration and will test it now.
Thats the results

2.11.2023, 16:08:51 M308 S1 H999
Measured H correction for port "temp1" is 3

2.11.2023, 16:09:07 M308 S1 L999
Measured L correction for port "temp1" is 1

gringo

The temperatures are not correct even after calibration. I print a technical filament 30 degrees colder than specified.

M308 S1 P"temp1" Y"pt1000" A"HotEnd"                                  ; configure sensor 1 as PT1000 on pin temp1
M950 H1 C"out1" T1                                                    ; create nozzle heater output on out1 and map it to sensor 1
M307 H1 R5.509 K0.341:0.695 D3.11 E1.35 S0.70 B0 V23.9                ; disable bang-bang mode for heater  and set PWM limit   
M143 H1 S280                                                          ; set temperature limit for heater 1 to 280C

droftarts

@gringo did you rest with a known value resistor, as @dc42 suggested?

Ian

deckingman

@gringo said in Duet3 6HC with Goliath Hotend PT1000 temperature too hot:

The temperatures are not correct even after calibration. I print a technical filament 20 degrees colder than specified.

Most likely the temperatures are correct but the reason why you find the best temperature is lower than the filament manufacturers recommendation is a function of your Goliath hot end with its very long melt zone and/or the position of the temperature sensor in relation to the nozzle. Specified temperatures can only ever be for guidance. Print temperature towers, find what works best for your hot end and ignore anything you might have read online.

gringo

The temperature range for the CR3D ABS FibCR20 is between 240-260 degrees, I now print at 190 degrees.
There is something wrong.

Unfortunately I don't have any resistore here with which I can test this

deckingman

@gringo You started off saying that you were using 30 degrees lower than specified. Then you said it was 20 degrees lower. Now you are saying 50 to 70. Which is it? But in any case, the only way you can eliminate any problem with the board is to check it using a resistor as suggested. They only cost a few cents. Alternatively, you could temporarily swap Goliath sensor or indeed the entire hot end with one from your one of your other printers. Or you could temporarily swap the boards with one from one of your other printers. You don't need connect and configure everything - just the hot end heater and sensor.

gringo

Thanks for the correction, I had mistyped.
In the post above it should read 30 and not 20 degrees.

I have 30 degrees difference with the Extrudr GreenTEC Pro.
50 degrees and more with the CR3D ABS FibCR20.

That was misleadingly expressed by me

I tested 2 PT1000. With both the same.

I think I will buy a 2K Ohms and a 1K ohms resistor for testing.