Heater Autotune Failure

[Hydros]

Hi, I'm having some trouble with my extruder. I'm setting up a duet wifi 2 with a makerbot replicator 2 shell and I'm trying to run the PID autotune using the command M303 H1 S240.

Each time I run it I get some values with an error:

This is how my extruder is setup in the config file:

[Veti]

can you post a picture of the heating curve from the ui?

[Hydros]

Sure, Just generated a new one

[Rushmere3D]

Do you have the correct thermistor selected? It's claiming to reach over 300°C in around 1 minute.

[Hydros]

Yes, I'm using a thermocouple with a pt100 daughter board. Its configured to spi.cs1 in the configuration file

[Veti]

that overshot by a mile.

what kind of hotend is that?

what is the wattage of the heater catridge?

[Hydros]

Its a makerbot replicator 2 hot end with a flexion extruder I have an older version of the heatsink but its the same thing: https://www.diabasemachines.com/product-page/single-flexion. The heater is 12V,40W

Just tried it again with a 100k NTC thermistor instead

[Hydros]

Just double checked, its running at 24V, could that be why its heating so quickly? I'm running the duet wifi 2 at 24v as well...

[Veti]

@Hydros

YES. DO NOT TURN ON YOU HEATER

the 12V 40W heater becomes a
24V 160W heater.

you have to buy a 24V heater catridge

[Hydros]

@Veti Will do, thanks!

[Veti]

@Hydros

And if your heated bed is 12V as well, do not turn that on either.

[Hydros]

@Veti don't have a heated bed yet, but if I get one, I'll keep that in mind!

[Phaedrux]

@Hydros said in Heater Autotune Failure:

Yes, I'm using a thermocouple with a pt100 daughter board.

Are you sure that's what you have? A thermocouple won't work on a PT100 daughter board.

Glad you noticed it was 24v, that is a dangerous situation.

[Hydros]

@Phaedrux

I think so. Here are the links to what I purchased: pt100 and the thermocouple and I configured it following this guide: https://duet3d.dozuki.com/Wiki/Connecting_thermocouples

@Veti @Rushmere3D

Thank you all for your help! I got the correct heater today and was able to complete the autotune.

[Phaedrux]

That's not a thermocouple, it is a PT100 sensor and daughterboard. So at least they are compatible with each other, at least in theory.

How do you have the sensor wired to the board?

Here is the correct documentation for what you have:

https://duet3d.dozuki.com/Wiki/Connecting_PT100_temperature_sensors

https://duet3d.dozuki.com/Wiki/PT100_temperature_sensor_daughter_board