Calibration with heat

I hope this is just a silly question that I just missed the answer.

I’ve tried to heat up the bed and nozzle before calibrating 5x5. As soon as I hit calibrate, the temps on both start to cool down.

Is there some way to tell it to leave the temp alone while calibrating? I’d like to leave it at around 175 on the nozzle and 50 on the bed.

There is a lot of discussion about this if you use search.
The summary is that the bed being on messes up the sensor.
Best alternative is to heat bed to 5-10º above printing temp and then run calibration. With carryover it will be close enough.
No need to heat the nozzle.
-S

Thank you for that - but if the heated bed messes up the sensor, should the bed be cold?

I’m not compelled to heat it up. My goal is to find a reasonably consistent method to get acceptable prints. Thermistor, leveling, tramming, warping, temperature, and filament quality. I’m sure there are others.

If leaving them cold is better, I’ll try that again.

Preheat is better

Snapmaker is in the middle of changing the firmware to allow a preheat.

They decided the difference in the sensing range is negligable against the movement of the bed.

You’re better off having it warm.
It’s just when the power is on to the bed that messes up the sensor with the magnetic field since it’s inductive.
-S

Hi,

I connected the printer to luban via the cable and run the following command: I M140 S60 (60 is the bed temp).

Thereafter, you can run the auto calibration on the printer

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it actually shuts the heater down, but you cant see that it does because the thermistor value does not update.

however, preheating for a while, then executing, is a good method because it takes time for the plate to return to its cold shape.

Thanks, that helps with the undstanding.