M307 "bad model parameters" please help
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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.
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@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.
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Okay that makes a lot of sense. Thanks.
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@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.
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can you give us some more details about the heater, chamber, and printer itself? Maybe with some more context we can give a better recommendation.
