Thermistor 500°C with Duet3

[Anopsia1000]

Hi,

Is there a way to use a thermistor 500°C with the Duet3

Sensors config is

M308 S1 P"121.temp0" Y"thermistor" T4606017 B5848 C5.548428e-8
M950 H1 C"121.out0" T1

My reading is -273°C, impossible to heat up. Always faulty.

Thanks.

[Stephen6309]

@anopsia1000 Check you connections, -273 usually means a short.

[dc42]

@anopsia1000 does it really have a resistance of 4.6Mohms at 25C? If so then it's going to be hard to read at room temperature.

How old is the tool board? If it wasn't running firmware 3.3 when you received it, then you may need to run calibration (using 3.3 or 3.4beta firmware). See https://duet3d.dozuki.com/Wiki/Calibrating_thermistor_and_PT1000_readings.

[Anopsia1000]

@dc42 Thanks for the answers.

Wiring is brand new, no shorts. I confirm the T25 R is 4606017 ohm.

board: duet 3mb6hc
firmware: 3.3 config w/ reprap online configurator.

Will try the calibration.

At room temp on a duet2 firmware 2 I have no issue beside the usual low accuracy at room temp.

[dc42]

@Anopsia1000

M308 S1 P"121.temp0" Y"thermistor" T4606017 B5848 C5.548428e-8

That command says that sensor 1 is connected to a tool board, not the 6HC main board. Is that correct?

[TLAS]

@anopsia1000
Please keep in mind that most thermistors are rated to ~250C. If you went above that, it’s a gamble if it’ll read correctly or survive without a short.

[zapta]

@anopsia1000 , can you share the specifications/datasheet of your thermistor?

[Gixxerfast]

@zapta It's most likely the Trianglelabs D500 thermistor.

Datasheet in here:
https://forum.duet3d.com/topic/24306/duet-2-wifi-problem-with-the-t-d500-thermistor