Setting custom thermistor error

General Discussion
1

Basic Information:

Printer Model: custom built
MCU / Printerboard: MKS Gen L V2.0
Host / SBC Rasberry Pi
klippy.log
klippyJan.log (124.8 KB)

I’m trying to set up a custom thermistor and either I can’t figure out how to read the thermistor datasheet to make the temperature resistance section or the data sheet is off. Can somebody point out my error here?

The thermistor resistance reads close to 230k at room temperature. I see that the resistance in the datasheet is nowhere near that at the room temperature range.

2

According to your information and the datasheet, you likely have a B57540G0234 thermistor.

The easiest way is to use the β-value of it, and since Epcos offers different ranges, you probably want to use the 25/100 value.

image
image1218×669 132 KB

Try:

[thermistor my_thermistor]
beta: 4264
3

Thanks for the response. I get this error when I do that.

according to this tutorial, I need at least one temperature and a resistance value.

Option ‘temperature1’ in section ‘thermistor Cube_Pro_thermistor’ must be specified

When I add

[thermistor Cube_Pro_thermistor]
temperature1: 20
resistance1: 230
beta: 4264

I get the error
MCU ‘mcu’ shutdown: ADC out of range

Sensor ‘extruder’ temperature -75.350 not in range 0.000:250.000

  • List item
4

Sorry, my answer was a bit sloppy. I thought the rest would be clear. The entire thing needs to look like:

[thermistor Cube_Pro_thermistor]
temperature1: 25 # The data sheet gives the reference at 25 °C
resistance1: 230000 # Resistance needs to be in Ω and not kΩ
beta: 4264
5

Thanks. I had missed that the resistance needs to be in ohms. I guess that was my problem in the first place.

In a somewhat related note, My temperature reads close to what I expect it to read, but it’s very bouncy. constantly bouncing around with up to 3 degrees fluctuation.

I wonder if its a bad thermistor or if it’s something that can be corrected. I’ll try heating it up to see if it stabilizes at higher temperatures.

Edit: Ok that worked. At 200 degrees it is stable after a pid tuning. So all good.