Thermostatic fan control on 2 hotends (Chimera)

oseiler · 5 Jun 2018, 03:37

I've set my hotend cooling fan to turn on at 50 degrees for H1 or 2 for printing with the Chimera (1 fan for both hot ends)
M106 P0 S255 H1:2 T50

Now when I use a single hotend on my printer, the second thermistor is not connected the fan will be always on. I think this might be because on the display the temperature for the second hotend is reported at 2000 degrees.

The firmware must know that the second thermistor isn't connected, because t doesn't report an error (as opposed to when using both hotends and unplugging the second which is detected and flagged). Is there a way to configure the fan to ignore the H2 temperature when H2 is not connected?

dc42 · 6 May 2018, 06:17

Are you switching between 2 different hot ends? If so then on the connector for the single hot end, you could fit a 100k resistor in place of the second thermistor.

oseiler · 8 May 2018, 04:54

I'm using different carriages with either the single E3D V6 or Chimera. Plugging a resistor into the unused plug when I'm not using the Chimera should work and I'll give it a try.

oseiler · 10 May 2018, 08:24

I've made a little plug with a 100k resistor that I use when only using 1 hotend and it works perfectly well (temp is reported at 24 .5 degrees).
Thanks for the adivce