Wednesday, October 24, 2007

Thermal Ware

Tacked a 50nF cap into C3 on the extruder board and hooked up the thermistor to P2. Set the Extruder0_Capacitor value to 0.00000005. Pulled up the Extruder Exerciser screen. Temperature was way off. Started reading the thermistor calibration page.

Did some measurements with a multimeter, meat thermometer and heat source. Got some R and T values. Plugged them into the formula. Got a beta and Rz value. Used those on the extruder settings. Pulled up the Extruder Exerciser again. Temperature jumping between 16C and 33C.

Tried the whole thing again with a different thermistor. Completely different beta and Rz. Temperature's consistent now but a bit on the high side.

Suspect the first thermistor was flakey and I was sloppy on the measurements for the second one. Will try again later when I have a bit more time.

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