Thursday, October 25, 2007

Smaller Cap


Found a 10nF cap on an old ComputerEyesRT board (circa 1991). No idea why I still had one lying around. Swapped out the 50nF cap. Adjusted the extruder capacitor setting to 0.00000001. Note: I've got two leads on the holes for C3 and have been trying out caps by soldering to the leads. Less wear on the board from soldering and desoldering.

Re-ran the profiler. Fewer I/O timeouts and false readings. Still noticing a change in duty cycle on the heater but it's less pronounced.

I haven't looked at any of the PIC code but I'm guessing the heater is controlled by a software PWM loop. If that's the case, temperature measurements and serial communication will mess with the duty cycle. Best you can do is avoid polling too often.

2 comments:

nophead said...

Hi Steve,
Have you been following the forum thread: http://forums.reprap.org/read.php?12,5215,page=2 ?

andreas has posted some improved code to fix intermittent readings.

Steve DeGroof said...

Nope, hadn't seen that. Thanks.