Just finishing off a homemade interface for GMFC.
Interestingly, if anyone's contemplating using a microstepping drive with 1/8 ustep or greater for gmfc.. don't!
The max speed from gmfc is entirely dependent on the timer values (for those who didn't know) So at 4khz, your max speed will be 4000 pulses per second.
so at full step (200 steps per rev).. 20 revs per sec
1/2 step 10 revs per sec
1/8 step 2.5 revs per sec.
So for any decent speed at 1/8 step, gmfc has to be driven by at leat a 10khz timer. Forunately, it accepts this happily, although I guess on slow PC's it might complain a bit.
Pwm frequency of the hotwire is also directly linked to the timer freq, so changing the timer rate, will also affect any heat settings.
Just some info for anyone wondering why they cant get huge speeds from their motors compared to other software like mach2 etc. |