On Tue, 26 Aug 2003 11:20:56 -0300, you wrote:
Normal Spin Count 2937 3090 2989
Current Spin Count 4813 4696 5216
Spin adder 1552 1751 1578
These particular values look pretty good. Remember the numbers are
multiples of 40us, so a Spin countof 2937 is .117 seconds per rev and 3090
is .120 seconds per rev or 512RPM and 500RPM respectively. This is not a
wide variance. But the Current Spin values indicate a slowdown to .192 sec
per rev or 312RPM, which is quite a slowdown, it is suspiciously close to
half the true speed which would occur if the sensor sometimes misses a pulse
or two.....
500rpm is set value, and motor never moves more than 2 or 3 rpm off
this under normal use
No missing pulses I can see?
You say there is no noticable slowdown, but these figure indicate quite a
reduction...I have to give some thought as to what would create this type of
situation.....
I just ran some tests on mine and cannot get the spinadder to go way up
unless the sensor is not feeding back. But if this was true then the Spindle
RPM would be jumping around quite a bit.....
What seems to happen is on hitting the first g32 line, the motor is
switched on momentarily and then off. Sometimes not enough to get 1
revolution - then spin adder goes up and up and at some value it
suddenly goes -ve value and motor starts. It also seems that all the
corrections are negative values, even when positive is called for?
On my machine there is a fair amount of inertia to overcome so changes
in speed are not instantaneous, to go from say 0 to 500rpm takes 3
seconds, 500 to 1000 another 3, 0-1000 also takes about 3. To stop
from 1000 takes 4 and 2 from 500.
Another thing I just though of - would altering the steps/unit help?
At the moment spindle range is 0-1100 with 500 steps per unit, vel
39.25, 250 acceleration - pulse width is 5uS and prechange 5uS.
--
Steve Blackmore
