Version 1.0 06/2001 |
(1) The required max. output pulse rate.
PRmax = Vmax*N/60 2047
PRmax = ( DDAcycle + 1) *1.024ms
PRmax : max. output pulse rate.
Vmax : max. speed (rpm).
N: the pulse number of stepping motor per revolution. (pulse/rev).
2.The required speed resolution.
The maximum output pulse number is Np(0~2047), therefore the speed resolution is Vmax(max. speed)/Np. The DDA cycle
can be obtained by following equation. Np
( DDAcycle + 1) *1.024ms
3.When choose large DDA cycle (DDA period), it will occur vibration between different pulse input which generally can be observed during acceleration or deceleration. So, the small DDA cycle , the smooth acceleration/deceleration curve as long as the speed resolution is acceptable.
Example: Stepping Motor
The specification of stepping motor is 500 pulse/rev, max. speed 500 rpm, speed resolution 2 rpm.
The required max. pulse rate
PRmax = 500 rpm*500/60 = 4166.67 pps
The maximum output pulse
Np = 500rpm/2rpm =250 pulse number
The DDA cycle can be calculated by follow equation
Np
( DDAcycle + 1) *1.024ms
250
4166.67 = ( DDAcycle + 1) *1.024ms DDA cycle = 58
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