ADLINK Technology PCI-8154, User Manual

Page: 59 / 228

Operation Theory 49
4.2.6 One axis position mode
Position mode means the motion controller will output a specific
amount of pulses which is equal to users’ desired position or dis-
tance. The unit of distance or position is pulse internally on the
motion controller. The minimum length of distance is one pulse.
However, in PCI-8154, we provide a floating point function for
users to transform a physical length to pulses. Inside our software
library, we will keep those distance less than one pulse in register
and apply them to the next motion function. Besides positioning
via pulse counts, our motion controller provides three types of
speed profile to accomplish positioning. There are 1st order trape-
zoidal, 2nd order S-curve, and mixed bell curve. Users can call
respective functions to perform that. The following char shows the
relationship between distance and speed profile. We use trapezoi-
dal shape to show it.
The distance is the area of the V-t diagram of this profile.