ADLINK PCI-8164 - Manual (Page 88)

76 Operation Theory
goes from StrVel to (StrVel + VSacc). In the second constant jerk
region during acceleration, the velocity goes from (MaxVel –
StrVel) to MaxVel. Between them, the linear region accelerates
velocity from (StrVel + VSacc) to (MaxVel - VSacc) constantly. The
deceleration period is similar in fashion.
Special case:
If you want to disable the linear region, the VSacc/VSdec must be
assigned 0 rather than 0.5 (MaxVel-StrVel).
Remember that the VSacc/VSdec is in units of PPS and it should
always keep in the range of [0 to (MaxVel - Strvel)/2 ], where “0”
means no linear region.
The S-curve profile motion functions are designed to always pro-
duce smooth motion. If the time for acceleration parameters com-
bined with the final position don’t allow an axis to reach the
maximum velocity (i.e. the moving distance is too small to reach
MaxVel), then the maximum velocity is automatically lowered (see
the figure below).
The rule is to lower the value of MaxVel and the Tacc, Tdec,
VSacc, VSdec automatically, and keep StrVel, acceleration, and
jerk unchanged. This is also applicable for trapezoidal profile
motion.