ADLINK PCI-8144 - Manual (Page 46)

36 Operation Theory
4.2.4 S-curve and Bell-curve speed profile
S-curve means the speed profile in accelerate/decelerate area fol-
lows a 2nd order curve. It can reduce vibration at the beginning of
motor start and stop. In order to speed up the acceleration/decel-
eration during motion, we need to insert a linear part into these
areas. We call this shape as “Bell” curve. It adds a linear curve
between the upper side of s-curve and lower side of s-curve. This
shape improves the speed of acceleration and also reduces the
vibration of acceleration.
a) For a purse S-curve, we define its shape’s parameter as below:
X Tacc: Acceleration time in second
X Tdec: Deceleration time in second
X StrVel: Starting velocity in PPS
X MaxVel: Maximum velocity in PPS
The PCI-8144 Tacc and Tdec are always the same.