ADLINK Technology PCI-8254, User Manual

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148 Motion Control Theory
2. Aborting forced
Characteristic of this kind of command is that the track transfer
to new command immediately. The controller makes no
smoothing treatment and so the motion track match with the
command exactly. In this mode speed component of each axes
may become un-smooth. You must pay special attention to
transfer speed and angle to prevent vibration from happening.
Figure 4-49: Velocity blending (method 2)
3. Aborting stop
After command is received the original interpolation command
slows down to stop (deceleration rate adjustable), new
interpolation command starts after movement fully stopped.
Take figure below. When executing a straight line interpolation
command from S1 to E1, a "abort - decelerate" interpolation
command is given at position E1’. The controller then slows down
according to given deceleration rate and stops at S2, and then
move to E2. Please note that if position is given by relative
distance the relative starting point is E1’ rather than S2.
Figure 4-50: Velocity blending (method 3)
E1
S1 E2
E1
S1
S2
E2