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High-Speed Input and Pulse Output Features
3–30
High-speed Input and Pulse Output Features
Pulse Output Mode generates three types of motion profiles. Most applications use
one type for most moves. However, each move can be different if required.
S
Trapezoidal – Accel Slope to Target Velocity to Decel Slope
S
Registration – Velocity to Position Control on Interrupt
S
Velocity Control – Speed and Direction only
The trapezoidal profile is the most
common positioning profile. It moves the
load to a pre-defined target position by
creating a move profile. The acceleration
slope is applied at the starting position.
The deceleration slope is applied
backwards from the target position. The
remainder of the move in the middle is
spent traveling at a defined velocity.
Trapezoidal Profile
Time
Accel Decel
Velocity
Start position Target position
Fixed Velocity
Trapezoidal profiles are best for simple point-to-point moves, when the distance
between the starting and ending positions of the move is known in advance.
Registration profiles solve a class of
motion control problems. In some
applications, product material in work
moves past a work tool such as a drill
station. Shown to the right, registration
marks on the scrap area of the work-piece
allow a machine tool to register its position
relative to the rectangle, to drill properly.
Home search moves allow open-loop
motion systems to re-calibrate (preload)
the current position value at powerup.
Registration profiles are a combination of
velocity and position control modes. The
move begins by accelerating to a
programmed velocity. The velocity is
sustained and the move is of indefinite
duration. When an external interrupt
signal occurs (due to registration
sensing), the profile switches from velocity
to position control. The move ends by
continuing motion a pre-defined distance
past the interrupt point (such as a drill hole
location). The deceleration ramp is
applied in advance of the target position.
Registration Profile
Accel Decel
Velocity
Interrupt
Velocity
Control Position
Control
Registration marks
Finished part area
Scrap
Area
Target position
direction of motion
The velocity profile controls only the
direction and speed of motion. There is no
target position specified, so the move can
be of indefinite length. Only the first
velocity value needs to be defined. The
remaining velocity values can be created
while motion is in progress. Arrows in the
profile shown indicate velocity changes. Velocity Profile
Time
Velocity
Choosing the
Profile Type
Trapezoidal
Profile Defined
Registration and
Home Search
Profiles Defined
Velocity Profile
Defined