Operation Theorem
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4.11 S-Curve Profile Motion
This mode is used to move one axis motor to a specified position (or distance)
with a S-curve velocity profile. S-curve acceleration profiles are useful for
both steppers and servo motors. The smooth transitions between the start of
the acceleration ramp and the transition to the constant velocity produce less
wear and tear than a trapezoidal profile motion. The smoother performance
increases the life of the motors and mechanics of a system.
Single axis and multi-axes are controlled from point to point or follow a
specific path like ARC. An absolute or relative motion can be performed. In
absolute mode, the target position is assigned. In relative mode, the target
displacement is assigned. In both absolute and relative mode, the
acceleration and the deceleration time in seconds can be different. The
_8136_motion_status()
function is used to check whether the movement is
complete( the pulse command is all sent). The following diagram shows the
trapezoidal profile. The target position or distance must be given in the unit of
pulse.
The physical length or angle of one movement is dependent on the motor
driver and the mechanism (includes the motor). Since absolute move mode
needs the information of current actual position, so “External encoder
feedback (EA, EB pins)” must be connected or the feedback source must be
assigned in
_8136_M_set_Feedback()
function if you don't have encoder on
axis0 to 2. You can assign the feedback source to be the command pulses
only if you are using axis0 to 2. Otherwise, you must connect an encoder
feedback signal on that axis.
These are some similar parameters in all motion functions. The str_vel and
max_vel parameters are given in the unit of pulse per second (pps). The Tacc
and Tdec parameters are given in the unit of seconds. They represent
accel./decel time respectively. You have to know the physical meaning of
“one movement” to calculate the physical value of the relative velocity or
acceleration parameters. The following diagram shows the meaning of these
parameters.
Time(sec)
Velocity(pps)
str_vel
Tdec
Tacc
max_vel
T
s
