MC1231A Datasheet, PDF (20/70 Pages) List of Unclassifed Manufacturers – Advanced Brushless Motor Control Chipset

will occur, and all new parameters will be ignored except the
position. See the section of this manual entitled "Command Error"
for more information..
Before switching to the S-curve point to point profile mode, the
axis should be at a complete rest.
When the axis is in the S-curve profile mode, the SET_MAX_ACC
command should be used to load the max. acceleration value. The
alternate acceleration loading command SET_ACC can not be
used.
Trapezoidal Point to Point
The following table summarizes the host specified profile parameters
for the trapezoidal point to point profile mode:
Profile
Parameter
Destination
Position
Maximum
Velocity
Accel.
Representation & Range
signed 32 bits
-1,073,741,824 to 1,073,741,823
unsigned 32 bits (1/216 scaling)
0 to 1,073,741,823
unsigned 32 bits (1/216 scaling)
0 to1,073,741,823
Units
counts
counts/smpl
counts/smpl2
In the trapezoidal point to point profile mode the host specifies a
destination position, a maximum velocity, and an acceleration. The
trajectory is executed by accelerating at the commanded acceleration to
the maximum velocity where it coasts until decelerating such that the
destination position is reached with the axis at rest (zero velocity). If it is
not possible to reach the maximum velocity (because deceleration must
begin) then the velocity profile will have no "coasting" phase. The
acceleration rate is the same as the deceleration rate.
A new maximum velocity and destination position can be specified
while the axis is in motion. When this occurs the axis will accelerate or
decelerate toward the new destination position while attempting to
satisfy the new maximum velocity condition.
When in Trapezoidal point to point profile mode, to change the
acceleration, the axis must come to a complete stop. After this has
occurred, a new acceleration value can be loaded. If the
acceleration parameter is changed during motion then a
'command error' will occur, and all updated parameters will be
ignored except the position. See the section of this manual
entitled "Command Errors" for more information.
Before switching to the Trapezoidal point to point profile mode,
the axis should be at a complete rest.
The following figure shows a velocity profile for a typical point to point
trapezoidal move, along with a more complicated move involving on the
fly changes to the maximum velocity and the destination position.
Vel.
Simple trapezoidal mode motion
Time
Vel.
change max
velocity
change target
position
Complex trapezoidal mode motion
Time
Velocity Contouring
The following table summarizes the host specified profile parameters
for the Velocity contouring profile mode:
Profile
Parameter
Maximum
Velocity
Acceleration
Representation & Range
unsigned 32 bits (1/216 scaling)
0 to 1,073,741,823
signed 32 bits* (1/216 scaling)
-1,073,741,824 to 1,073,741,823
Units
counts/smpl
counts/smpl2
* negative numbers using 1/216 scaling are handled no
differently than positive numbers. For example if an
acceration value of -1.95 counts/sample time2 is desired, -
1.95 is multipled by 65,536 and the result is sent to the
chipset (-127,795 dec. or fffe0ccd hex).
In this profile mode the host specifies two parameters, the commanded
acceleration, and the maximum velocity. The trajectory is executed by
continuously accelerating the axis at the commanded rate until the max.
velocity is reached, or until a new acceleration command is given.
The maximum velocity value must always be positive. Motion
direction is controlled using the acceleration value. Positive
acceleration values result in positive motion, and negative
acceleration values result in negative motion.
There are no restrictions on changing the profile parameters on
the fly. Note that the motion is not bounded by position however.
It is the responsibility of the host to generate acceleration and
max. velocity command values which result in safe motion, within
acceptable position limits.
The following figure shows a typical velocity profile using this mode.
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