User Manual

Table Of Contents
Mode description
Advanced Digital Motor Controller User Manual 155
SECTION 12
Closed Loop
Count Position
Mode
In the Closed Loop Position mode, the controller can move a motor a precise number of
encoder counts, using a predefined acceleration, constant velocity, and deceleration. This
mode requires that an encoder be mounted on the motor.
Mode description
The desired position is given in the number of counts. Using acceleration, deceleration
and top velocity, the controller computes the position at which the motor is expected to
be at every one millisecond interval. A PID then computes the power to give to the motor
in order to maintain that position. A comparator looks at the desired position and the com-
puted current position and issues a Destination Reached flag. The figure below shows a
representation of this mode.
Measured Position
Destination
Reached
-
=
Sensor
Desired End Position
Desired Velocity
Desired Position
at Instant
Desired Acceleration
Trajectory
Computation
PID
Motor
FIGURE 12-1 Closed Loop Position mode