Operation and Maintenance Manual
4.1.2 Point
4.1.2.1 Single Point Commands
Positioner moves to the axis point reference, as sent by the PTx command,
and comes to rest there. The amplifier continues to supply current as needed
to hold the position against external forces.
If the positioner has been switched from LOCAL to REMOTE and no point
command has been sent, the axis point reference is the place where the
positioner came to rest.
When a single PTx command is send while the ACU is in Remote and Point
mode, the positioner moves to the commanded point using a trapezoidal
velocity profile.
If the Continuous Rotation bit (bit #5) in Control Word #1 is set, the direction
of motion is the shortest route, and the user has no control over the direction.
If it is not set, the direction of motion is according to the commanded values.
For example, if the position is +170.000 and the user wishes to move 20
degrees CW, the commanded point must be +190.000. If he wishes to reach
the same point by a 340 degree motion CCW, the commanded point must be -
170.000.
The acceleration is determined by the value of the MAx parameter.
The maximum speed is determined by the step size, the MVx parameter, and
the "Full-Speed Step" bit (bit #6) in Control Word #2. If "Full-Speed Step" is
set, the maximum speed will be the MVx parameter for all step sizes greater
than MVx
2
/MAx. For smaller steps, the velocity profile will be triangular. If
"Full-Speed Step" is zero, the maximum velocity will be according to the
formula sqrt(step*MAx/5.0), or MVx, whichever is less. For applications
where there are many small, irregular position corrections being commanded,
and response time is not critical, this formula provides smoother motion with
good response time.
4.1.2.2 Repeated Point Commands (Track Mode)
If a series of point commands are sent when in point mode, and the time delay
between commands is less than the maximum update-time (UTx) parameter,
the points will be interpreted as a continuous trajectory. Instead of coming to
rest, the positioner extrapolates the trajectory based on the last two points