Motion Control
MultiFlex PCI 1000 Series User's Manual
117
Motion Complete Indicators
When the controller receives a move command, the Trajectory Generator calculates a velocity profile.
This profile is based on:
The target position (absolute or relative)
The user defined trajectory parameters (velocity, acceleration, and deceleration)
The user selected velocity profile type (trapezoidal, s-curve, parabolic)
The velocity profile, as calculated by the trajectory generator, is made up by a series of calculated
‘Optimal Positions’ that are evenly spaced along the motion path in increments of 1 msec’s. For an analog
command servo axis these 1 msec optimal positions are passed to the PID filter, which then performs a
linear interpolation, calculating intermediate target points every 250 usec's.
Velocity
(encoder counts per second)
Time (msec's)
4
8
12
16
20
25000
50000
100000
75000
= Optimal positions
Optimal position - Actual position = Following error
calculated trajectory complete
(status bit 3 set)
= Calculated trajectory
= Actual trajectory
= Following Error
For a
closed loop servo
, when the
calculated optimal position
of an axis is equal to the
move target
,
the calculated ‘digital trajectory’ of the move has been completed and the
MC_STAT_TRAJ
status flag
(MCCL status trajectory complete bit 3) will be set (as shown in the Status Panel graphic below). For a
closed loop stepper
axis when the
encoder position is equal to the move target
, the trajectory of the
move has been completed and the
MC_STAT_TRAJ
status flag will be set. For an
open loop stepper
axis when the
step count (pulses issued) is equal to the move target
, the trajectory of the move has
been completed and the
MC_STAT_TRAJ
status flag will be set.
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