ADLINK PCI-8164 - Manual (Page 84)

72 Operation Theory
4.1.3 Trapezoidal motion
This mode moves a singe axis motor to a specified position (or
distance) with a trapezoidal velocity profile. The single axis is con-
trolled from point to point. 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 cases,
the acceleration and deceleration may be different. The function
_8164_motion_done() is used to check whether the movement
is completed.
The diagram shows the trapezoidal profile.
The card supports 2 trapezoidal point-to-point functions. In the
_8164_start_ta_move() function, the absolute target position
must be given in units of pulses. The physical length or angle of
one movement is dependent on the motor driver and mechanism
(including the motor). Since absolute move mode needs the infor-
mation of current actual position, the “External encoder feedback
(EA, EB pins)” should be set in _8164_set_feedback_src()
function. The ratio between command pulses and external feed-
back pulse input must be appropriately set by the
_8164_set_move_ratio() function.
In the _8164_start_tr_move() function, the relative displace-
ment must be given in units of pulses. Unsymmetrical trapezoidal
velocity profile (Tacc is not equal Tdec) can be specified with
both
_8164_start_ta_move() and
_8164_start_tr_move() functions.