Trapezoidal Motion. ADLINK Technology PCI-8136M

4.10 Trapezoidal Motion

This mode is used to move one or more axes to a specified position (or distance) with a trapezoidal velocity profile. Single axis and multi -axes are controlled from point to point or follow a specific path like ARC. 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 absolute and relative mode, the acceleration and the deceleration time in seconds can be different. The _8136_motion_status() function is used to check whether the movement is complete( the pulse command is all sent).

The following diagram shows the trapezoidal profile. The target position or distance must b e given in the unit of pulse.

The physical length or angle of one movement is dependent on the motor driver and the mechanism (includes the motor). Since absolute move mode needs the information of current actual position, so “External encoder feedback (EA, EB pins)” must be connected or the feedback source must be assigned in _8136_M_set_Feedback() function if you don't have encoder on axis0 to 2. You can assign the feedback source to be the command pulses only if you are using axis0 to 2. Otherwise, you must connect a encoder feedback signal on that axis. An example for PTP motion function is as follows:

_8136_Start_TR_Move(CardNo, Distance, str_vel, max_vel, Tacc,

Tdec)

There are some similar parameters in all motion functions. The str_vel and max_vel parameters are given in the unit of pulse per second (pps). The Tacc and Tdec parameters are given in the unit of seconds. They represent accel./decel time respectively. You have to know the physical meaning of

“one movement” to calculate the physical value of the relative velocity or acceleration parameters. The following formula gives the basic relationship between these parameters. max_vel = str_vel + accel*Tacc;

0=max_vel+decel*Tdec where accel/decel represents the acceleration/deceleration rate in unit of pps/sec. The area inside the trapezoidal profile represents the moving distance.

Operation Theorem

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max_vel str_vel

Tacc

Tdec

Relative Functions:

_8136_P_Initial() refer to section 5.2

_8136_Motion_Stop() refer to section 5.18

_8136_Motion_Status() refer to section 5.12

_8136_Start_TR_Move(),_8136_Start_TA_Move() refer to section

5.13

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• Operation Theorem