Specifications

Trapezoidal Profile Operation
Trapezoidal Profile Applications
The trapezoidal profile is best suited for simple point-to-point moves, when the target
position is known in advance. Starting velocities must be within the range of 40 pps to 1k
pps. The remainder of the profile parameters are in the profile parameter table.
The time line of signal traces below the profile indicates the order of events. The HSIO uses
logical output Y0 as the Start input to the HSIO, which starts the profile. Immediately the
HSIO turns off the Profile Complete signal (SP104), so the ladder program can monitor the
progress of the move. Typically a ladder program will monitor this bit so it knows when to
initiate the next profile move.
If you are familiar with motion control, you’ll notice that we do not have to specify the
direction of the move. The HSIO function examines the target position relative to the current
position, and automatically outputs the correct direction information to the motor drive.
Notice that the motion accelerates immediately to the starting velocity. This segment is useful
in stepper systems so we can jump past low speed areas when low-torque problems or a
resonant point in the motor might cause a stall. (When a stepper motor stalls, we have lost
the position of the load in open-loop positioning systems). However, it is preferable not to
make the starting velocity too large, because the stepper motor will also “slip” some pulses due
to the inertia of the system.
When you need to change the current position value, use logical Y1 output coil to load a new
value into the HSIO counter. If the ladder program loads a new value in CT76/CT77
(V1076/V1077), then energizing Y1 will copy that value into the HSIO circuit counter. This
must occur before the profile begins, because the HSIO ignores Y1 during motion.
DL05 Micro PLC User Manual, 6th Edition, Rev. C
E–31
Appendix E: High-speed Input and Pulse Output Features
1
2
3
D
E
6
7
8
9
10
11
1
1
14
A
B
C
D
Trapezoidal Profile
Time
Accel Decel
Velocity
Start position
Target position
Target Velocity
Starting
V
elocity
Start
Profile
Complete
Y0
SP104