User`s manual

7-26 Motion Mate™ DSM314 for Series 90™-30 PLCs User's Manual – January 2001 GFK-1742A
7
Example 2: Changing the Acceleration Mode During a Profile
The following example shows how a different acceleration, and an even acceleration mode, can be
used during a profile using CMOVEs. The first CMOVE accelerates linearly to the programmed
velocity. Because the second CMOVE’s velocity is identical to the first, the first CMOVE finishes
its move without changing velocity. The acceleration of the second move is S-curve as it
decelerates to zero velocity.
ACCEL 2000
VELOC 6000
CMOVE 13000, ABS, LINEAR
ACCEL 4000
CMOVE 15000, INCR, S-CURVE
Figure 7-6. Changing the Acceleration Mode During a Profile
Example 3: Not Enough Distance to Reach Programmed Velocity
CMOVES and PMOVES can be programmed that do not have enough distance to reach the
programmed velocity. The following graph shows a CMOVE that could not reach the
programmed velocity. The DSM314 accelerates to the point where it must start decelerating to
reach the programmed position of C1 at the velocity of the second CMOVE.
ACCEL 2000
VELOC 8000
CMOVE 7000, INCR, LINEAR
ACCEL 10000
VELOC 2000
CMOVE 4400, INCR, LINEAR
Figure 7-7. Not Enough Distance to Reach Programmed Velocity
Example 4: Hanging the Move When the Distance Runs Out
A serious programming error involves “hanging” (i.e. leaving no desirable options for the
command generator) the move at a high velocity when the distance runs out. In the following
example, the first CMOVE accelerates to a high velocity. The second CMOVE has an identical
velocity. However, the distance specified for the second CMOVE is very short. Thus, the axis is
running at a very high velocity and must stop in a short distance. If the programmed acceleration
t
C
-L C-S
1
3000
t
v
C
1C2
7000