Omron CS1W-213 - REV 02-2008, Operation Manual

Page: 374 / 401

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Estimating Times and Pulses for Acceleration/Deceleration Appendix B
The following section describes the deceleration time when the speed command is changed during positioning
and the acceleration/deceleration time designation is set to 1.
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Calculating Deceleration Time If Speed Is Changed during
Positioning
If the acceleration/deceleration time designation (m + 19 for the X axis) is set so that the deceleration time is
directly set as the time from the present speed to the target speed, the time to reach the target speed and the
positioning time will be specified as the time from the present speed until operation stops when positioning is
completed. In the following conditions, however, deceleration will start immediately toward 0 pps rather than
using the specified deceleration time.
This immediate deceleration will occur when all of the four conditions are met.
1. The acceleration/deceleration time designation is set to directly set the deceleration time as the time from
the present speed to the target speed.
2. The speed is changed during positioning.
3. The target speed at that time is less than half of the present speed.
4. The speed is changed at a position beyond the deceleration start limit position calculated from the target
speed and deceleration time in condition 3 above.
In other words, consider the deceleration rate for the final deceleration from the target speed to the completion
of positioning and determine whether the deceleration rate can be maintained if deceleration is performed from
the present position to determine whether deceleration will be preformed in the specified deceleration time.
The following provides a description using a specific example.
Figure 1 illustrates movement to a final target position of 216,000. If the speed is switched to 400 pps in the
proximity of 193,000, operation will be performed as in figure 3 rather than figure 2.
Time (ms)
Time (ms)
500
500
10,000
500
Time (ms)
Speed
Speed
Speed (pps)
12,500
500
10,000,
400
10,000
400
Figure 1: Normal Operation
If there is no change in
speed, operation will stop at
the target position in the
specified deceleration time.
Figure 2:
The Unit may operate as in
figure 3 rather than as in
figure 2.
Figure 3:
Calculation of the
deceleration start limit for the
Unit