317
Inverter Positioning
Section 7-3
Traditional Inverter Positioning
The PLC counts the feedback pulses from the encoder using a high-speed
counter. When a deceleration point is reached, the speed is changed to con-
trol the stop position. If the precision of the stop position must be increased,
the stop position must also be detected to control positioning.
PLC
Speed change judgments
Multi-step or
speed
commands
Inverter
Power
supply
frequency
Inductive motor
Encoder
Feedback pulses
If Positioning Speed Is Increased:
Frequency
Calculated speed-
change point
Point where speed was
actually changed (High speed
results in positioning error.)
Preset
deceleration
Position
Actual
Settings
Positioning
error occurs
Positioning
error occurs!
Command
output
Setting
Actual
Changing the speed
is delayed.
Time
If Positioning Accuracy Is Increased:
Frequency
Calculated speed-
change point
Points where speed was
actually changed
Low-speed
operation
Actually stopping
point
Calculated
stopping
point
Time
Position
Actual
Settings
Positioning
error occurs
Positioning
error
continues
Error is reduced
by using a low
speed
Positioning
error is
reduced
Command
output
Setting
Actual
Time
Stopping position
is reached faster
due to high-speed
positioning error.
Stopping from a low speed is necessary to prevent positioning error.
The speed of high-speed operation produces error, requiring that
the deceleration start position be calculated and adjusted so that
a low speed is achieved near the stopping point.
The need for low-speed operation near the stopping position
increases the positioning time. PLC
Summary of Contents for CP1L-EL20DR-D
Page 3: ...CP1L EL20D CP1L EM30D CP1L EM40D CP1L EL EM CPU Unit Operation Manual Produced July 2017...
Page 4: ...iv...
Page 10: ...x...
Page 22: ...xxii...
Page 34: ...xxxiv Software Licenses and Copyrights 7...
Page 192: ...158 Trial Operation and Debugging Section 5 3...
Page 250: ...216 Automatic Clock Adjustment and Specifying Servers by Host Name Section 6 7...
Page 666: ...632 Trouble Shooting Section 11 7...
Page 696: ...662 Standard Models Appendix A...
Page 805: ...771 Connections to Serial Communications Option Boards Appendix F Connecting to Unit...
Page 806: ...772 Connections to Serial Communications Option Boards Appendix F...
Page 836: ...802 PLC Setup Appendix G...
Page 838: ...804 TCP Status Transitions Appendix H...
Page 840: ...806 Ethernet Network Parameters Appendix I...
Page 842: ...808 Buffer Configuration CP1L EL EM Appendix J...
Page 844: ...810 Ethernet Specifications Appendix K...
Page 851: ...Index 817 work words 118 write protection 447...
Page 852: ...818 Index...
Page 854: ...820 Revision History...
Page 855: ......