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2 Motion Control Configuration and Principles
NJ-series CPU Unit Motion Control User’s Manual (W507)
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Motion Control Configuration
A control system built with Servo Drives generally controls motor operation with a semi-closed loop.
The semi-closed loop uses an encoder attached to the motor to detect the amount of rotation that has
been performed by the motor in response to the command value. This is provided as feedback of the
machine’s travel distance. The following error between the command value and actual motor rotation is
calculated and control is performed to bring the following error to zero.
In a machine configuration that uses the MC Function Module, no feedback information is provided for
the commands from the user program in the CPU Unit. A feedback system is built into the Servo Drive.
•
When motion control instructions are executed in the user program, the MC Function Module inter-
prets the resulting commands.
•
The MC Function Module then performs motion control processing at a fixed period based on the
results of the command interpretation. It generates command values to send to the Servo Drive. The
following command values are generated: target position, target velocity, and target torque.
•
The command values are sent by using PDO communications during each process data communica-
tions cycle of EtherCAT communications.
•
The Servo Drive performs position loop control, velocity loop control, and torque loop control based
on the command values received during each process data communications cycle of EtherCAT com-
munications.
•
The encoder’s current value and the Servo Drive status are sent to the CPU Unit during each process
data communications cycle of EtherCAT communications.
Additional Information
•
Motion control processing and process data communications in EtherCAT communications are
performed during the same time period.
•
The MC Function Module controls the Servo Drive, which contains the position control loop,
velocity control loop, and torque control loop.
NJ-series CPU Unit
A feedback system is not configured.
A feedback system is configured.
Servo Drive
User program
MC Function
Module
EtherCAT
Communications
Master Module
EtherCAT
communications
Communications
processing
Command
interpretation
Data processing
Motion
control
instruction
Communica-
tions
processing
Status
Position
control
Velocity
control
Torque
control
Command
interpretation
M
E
Summary of Contents for NJ501-1300
Page 12: ...Sections in this Manual 10 NJ series CPU Unit Motion Control User s Manual W507...
Page 18: ...16 NJ series CPU Unit Motion Control User s Manual W507 CONTENTS...
Page 22: ...Read and Understand this Manual 20 NJ series CPU Unit Motion Control User s Manual W507...
Page 34: ...Revision History 32 NJ series CPU Unit Motion Control User s Manual W507...
Page 86: ...3 Configuring Axes and Axes Groups 3 28 NJ series CPU Unit Motion Control User s Manual W507...
Page 122: ...5 Motion Control Parameters 5 24 NJ series CPU Unit Motion Control User s Manual W507...
Page 158: ...6 Motion Control Programming 6 36 NJ series CPU Unit Motion Control User s Manual W507...
Page 166: ...7 Manual Operation 7 8 NJ series CPU Unit Motion Control User s Manual W507...
Page 182: ...8 Homing 8 16 NJ series CPU Unit Motion Control User s Manual W507...
Page 346: ...10 Sample Programming 10 92 NJ series CPU Unit Motion Control User s Manual W507...
Page 422: ...Appendices A 18 NJ series CPU Unit Motion Control User s Manual W507...
Page 423: ...Index 1 NJ series CPU Unit Motion Control User s Manual W507 I Index...
Page 430: ...Index 8 NJ series CPU Unit Motion Control User s Manual W507 Index...