User's Manual

PMAC User Manual
Table of Contents v
Axis Position Scaling ..........................................................................................................................................79
Leadscrew Compensation...................................................................................................................................79
Backlash Compensation......................................................................................................................................82
Torque Compensation Tables .............................................................................................................................84
SETTING UP PMAC COMMUTATION ...............................................................................................................87
Introduction .............................................................................................................................................................87
Incremental Encoder Feedback Requirement..........................................................................................................87
Phase Referencing...................................................................................................................................................87
Two-Analog-Output Requirement...........................................................................................................................87
Basic Parameter Specification.................................................................................................................................88
Counts per Commutation Cycle..........................................................................................................................88
Angle Between Phases ........................................................................................................................................88
Permanent Magnet Brushless Motor Commutation ................................................................................................89
Getting the Polarity Right...................................................................................................................................89
Power-on Phasing Search ..................................................................................................................................89
Phasing Referenced to Absolute Sensor .............................................................................................................92
Phasing Referenced to Hall-Effect Sensor..........................................................................................................94
Phase Advance....................................................................................................................................................95
Switched Reluctance Motor Commutation..............................................................................................................96
AC Induction Motor Commutation .........................................................................................................................96
Setting the Slip Gain ...........................................................................................................................................96
Setting the Magnetization Current......................................................................................................................97
Experimental Setting of Induction Motor Parameters........................................................................................98
Open-Loop Microstepping Commutation ...........................................................................................................99
Setting the I-Variables ......................................................................................................................................100
Using the Motor................................................................................................................................................101
User-Written Commutation Algorithm .................................................................................................................101
Memory Space, Software Interface, and Program Restrictions........................................................................101
CLOSING THE SERVO LOOP ............................................................................................................................103
The Purpose of the Servo Loop.............................................................................................................................103
Servo Update Rate.................................................................................................................................................103
Reasons to Increase Rate..................................................................................................................................103
Reasons to Decrease Rate.................................................................................................................................103
Ramifications of Changing the Rate .................................................................................................................103
Amplifier Types ....................................................................................................................................................104
Velocity-Mode Amplifiers .................................................................................................................................104
Torque-Mode Amplifiers...................................................................................................................................104
Voltage-Mode Amplifiers..................................................................................................................................105
Sinusoidal-Input Amplifiers ..............................................................................................................................105
Pulse-and-Direction Amplifiers........................................................................................................................106
Hydraulic Servo Amplifiers ..............................................................................................................................106
PID Servo Filter ....................................................................................................................................................106
How the PID Filter Works................................................................................................................................106
Tuning the PID Filter .......................................................................................................................................107
Actual PID Algorithm .......................................................................................................................................108
Notch Filters..........................................................................................................................................................108
Automatic Notch Specification..........................................................................................................................109
Manual Notch Specification..............................................................................................................................109
Other Uses of the Notch Filter..........................................................................................................................110
Extended (Pole-Placement) Servo Filter ...............................................................................................................111
User-Written Servo Filter......................................................................................................................................111
What is needed to write the Filter.....................................................................................................................112
Download and Enable Procedure.....................................................................................................................112
Memory Space, Software Interface, and Program Restrictions.............................................................................112
Usable Data Spaces..........................................................................................................................................112