User manual

Geo Brick Drive User Manual
Motor Setup 201
Commutation Cycle Size: Ixx70, Ixx71
The ratio of Ixx70/Ixx71 represents the number of encoder counts per electrical cycle. For an AC
Induction Motor, we will limit the explanation for digital quadrature feedback devices since they are the
most widely used for this type of motor.
Digital Quadrature Feedback
Ixx70= {Number of pole pairs of the motor} –User Input
Ixx71= {Number of counts per revolution} –User Input
ADC Offsets: Ixx29, Ixx79
The ADC offsets importance may vary from one system to another, depending on the motor(s) type and
application requirements. They can be left at default of zero especially if a motor setup is to be
reproduced on multiple machines by copying the configuration file of the first time integration. However,
they should ultimately be set to minimize measurement offsets from the A and B-phase current feedback
circuits, respectively (read in Suggested M-variables Mxx05, Mxx06).
Current-Loop Tuning: Ixx61, Ixx62, Ixx76
The current-loop tuning is done as in any Turbo PMAC digital current loop setup. The PMACTuningPro2
automatic or interactive utility can be used to fine-tune the Current-Loop. An acceptable Current-Loop
step response would look like:
Note
Current-Loop Natural Frequencies in the range of 200-500 Hz are
good enough for most applications. Tuning the current loop too tightly
(Natural Frequency > 800Hz) can have deteriorating effects on the
position loop tuning.