Rockwell Automation 22D PowerFlex 40P User Manual, FRN 3 User Manual
Page 172
F-4
Encoder Usage and Position StepLogic Application
[Bus Reg Mode] default setting is option 1 “Enabled”. If the
deceleration time is too short, the drive may overshoot the desired
position. For best results, a longer deceleration time may be necessary.
[Bus Reg Mode] can be disabled to provide precise stopping
movements, but the deceleration time will need to be manually tuned so
that it is long enough to avoid F5 OverVoltage faults.
[DB Resistor Sel] default setting is 0 “Disabled”. If improved
deceleration performance is required a Dynamic Brake resistor can be
used. If used, this parameter should be set to the appropriate setting for
the resistor selected.
[Motor NP Poles] must be set to match the number of motor poles
on the motor driven by the PowerFlex 40P drive.
[Encoder PPR] must be set to match the number of pulses per
revolution of the encoder used (i.e., 1024 PPR Encoder).
[Counts Per Unit] sets the number of encoder counts that will be
used to define one position unit. This allows the encoder positions to be
defined in terms of units important to the application. For example, if
1cm of travel on a conveyor belt requires 0.75 turns of the motor, the
motor encoder is 1024 PPR, and the Motor Feedback type is set to
Quadrature, then this parameter would need to be set to (4 x 1024 x 0.75)
= 3072 counts for 1cm of travel. Then all other positions could be setup
in units of “cm”.
[Encoder Pos Tol] indicates the desired position tolerance for the
system. This will determine how close the drive must be to the
commanded position before the drive will indicate “At Home” or “At
Position” in units of raw encoder pulses. This has no effect on the actual
positioning control of the motor.