Appendix F
Encoder Usage and Position
StepLogic Application
Encoder Usage
The PowerFlex 40P includes a pulse-train/encoder input. When E216
[Motor Fdbk Type] is set to a value other than zero, the drive is set to use
an encoder. The drive will use the encoder in several ways depending on
the settings of other parameters. The drive will use the encoder as shown
below (listed in order of priority):
1. If enabled by P038
[Speed Reference], the encoder will be used
directly as a commanded speed (normally used with a pulse train) or
as a position reference (normally used with a quadrature encoder).
2. If not enabled by P038
[Speed Reference], when the PID Feedback
or PID Reference are set to use an encoder than the PID function will
use the encoder or pulse train input.
3. If not enabled by P038
[Speed Reference] or the PID parameters,
then if E216
[Motor Fdbk Type] is set the encoder is used for direct
feedback and trim of the speed command. The normal slip
compensation is not used in this case. Instead the drive will use the
encoder to determine actual output frequency and adjust the output
frequency to match the command. Parameters E220
[Ki Speed Loop]
and E221 [Kp Speed Loop] are used in this control loop. The
primary benefit of this mode is increased speed accuracy when
compared to open-loop slip compensation. It does not provide speed
bandwidth improvement.
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