TTL encoder: Actual speed value, quantisation, nact filter time constant C0497

Answer:
The speed actual value is created with encoder feedback (incremental encoder) by counting the incoming encoder increments (four fold evaluation included) within one sampling period (distance per time).
The quantisation (smallest describable modification) of the speed actual value is improved:

In case of 9300 the sampling period for the encoder evaluation is 125 µs. An encoder with 2048 pulses leads to a speed quantisation of 58.6 rpm. This rough quantisation is visible in signal 'MCTRL-NACT'.

Nact filter for speed control:
For the speed control an actual value smoothed by the nact filter (C0497 nact filter constant) is, however, used in order to ensure smooth running.

Highly-dynamic applications:
Generally, the nact filter has a dead time effect in the control loop. In applications with high demands on the dynamic and less demands on the smooth running characteristic an improvement of the following-error-behaviour can be realized, provided that the nact filter constant (CD0497) is reduced from 2 ms to 1 ms / 0 ms.  With a lower dead time in the speed control loop the speed controller can react and correct the following error more quickly. Consequently, dynamic operations with a smaller following error can be executed.

Resolver, Sin/Cos encoder:
The error curve of a resolver shows bigger tolerances than the one of incremental encoders, but the resolver evaluation offers speed actual value of higher resolution (finer quantisation). The higher resolution has a positive effect on the drive's smooth running, especially in case of low speed. This is also valid for sine / cosine encoders due to the additional high resolution via the sine / cosine signals.

Diagram: Speed actual value MCTRL-NACT in case of encoder feedback (2048 pulses)