VelFilter

General

Functional Description

Is used to enter the time constant of a first order low pass filter in the velocity control loop in ms. The filter affects the actual velocity in the feedback of the velocity controller circuit. Using this filter, high frequency oscillations can be suppressed which may occur for example, in the case of a two-mass oscillator with rigid coupling.

If the filter is set too low, high-frequency resonances of the mechanics may lead to the control loop becoming unstable. If the filter is set too high, the dynamic of the control loop is reduced in the first instance; even higher values may lead to the control loop becoming unstable. The optimal conditions must be determined.

NOTE: In the case of a loose coupling (belts, chains, ...) it is better to set VelFilter and CurrRefFilter to 0 and, if necessary, to reduce the velocity controller parameters (Vel_P_Gain and Vel_I_Gain) as well.

NOTE: The parameter value is transferred from the master to the slave via the parameter channel of the Sercos at every access. Typically, this takes about 10 ms. However, times up to 1 s can occur if there is a lot of data transferred on the parameter channel.

NOTE: This parameter can be determined as of firmware version V01.35.x.0 by using the AutoTune automatic controller optimization.

This parameter has no effect for asynchronous motors in open-loop V / f mode (ControlMode = open-loop control / 1).