ASCII - Command BQMODE    
Syntax Transmit BQMODE [Data]    
Syntax Receive BQMODE <Data>   Available in  
Type Variable rw   MMI No
ASCII Format Integer8   CANBus Object Number 3666 (hex)
DIM -   PROFIBUS PNU 1958 (dec) IND = 1 (dec)
Range 0...4   DPR 358 (dec)
Default 1    
Opmode All   Data Type Bus/DPR Integer8
Drive State -   Weighting  
Start Firmware 1.0    
Configuration No   Last Change of this Object 1.3
Function Group filter   EEPROM Yes
Short Description Filter selection

Description

Status Short Description Description
BQMODE=0 filter turned off
BQMODE=1 compatibility mode In this mode, the filter is selected due to the settings of ARLPF, ARHPF, ARLPD and ARHPD. The filter is selected as follows:

ARLPF > 0,ARHPF > 0,ARLPD = ARHPD = 0 : PID-T2 filter (1st-order lag compensator)
ARLPF > 0, ARHPF > 0, ARLPD > 0, ARHPD = 0 : notch /bi-quad
ARLPF > 0, ARLPD > 0, ARHPD = ARHPD = 0 : 2nd-order low-pass (n/a)
ARLPF = ARHPF = ARLPD = ARHPD = 0 : filter turned off
BQMODE=2 PID-T2 filter (1st-order lag compensator) The PID-T2 filter is only activated if the following conditions are met:

ARLPF > 0, ARHPF > 0.

PID-T2 filters can be used effectively to reduce the torque ripple and resonances from the motor, gearbox and a coupled load.

The transfer function is TF
BQMODE=3 notch / bi-quad filter The notch / bi-quad filter is only activated if the following conditions are met:

ARLPF > 0, ARHPF > 0, ARLPD > 0, ARHPD = 0.

Notch filters an be used to suppress single resonances because they offer a high attenuation for a small frequeny range. However, even small deviations between filter frequency and resonance frequency degrade the effect of this filter type dramatically. This high paramter sensitivity makes notch filters difficult to set up.

Bi-quad filters can be used effectively to compensate for resonances in a two-mass servo system. If set up properly, this filter type helps to increase the stability margins which allows for a higher gain and thus a higher bandwidth of the velocity loop.

The transfer function is TF


Note:

If ARLPF = ARHPF, ARLPD > 0 and ARHPD = 0, the filter acts as a notch filter, otherwise it acts as a bi-quad filter.
BQMODE=4 2nd-order low-pass filter The 2nd-order low-pass filter is only activated if the following conditions are met:

ARLPF > 0, ARLPD > 0.

For general examples of low-pass filter usage, see ARLP2. If a 1st-order low-pass filter exhibits too much phase lag below the cutt-off frequency or too little signal attenuation above the cutt-off frequency, a 2nd-order low-pass filters can be used to improve the behavior.

The transfer function is TF