Rockwell Automation Publication 750-AT006D-EN-P - January 2022
23
Chapter 1 Background
Table 4 - Velocity Feedback Filter Parameters
Parameter No. Parameter Name
Description
10:1000
[Pri Vel Fb Sel]
Enter the 2-digit port location followed by the 4-digit parameter number of the primary feedback device. For encoderless operation,
10:1048 [Open Loop Virtual Encoder] is selected as primary velocity feedback.
10:1001
[Vel Fb Taps]
Sets the number of primary FIR taps used to calculate velocity as the derivative of position over a sample time corresponding to 2
n
number of taps.
10:1002
[c Vel Fb LPF BW]
Automatically calculated for
the primary velocity
feedback low pass filter
bandwidth.
It is applied to the drive when
10:905 [System C/U Select] =
Calculated (0).
It is calculated as a function
of the listed parameters and
it affects the DMTC and
10:906 [System BW] values.
• 10:407 [Motor Poles] – This parameter is the number of motor poles (p). It is calculated as follows:
– p = round (120 x [Motor NP Hertz] / [Motor NP RPM])
• Primary Encoder Resolution – This parameter is the total resolution in edge counts per revolution
(EPR) specified by parameters on the primary feedback option card.
– Primary Encoder Resolution: The total resolution in edge counts per revolution (EPR) specified
by parameters on the primary feedback option card.
– Low-Resolution Example: Resolution = 1024 pulses per revolution * 4 quadrature edge counts
per pulse = 4096 EPR (12-bit). The low-resolution PPR comes directly from a parameter on the
option card. When both A and B channels are selected for an incremental encoder, the edge
count multiplier is 4. This value is the typical and default setting. When only channel A is
selected, then the edge count multiplier is 2.
– High-Resolution Example: Resolution = 1024 pulses per revolution * 1024 edge counts per pulse =
1,048,576 EPR (20-bit). For high-resolution devices, the overall resolution choices are 20-bit
default or an optional 24-bit when the corresponding configuration bit is selected.
– Encoderless Mode: If the primary feedback (10:1000 [Pri Vel Fb Sel] is set to Open Loop Velocity
Feedback, 10:1002 [c Vel Fb LPF BW] will be set to 10 Hz when 10:905 [System C/U Select] =
Calculated (0).
10:1003
[u Vel Fb LPF BW]
Sets the primary velocity feedback low pass filter bandwidth.
This value is applied to the drive when 10:905 [System C/U Select] = User Entered (1).
10:1004
[c Vel Fb LPF Gn]
Displays the calculated value of the primary velocity feedback filter gain. This gain value is applied when parameter 10:905 [System
C/U Sel] is set to Calculated (0).
The calculated filter gain is always zero. Because this is a Lead Lag Filter, a filter gain of zero will configure the filter as a Low Pass
Filter. See
.
This filter determines the amount of filtering applied to the primary velocity feedback channel and is only active in Flux Vector
motor control modes.
10:1005
[u Vel Fb LPF Gain]
Sets the primary velocity feedback filter gain. The parameter's value sets the
mode of the filter and gain of its first order transfer function.
• Value is applied when parameter 10:905 [System C/U Sel] is set to User
Entered (1).
• Value affects the filtering applied to the primary velocity feedback channel
and is only active in Flux Vector motor control modes. Entering a value of 1
turns off the filter.
• For a low pass filter, enter a value of 0. This is the
user default and the calculated gain value.
• For a lag-lead filter, enter a value between 0 and 1.
• For a lead-lag filter, enter a value greater than 1.
10:1006
[Alt Vel Fb Sel]
Enter the 2-digit port location followed by the 4-digit parameter number of the alternate feedback device.
10:1007
[Alt Vel Fb Taps]
Sets the number of alternate FIR taps used to calculate the derivative of position
10:1008
[c AltVelFbLPF BW]
Automatically calculated for
the alternate velocity
feedback low pass filter
bandwidth. It is applied to the
drive when 10:905 [System C/
U Select] = Calculated (0).
It is calculated as a function
of the listed parameters and
it affects the DMTC and
10:1010 [Alt Fb GnScale]
values.
• 10:407 [Motor Poles] – This parameter is the number of motor poles (p). It is calculated as follows:
– p = round (120 x [Motor NP Hertz] / [Motor NP RPM])
• Alternate Encoder PPR and Configuration – This parameter is the total resolution in edge counts
per revolution (EPR) specified by parameters on the alternate feedback option card.
– Low-Resolution Example: Resolution = 1024 pulses per revolution * 4 quadrature edge counts
per pulse = 4096 EPR (12-bit). The low-resolution PPR comes directly from a parameter on the
option card. When both A and B channels are selected for an incremental encoder, the edge
count multiplier is 4. This value is the typical and default setting. When only channel A is
selected, then the edge count multiplier is 2.
– High-Resolution Example: Resolution = 1024 pulses per revolution * 1024 edge counts per pulse =
1,048,576 EPR (20-bit). For high-resolution devices, the overall resolution choices are 20-bit
default or an optional 24-bit when the corresponding configuration bit is selected.
– Encoderless Mode: If the alternate feedback (10:1006 [Alt Vel Fb Sel] is set to Open Loop Velocity
Feedback, 10:1002 [c Vel Fb LPF BW] will be set to 10 Hz when 10:905 [System C/U Select] =
Calculated (0). 10 Hz = 5 times system bandwidth.
10:1009
[u AltVelFbLPF BW]
Sets the alternate velocity feedback low pass filter bandwidth.
This value is applied when 10:905 [System C/U Select] = User Entered (1).
10:1021
[c AltVelFbLPF Gn]
Displays the calculated value of the alternate velocity feedback filter gain. This gain value is applied when parameter 10:905
[System C/U Sel] is set to 'Calculated' (0).
The 'calculated' filter gain is always zero. Because this is a Lead Lag Filter, a filter gain of zero will configure the filter as a Low Pass
Filter. See
.
This filter determines the amount of filtering applied to the alternate velocity feedback channel and is only active in Flux Vector
motor control modes.
10:1022
[u AltVelFbLPF Gn]
Sets the alternate velocity feedback filter gain. This parameter's value sets
the mode of the filter and gain of its first order transfer function.
• Value determines the amount of filtering applied to the alternate velocity
feedback channel and is only active in Flux Vector motor control modes.
• Entering a value of 1 turns off the filter.
• For a low pass filter, enter a value of 0. This is the
user default and the calculated gain value.
• For a lag-lead filter, enter a value between 0 and 1.
• For a lead-lag filter, enter a value greater than 1.
– This value is applied when parameter 10:905
[System C/U Sel] is set to 'User Entered' (1).
