Rockwell Automation Publication MOTION-RM003I-EN-P - February 2018 259
calculations are performed; the System Damping attribute value is simply
updated. An SSV to the System Damping attribute also updates the
Damping Factor attribute value.
The value for this attribute can also be updated through a Set service to the
Damping Factor attribute. When derived from the Damping Factor attribute, no
calculations are performed; the System Damping attribute value is simply updated.
A Set or SSV to the System Damping attribute also updates the Damping Factor
attribute value.
System Bandwidth
Usage Access T Data
Type
Default Min Max Semantics of Values
Required - C
(Derived from
Servo Bandwidth)
Set/SSV
REAL 0 0
Loop Bandwidth Units
A Set or SSV to the System Bandwidth attribute value calculates and updates the
applicable loop gain attribute values based on the current System Damping (Z).
The System Bandwidth attribute is designed to be used to implement a single
'knob' Manual Tuning procedure. If the drive is configured for Velocity Loop
operation, the System Bandwidth is equivalent to the bandwidth of the velocity
loop. If the drive is configured for Position Loop operation, the System Bandwidth
is equivalent to the bandwidth of the position loop. In addition to calculating and
updating the Loop Bandwidth attribute values, an update to this attribute also
updates the Integral Bandwidth attributes as well as the Feedforward attributes
according to the Gain Tuning Configuration Bits setting.
The following configurations impact the calculations for this attribute as follows:
• Position Loop Operation
If the drive is configured for Position Loop operation the following
calculations apply:
Position Loop Bandwidth = System Bandwidth
Position Integer Bandwidth = 0.25 Damping Factor
2
* System Bandwidth
Velocity Loop Bandwidth = 4 * Damping Factor
2
* System Bandwidth
Velocity Integer Bandwidth = System Bandwidth
Velocity Error Tolerance = 2 * max(Max Accel, Max Decel) / Velocity Loop
Bandwidth (rad/s)
• Velocity Loop Operation