Rockwell Automation 1784-PM16SE SoftLogix Motion Card Setup and Configuration Manual - Manual (Page 405)

Publication 1784-UM003A-EN-P – June 2003
Motion Object Attributes 397
The output filter is particularly useful in high inertia applications where
mechanical resonance behavior can severely restrict the maximum bandwidth
capability of the servo loop.
Torque Scaling The Torque Scaling attribute is used to convert the acceleration of the servo
loop into equivalent % rated torque to the motor. This has the effect of
“normalizing” the units of the servo loops gain parameters so that their values
are not affected by variations in feedback resolution, drive scaling, motor and
load inertia, and mechanical gear ratios. In fact, the Torque Scaling value, when
properly established, represents the inertia of the system and is related to the
Tune Inertia value by a factor of the Conversion Constant. The Torque Scaling
value is typically established by the drive’s automatic tuning procedure but the
value can be manually calculated, if necessary, using the following guidelines.
Torque Scaling = 100 % Rated Torque / (Acceleration @ 100% Rated
Torque)
.
For example, if this axis is using position units of motor revolutions (revs), and
that with 100% rated torque applied to the motor, the motor accelerates at a
rate of 3000 Revs/Sec
2
, the Torque Scaling attribute value would be calculated
as shown below.
Torque Scaling = 100 % Rated / (3000 RPS
2
) = 0.033 % Rated/ Revs
Per Second 2
Note: If the Torque Scaling value does not reflect the true torque to
acceleration characteristic of the system, the gains also does not reflect
the true performance of the system.
Integrator Hold Enable When the Integrator Hold Enable attribute value is configured TRUE, the
servo loop temporarily disables any enabled integrators while the command
position is changing. This feature is used by point-to-point moves to minimize
the integrator wind-up during motion. When the Integrator Hold Enable
attribute value is FALSE, all active integrators are always enabled. .
GSV/SSV Access Attribute Name Data Type Values
SSV/GSV Torque Scaling REAL
%Rated/ Position Units Per Second
2
GSV/SSV Access Attribute Name Data Type Values
SSV/GSV Integrator Hold Enable SINT 0 = disabled
1 = enabled