Rockwell Automation 1784-PM16SE SoftLogix Motion Card Setup and Configuration Manual - Manual (Page 349)

Publication 1784-UM003A-EN-P – June 2003
Motion Object Attributes 341
Torque Offset Torque Offset compensation can be used to provide a dynamic torque
command correction to the output of the velocity servo loop. Since this value
is updated synchronously every Coarse Update Period, the Torque Offset can
be tied into custom outer control loop algorithms using Function Block
programming.
Output Offset Another common situation when interfacing an external Servo Drive,
particularly for velocity servo drives, is the effect of drive offset. Cumulative
offsets of the servo module’s DAC output and the Servo Drive Input result in
a situation where a zero commanded Servo Output value causes the axis to
“drift”. If the drift is excessive it can play havoc on the Hookup Diagnostic
and Tuning procedures as well as result in a steady-state non-zero position
error when the servo loop is closed.
Output offset compensation can be used to correct this problem by adding a
fixed value, called Output Offset, to the Servo Output. This value is chosen to
achieve near zero drive velocity when the uncompensated Servo Output value
is zero.
GSV/SSV Access Attribute Name Data Type Values
SSV/GSV Torque Offset REAL %
Range: -100% to 100%
GSV/SSV Access Attribute Name Data Type Values
SSV/GSV Output Offset REAL Volts
Range: +/-10