Rockwell Automation 1784-PM16SE SoftLogix Motion Card Setup and Configuration Manual - Manual (Page 333)

Publication 1784-UM003A-EN-P – June 2003
Motion Object Attributes 325
Velocity Servo with Torque Servo
Drive
This configuration provides velocity servo control using an external torque
loop servo drive. Synchronous input data to the servo loop includes Velocity
Command, Velocity Offset, and Torque Offset. These values are updated at
the coarse update rate of the associated motion group. The Velocity Command
value is derived directly from the output of the motion planner, while the
Velocity Offset and Torque Offset values are derived from the current value of
the corresponding attributes. These offset attributes may be changed
programmatically via SSV instructions which, when used in conjunction with
future Function Block programs, provides custom “outer” control loop
capability.
Figure 13.9 Velocity Servo with Torque Servo Drive
d/dt
Low
Pass
Filter
Vel P
Gain
Output
Limit
Position
Accum-
ulator
Σ
Velocity
Command
(Coarse)
Fine
Interpolator
Velocity
Command
Velocity
Error
Velocity
Feedback
16-bit
Encoder
Counter
Marker
Latch
Torque
Servo
Drive
Ch Z
Marker
Input
Marker
Event
Handler
Regist.
Event
Handler
Watch
Event
Handler
Watch
Event
Registration
Event
Homing
Event
Regist.
Latch
Registration
Input
Acc
FF
Gain
d/dt
Σ
Vel I
Gain
Velocity
Integrator
Error
16 Bit
DAC
Position
Feedback
(Coarse)
Error
Accum
-ulator
Low
Pass
Filter Output
Scaling
Friction
Comp.
Output
Offset
&
Servo
Polarity
Servo
Output
Level
Output
Filter
BW
Encoder
Polarity
Velocity
Offset
Watch
Position
Torque
Offset
Σ
AQB
Encoder
Ch A/B
Encoder
Input
Motor
Servo Config = Velocity Servo