Velocity feedback, Velocity error, Velocity integrator error – Rockwell Automation 1784-PM16SE SoftLogix Motion Card Setup and Configuration Manual User Manual
Page 312: Acceleration command
Publication 1784-UM003A-EN-P – June 2003
304 Motion Object Attributes
Velocity Feedback
Velocity Feedback is the actual velocity of the axis as estimated by the servo
module, in the configured axis Position Units per Second. The Estimated
Velocity value is computed by applying a 1 KHz low-pass filter to the change
in actual position over the servo update interval. Velocity Feedback is a signed
value—the sign (+ or -) depends on which direction the axis is currently
moving.
Velocity Error
Velocity Error is the difference, in configured axis Position Units per Second,
between the commanded and actual velocity of a servo axis. For an axis with
an active velocity servo loop, velocity error is used, along with other error
terms, to drive the motor to the condition where the velocity feedback is equal
to the velocity command.
Velocity Integrator Error
Velocity Integrator Error is the running sum of the Velocity Error, in the
configured axis Position Units per Second, for the specified axis. For an axis
with an active velocity servo loop, the velocity integrator error is used, along
with other error terms, to drive the motor to the condition where the velocity
feedback is equal to the velocity command.
Acceleration Command
Acceleration Command is the current acceleration reference to the output
summing junction, in the configured axis Position Units per Second
2
, for the
specified axis. The Acceleration Command value, hence, represents the output
of the inner velocity control loop. Acceleration Command is not to be
confused with Command Velocity, which represents the rate of change of
Command Position input to the position servo loop.
GSV/SSV Access
Attribute Name
Data Type
Values
GSV
Velocity Feedback
REAL
Position Units / Sec
GSV/SSV Access
Attribute Name
Data Type
Values
GSV
Velocity Error
REAL
Position Units / Sec
GSV/SSV Access
Attribute Name
Data Type
Values
GSV Velocity
Integrator
Error
REAL
Position Units – mSec / Sec
GSV/SSV Access
Attribute Name
Data Type
Values
GSV Acceleration
Command
REAL
Position Units / Sec
2