Rockwell Automation 20D PowerFlex 700S with Phase I Control Reference Manual - Manual (Page 135)

Rockwell Automation Publication PFLEX-RM002D-EN-E - August 2013 135
Detail Drive Configuration and Operation Chapter 1
Speed Reference Bypass and Delayed Speed Reference
By default, parameter 37 [Spd Ref Bypass] is linked to [S Curve Spd Ref ].
However, if you wish to bypass the rest of the speed reference control loop, [Spd
Ref Bypass] gives the capability to link to other parameters.
Parameter 45 [Delayed Spd Ref ] is delayed by one scan of the speed control loop.
[Spd Ref Bypass] can be linked to [Delayed Spd Ref ] instead of [S Curve Spd
Ref ] for use in SynchLink applications. See SynchLink on page
160 for more
details.
Inertia Compensation
Inertia compensation is used to calculate the level of torque required due to load
inertia during speed changes. For more information on inertia compensation, see
Inertia Compensation on page
68 .
Friction Compensation
The friction compensation block is used to calculate breakaway torque and the
torque needed just to keep the motor running at a constant speed due to friction.
For more information on friction compensation, see Friction Compensation on
page
64 .
Virtual Encoder
The virtual encoder block generates a position counter based on the speed
reference in [S Curve Spd Ref ]. Parameter 61 [Virt Encoder PPR] is used to
specify the desired pulses per revolution for the virtual encoder. The virtual
encoder block will count at a rate of 4 times [Virt Encoder PPR] per one
revolution of the motor. For example, if [Virt Encoder PPR] is 1024, the virtual
encoder block will count at a rate of 4096 units per one revolution of the motor.
Parameter 62 [Virt Encdr Posit] is a 32 bit integer that contains the pulse count
output of the virtual encoder block. This parameter is used for position follower
applications (see the Follower section of the Position Loop).
43
45
Delayed Spd Ref
Link
Spd Ref Bypass S Curve Spd Ref
Delay
One
Scan
37