Specifications

Positioning Drive Setup Ver. 0002 PSU - 5
PSU.4 VELOCITY FEEDFORWARD
It is complementary to proportional control. Its function at the drive is identical to that of
parameter "FFGAIN" (P25) at the Fagor CNC.
The effect of the anticipated command "Feedforward" helps reduce the following error without
increasing the gain, thus maintaining system stability.
Feedforward gain setting
Set up the effect of the velocity Feedforward using this parameter:
PP216 -S296- VelocityFeedForwardPercentage
It indicates the portion of the final velocity command that is anticipated to the movement which
does not depend on the following error (open loop). The rest of the final velocity command will
be due to the proportional gain. See the previous block diagram.
Example:
S296=8080% of the velocity command comes from the feedforward
20% of the velocity command comes from the proportional effect
The following values can be used as a rule of thumb:
Machines with low machining feedrates between 40 and 60%
Machines with normal machining feedrates between 60 and 80%
Fast machines (laser, plasma) between 80 and 100%