Programming
890CS Common Bus Supply - Frames B & D; 890CD Common Bus Drive and 890SD Standalone Drive - Frames B, C & D
Page
D-77
8
9
10
A
B
C
D
E
1
2
3
4
5
6
7
Functional Description
The Position and Speed loop generates a current setpoint to feed the current loop. This loop can be divided into 3 main
sections :
1.
Position loop : compares the position setpoint and the actual position, generates a tracking error (position error) that feed
a PI.
2.
Speed loop : takes the output of the position loop, adds the speed feedforwards then substracts the actual speed to
generate the speed error. The speed error feeds a PI to computes an acceleration setpoint to which the acceleration
feedforwards are added to compute the acceleration setpoint.
3.
Current setpoint generator : the acceleration setpoint is then converted to a torque setpoint (given the load and motor
inertias). The gravity and frictions are added to that torque setpoint that, with the motor’s parameters, turns into a current
setpoint.
