BECKHOFF AX2000 - Manual (Page 9)

III.5.2 Optimization
The starting of motion tasks with the aid of commissioning-software functions is only
permitted in combination with an interlock device according to EN292-1, that operates
directly on the drive circuitry.
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Start motion task :
- Click on the POSITION button
- Select moton task 1, click on START, motion task 1 is started and, because of
the definition of the motion task sequence, the drive moves in position-controlled
reversing operation.
Optimize parameters (Click on the POSITION DATA button)
PID-T2, FEEDBACK :
The speed controller is not used in OPMODES4, 5 and 8. The position controller
includes an integral speed controller, that takes on the preset parameters for PID-T2
and FEEDBACK from the screen page “Speed controller”.
KP, Tn :
If KP is set too low, the position controller tends to oscillate. Use the value for the
optimized speed controller for KP. Tn should be 2...3 times as large as the Tn value
for the optimized speed controller.
KV :
The acceleration behaviour of the motor should be well damped (no tendency to
oscillation) with a minimum following error. If KV is larger, the tendency to oscillation
increases. If it is smaller the following error increases and the drive becomes too soft.
Vary KV until the desired response is achieved.
FF :
The integral component of the control loop is in the position controller, not the speed
controller, so no following error results at constant speed (pure proportional control).
The following error that arises during acceleration is affected by the FF parameter.
This error is smaller if the FF parameter is increased. If increasing FF does not
produce any improvement, then you can increase KP a little, to make the speed
control loop somewhat stiffer.
If the drive does not run satisfactorily under position control, first look for external causes such as :
l mechanical play in the transmission chain (limits the KP)
l jamming or slip-stick effects
l self-resonant frequency of the mechanical system is too low
l poor damping, drive is too weakly dimensioned
before trying to optimize the control loop again.
Quick Start 9
BECKHOFF
06.00
Optimization