Optimization
The starting of mo tion tasks with the aid of commissio ning-software functio ns is
only permitted in combination with an interlock device according to EN292-1, that
operates directly o n the drive circuitry.
1.
Start motion task:
- Click on the POSITION button
- Select motion task 1 on screen page POSITION DATA, 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.
2.
Optimize parameters (Click on the POSITION DATA button)
3.
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".
4.
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.
5.
KV:
The acceleration behavior 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.
6.
FF:
The integral component of the control loop is in the position controller, not the speed controller, so no following error results at
Jog Mode (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.
22 Setup Software
Axis Commissioning Checklist Procedures 07/03 BECKHOFF
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