Lenze 931E/K Small Drives Control - Manual (Page 35)

Commissioning
Speed control
Optimisation strategies
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35 SW−HB 13.0002−EN 4.1
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Stop!
Excessive speed jumps may damage or destroy your system / mechanical
components. Please observe the load limits for the mechanical components.
Optimisation strategies
The behaviour of the speed controller can be monitored by recording the response to a
speed jump. For this, select "Speed control" and deactivate the ramp functionality, if any,
in the setpoint selector menu. A speed jump can be reached by entering setpoint jumps via
the RS232 interface. As an alternative, you can use the setpoint selection via an analog
input and short−circuit the analog input to reach a jump.
The speed controller response can be monitored by using the oscilloscope function. See the
chapter "Using the oscilloscope function". (
¶ 115)
Set the oscilloscope channels to the actual speed (raw) and the speed setpoint to display
the step response of the speed controller.
)
Note!
In general, the gain factor and the time constant must not be changed
abruptly but only gradually.
To start with, select a comparatively long integral−action time between 8 msec
and 10 msec and gradually increase the gain. Only reduce the integral−action
time step−by−step after having found the right setting by increasing the gain.
Changing the values may have the following effects:
ƒ If the setting is too hard, the speed controller will become unstable.
ƒ If the setting is too soft, the drive will not be stiff enough. This would lead to
following errors during operating.
)
Note!
The speed controller parameters are not independent of each other. I.e. if a
measuring curve changes from one test to another, this may be due to
different reasons. Therefore, only change one parameter at a time: either only
the gain factor or only the time constant.