Siemens SINUMERIK 840D sl Commissioning Manual page 198

Optimize the drive.
11.2 Frequency response measurements
● Averaging
● Settling time
● Offset
Measurement: Setpoint step change and setpoint ramp
The transient or positioning response of the position control in the time range, and in
particular the effect of setpoint filters, can be assessed with the step and ramp stimulation
functions.
Possible measured variables:
● Actual position value (active position measuring system)
● Control deviation (following error)
Measuring parameters
● Amplitude
● Measurement time
● Settling time
● Ramp time
● MD32400 AX_JERK_ENABLE (axial jerk limitation) = 1
● MD32410 AX_JERK_TIME (time constant for the axial jerk filter).
● Offset
198
Bandwidth = 1 / (2 * 2*10
max
The accuracy of the measurement and measurement duration increase with this value. A
value of 20 is normally suitable.
This value represents the delay between recording of the measured data and injection of
the test setpoint and offset. A value of between 0.2 and 1 s is recommended. Do not set
too low a value for the settling times or the frequency response and phase diagrams will
be distorted.
The measurement requires a slight speed offset of a few motor revolutions per minute.
The offset must be set such that no speed zero crossings occur at the set amplitude.
Determines the magnitude of the specified setpoint step change or ramp.
This parameter determines the period of time to be recorded (maximum: 2048 position
controller cycles).
This value represents the delay between measured data recording / test setpoint output
and the injection of the offset.
The position reference value is specified with the "Setpoint ramp" basic measurement
according to the set ramp time. In this case, the acceleration limits which currently apply
to the axis or spindle are effective.
A jerk-controlled motion can be set for a specific axis with:
The position setpoint and the actual value of the active measuring system are recorded in
each case.
The step is stimulated from standstill or starting from the constant traverse speed set in
this parameter.
) = 250 Hz
-3
Commissioning Manual, 07/2007, 6FC5397-2AP10-3BA0
IBN CNC: NCK, PLC, drive