Siemens SINUMERIK 840Di sl Commissioning Manual page 521

Figure 14-4
At maximum axis velocity, there is a (virtual) step change in the velocity (continuous line).
The curves represented by the dashed line correspond to a realistic, finite value. The offset
component is excluded from the display graphic in order to emphasize the transient
processes.
Measurement: Setpoint step change
To avoid overloading the mechanical system of the machine, the step height is limited to the
value specified in the machine data during the "Setpoint step change" measurement:
● MD32000 $MA_MAX_AX_VELO (maximum axis velocity).
This may result in failure to achieve the desired step height.
Measurement: Setpoint ramp
With measurement "Setpoint ramp", the following machine data influence the measurement
result:
● MD32000 4MA_AX_AX_VELO (max. axis velocity)
● MD32300 $MA_MAX_AX_ACCEL (maximum axis acceleration)
Manual
Commissioning Manual, 05/2008, 6FC5397–4CP10–4BA0
Signal chart for position setpoint/ramp measuring function
The maximum axis velocity limits the ramp gradient (velocity limitation). The drive does
not reach the programmed end position (amplitude).
The maximum axis acceleration limits the velocity change (acceleration limitation). This
leads to "rounding" on the transitions at the beginning and end of the ramp.
CAUTION
In normal cases the machine data corresponds exactly with the load capacity of the
machine kinematics and should not be changed (increased) as part of the
measurements:
• MD32000 $MA_MAX_AX_VELO (maximum axis velocity).
• MD32300 $MA_MAX_AX_ACCEL (maximum axis acceleration)
Drive Optimization with HMI Advanced
14.4 Frequency response measurements
521