Siemens SINUMERIK 840Di Manual page 429

06.03
Measurement
parameters:
Setpoint step
change and
setpoint ramp
 Siemens AG, 2003. All rights reserved
SINUMERIK 840Di Manual (HBI) – 06.03 Edition
Offset
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.
The transient response and positioning response of the servo loop in the time
range, in particular, the effect of setpoint filters, can be assessed using the step
excitation and the ramp excitation.
If an offset value other than zero is input, the step change is stimulated during
traversal. For the sake of clarity, the displayed position actual value does not
include this speed offset. The following measurement quantities are possible:
– Actual position value (active position measuring system)
– Control deviation (following error)
Amplitude
This parameter determines the height of the preset setpoint step change or
ramp.
Measurement time
This parameter determines the period of time to be recorded (maximum value:
2048 position controller cycles).
Settling time
This value represents the delay between measured data recording/test setpoint
output and the injection of the offset.
Ramp duration
In basic setting Setpoint ramp the position setpoint is preset according to the
set ramp duration. In this case, the acceleration limits which currently apply to
the axis or spindle are effective.
A jerk-controlled motion can be set axis-specifically using
S
MD 32400 AX_JERK_ENABLE (axial jerk limitation) =1
S
MD34210 AX_JERK_TIME (time constant for the axial jerk filter).
The position setpoint and the actual value of the active measuring system are
recorded.
Offset
The step is stimulated from standstill or starting from the constant traverse
speed set in this parameter.
13 Drive Optimization using HMI Advanced
13.4 Frequency response measurement
13-429