Siemens SINUMERIK 840C Installation Instructions Manual page 642

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9.2.6 Position control loop (axis and spindle) – measurement parameters (9 basic settings – as from SW 3)
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Notes In order to ensure a more gentle machine setting, the lowest possible values
should be set for amplitude and offset. Excessively high input values result in
the output of alarm messages such as "1560 Speed setpoint alarm limit violated".
The only quantity which can be measured is the position actual value from the
active (current) measuring system.
When speed actual value or following error is selected, the dialog box 160043
Measurement/measured-qty combin. not allowed appears when the Start
softkey is selected.
D 2nd measurement type: Setpoint step change
The transient or positioning response of the position control in the time range can
be assessed with the step stimulation function.
If an offset value other than zero is input, the step change is stimulated during
traversal. The displayed position actual value does not include this speed offset.
The effect of the setpoint smoothing filter can be checked on the basis of the
position setpoint characteristic.
You can select the menu with the parameters for measuring the speed control
Meas.
loop with this softkey.
parameter
Notes You enter the measurement parameters in the selected display. These
parameters are managed internally as configuration data rather than machine
data, i.e. they are not initialized when the machine runs up. Data can be input in
two different ways:
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A fixed pre-trigger time corresponding to 10 % of the measurement time is set for
the recording, i.e. the setpoint step change is also visible in the setpoint signal
display. If the settling time setting is lower than this 10 % value, then the pre-trig-
ger time is limited to the settling time.
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Measurement
parameter settings
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SINUMERIK 840C (IA)
Averaging operations
The higher this value is set, the more accurate the measurement and the lon-
ger the measurement time. You should normally enter a value of 20.
Settling time
This value represents the delay between the start of measured data recording
and injection of the test signal and offset. Set the value to between 0.2 and
1 s.
Manual input
Input by loading of an existing, complete data set with the aid of file functions.
Amplitude
This parameter determines the magnitude of the specified setpoint step
change.
Offset
The step is stimulated from standstill or starting from the constant traverse
speed set in this parameter.
Measurement time
This parameter determines the period of time to be recorded.
Settling time
This value represents the delay between the start of measured data recording
and the injection of the test signal and the offset.
Ramp time
When the basic setting "Setpoint ramp" is selected, the position setpoint is
changed according to the set ramp time. In this case, the acceleration is
specified in accordance with the acceleration limits which currently apply for
the axis or spindle
These limits must be set in "Controller parameters NC"
Spindle: NC MD 4780–4850
Axis: NC MD 2760
9 Drive Servo Start-Up Application (as from SW 3)
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