OrderTracking (FPScript)
OrderTracking (FPScript)
Calculates an order tracking analysis for speed-dependent oscillations. For order tracking, the oscillatory signals measured at a certain speed are subjected to a Fourier transform (FFT). Individual spectral lines whose frequencies correspond to a multiple of the base frequency determined by the speed are then taken from the spectrum.
Syntax
OrderTracking(Orders, BandWidth, WindowLength, WindowSpacing, Window, SignalType, SignalSeries)
or
OrderTracking(Orders, BandWidth, WindowLength, WindowSpacing, Window, SignalType, Signal1, Speed1 [, ... , SignalN, SpeedN] [ , ImpulseCount ])
or
OrderTracking(Orders, BandWidth, WindowLength, WindowSpacing, Window, SignalType, SegmentLength, SpeedsOrTimes, Signal, Speed [ , ImpulseCount ])
The syntax of the OrderTracking function consists of the following parts:
Part |
Description |
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Orders |
The data set with the orders of the spectral lines to be taken from the spectra. Permitted data structures are data series. All real data types are permitted. If the argument is a list, then the first element in the list is taken. If this is also a list, then the process is repeated. |
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BandWidth |
The bandwidth as a percentage of the speed corresponding to the order (order * speed), in which the respective largest spectral line is to be searched for. Permitted data structures are scalar value. All real data types are permitted. The argument is transformed to the unit %. The value must be greater or equal to 0 % and less or equal to 100 %. If the argument is a list, then the first element in the list is taken. If this is also a list, then the process is repeated. |
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WindowLength |
The binary logarithm of the desired window length (for instance: 5 corresponds to window length 32). A value of 0 selects the maximum possible window size, i.e. the highest possible power of two, which is smaller than the number of data to be transformed. Only one FFT per speed is calculated in this case. If you specify a window length, then an averaged spectrum (periodogram) is formed. Permitted data structures are scalar value. All integral data types are permitted. The value must be greater or equal to 0 and less or equal to 30. If the argument is a list, then the first element in the list is taken. If this is also a list, then the process is repeated. |
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WindowSpacing |
The desired window spacing, which may also be smaller than the window size. A value of 0 corresponds to windows arranged directly next to each other. Permitted data structures are scalar value. All integral data types are permitted. If the argument is a list, then the first element in the list is taken. If this is also a list, then the process is repeated. |
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Window |
Specifies whether a taper window is to be applied to the segments of the signal before their transformation, and if so, with which function. The argument Window can have the following values:
If the argument is a list, then the first element in the list is taken. If this is also a list, then the process is repeated. |
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SignalType |
Specifies whether the signals specified are time or angle signals. The argument SignalType can have the following values:
If the argument is a list, then the first element in the list is taken. If this is also a list, then the process is repeated. |
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SignalSeries |
The signal series to be analyzed. The Y component contains the oscillations to be transformed, the X component contains the sampling times or sampling angles, and the Z component contains the speeds for which the individual oscillatory signals were measured. If no unit is specified for the X component, s or rad is used. If no unit is specified for the Z component, 1/min is used. If ORDERTRACKING_ANGLE was specified as the signal type and a number of samples per revolution were specified, then the X component is ignored. Permitted data structures are signal series. All real data types are permitted. For the X component additional restrictions do apply. The values must have a constant spacing. If the argument is a list, then the function is executed for each element of the list and the result is also a list. |
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Signal1, ..., SignalN |
The time or angle signals to be analyzed. If ORDERTRACKING_ANGLE was specified as the signal type, and a number of samples was specified per revolution, then the data series can also be specified and any X components that may be present will be ignored. Permitted data structures are signal. All numeric data types are permitted. For the X component additional restrictions do apply. The values must have a constant spacing. If the argument is a list, then the first element in the list is taken. If this is also a list, then the process is repeated. |
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Speed1, ..., SpeedN |
The data sets with the speeds belonging to the signals. If data series are specified, a mean value is formed. If the argument ImpulseCount was specified, then the speed data are interpreted as impulse signals and are converted into speeds using the ImpulseToFrequency function. Permitted data structures are scalar value, data series and signal. All real data types are permitted. For the X component additional restrictions do apply. The values must have a constant spacing. If the argument is a list, then the first element in the list is taken. If this is also a list, then the process is repeated. |
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SegmentLength |
The size of the signal segments to be formed for the analysis for the FFT. Permitted data structures are scalar value. All integral data types are permitted. If the argument is a list, then the first element in the list is taken. If this is also a list, then the process is repeated. |
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SpeedsOrTimes |
The speeds or times for which an order analysis is to be performed. The distinction is made by the unit of the data set or by the argument SignalType. Permitted data structures are data series. All real data types are permitted. If the argument is a list, then the first element in the list is taken. If this is also a list, then the process is repeated. |
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Signal |
The time or angle signal to be analyzed. Permitted data structures are data series and signal. All real data types are permitted. For the X component additional restrictions do apply. The values must have a constant spacing. If the argument is a list, then the first element in the list is taken. If this is also a list, then the process is repeated. |
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Speed |
The current speed belonging to the signal. This does not have to be measured synchronously with the signal. If both data sets are present as time signals, they are synchronized via the X values. Permitted data structures are data series and signal. All real data types are permitted. For the X component additional restrictions do apply. The values must have a constant spacing. If the argument is a list, then the first element in the list is taken. If this is also a list, then the process is repeated. |
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ImpulseCount |
A scalar value with the number of impulses per revolution. If you specify this argument, then the speed data is interpreted as impulse signals and converted using the ImpulseToFrequency function. Permitted data structures are scalar value. All real data types are permitted. If the argument is a list, then the first element in the list is taken. If this is also a list, then the process is repeated. |
Remarks
The result always has the data structure signal series.
You can use the function in the three variations specified above. The first variant analyzes a signal series with several signals that were measured at various, constant speeds. The second variant analyzes several individual time signals that were measured at various, constant speeds. Each time signal is assigned the speed at which it was measured. The third variant analyzes a single ramp-up signal across the complete speed spectrum to be analyzed. In this case, the speeds to be evaluated are specified as an additional data series. These speeds are searched for in the speed data set measured synchronously with the signal in order to create corresponding time segments for the order tracking.
The result of the order tracking is a signal series in all variants. The Y component contains the spectral lines extracted as orders, the X component contains the orders, and the Z component contains the speeds. For spectral lines, you are dealing with complex amplitudes, i.e. the amount of such a complex value directly specifies the amplitude of a particular cosine oscillation and the phase specifies the particular phase shift.
Available in
Option Order Tracking
Examples
Absolute(OrderTracking(Orders, 5 %, 0, 0, ORDERTRACKING_RECT, _
ORDERTRACKING_TIME + 60, 8192, Speeds, Signal, Speed))
Analyzes an individual ramp-up signal across the complete speed spectrum to be analyzed. Please refer to the related OrderTracking.fpd project database.
See Also
Order Tracking Analysis Object