You can tailor the Simulation Data Inspector comparison process to fit your requirements in multiple ways. When comparing runs, the Simulation Data Inspector:
Aligns signal pairs in the Baseline and Compare To runs based on the Alignment settings.
The Simulation Data Inspector does not compare signals that it cannot align.
Synchronizes aligned signal pairs according to the specified Sync Method.
Interpolates data in signal pairs as specified by the Interpolation Method.
Computes the difference of the signal pairs.
Compares the difference result against specified tolerances.
When the comparison run completes, the results of the comparison are added in the navigation pane.
|Signal from Baseline does not align with a signal from Compare To.|
When you compare signals of different lengths, the Simulation Data Inspector compares the signals on their overlapping interval.
Aligning the signals is the first step in a comparison. In the alignment step for a run comparison, the Simulation Data Inspector decides which signal from the Compare To run pairs with a given signal in the Baseline run. When you compare signals with the Simulation Data Inspector, you complete the alignment step by selecting the Baseline and Compare To signals.
The Simulation Data Inspector aligns signals using their properties. In the Alignment tab of the Preferences window, you can specify the priority order for each of the signal properties used for alignment. The Align By field specifies the highest priority property. The priority drops with each subsequent Then By field. Always specify a primary alignment property in the Align By field, but you can leave any number of the Then By fields blank.
From each drop-down, you can select
Signal Name. By
default, the Simulation Data Inspector is configured to first align signals by data source,
then path, then SID, and then signal name.
|Data Source||Path of the variable in the MATLAB® workspace for data imported from the workspace|
|Path||Block path for the source of the data in the model|
Numeric signal identifier
For more information about SIDs, see Locate Diagram Components Using Simulink Identifiers
|Signal Name||Name of the signal in the model|
You can choose how the Simulation Data Inspector synchronizes signals when their time
vectors do not contain all the same sample times. You can select
intersection as the synchronization method.
When you specify
union synchronization, the Simulation Data Inspector
builds a time vector that comprises every sample time represented between the two signals.
For each sample time not originally present in either signal, the Simulation Data Inspector
interpolates the value. When you specify
the Simulation Data Inspector uses only the sample times present in both signals in the
Choosing between the two options is a trade off between speed and accuracy. The
interpolation required by
union synchronization takes time, but provides
a more precise result. When you use
intersection synchronization, the run
completes quickly because the Simulation Data Inspector computes fewer data points and does
not interpolate. However, some data is discarded in the process.
You can choose to interpolate your data with a zero-order hold (zoh) or a linear
approximation. When you specify
zoh in the Interpolation
Method, the Simulation Data Inspector replicates the data of the previous
sample for interpolated sample times. When you specify
interpolation, the Simulation Data Inspector uses samples on either side of the interpolated
point to linearly approximate the interpolated value.
You can specify absolute, relative, and time tolerances in the Simulation Data
Inspector. You can specify all tolerances globally, at the top of the graphical viewing
area, or on a signal by signal basis in the properties pane. To use a signal tolerance,
change Override Global Tol to
When you specify multiple tolerance, sometimes each tolerance yields a different answer for what the tolerance is at each point. The Simulation Data Inspector computes the overall tolerance band by selecting the most lenient tolerance result for each data point.
First, the Simulation Data Inspector computes the tolerance band using only the absolute and magnitude tolerances:
The upper boundary of the tolerance band is formed by adding
tolerance to the Baseline signal. Similarly, the
lower boundary of the tolerance band is formed by subtracting
from the Baseline signal.
To apply the time tolerance, the Simulation Data Inspector looks at a time interval
[(t-timeTol), (t+timeTol)]. For the upper boundary of the
tolerance band, the Simulation Data Inspector selects the maximum value on the interval for
each data point. For the lower boundary of the tolerance band, the Simulation Data Inspector
selects the minimum value on the interval for each data point.