Visualize, measure, and analyze transitions and states over time
The Logic Analyzer is a tool for visualizing and inspecting signals in your Simulink® model. Using the Logic Analyzer, you can:
Debug and analyze models
Trace and correlate many signals simultaneously
Detect and analyze timing violations
Trace system execution
Detect signal changes using triggers
For keyboard shortcuts, click
|Ctrl+X||Cut||Wave is selected|
|Ctrl+C||Copy||Wave is selected|
|Ctrl+V||Paste||Wave is selected|
|Delete||Delete||Wave is selected|
|Shift+Ctrl+-||Zoom out around active cursor||Always|
|Shift+Ctrl++||Zoom out around active cursor||Always|
|Shift+Ctrl+C||Move display to active cursor||When cursor is not in the display range|
|Space||Zoom out full||Always|
|Tab, Right Arrow||Next transition||Digital format wave is selected|
|Shift+Tab, Left Arrow||Previous transition||Digital format wave is selected|
|Ctrl+A||Select all waves||Always|
|Up Arrow||Select wave above selected||Wave is selected|
|Down Arrow||Select wave below selection||Wave is selected|
|Ctrl+Up Arrow||Move selected waves up||Wave is selected|
|Ctrl+Down Arrow||Move selected waves down||Wave is selected|
|Escape||Unselect all signals||Wave is selected|
|Page Up||Scroll up||Always|
|Page Down||Scroll down||Always|
On the Simulink toolstrip Simulation tab, click the Logic Analyzer app button. If the button is not displayed, expand the review results app gallery. Your most recent choice for data visualization is saved across Simulink sessions.
To visualize referenced models, you must open the Logic Analyzer from the referenced model. You should see the name of the referenced model in the Logic Analyzer toolbar.
The Logic Analyzer supports several methods for selecting data to visualize.
Select a signal in your model. When you select a signal, an ellipsis appears above the signal line. Hover over the ellipsis to view options and then select the Enable Data Logging option.
Right-click a signal in your model to open an options dialog box. Select the Log Selected Signals option.
Use any method to select multiple signal lines in your model. For example, use Shift+click to select multiple lines individually or CTRL+A to select all lines at once. Then click the Logic Analyzer button arrow and select Log Selected Signals.
When you open the Logic Analyzer, all signals marked for logging are listed. You can add and delete waves from your Logic Analyzer while it is open. Adding and deleting signals does not disable logging, only removes the signal from the Logic Analyzer.
Open the Logic Analyzer and select Settings from the toolstrip. A global settings dialog box opens. Any setting you change for an individual signal supersedes the global setting. The Logic Analyzer saves any setting changes with the model (Simulink) or System object™ (MATLAB®).
Set the display Radix of your signals as one of the following:
Hexadecimal — Displays values as symbols from zero to nine and A to F
Octal — Displays values as numbers from zero to seven
Binary — Displays values as zeros and ones
Signed decimal — Displays the signed, stored integer value
Unsigned decimal — Displays the stored integer value
Set the display Format as one of the following:
Automatic — Displays floating point signals in
format and integer and fixed-point signals in
Digital format. Boolean signals are
displayed as zero or one.
Analog — Displays values as an analog plot
Digital — Displays values as digital transitions
Set the display Time Units to one of the following:
Automatic — Uses a time scale appropriate to the time range shown in the current
Set the Boolean Highlighting to one of the following:
Rows — Adds a highlighted background for the entire Boolean signal row.
Select Highlight boolean values to add highlighting to Boolean signals.
Gradient— Adds color highlighting to Boolean signals based on value. If the signal
true, the highlight fades out below. If the signal value is
the signal fades out above. With this option, you can visually deduce the value of the signal.
Inspect the graphic for an explanation of the global settings:
Font Size, and
Font Size applies only to the text within the axes.
By default, when your simulation stops, the Logic Analyzer shows all the data for the simulation time on one screen. If you do not want this behavior, clear Fit to view at Stop. This option is disabled for long simulation times.
To display the short names of waves without path information, select Display short wave names.
You can expand fixed-point and integer signals and view individual bits. The Display Least Significant bit first option enables you to reverse the order of the displayed bits.
If you stream logged bus signals to the Logic Analyzer, you can display the names of the signals inside the bus using the Display bus element names option. To show bus element names:
Add the bus signal for logging.
In the Logic Analyzer settings, select the Display bus element names check box.
Run the simulation.
When you expand the bus signals, you will see the bus signal names.
Some special situations:
If the signal has no name, the Logic Analyzer shows the block name instead.
If the bus is a bus object, the Logic Analyzer shows the bus element names specified in the Bus Object Editor.
If one of the bus elements contains an array, each element of the array is appended with the element index.
If a bus element contains an array with complex elements, the real and complex values (
Bus signals passed through a Gain block are labeled
If the bus contains an array of buses, the Logic Analyzer prepends the element name with the bus array index.
Open the Logic Analyzer and select a wave by double-clicking the wave name. Then from the Wave tab, set parameters specific to the individual wave you selected. Any setting made on individual signals supersedes the global setting. To return individual wave parameters to the global settings, click Reset.
Open the Logic Analyzer and select a wave by clicking the wave name.
From the Logic Analyzer toolstrip, click . The wave is removed from the Logic Analyzer.
To restore the wave, from the Logic Analyzer toolstrip, click .
A divider named Restored Waves is added to the bottom of your channels, with all deleted waves placed below it.
The Logic Analyzer trigger allows you to find data points based on certain conditions. This feature is useful for debugging or testing when you need to find a specific signal change.
Open the Logic Analyzer and select the Trigger tab.
To attach a signal to the trigger, select Attach Signals, then select the signal you want to trigger on. You can attach up to 20 signals to the trigger. Each signal can have only one triggering condition.
By default, the trigger looks for rising edges in the attached signals. You can set the trigger to look for rising or falling edges, bit sequences, or a comparison value. To change the triggering conditions, select Set Conditions.
If you add multiple signals to the trigger, control the trigger logic using the Operator option:
AND - match all conditions.
OR - match any condition.
To control how many samples you see before triggering, set the
Display Samples option. For example, if you set
this option to
500, the Logic Analyzer tries
to give you 500 samples before the trigger. Depending on the simulation, the
Logic Analyzer may show more or fewer than 500 samples
before the trigger. However, if the trigger is found before the 500th
sample, the Logic Analyzer still shows the trigger.
Control the trigger mode using Display Mode.
Once - The Logic
Analyzer marks only the first location matching the
trigger conditions and stops showing updates to the Logic
Analyzer. If you want to reset the trigger, select
Rearm Trigger. Relative to the
current simulation time, the Logic Analyzer shows
the next matching trigger event.
Auto - The Logic
Analyzer marks every location matching the trigger
Before running the simulation, select Enable Trigger. A blue cursor appears as time 0. Then, run the simulation. When a trigger is found, the Logic Analyzer marks the location with a locked blue cursor.
The Logic Analyzer can stream only a single instance of a multi-instance Model block. If the same model is opened across different windows, those models will share the same Logic Analyzer. This example shows how to select an instance of a multi-instance Model block for logging on the Logic Analyzer.
Open the multipleModelInstances model:
The model contains three instances of the
Double-click any of the Model blocks to open the model referenced by all three Model blocks.
Open the Logic Analyzer in the referenced model by double-clicking the logging symbol next to the Moving Average block.
You should see
[multipleModelInstances] in the toolbar of the Logic
From the Logic Analyzer window, run the model. By running the simulation
from a referenced version of
runs the top model (
referenced models (
referencedModel). The Logic
Analyzer displays a single instance of a multi-instant
When you run a simulation, the logic analyzer runs the model listed in the Logic Analyzer toolbar. If this model is a referenced model, the toolbar also lists the top model and you will see results from running the top model.
To view results from the referenced model in isolation, you must open the referenced model as a top model.
To switch between instances, from the Simulink Editor menu, on the Simulation tab open the Prepare gallery and select Normal Mode Diagram > Subsystem & Model Reference > Model Block Normal Mode Visibility. Select Model Instance 3 and then click OK.
multipleModelInstances model again. The
Logic Analyzer displays
Model Instance 3
The Logic Analyzer enables you to bit-expand fixed-point and integer waves.
In the Logic Analyzer, click the arrow next to a fixed-point or integer wave to view the bits.
The least significant bit and the most significant bit are marked with lsb and msb next to the wave names.
Click Settings, and then select Display Least Significant bit first to reverse the order of the displayed bits.
This example shows how to use a trigger to verify that the signals are matching the design.
Open the Programmable FIR
Filter model (
Open the Logic Analyzer and select the Trigger tab.
To add a trigger, in the toolstrip, select Attach
Signals and attach the write enable
En signal. An icon appears in front of the signal name to
indicate it is attached to a trigger. The icon changes depending on the type
Select Set Conditions and change the trigger
condition for the
Write En signal to Falling
Edge. The trigger will show when the write enable signal was
Write Done signal to the trigger. Keep the
trigger condition for this signal as the default,
Edge. Now, the trigger will also show when the write was
If you open the Set Conditions drop down, you see an
Operator field. This field appears when multiple
signals are attached to the trigger. Change the operator to
OR so that the trigger will show instances
where a write was started or completed.
Set the Display Mode to
Auto. With this setting, the Logic
Analyzer marks all locations where the trigger conditions are
Select Enable Trigger and run the simulation.
Each time the trigger conditions are met, the Logic Analyzer
marks the time with a locked blue cursor. At each marked location,
Write En is
1. If you examine each location
marked by a trigger, you can verify that each time a write is sent, it is
The Logic Analyzer does not support frame-based processing.
If you enable the configuration parameter Log Dataset data to file, you cannot stream logged data to the Logic Analyzer.
While the simulation is running, you cannot zoom, pan, or modify the trigger.
Signals marked for logging for the Logic Analyzer must have fewer than 8000 samples per simulation step.
To visualize constant signals, in the settings, you must set the
marked for logging are visualized as a continuous transition.
Integers larger than 64 bits and fixed-point signals larger than 128 bits are not supported.
You cannot visualize Data Store Memory block signals
in the Logic Analyzer if you set the
Log data store
data parameter to on.
To visualize signals in referenced models, open the Logic Analyzer from the referenced model.
You may see performance degradation in the Logic Analyzer for large matrices (greater than 500 elements) and buses with more than 1000 signals.
The Logic Analyzer does not support Stateflow® state or chart signals.
The following table shows which simulation modes are supported by the Logic Analyzer:
|Mode||Supported||Notes and Limitations|
You cannot use the Logic Analyzer to
visualize signals in Model
blocks with Simulation mode set to
Data is not available in the Logic Analyzer during simulation.
If you simulate a model with the simulation mode set to rapid accelerator, after simulation the following signals cannot be visualized in the Logic Analyzer:
For more information about these modes, see How Acceleration Modes Work (Simulink).