LabVIEW Graphs and Charts

LabVIEW is a graphical programming platform enabling engineers to build automated test systems efficiently. It provides key capabilities, including a native user interface, a range of engineering analysis functions, Nigel AI, and more.

You can use LabVIEW to create various types of charts and graphs and customize them according to your needs. The charts and graphs display data visually and allow you to perform in-depth analysis.

This article covers several LabVIEW chart and graph types, including waveform, XY, intensity, and 3D graphs.

Table of Contents

• LabVIEW – An Overview
• LabVIEW Data Types
• Graphical System Design using LabVIEW
• LabVIEW Charts
• LabVIEW Graphs
• Customizing Charts and Graphs in LabVIEW
• Exporting Images of Graphs, Charts, and Tables
• Dynamically Formatting Waveform Graphs
• 3D Graphs In LabVIEW
• Frequently Asked Questions

LabVIEW – An Overview:

LabVIEW, a product of National Instruments, analyzes data and generates insightful visualizations to help understand trends, system behavior, and more.

Whether working with time-based, multidimensional, or digital signals, LabVIEW allows you to create detailed data visualizations. As a result, it is widely used in industries, research centers, academia, and other key areas.

LabVIEW Data Types:

Waveform Data Type:

The waveform data type stores waveform data, start time, and other properties. You can create a waveform using the build waveform function.

When you wire waveform data to a waveform graph or chart, the graph or chart automatically plots a waveform. It uses the waveform's properties. You can use the Build Waveform function to create a digital waveform.

For controls and indicators of some data types, LabVIEW will automatically coerce the waveform. This allows you to make the connection, even if the terminal’s required data type is not explicitly the waveform type.

Example:

If you connect a waveform wire to a numeric indicator, a red dot will appear on the block diagram icon. This indicates that coercion is being applied. The last value of the Y array in that waveform will be displayed on the indicator on the front panel.

If you connect the waveform to a 1D array indicator, LabVIEW will simply pass the Y data to that indicator.

Dynamic Data Type:

The dynamic data type accepts data from and sends data to the following types. Most Express VIs accept and/or return the dynamic data type. Here, a scalar data type is a floating-point number or a Boolean value.

• 1D array of scalars
• 1D array of scalars—most recent value
• 1D array of scalars—single channel
• 2D array of scalars—columns are channels
• 2D array of scalars—rows are channels
• Single scalar
• Single waveform

Digital Waveform Data Type:

The digital waveform data type contains the start time, delta 'x', data, and other aspects of the digital waveform. The Build Waveform function creates a digital waveform.

• Properties:
  • If you wire digital waveform data to the digital waveform graph, the graph plots a waveform based on the time and other data of the digital waveform.
  • You can wire digital waveform data to a digital data indicator. It allows you to view the samples and signals of a digital waveform.

Graphical System Design using LabVIEW:

The graphical system in LabVIEW visualizes data through charts and graphs with real-time analysis. 

Components of the graphical system:

• User interface – It includes the front-panel elements, such as buttons, sliders, and graphs. It helps handle inputs and outputs.
• Graphical output – It includes various graph types that represent data.
• Data flow programming – LabVIEW follows a data-flow approach. It effectively integrates user inputs and system outputs.

LabVIEW Graphs and Charts

LabVIEW charts and graphs visualize a wide range of data types, including time series, sensor outputs, and statistical data.

Understanding the difference between charts and graphs is essential. Let’s understand exactly what they are.

• Charts are highly suitable for visualizing dynamic, continuous, time-based, and real-time data.
  
  Examples include waveform charts and strip charts.
  
  
• Graphs are the best way to display static, non-relational, and non-continuous data.
  
  Examples include XY graphs, intensity graphs, and 3D graphs.

LabVIEW Charts

LabVIEW charts help visualize complex data in multiple forms. Let’s discuss them in the following.

• Waveform Charts

The waveform charts in LabVIEW let you display continuous data as a time series. They help monitor real-time data acquisition systems, temperature changes, and voltage fluctuations.

The waveform chart is a numeric indicator that displays one or more data plots, usually acquired at a constant rate. Here, the X-axis shows data points, and the Y-axis shows signal values.

• • Key Features
    • Waveform charts handle dynamic signals efficiently.
    • They can display multiple plots in a single graph.
    • They are updated with real-time data changes.
    • They maintain the history of data from previous updates.
  • Applications:
    • These charts help monitor sensor outputs.
    • They are used in oscilloscopes and function generators.
    • They can visualize time-dependent signals used in control systems and embedded systems.
    • They help visualize measurement trends and identify anomalies in real-time data.

Example

The Figure below shows a LabVIEW waveform chart.

In LabVIEW, you can generate the waveform chart with a single plot. You can view data points on the chart and increment their values.

• • Displaying Multiple Plots on Waveform Charts

You need to bind numeric data into clusters to create multiple plots on a waveform chart. You can use an array of clusters to pass multiple points to create plots in a single update.

• Strip Charts:

A strip chart is similar to a waveform chart. It displays new data over time while keeping the old values intact.

• • Key Features:
    • A strip chart displays data that shifts continuously from left to right.
    • It is suitable for measuring long-duration signals effectively.
    • It can display multiple plots for various time ranges.
  • Applications:
    • It is used in data loggers to display temperature and pressure measurements.
    • It is suitable for monitoring systems that have multiple data channels.
      
      
• Intensity Charts:

In Intensity charts, new data appears on the right side. The old data appears on the left. When new data arrives, the old data automatically shifts to the left on a 2D plot.

• • You can set the color mapping for an intensity chart with the color scale.
  • The color scale consists of at least two arbitrary markers. One marker has a numeric value, and another has a display color.
  • The intensity graphs and charts are limited to 254 colors.
  • The colors displayed on an intensity graph correspond to the numeric values of the specified colors.

The figure below shows an example of an intensity chart.

The intensity chart is similar to the waveform chart in many ways. This includes the scale legend and graph palette. However, it uses color as a third dimension. Color mapping visually indicates data ranges and supports multidimensional data.

Related article: Local and Global Variables in LabVIEW

LabVIEW Graphs:

Like charts, LabVIEW provides powerful graphing capabilities for data analysis, trend monitoring, and visualizing system behavior.

Let’s look at the various LabVIEW graph types below.

• Intensity Graphs:

The intensity graph does not retain previous data values and does not include update modes. Each time new data values are passed to an intensity graph, they replace the previous data.

Like other graphs, the intensity graph can have cursors. Each cursor displays the x, y, and z values for a given point on the graph. An intensity graph or chart uses color to display 3D data on a 2D plot.

• • Color mapping in intensity graphs:
    
    When you set the color mapping for an intensity graph or chart, you configure its color scale. The color scale consists of at least two arbitrary markers, each with a numeric value and a corresponding display color. 
    
    The colors displayed on an intensity graph or chart correspond to the numeric values assigned to those colors. Color mapping is useful for visually indicating data ranges, such as when plot data exceeds a threshold.
    
    You can set the color mapping for the intensity graph and chart programmatically using the property node in two ways. Typically, you specify the value-to-color mappings in the property node.
• XY Graphs in LabVIEW:

You can visualize data in X and Y coordinates using LabVIEW’s XY graph. An XY graph is a general-purpose, Cartesian graph with which you can plot multivalued functions. The graph can be circular or a waveform with a varying time base.

Moreover, you can display the Nyquist and Nichols plots on the XY graph. Lines and labels on these planes will match the color of the Cartesian lines.

• • Key Features:
    • An XY graph displays multiple datasets in a single graph with different colors and markers.
    • It can visualize non-continuous or time-independent signals.
  • Applications:
    • This graph is widely used in control systems, signal processing, and mathematical data analysis.
    • It is the perfect platform for displaying mathematical functions and relationships between variables.
    • It is used in electrical engineering to plot a voltage-versus-current graph.
    • It helps to analyze trends and compare experimental datasets.

Example:

The following figure shows an example of an XY graph.

 

The XY graph can display plots with any number of points. It mainly supports multiple data types. You can display single and multiple plots on XY graphs.

• • Displaying a Single Plot on an XY Graph:

The XY graph accepts three data types for single-plot XY graphs.

• • • The XY graph accepts a cluster containing X and Y arrays.
    • It accepts an array of points, where each point is a cluster containing an X value and a Y value.
    • It accepts an array of complex data, with the real part plotted on the X-axis and the imaginary part on the Y-axis.
      
      
  • Displaying Multiple Plots On an XY Graph:

The XY graph accepts three data types for displaying multiple plots.

• • • It accepts an array of plots, where each plot is a cluster containing an x array and a y array.
    • The XY graph also accepts an array of clusters of plots, where a plot is an array of points. A point is a cluster that contains an x-value and a y-value.
    • The XY graph also accepts an array of clusters of plots, where each plot is an array of complex data.
      
      
• Waveform Graphs

The waveform graph displays one or more plots for evenly sampled values. It only plots single-valued functions, such as time-varying functions acquired. However, it can also display value points and support multiple data types.

The image below shows a waveform graph.

You can display single and multiple plots on a waveform graph. These graphs support waveform and dynamic data types, allowing a single plot per graph.

The waveform graph supports a 2D array of values, allowing multiple plots on a single graph.

Difference between Waveform Graphs and Waveform Charts:

Waveform Charts	Waveform Graphs
Waveform charts continuously accept data and display plots.	They display graphs using an array of values at once.
They are dynamic and updated with real-time data	They are static and updated with data at specific intervals
They are ideal for monitoring live signals. You can view real-time updates with these charts.	They are suitable for analyzing a complete data set and tracking trends.

• Intensity Graphs

An Intensity graph in LabVIEW is a powerful tool for representing the magnitude of values with varying color intensity. It will be highly beneficial when working with data with spatial and intensity dimensions.

The intensity graph is similar to the intensity chart but does not retain previous data values. It replaces the old values every time new data arrives.

Like other graphs, the intensity graph has cursors. Every cursor displays the x, y, and z values for the specified point on the graph.

Let’s explore more about intensity graphs.

After you plot a block of data on an intensity chart, the origin of the Cartesian plane shifts to the right of the last data block. When the chart processes new data, the new values appear to the right of the old ones. When a chart display is full, the oldest data values scroll off the left side of the chart. This behavior is similar to the behavior of a strip chart. 

• • Key Features:
    • An Intensity graph displays datasets in matrix form.
    • It supports both 1D and 2D data visualizations of complex datasets.
    • It is ideal for visualizing heatmaps and images.
  • Applications:
    • Intensity graphs support visualizing temperature distributions.
    • They effectively display images with varying intensities.
    • They are widely used in the analysis of scientific and engineering data.
    • They help visualize GIS data.
      
      
• 3D Graphs:

3D graphs in LabVIEW enable visualization of data in 3-dimensional space. When you need to display data with multiple variables, using 3D graphs is the best solution. The 3D graphs in LabVIEW are easy to use and customizable.

In 3D graphs, you can create graphs in 3D coordinates (X, Y, and Z) to represent data in a spatial view. In three dimensions, you can visualize an object's motion, time-frequency analysis, and surface temperature distribution.

• • Key Features:
    • A 3D graph visualizes surfaces, data points, and volumes.
    • It interprets relationships between multiple variables.
    • It supports interactive rotation and zooming.
  • Applications:
    • The 3D graph displays plots of multiple variables in complex scientific simulations.
    • It helps in visualizing mathematical surfaces and functions.
    • It helps to create 3D models of physical systems, such as fluid dynamics and structural mechanics.
    • It supports visualizing data points and volumes.
    • It can display the temperature distribution on a surface, the motion of an airplane, etc.
  • Types of 3D Graph: LabVIEW provides several types of 3D graphs to visualize data. Let’s outline them below.
    • Scatter– This graph has two axes, each representing a data set.
    • Comet– A circle that traces the data point on the display in which the trailing segment follows the head.
    • Mesh – It is a collection of vertices, edges, and faces that define the shape of an object.
    • Bar – It is used to visualize data with different proportions in a single view.
    • Ribbon – It appears to be a coiled ribbon formed with smooth curves.
    • Pie – It is a simple and efficient tool for comparing various data
    • 3D Surface Graph – It includes a surface in 3D space.
    • 3D Curve Graph – It includes lines in 3D space.
    • 3D Parametric Surface Graph – It displays a parametric surface in 3D.
      
      
• Digital Waveform Graphs in LabVIEW

A digital waveform graph displays the digital data. It plots logic levels (0s and 1s) over time, representing the behavior of digital systems.

You can use this graph to display digital data, especially when you work with timing diagrams or logic analyzers. The graph accepts the digital waveform data type, the digital data type, and an array of those data types as input.

LabVIEW includes the waveform graph to display data acquired at a constant rate. The graph displays one or more plots of evenly sampled measurements. It plots only single-valued functions, such as y = f(x), with points evenly distributed along the x-axis, as in time-varying waveforms acquired.

• • Key Features:
    • A digital waveform graph is ideal for displaying clock pulses and logical high/low levels.
    • It supports multi-signal analysis.
  • Applications:
    • It helps to visualize digital data transmission in communication systems.
    • It is used in timing diagrams and logic analyzers.
    • It helps analyze PWM and other signals in digital circuits.

Example

The digital waveform graph accepts digital data and an array of this data type as input. It displays data as digital lines and buses, as shown in the image below.

In the image above, the Virtual Instrument (VI) converts the elements of the number array into digital data and displays their binary representations on the graph.

Further, ‘0’ appears without a top line in the graph, indicating a zero-bit value. Similarly, the number 255 appears to lack its bottom bit, indicating that the bottom bit is 1.

Now that you have understood the features of LabVIEW charts and graphs. They help users interpret data efficiently and make data-driven decisions.

Related article: LabVIEW Programming

Customizing Charts and Graphs in LabVIEW

LabVIEW charts and graphs are highly customizable, so you can adjust their visual appearance to meet your requirements.

Each graph and chart offers a variety of options for customizing its appearance, conveying additional information, or emphasizing facts.

Let’s take a short look at them in the following.

• • Appearance – You can change the color, line styles, and markers of LabVIEW charts and graphs.
  • Multiple Plots – You can display multiple plots on a graph to analyze relationships and track trends.
  • Scales and Axes – You can modify axis labels, titles, legends, ranges, and grid lines to make the chart more informative.
    
    
• Customizing Graphs:

Each LabVIEW graph has options that you can use to customize the graph to match your data display requirements.

For example, you can modify the behavior and appearance of graph cursors or configure graph scales.

• • Using Graph Cursors:

You can use a graph cursor on a graph to read the exact value of a point on a plot or a point in the plot area. The cursor value displays in the cursor legend.

The cursor mode defines the cursor position. The cursor includes the following modes:

1. 1. 1. Free – It moves the cursor freely within the plot area, regardless of plot positions.
      2. Single-plot – It positions the cursor only on the plot associated with the cursor. You can move the cursor along with the associated plot.
      3. multi-plot – It positions the cursor only on a specific data point in the plot area. The multi-plot cursor reports values at the specified x-value for all of the plots with which the cursor is associated. You can position the cursor on any plot in the plot area. 

You can customize the appearance of the cursor in several ways. You can label the cursor on the plot, specify the color of the cursor, and specify a line, point, and cursor style. 

• • Using Graph Annotations

You can use annotations on a graph to highlight data points in the plot area. The annotation includes a label and an arrow that identifies the annotation and data point. A graph can have any number of annotations. 

You can use the Lock Style pull-down menu in the Create Annotation dialogue box to specify how the annotation snaps to plots in the plot area. 

The Lock Style component includes the following options:

• • • Free - It allows you to move the annotation anywhere in the plot area.LabVIEW does not snap the annotation to any plots in the plot area.
    • Snap to All Plots - It allows you to move the annotation to the nearest data point along with any plot in the plot area.
    • Snap to One Plot - It allows you to move the annotation only along the specified plot.
  • Autoscaling

All graphs and charts can automatically adjust their horizontal and vertical scales to fit the data you wire to them. This behavior is called autoscaling. 

By default, autoscaling is enabled for the graph or chart. However, autoscaling can slow performance. You can use the operating tool or the labeling tool to change the horizontal or vertical scale directly.

• • Customizing Graph And Chart Appearance

LabVIEW allows you to customize the appearance of a graph or chart by showing or hiding options.

• • • Plot legend - It defines the colors and styles of plots. You can resize the legend to display multiple plots.
    • Scale legend - It defines labels for scales and configures scale properties.
    • Graph palette - It lets you move the cursor and zoom in.
    • Cursor legend (Graph only) - It displays a marker at a defined point coordinate. You can display multiple cursors on a graph.
    • Scrollbar - It scrolls through the data in the graph or chart. Use the scroll bar to view data that the graph or chart does not currently display.
    • Digital Display (Waveform chart only) - It displays the numeric value of the chart.

Exporting Images of Graphs, Charts, and Tables:

When you export a simplified image, LabVIEW exports only the control or indicator, digital display, plot legend, and index display, and does not export scrollbars, the scale legend, the graph palette, or the cursor palette.

You can export images into the following formats:

• • Windows .emf, .bmp, and .eps files
  • Mac .pict, .bmp, and .eps files
  • Linux .bmp and .eps files

You can save the image to the clipboard or to disk. 

Dynamically Formatting Waveform Graphs:

You can wire a dynamic data type output to a Waveform Graph to automatically format the plot legend and x-scale time stamp for the graph.

Example:

If you configure the Simulate Signal Express VI to generate a sine wave and to use absolute time and wire the output of the Simulate Signal Express VI to a waveform graph, the plot legend of the graph automatically updates the plot label to sine. The X-scale displays the time and date when you run the VI. 

You can wire the dynamic data type to an indicator that best suits the data. Indicators include graphs, charts, or numeric indicators. However, because dynamic data is automatically converted to match the indicator it is wired to. Express VIs can slow down block diagram execution.

The dynamic data type is for use with Express VIs. Most other VIs and functions that ship with LabVIEW do not accept this data type. To use a built-in VI or function to analyze or process the data that the dynamic data type includes, you must convert the dynamic data type.

Read: LabVIEW Interview Questions

3D Graphs In LabVIEW:

LabVIEW 3D Graphs are used to plot data in three dimensions. Changing the properties of a three-dimensional graph allows you to visualize data in three dimensions.

For many real-world data sets, such as surface temperature distributions, joint time-frequency analysis, and airplane motion, you need to visualize data in three dimensions. 

With the 3D graphs, you can visualize three-dimensional data and alter the way that data appears by modifying the 3D graph properties.

LabVIEW includes the following types of 3D graphs:

• 3D surface graph: Draws a surface in 3D space.
• 3D parametric surface graph: Draws a parametric surface in 3D space.
• 3D curve graph: Draws a line in 3D space.

You can use the 3D graphs in conjunction with the 3D Graph VIs to plot curves and surfaces. A curve consists of individual points on the graph, each with X-, Y-, and Z-coordinates. The VI then connects these points with a line. A curve is ideal for visualizing the path of a moving object, such as an airplane's flight path. 

Frequently Asked Questions:

1) What is LabVIEW?

Ans: LabVIEW stands for Laboratory Virtual Instrument Engineering Workbench. It is a graphical programming platform widely used in engineering and research.

2) What are the advantages of LabVIEW?

Ans:

• Drag and drop programming.
• Support for cross-platform
• User-friendly interface
• Low learning curve
• Cost-efficient

3) Is LabVIEW worth learning?

Ans: AmbitionBox reports that LabVIEW developers in India can earn up to 650,000 INR per year with 1-7 years of experience. Talent.com reports that they can earn between $100,000 and $148,000 in the USA. LabVIEW professionals can secure lucrative jobs at top companies such as HCLTech, Bosch, L&T, and UST.

4) Is Learning LabVIEW easy for beginners?

Ans: Yes, even beginners can learn LabVIEW quickly. With constant focus and passion for learning, you can learn LabVIEW quickly.

5) What job roles can I apply for after learning LabVIEW?

Ans: 

• Test Engineer
• LabVIEW Developer/Engineer
• Systems Engineer
• Field Application Engineer
• Embedded System Developer

Conclusion

Well! We hope that this tutorial has provided you with good exposure to LabVIEW waveform charts, intensity charts, XY graphs, and more. Now you must have a clear understanding of LabVIEW customization, dynamic formatting, and 3D visualization.

If you wish to learn more about LabVIEW charts and graphs, you can sign up for LabVIEW training with MindMajix. By the end of the training, you will become a master in developing data visuals in LabVIEW.