Using LabVIEW 2010 to Achieve More Efficient Measurements

Table of contents

1. MAX
2. NI-DAQmx Driver Software
3. Custom Front Panels
4. Example Finder and LabVIEW Community
5. The Easiest Way to Acquire, Analyze, and Log Data

LabVIEW 2010 is a graphical programming environment that makes it easy to use any sensor to measure on any PC bus. Compared with traditional text-based programming languages, LabVIEW can help you collect data more efficiently, whether it is a simple temperature measurement or data capture of a complex system with 10,000 channels.

LabVIEW programs are called virtual instruments (VIs). Each VI includes a front panel and a block diagram. The front panel is equivalent to the user's operating interface, on which various controls such as buttons, switches, graphics, and tables can be placed.

Figure 1. The LabVIEW front panel is the user interface that can be customized with controls such as buttons, knobs, graphs, and charts.

On the program flowchart, you can develop graphical code to collect and analyze measurement data, derive and reuse code, and interact with front panel controls.

Figure 2. On the block diagram, you can write graphical code consisting of nodes, wires, and loop structures.

Data acquisition applications generally include signal acquisition, displaying data in a graph or chart on the front panel, and saving data to a file. In LabVIEW, these functions can be easily implemented, and its configuration and creation are very unique.

MAX

All NI data acquisition (DAQ) devices include Measurement & Automation Explorer (MAX), a configuration and testing tool. MAX features include:

* Use interactive test panels to configure and test data acquisition hardware
* Query device pinouts and documentation
* Create virtual channels

Test Panel

MAX can display all data acquisition devices connected to the computer. In MAX, you can open the test panel of the device and use it to verify whether the signal connection is correct and observe the specific signal value in real time (as shown in Figure 3).

Figure 3. In the Test Panel in MAX, you can test the functionality of your data acquisition device and verify signal connections.

Device Pins

In MAX, right-click the data acquisition device and select "Device Pins" to immediately view the terminals corresponding to the device's analog, digital, and counter channels (as shown in Figure 4).

Figure 4. Use MAX to quickly query device pinouts.

Virtual Channel

In MAX, you can create virtual channels to map configuration information to a specific physical channel on the device, such as scaling factors and input limits. MAX has many virtual channel measurement types, including pressure, force, and torque (see Figure 5). By using virtual channels, you can quickly convert raw voltage into engineering units, such as Newtons or pounds per square inch.

Figure 5. You can use MAX to create virtual channels and set parameters such as scaling factors, input limits, and engineering units.

NI-DAQmx Driver Software

All NI data acquisition devices include NI-DAQmx, a comprehensive hardware driver that includes the DAQ Assistant and a low-level application programming interface (API)
.

The DAQ Assistant is a dialog-based wizard, accessed from MAX or LabVIEW, that allows you to create virtual channels and measurements without programming.

Figure 6. The DAQ Assistant helps you quickly acquire or generate data without programming.

NI-DAQmx API

Although the DAQ Assistant provides a quick and easy way to acquire or generate data without programming, more advanced users may need increased flexibility and low-level control. For them, the DAQ Assistant alone is not enough. The NI-DAQ driver provides a comprehensive API that includes basic and advanced functions that can be used to control parameters such as timing, synchronization, data processing, and execution control (as shown in Figure 7).

Figure 7. Use the API provided by NI-DAQmx to specify advanced parameters such as triggering and synchronization. [page]

Custom front panel

LabVIEW 2010 has hundreds of controls, including drag-and-drop controls, graphics, and 3D drawing tools, which can help you quickly create graphical user interfaces. Right-click these built-in controls to customize their position, size, alignment, scale, and color in seconds.

Figure 8. LabVIEW front panels make it easy to create custom user interfaces, including charts, knobs, and buttons.

Figure 8 shows two controls—Number of Measurements and Delay (sec) and a waveform graph indicator named Temperature Graph. You can see the results generated by this VI on the Temperature Graph indicator by changing the values ​​of the Number of Measurements and Delay (sec) control inputs. The results that this VI generates on the indicator are based on the code that you create on the block diagram.

In LabVIEW 2010, you can completely customize the front panel using custom controls, graphics, and decorations (see Figure 9).

Figure 9. Advanced users can fully customize the look and feel of a LabVIEW front panel.

Example Finder and LabVIEW Community

LabVIEW 2010 includes hundreds of example VIs to help you quickly implement data acquisition applications. You can search for examples using the LabVIEW Example Finder (see Figure 10).

Figure 10. The LabVIEW Example Finder includes hundreds of example VIs for specific applications and industries.

NI Developer Community

In the NI Developer Community, you can exchange the latest sample code, technical guides, reference books, and more with engineers and scientists around the world. While sharing development experience, you can also learn the latest technology and get in touch with experts who develop the same application of LabVIEW or other NI products. Visit the community at ni.com/community

The easiest way to collect, analyze and record data

The easiest and most flexible way to acquire, analyze, and log measurement data is with LabVIEW 2010. And with tools like MAX, NI-DAQmx, and the LabVIEW Example Finder, you can quickly create your application and customize it to your system and needs.