Designing a Biosignal Logger Part 3: Logging a Biosignal (Biomedical Toolkit)

In Part 2 of this tutorial, you designed a VI to preprocess an acquired biosignal by calculating the RMS value of the biosignal. You also used waveform graphs to view both the original biosignal and the preprocessed biosignal. In Part 3 of this tutorial, you design a VI to log the original biosignal and the preprocessed biosignal to a file.

What to Use

Use the following objects to log the original biosignal and the preprocessed biosignal to a file:

Build Array Function		Convert to Dynamic Data Express VI		Write Biosignal Express VI
Add		Add		Add

What to Do

Create the following block diagram to log the original biosignal and the preprocessed biosignal to a file.

The following list describes important details about the previous diagram:

	Use the Build Array function to build an array of the original biosignal data and the preprocessed biosignal data. When you place the function on the block diagram, the function has only one input available. Add inputs to the node by right-clicking an input and selecting Add Input from the shortcut menu or by resizing the node.
	Use the Convert to Dynamic Data Express VI to convert the combined biosignal data back into dynamic data type. The Write Biosignal Express VI can log only biosignals that are dynamic data type. Select 1D array of waveform from the Input data type listbox in the Configure Convert to Dynamic Data dialog box.
	Use the Write Biosignal Express VI to log the combined biosignal data. Complete the following steps to configure the Write Biosignal Express VI: Enter the path and name of the file to use to save the logged biosignal data in File path (new or existing). You can also click to navigate to the folder where you want to save the logged biosignal data. Enter a group name for the logged biosignal data into the Group name text box. Click OK to close the dialog box and return to the block diagram.

After you complete this part of the tutorial, you can run the VI to log both the original biosignal and the preprocessed biosignal to a file. After you log biosignals to a file, you can use the data for further analysis, such as extracting ECG features from ECG data.

Examples

Refer to the Designing a Biosignal Logger project in the labview\examples\Biomedical\Tutorials\ directory for a completed version of the VI from this part of the tutorial.

Where to Go from Here

This tutorial introduces a basic version of a biosignal logger that uses the Biosignal RMS VI for biosignal preprocessing. For a similar version of the biosignal logger you design in this tutorial with variable preprocessing functionality, refer to the Biosignal Logger VI in the labview\examples\Biomedical\Biosignal directory.