Biomedical User Group Documents

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This document informs you how to define an NI-DAQmx scale using the Biosignal Calibrator.

Biosignal Calibrator

When using an NI DAQ device with a sensor to acquire biosignals, you must first define an NI-DAQmx scale for the sensor that you use. The Biosignal Calibrator enables you to create new NI-DAQmx scales for each sensor. You can define different calibration parameters by choosing different calibration methods and adding data points to user-created scales. The Biosignal Calibrator supports three calibration methods: Linear, Polynomial and Table Mapping.

Create a NI-DAQmx Scale

Open the Biomedical Workbench and navigate to the second page. Click the Biosignal Calibrator icon to open this application.
Click Add Scale. The Input Scale Name dialog box appears.
Enter a scale name and click OK to close this dialog box to add a new scale with the default calibration function of “y=x”to the listbox.

Configure a DAQ Channel

Click DAQ Settings to open the DAQ Settings dialog box.
Select a device from the Device name pull-down menu.
In the Channel Information section, select a channel from the Physical channel pull-down menu. Specify the name and input range of the channel.
Click Add as New Channel to add these settings to a channel.
Click OK to confirm the settings and close the dialog box.
After configuring the DAQ channel, the Add/Remove point pull-down menu will change to From DAQ.

Edit a Scale by Adding Data Points

Select a calibration method from the Calibration method pull-down menu.
Specify the scale unit in the Scale unit field.
Click + in the Add/Remove point section to open the Add Point dialog box.
This dialog box displays a control that shows the pre-scaled value acquired from DAQ.
Click the pause button when the control shows the acquired value you want.
Enter the scaled value in the Scaled value field.
Click OK to add a point to the graph. The formula on the bottom of the graph updates according to the points you add.