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How do I Enable IEPE Excitation Programmatically?

Hardware: PXI/CompactPCI>>Controllers

Problem:
I am using hardware that needs IEPE excitation enabled. How do I programmatically turn on IEPE excitation?

Solution:
You can enable the IEPE Excitation on your DAQ device two different ways: Create a task in Measurement and Automation Explorer or use DAQmx code protocol in LabVIEW.

Create Task in Measurement and Automation Explorer

Browse to your IEPE capable device under Devices and Interfaces, right-click on it to bring up the drop-down menu shown below, and select the Create Task Option.

Once the "Create New NI-DAQmx Task.." box pops up, browse to Aquire Signals»Analog Input»Acceleration and then choose the Physical Channels you want to monitor. You can name the task anything you want. After this is done, a configuration window should open in Measurement and Automation Explorer. You can configure all the parameters for your aquisition. The excitation value is labeled "Iex Value(A)" and the value here will be the excitation value sent to your third party device. After this, save the task. You can now either run this task in Measurement and Automation or you can pass the task into LabVIEW. You pass the task into LabVIEW by creating a constant off of the Task In input of the DAQmx Create Channel.vi and then completing the proper DAQmx coding shown below.

Create DAQmx code protocol in LabVIEW

If you don't want to create a task in Measurement and Automation Explorer, then you can set up DAQmx code in LabVIEW to enable IEPE excitation. This is done by using a DAQmx Create Channel.vi set to Analog Input»More»Custom Voltage with Excitation and also a DAQmx Channel Property Node.vi in the DAQmx code line. The excitation options can be found in the DAQmx Channel Property Node under Analog Input»General Properties»Signal Conditioning»Excitation. The options are Excitation Source, Excitation Value, Use Excitation for Scaling, Excitation Actual Value, DC or AC, and Voltage or Current. Once you have browsed to these options, you must right-click on the property node and choose "Change All To Write" so you can write values to these properties. Once everything is configured for your application, then you can add the property node right after the DAQmx Create Channel.vi but before the DAQmx Start.vi. The end resulting code should look something like the picture below.

Report Date: 10/22/2008
Last Updated: 01/20/2009
Document ID: 4QLCTPH1

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