Data Acquisition

The following is a documentation of the specifics of the user interface of our code with the data acquisition system.

The Data Acquisition System is controlled in LabVIEW by a modified version of the DAQ Assistant Express VI. The main modifications were changing the set parameters of the VI to be controls on the front panel, shown in the pictures below. These controls can be edited between runs by the user. This allows for a different device to be selected, different channels to be selected, and changes in the configuration of the data measurements, without rewriting code.

A few DAQ parameters, sampling rate and number of samples, are not directly controlled by the user. They are instead determined within the code based on the Sound Format settings as well as the duration of the generated signals. Specifically, the chirp and zero pad durations or the Tone DAQ buffer size in the Signal Type Control. The rest of the DAQ settings are controlled in Acquisition and Sampling Control.

Device Name: controls the device being used by changing the beginning of the concatenated string used by the DAQ Assistant to identify the device.

Number of Channels: chooses how many of the channels of the device will be monitored by the system.

Channel Number Offset: allows for any consecutive channels to be selected at once, that is, channels 0 and 1 could be skipped and channels 2 through 5   would be the four measured.

 

 

 

Generated Device Channel Names: This is not a control, but rather, it is an indicator which allows a user to check that the channel name is input properly.

 

 

 

 

 

Max/Min: controls set the range over which the DAQ is measuring, effectively setting the maximum amplitude that can be detected.

Input Terminal Configuration: determines how the voltage is measured. It can be set to Differential,    psuedodifferential, RSE, NRSE, and default.

The two remaining controls are best left blank.