swept sine generation - sounds and vibration tool kit

[chakko]

Hello,
I am vorking on a dynamic identification project and I am trying to generate a swept sine to a sensor. I use the swept sine generation of swept sine measurement vi in sound and vibration toolkit it works properly but in the same vi I cannot use daq assistant as analog input, it does not work. What can be the possible reason?
I just need a swept sine and daq assistant to get the response of the sensor and then find its impedance magnitude and phase by some methods such as integration or correlation, but I have spent a lot of time on generating swept sine, I have also tried to use some swept sine generation vi in this forum but also I cannot figure them out. I just need start freq, stop freq, # of steps, step or block duration. Could you please help me on this topic?
Thank you...

[BrowningG]

Hello Chakko,

Thanks for contacting National Instruments. 

The DAQ driver only allows one instance of a task type to be run at a time.  This means that only one analog input task and one analog output task can be run at a time.  The sound and vibration toolkits VIs setup both analog output and analog input tasks for your device.  This is most likely the reason why you cannot setup the DAQ assistant with an analog input task since there is most likely an analog input task already running. 

Chapter 13 of the Sound and Vibration Toolkit manual has several images of example programs using the swept sine measurement VIs.  These examples can be found in the NI Example finder from LabVIEW by going to Help-> Find Examples.  From there you can browse to the swept sine examples by following the path: Toolkits and Modules->Sound and Vibration->Analyzing and Processing Signals->Swept Sine Measurements.  The example titled SVXMPL_Swept Sine FRF (DAQmx) allows you to set the start frequency, stop frequency, number of steps, and block duration. 

The Sound and Vibration toolkit allows for integration in both in the frequency and time domains.  Chapter 7 of the Sound and Vibration Toolkit manual goes over the methods used by the integration VIs. 

Please post back if you have any more questions.