Read from measurement file - Error in sample clock

[rafaelcampos]

Hi, guys.

I'm new to LabVIEW and I am working on a project that consists of acquiring data from a accelerometer (PCB Model 353 B03), filtering the signal and presenting a graph with the RMS amplitude and the power spectrum.

I already have a VI to acquire data from the accelerometer and display the result that I want, but I'm trying now to work this data at home, away from the accelerometer. So, I write my original data with a "Write to Measurement File" and on my home computer I have a VI that tries to read this data and apply the same filtering to display the same results (RMS amplitude and Power Spectrum).

The problem is that when my acquired data passes through the DAQ Assistant, an error (-200077) appears stating this:

I believe that the error comes from the configuration of the DAQ Assist. I don't know which Rate and number of Samples I should insert to fix this error.

I'm sending both files in case someone wants to take a look into them.

Help will be much appreciated.

[Wolleee]

Hi rafael,

I didnt actually go through your vis but i can see in the error image that your requested value for your sample closk is lower than the minimum value that will be accepted.  So simply change your sample clock value.

[rafaelcampos]

Thanks for the answer, Matt

I've tried to change the sample clock value and it doesn't solve the problem. I don't understand where this value stated in the error comes from as the rate that I chose in the DAQ Assistant is currently at 25600 Hz and changing it does not change the value that appears in the error message.

I believe that the rate value comes from the file that I'm reading and changing it in the DAQ assistant will not help me. I may be wrong on this.

[RavensFan]

The problem is that you wired the blue dynamic data type wire into the Signals input of your DAQ assistant.  It doesn't matter what you configured in the express VI, when you wire something in, it overwrites it.

Reading the error messags gives you a clue.  It says the requested value is -1.244e-3.  A negative value makes no sense for a sample rate, and that is why it is less than the mininum value.  That -1.244e-3 is probably the first value in the signal that you are reading.

[rafaelcampos]

I think I solved it. It was just a matter of wiring my signal input directly into the filter. There is no need for the DAQ Assistant there. I think it is working properly now. Thanks guys.

[RavensFan]

If you didn't need the DAQ assistant, why was it there?  It looked like you were trying to use it for an analog output.

[rafaelcampos]

I thought I needed it, but my goal is to simply get the read data, which is analog, and apply the filters to it in order to get the amplitude. So, I believe that the DAQ Assistant should not be placed there, as I am not acquiring data from a physical device in this VI.