real frequencies in power spectrum by using signalexpress

[basit]

Dear,

a-I am using NI Express Workbench version 1.1.0 (Labview Signal express) to acquire data by using  BNC 2090 Data Acquisation board from  accelerometers attached to the model excited by shaker. The signal express program consist of the following simple steps

1- NI-DAQ max Acquire (acceleration from 3 different channels

2- Power Spectrum giving ‘’magnitude’’ etc

3- Save to ASCII (Acceleration of each channel in time domain)

4- Save to ASCII (Acceleration of the selected channel in frequency domain)

The problem is in 4^th step that the frequency recorded seems to be fictitious i.e., exceptionally high in the range of  3x10⁹ and so, which is absolutely wrong because the excitation frequency of the shaker is  just 1 to 5 Hz which is even clearly seen by the peak from power spectrum display in the range below 5Hz. Then why I am getting such record of unbelievable high frequencies in data file. Your help to get real frequencies in data file would be highly appreciated.

b- The hardware for the data acquisition is BNC 2090 with my old laptop having a DAQ card with PCMCIA slot but now I want to use it (BNC 2090) with a laptop which has express card slot. Is it possible either to connect BNC 2090 with a laptop which has express card slot or what other cheapest possible alternative/product you have to serve the purpose? Do you have some thing for this purpose having USB to get rid of these slot problems? Please send me its detail with price.

Thanks with regards

Basit Khalid

TUWIEN

[Ken_Tobler]

 Dear Sir,

The results should come from the step 2 (Calculation of the power spectrum)

Are the Result of the power spectrum correct? Or does the values also are to high?

Or chech the regional settings of your operating system. Changing from German to Englisch does resolve the problem? It could be a decimal point (komma or point) problem.

Best regards

Ken