Time Conversion

[tommychak]

I am a new user of the SignalExpress (Tektronix Edition). I need to calculate the electrial power on the labview (School Project), but I am restricted to calculate the power information (such as power factor, real power, apparent power, freq, etc) just based on Voltage and Current waveform which are measured by the SignalExpress with the hardware of Tektronix CRO (TDS3032B). After I record the voltage and current data which output as tdms file, I found the format of that is not like the below:

Amplitude	Time
2	0.1
4	0.2
5	0.3
4	0.4
3	0.5
1	0.6

Does the labview provide any vi which can help to convert my attached tdms file to a normal format amplitude vs time?

[STASHkal]

I think you can already view your data but just in case: http://www.ni.com/example/27944/en/

Were you expecting something different than 13 evenly spaced points of data?  The attached files look like they have data in column 1 and a time stamp in column 3.  

[tommychak]

Thanks for your reply, StaysKool.

Actually, I can already open this tdms file. But the data is like below:

Amplitude	Time
2	0.1
4	0.2
5
4
3
1

The quantity of timestamp data (130k in my attached !!!) is not equal to  the quantity of amplitude (only 13 in my attached) .

When I put this tdms file to the labview 2012, it is very difficult to manipulate and do the calculation.

For example, when I calculate the energy (kWh)  the time accuracy is required 

Any labview program (.vi or example) is able that just put this type tdms file on the program and then automatically show all of the electrical power information?

[STASHkal]

"The quantity of timestamp data (130k in my attached !!!) is not equal to  the quantity of amplitude (only 13 in my attached) ."

Should be 

"The quantity of timestamp amplitude data (130k in my attached !!!) is not equal to  the quantity of amplitude timestamp (only 13 in my attached) ."

Is that correct?  If not then I am misreading your data file.

What does your program in signal express look like at the moment?  An acquire followed by a write to file?  

I noticed one other weird thing about your data.  The last two timestamp values are the same.  Seems odd.  

There probably isnt prewritten code to do the exact calculations you want.  However, It shouldn’t be to hard to write it in whatever language you want.  I was a mechE in School but at the worst you would do some numerical integration. Right?  

[tommychak]

Thank you for your correction, you are right.

I just use the SignalExpress to record the voltage and current data as a tdms file, and I want to put this file on the LabVIEW for the additional manipulation. But now it seems very difficult to write a program based on this format.

I am studying the Electical Eng. , I just remember some basic numerical integration. that's why I want to use the LabVIEW to help me for calculating it.

[STASHkal]

Why not do your data acquisition in LabVIEW too?  That way you can acquire, manipulate and save data in the same program?