split tdms into channels

[bns2804]

Hello,

I have a recorded data to a TDMS file from labview with parameter one channel only. I want to split my single channel data into a group of channels. Is there a way to do it in DIAdem or Labview??

Thanks.

[Brad_Turpin]

Hi bns,

I'm not familiar with that one-channel-only parameter in LabVIEW.  Are you writing CAN data to the TDMS file or regular sensor data as arrays/waveforms?  In general both LabVIEW and DIAdem can demultiplex your single channel into many, but the difficulty will depend on the details of how the data were saved.

How many channels of data do you expect to have at the end?  Are they all the same sampling rate, or do they have different sampling rates?

Brad Turpin

DIAdem Product Support Engineer

National Instruments

[bns2804]

I am writing the values of power spectral desnity to a tdms file. However I have a high sampling rate of 200K samples per second and hence a bandwidth of 100 kHz.  I am now having almost 600,000 channels when i read the TDMS file but all the data sets are merged.  One iteration will store values from 0- 100Khz and then the loop will start again, i wanted to split the data to channels so that one iteration produces one channel only as it is the case for one column per channel.

Thank you 

[Brad_Turpin]

Hi bns,

I'm still looking for answers to the following questions:

1) How many channels of data do you expect to have at the end?

2) Are they all the same sampling rate, or do they have different sampling rates?

Do you have a sample file small enough to post?

Brad Turpin

DIAdem Product Support Engineer

National Instruments

[bns2804]

Hello
Yes all of them are at the same sampling rate and upto now, all the data is recorded into a single channel only. I would like to split the channels after one loop i.e one set of values from 0-100kHz has been recorded and repeart it for every iteration.
Unfortunately i had recorded data over hours hence making the files quite bulky  of nearly 1 GB.

Thank you for your concern and help.

[Brad_Turpin]

Hi bns,

If the values are stored end-to-end, that is, all the values from channel X are stored in one contiguous block, then you can use the following command to copy those values out of the large merged channel into the desired subset channel.

Call DataBlCopy(ChnNoStr, ChnRow, ValNo, ChnNoStr1, TargetLine)

If your data is stored interleaved, then you'll need to create a new "Channel_ID" channel that lists the desired subset channel id or name, then use the Channel Calculator to split out just the (non-contiguous) rows for each subset channel.

Brad Turpin

DIAdem Product Support Engineer

National Instruments