acquire,log & delete some data

[Jimmy.Z]

Hello,

I'm stuck on a problem of erasing data acquisition tdms 3 analog data signals file with a DAQmx acquisition module. Analog signals are sampled 4MS / s and I keep in the file offset (ms) data. I also have a memory overflow after a while the VI runs.
I created a VI snipette the committment in question.

[crossrulz]

I don't understand what it is you are attempting to accomplish with that bottom loop.  Do you just want the TDMS file to contain the last X samples?  Are you trying to create a new TDMS file when the current one gets so large?  I have a feeling all of this could be done automatically for you in the DAQmx API.

[Jimmy.Z]

I want to erase data exceeding the offset (negative integer in reality) the least recent. I have already tried with the Log module DAQmx and I can not erase data simultanously  the acquisition task is launched. But if i stopt the task and opened the tdms to erase the data and start a task then hi created  groups in the TDMS file that are simply incremented with the same channels.

thank you...

[robertpf]

Hi Jimmy.Z,

If I understood you correctly you would like to do an inverted append, adding the data to the TDMS file from the top, while removing data older than XX ms?

Do you use the NI PXI-4498 for acquiring the data? It is rated for ~200kS/s, so I don't get it how you can use it (without getting error messages) for 4 MS/s?

How does your computer setup look like, are you running a 64-bit OS? LabVIEW 32-bit? How much RAM?

In the subVI initiating the TDMS reference, what is the setting for "disable buffering?" in the RDMS Open Function?

How large are your TDMS-files? Please upload one of your log files with the proper content. In the meantime I'm adding some general links on memory errors and TDMS buffering:

File Buffering with TDMS Files

http://zone.ni.com/reference/en-XX/help/371361L-01/lvconcepts/fileio_tdms_file_buffering/

Memory Growth with TDMS Write

http://digital.ni.com/public.nsf/allkb/961EDE096E98E87D862579ED0068BFF9?OpenDocument

Why Do I Get an "Out of Memory" Error in LabVIEW Even Though My OS Reports Enough Free Memory?

http://digital.ni.com/public.nsf/allkb/F3FB3A32B51BF33E8625763100704136?OpenDocument

How Much Memory can LabVIEW 32-bit or 64-bit Use?

http://digital.ni.com/public.nsf/allkb/AC9AD7E5FD3769C086256B41007685FA

How do I Prevent Memory Errors when Appending Large TDMS Files?

http://digital.ni.com/public.nsf/allkb/FC96E54927FEEB1186257C5B00382297?OpenDocument

Best regards,

[Jimmy.Z · Accepted solution]

Hi,
I found a solution using the creation of a new TDMS file module after an offset time, I only keep the last two newer files and other I erase them progressively.

Now I want to concatenate the two in order to come and erase that which is concatenated with each other. but in the concatenated file he created me another group of the same tracks added file and not add them to the end of each path that is the same.

NI community I want your help to solve this problem without using the DIADEM for I have not ...

I post the attachment VI, the recording and erasing part is over ....

NI community thank you ....