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Scope card data from device buffer to TDMS file

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How to transfer Scope card data from device buffer to TDMS file directly bye passing LabVIEW and  Windows buffers. Similarly like DAQmx configure logging(VI) do we have any function for Scope?

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Accepted by topic author Somu26

The NI-SCOPE API does not have the capability to log acquired data directly to disk like the DAQmx API provides.  All data must be fetched from the onboard memory, which causes the data to be transfered to the NI-SCOPE kernel driver via DMA, and then a copy must occur to transfer the data from kernel space into user space (LabVIEW), at which point it can be manipulated.  

 

The main reason for this flow is because calibration scaling occurs in the NI-SCOPE driver, and not in the hardware.  So, if you were to log data directly to disk like DAQmx, it would store the raw ADC codes, without calibrated correction.  The NI-SCOPE API provides a way to retrieve the scaling coefficients should you want to apply them at a later time after fetching the data from the hardware.  For optimizing data streaming applications, this is reccomended.

 

The only exception to the logging directly to disk would be the Reconfigurable Oscilloscope PXIe-5171R.  Since it's firmware is implemented with LabVIEW FPGA using the Instrument Design Libraries, the code is open for modification.  With the open nature of this software stack, it is possible to implement "direct to TDMS" functionality with the LabVIEW FPGA Read Region Node.

 

I hope this helps!

-Nathan

Systems Engineer
SISU
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Thank you Nathan

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Hi Nathan,

 

The same applies to HSDIO card also or do we have any option to transfer data directly to TDMS file from HSDIO card? 

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Sorry for the delay, but I am not as familliar with our HSDIO products.  It appears that there is a "Direct DMA" capability for HSDIO:

http://zone.ni.com/reference/en-XX/help/370520K-01/hsdio/direct_dma/

 

You can also checkout these examples:

https://decibel.ni.com/content/docs/DOC-29085
https://decibel.ni.com/content/docs/DOC-29086

 

I hope this helps!

-Nathan

Systems Engineer
SISU
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Thank you Nathan

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