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PXIe-5122 continuous stream 2 channels to disk with 100MS/s

Hey,

I am currently trying to find a way to stream 2 channels to disk with 100MS/s with my PXIe-5122. According to the product specification, the card should be able to do this. 

Unfortunately, I have'nt seen any programs.

What I have are two loops, one for the DAQ and one to empty the onboard memory using a queue and writing the fetched waveform data into a tdms file. I keep obtaining the error, that samples in the onboard memory are overwritten... therefore, the VI doesn't empty the onboard memory in sufficient speed.

Does anybody know how I could solve this problem? Or does anybody have a program?

 

Thanks for the help!

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Hi lehrm,

 

you are writing about that you didn#t see any application for the 5122. If you mean examples, there are a lot of examples installed on your system when you install the driver sw for the device. eg. there is an example called niScope EX Stream to Disk, that seems to be interesting for your issue

 

Examples are available in the Example Finder of LabVIEW, in the folder: "Hardware Input and Output" -> "Modular Instruments" -> NI-SCOPE (High Speed Digitizer)" -> "Continious Acquisition".

This can give you first ideas! 

Kind regards
Tobias S.
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Thanks. I have already tried them all. The given examples work fine for lower sample rates. But it's said in the description of the examples that this error could accure for high sample rates. But a solution is not given, and it's pointless to build a card to read with 100MS/s if there is no way of getting the fetches samples onto my disk. There has to be another way...

 

Cheers.

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Hello, I am also facing the problem you encountered at that time. Do you remember how it was solved at that time? Thank you for all your replies.

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If you are trying to read 100Ms/s from 2 channels then that means that you are acquiring 200MS/s. If we consider each sample as float (64bit), then each sample is 8 byte of data, 200MSx8 = 1600M bytes of data. So you are trying to write around 1.5GB of data to hard drive. 

Conventional hard drives provides writing speed of 40MB per second so whatever you are trying to do is not possible with hard disk drive.

If you want to perform this task then you will need a raid drive or SSD. You can check below link for PXI storage devices with high throughput.

 

https://www.ni.com/en-in/shop/hardware/products/pxi-data-storage-module.html


CLD Using LabVIEW since 2013
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