How to log the data by a USB data acquistion with high sample rate in Labview

[gnatjian]

Hello All,

I am using a USB6361 to acquire a analog data with sample rate 100K. The program in labview looks as below which is a simple DAQ configuration. Use the VI for wrting the data to excel file. The configuration (Sample rate is 10000Hz) in the following pic can works well.Analog DAQ

However, when I use a high sample frequence (100K Hz) which I need for my project, the error popped up as below. I tried to increase the number of samples, the error is still there. If I do not enable the write to file VI, there is no issue with this program.

Could someone help with this? ThanksError

Finally when I try to test two channels, I got the following wave form after I run the model, but actually I did not connect any cable to the second channel. Why does the second channel (voltage1) also show almost same value as the first channel which is connected to a function generator.

 Curve with Two Channels

Regards,

Jian

[crossrulz · Accepted solution]

You logging is slowing down the loop too much.  File IO is just slow.  That is the nature of computers.  But you can be a lot more efficient with how you are logging.  If an Excel format is not a requirement, what I would do is get rid of the Write To Measurement File.  You can then go into the DAQ Assistant and then the Logging tab.  You can configure DAQmx to stream the data straight to a TDMS file.  Then as long as you have the TDMS Excel add-on installed (comes with LabVIEW), you can still look at your data in Excel.

[psuedonym]

I have found that the fastest way to log data is to log to memory mapped files which essentially uses the PC's RAM to store the data.

[gnatjian]

Thanks for reply. I found that if I choose TDM or TDMS format, the data can stored successfully based on this 100K sample rate.

[gnatjian]

Thanks. It works now based on your suggestion.