Long duration data acquisition with USB-6002

[estebanrestrepo7]

Hi,

I'm using a USB-6002 DAQ card to take measurements for a fatigue test. The test is supposed to last for 3 months without interruption. The data acquisition is set to Finite Samples with a sampling rate of 1kHz and taking 100 samples. This acquisiton task is set inside a main loop which executes every two seconds. The problem is that after 3 to 5 days of testing the USB6002 stops working correctly and instead of taking the measurements in 0.1 seconds it takes 15 seconds and sends an error. I have reproduced this error in different computers, with and without sensors connected to the DAQ card and with different USB-6002 cards, always after 3 to 5 days of continuous testing, and the only solution is to disconnect the usb cable and connecting the DAQ card again.

Is it possible that the USB-6002 isn't capable of working continuously for a long period of time? Or is there any ideas of where this problem may come from?

Due to confidentiality reasons I can't upload the complete code but I attach the acquisition subVI.

[johnsold]

Generally it is better to create, start, and stop tasks once, outside a loop and do the read as many times as necessary inside the loop.  You have created that task >2.5 million times in 3 days so that may be part of the problem.

Exactly what error code and error message do you get? That information can be useful in determining the problem. 

"Code slows down over days" is often a clue that somewhere in the code you are building an array or string continually until it outgrows available memory or that references are being opened but not closed.

The use of tunnels set to "use default if unwired" is also often a clue with new users of LabVIEW that the structure of the program may result in behavior different from wht you want, although very consistent with dataflow.

Lynn

[estebanrestrepo7]

Hi and thanks for your reply,

The error code I get is error -224606 Internal Software Error in MIO. Additionally I don't have any problems with memory caused by arrays or references.

For instance I will change the VI so that I create the task only one time as you said, but please let me know if you have any other ideas of where the error might come from.

Regards