Attempting to write data to file, but getting error 200279

Question

I am having trouble when writing data to a file. About 10 seconds into the saving process, I get the error 200279. I have done some research on the topic, but am unable to corect my code. I believe I do not want to increase the buffer size, but would rather, I assume, read the data more frequently. The way I save my file is, before running the VI, I assign a location and name of the file (e.g. data.csv). The date and time is appended to the end of the actual file when the I begin to save the data (e.g. data_07-26-13_122615.csv). If the file does not exist, it creates a new file, then appends data to that file after every loop iteration. The reason I did it this way was so I do not have to worry about running out of memory, but apparently my code is flawed. 
I will include a copy of the flawed section of my code. Any help would be greatly appreciated.
Thanks.
Solved!
Go to Solution.
Attachments:
data_acquisition.vi ‏127 KB

Answer 1

Your problem is that writing to disk is slow.  It is slow enough that it is causing your DAQ buffer to overflow and cause the error and loss of data.  What you need to do is implement a Producer/Consumer.  This will put the daq and the logging to disk in seperate loops.  This will allow the DAQ to run at the speed it needs to keep up with incoming samples and the writing to disk can run at whatever rate it can.  You send the DAQ data to the logging loop using a queue.
You might also want to think about changing how you write to the file.  That VI is constantly opening and closing the file, which is a very slow process if you are doing it inside of a loop.
There are only two ways to tell somebody thanks: Kudos and Marked Solutions
Unofficial Forum Rules and Guidelines