Concerned about memory usage

[Intern Liz]

I have a vi that I have put together with various subvis. Right now it is set up to read data from a file and find the fft and convert that fft to velocity and displacement. In the long run the read from file will be please with a DAQmx setup. I will be reading data from an accelerometer and then sending it to the fft sections. My concern is the amound of memory that something like this will take up. It will generally run at a sampling rate of about 2kHz but occasionaly that could go up to 25kHz. Does this program look like it can handle something like that without being extremely slow or crashing the computer. I am looking for any suggestions to make this a better program. the main program is named event read from file.

[johnsold]

Liz,

How much data will you actually have at any one time?

A 25 kHz sampling is not likely to be a problem unless you have many channels and are accumulating data for a long time. If you have a few MB of data or less, you will probably not have any problems. If you go above 100 MB you will need to be very careful to avoid making unnecessary data copies.

Search for a white paper on Managing Large Datasets. It is on the Forum archives or elsewhere the NI web site. I do not recall the exact title.

Lynn

[Intern Liz]

The data acquisition section could run for any possible amount of time. When it is time to save data it will most likely be for about 15 seconds. That 15 seconds of data is what would be passed around to the other sections of the vi to be analyzed. I think any set of data would be less than 10 MB.

[Tohatsu]

25KS and 15s of doubles (64bits) would create approx 3megs of raw data.

[DFGray]

The tutorial is called Managing Large Data Sets in LabVIEW.  It has not been updated for LabVIEW 8.5 yet, so check out the In Place Element structure if you are using LabVIEW 8.5.