how much time do I need to process the data

[mhtl]

Re. my previous question.

I will be scanning 26 analogue channels at 7 khz into the PCI 6024E using a SCXI 1000 with an 1100 temperature module and the voltage signals going into the 1180 direct feedthrough.

I would like to acquire up to 3 seconds of data at 7 khz on all 26 channels. I then would 'decimate' the 20 thermocouple channels down to a sample rate of about 700 hz from 7 khz and then display the temperature profiles on a chart and then write the data to disk for all 20 channels writing only the reduced number of samples for each channel.

Two of the 7 khz inputs I would do an RMS calculation on and then display the results and also write the results of the RMS to a different file.

The program then needs to
be ready to sample new data again for three seconds.

The computer is a P3 500 MHz with 327 MB ram.

Another part of the question would be suggestions about how to write the program so that we could be sampling new data while the program is processing the old data and writing to disk.

[Russell]

Hello mhtl,

If your question is how long will it take to process the tasks you mentioned, there's really no way to tell. This not only depends on the machine, but how you implement it. Certainly, tasks such as this are possible. In fact, we have a good example program that shows you a good structure using threads and queues.

Running Multiple Tasks in LabVIEW

(Make sure you select the "advanced" VI inside the llb file.) This example puts the three tasks, acquire, analyze, and present into three separate threads so that they are all acting simultaneously. (Which I believe was your question.) In your "analyze" V
I, you could be processing your data while the "show data" VI is simultaneously writing previous data to file. There is a good tutorial linked to the page I mentioned above as well. This topic is also covered in our LabVIEW Advanced training course if you're interested.

I hope this helps!

Russell
Applications Engineer
National Instruments
http://www.ni.com/support