Viewing data continuously in Labview

[trodriguez]

I am currently using two channels from a USB-6251 that bring in two EMG (muscle activation) voltage signals. I am trying to graph both of these and display the waveform in realtime using Labview and the DAQ assistant. The issue is that I am only able to view a very small amount of data (< 1 second). I would like to see at least 10 seconds of data.

 It is my understanding that

Time = Samples to Read / Rate

So by increasing my sampling rate or decreasing my samples to read should increase the amount of time of data that I see on the graphs. However, the lowest I can go for samples to read is 30, thus making the required sampling rate really high. So high that I had to add a delay to the VI in order to prevent CPU slowing. I am hesitant to add too much of a delay since the purpose of viewing the data in realtime is for live feedback.

Is there another way to do this I am new to labview so I am still learning all of its capabilities.

Thank you in advance for you help!

I've attached some pictures of my setup

[Dennis_Knutson]

Your basic arithmetic is all backwards. In order to increase the time, you would decrease the sample rate or increase the number of samples. If you had a sample rate of 5000 s/sec and you requested 2500 samples, you would see .5 seconds worth of data. If you decreased the sample rate to 2500 s/sec and kept the number of samples the same, you would acquire 1 second of data. If you kept the sample rate the same and increased the number of samples to 5000, you would acquire 1 second of data. To acquire 10 seconds worth of data, instead of decreasing sample rate or increasing the number of samples, you might want to keep the old data in a shift register and just append the newly acquired data to that. You could also switch to using a chart instead of a graph. A chart keeps the old data (up to the history size you define). A graph doesn't.