correct time on waveform graph

[peterj5080]

Hi,

I am using the DAQ assistant to collect data from 7 channels. I am plotting this data on a waveform graph, but noticed the time axis was not correct. It seems that I need to change the x-axis multiplier to get the correct time, however I have a quick question regarding what this multiplier should be.

In the DAQ assistant, I am collecting continuous samples of the 7 channels with "samples to read" = 100 and "rate" = 20 Hz. I have tried reading the help forums but I am still unsure about how the DAQ is actually collecting the data. Is the current set up collecting 20 samples per second for every channel, or is that 20 samples all together across 7 channels? So, to set the right x-axis multiplier should I be using a multiplier of (1/20), (1/140) or some other value?

In the continuous mode, the buffer should be set by the "samples to read", and I think I have done that correctly. However, please let me know if I have not.

Thank you very much for any help, my VI is attached in case I didn't add some relevant details.

[crossrulz]

Change your graph to a chart.  Then you won't have to keep appending to your waveforms.  The chart takes care of it all for you.

[peterj5080]

Thanks for the reply. I would still like to display the elapsed time on the chart as the VI runs, I found a tutorial online, but would still need to know how the sample rate is interpereted. Additional help is appreciated.

Thanks.