And your jpeg doesn't show an error. It just shows a waveform chart that is continuously zero.
Do you have any error handling in your VI? Anything that shows errors on a VISA read, or perhaps a conversion from the string read in to the numeric data you are plotting on the chart?
You should put some error indicators in your VI, and an indicator that shows the string that is being read in by the VISA read. It can help you debug the code while it is running.
