Let's clean up many of the problems you have with your VI first.
1. Do you really want to configure the serial port every iteration of the while loop? The Serial Configure should be before the loop. You don't need the VISA Open at all.
2. Bytes at Port is the wrong thing to use 99% of the time. I'm going to assume (since the serial configure is set for a termination character) that the string coming in is some digits and a linefeed character. Take advantage of that and set the bytes to read at VISA Read to be a larger number.
3. Converting from an array to a cluster then unbundling is pure Rube Goldberg. Use Index Array to get the first and second elements of the array. (Index Array is expandable by dragging the bottom border downwards to give multiple outputs.)
4. You have a lot of redundant code where you make numerous comparisons and drive numerous case structures. Wire your integer to a case structure and have a separate case for each of 1, 2, 3, 4, 5, Anything in the true case for the respective comparison will just go into the correct case.
5. Your case structures don't do anything productive. You are just appending Trues to then end of the array. And the array to cluster unbundle dance mentioned earlier just yields the same 1st and 2nd true in the indicators.
6. I see clock functions in each case, but you aren't trying to do anything with them. It seems to me that value is what you want to store in the feedback node, and you'd take the difference in time between the current value and previous time and append that into an array.
I would recommend you learn more about LabVIEW from here. How to Learn LV
