The same problem occurs on my VI too. There is no error writing the data into .lvm, when I try to read it, it turns out NaN value or zeros.
I got only one value written to the .lvm file. When I try to read it, it gives out an array of zeros, or NaN values.
Here is a simple vi illustration;
There are several topics on this issue, there must be anyone to solve this problem, I guess and hope.
This problem occurs when you attempt to read from the same file multiple times. The Express VI will not let you do this, unless you reset it in-between calls.
If you want to view different pieces of data from the same file, you should either perform the task manually with the File I/O pallette, or store the read data in a shift register and then use this whenever you want to re-read the data.