I don't understand this ":/value.csv" filename. That is the name for a file that would ordinarily be compiled into your program as a resource. You can't write to it from a logging process, because it doesn't really exist as a disk file. So if you keep trying to load the same file (from resources), of course the content never changes.

As anda_skoa has asked, where is your code for watching the log file on disk and reacting if it changes? You should have a QFileSystemWatcher or some other object that is watching this file, and slot connected to its signal that tells your app when the file has changed. Then you load it into your model using the name of the log file on disk, not the name of the file from the resources.