I have no idea what you really need. You have only said you need to update something every x number of seconds. You have a loop that runs every x number of seconds so all that you need to do is place your read inside this loop. I don't see the point of the reference or the property node.
p.s. In order to make your while loop a bit more responsive, you might want to use the Elapsed Time function wired to a case structure or a while loop with an event structure.
