Property nodes are very much like a local variable in concept. If you write click a property node (value) you can change it from read to write. If the node is on "read" then when the property node reads a value, it will update the value of the origional item that its property is for. If you change the property node to the write direction, then the property node will have the value of your origional item that the property is for, but the property node will only output the value of that item. Hopefully that makes sense.
There are two types of property nodes, one is value and one is value signaling. The value signaling is useful when you are using event structures and you do want labview to act upon an event change that deals with the value change.
Hopefully that made sense.
