Value Signalling through Property Nodes... What is it doing?

[IEC]

Just wondering if someone can fill me in on what is actually happening when I use the property node to change the value of something... and what's the difference when I use the value(signaling) property as opposed to the value?

I use the property nodes a lot in my VIs instead of creating local variables or passing by wires.... should I do that?

Thanks,

jonathan

[Dr._Imad]

Refer to this thread:

http://forums.ni.com/ni/board/message?board.id=170&message.id=58949&requireLogin=False

To capture a value change of a control/indicator/local variable, the value change does not trigger events that can be captured by an event structure.  The value signalling will.

<<I use the property nodes a lot in my VIs instead of creating local variables or passing by wires.... should I do that? >>

Property nodes go through the user interface thread and therefore are slower.  Using local variable is fine, however, each occurance of the variable will have a duplicate memory location of the variable itself.   Not a problem unless you start worknfg with arrays.  The best is to pass values by wires, faster and avoids potential race conditions.

[altenbach]

---

@IEC wrote:

and what's the difference when I use the value(signaling) property as opposed to the value?

---

Writing a Value(signaling) property triggers a value changed event (e.g. to be sensed by an event structure), while writing to a plain value property does not fire an event. (Writing to a local variable also does not fire an value changed event).

---

@IEC wrote:

I use the property nodes a lot in my VIs instead of creating local variables or passing by wires.... should I do that?

---

Passing by wire is always the preferred method, second choice is a local variable. Reading and writing value properties is significantly more expensive! For an benchmark example, see this post . In the quoted case, a value property node is over 600 times slower than a wire!