Acquiring RMS Voltage values when it changes

[guhal]

Hi all,
I just started using data acquisition in labview and my first VI needs to acquire a voltage signal from a analog imput. I would like to know if it is possible to get the RMS voltage value of this signal, every time that value changes, and build an array with them.
I'm sorry if it is a trivial question, but I am having some issues trying to get and trigger a discrete signal from a continuous voltage signal.

Thanks in advance for your help.

[Henrik_Volkers]

What is a change in value?   Remember there is noise 😉 

Will this be line frequency AC voltage?  

How fast is the change?

Some time for settle?

Capture some periodes of the signal (or just a fixed number of samples) in a loop, use the RMS vi, wire the result in a shift register in the first run , next time compare old and new value, if absolute difference is greater than  limit, store/display time and new value and store it again in the shift register

[guhal]

I think I just got it.

I very much appreciate your support.

Danke schon.