Power factor, reactive, active and apparent power

Question

Good morning,
I have a VI that make some math calc and give me the power factor from the system, but when I'm trying to show it in a waveform graph I have some problems.
First I have to fix the scale: -1 to 1 
Second that you all know if the values go high than 1 the value has to be negative -0.999 -0.98 
How could I work on Y axis to change it when I'm trying to show a graph of power factor? I think about use property node to work on Y axis... but maybe have an easier way!
And also if someone know an easier way to calculate power factor,
Reactive, Active and Apparent power I would be glad if someone can help me on that!
Thanks

Answer 1

Hey Jeff,
This program  was made in LabVIEW 7.1
I will upload the code but I will tell here more or less what it do.
You won't be able to run the problem because it's open a file that I have recorded with another program and save a new file.
To get real power (p) = I took the average of instantaneous power 
P=V x I
Apparent power (S) =  Vrms x Irms
Reactive power (Q) = SQRT (S^2 - P^2)
Power Factor = P/S
This is the math, the problem is I need to adjust the graph to power factor
and we know that power factor goes -1 to 1
How can I make LabVIEW understand if a value go high than 1 so it's negative? my problem is that!
I will make a second post to upload the other 2 VI's
Message Edited by EduU on 03-12-2010 06:12 AM
Attachments:
Conversor4V4I-A teste3.vi ‏119 KB
Le Dados Conv 4v4i S5 1 grafico.vi ‏236 KB
conv_hora.vi ‏17 KB