How to measure rms value of current and voltage by using LabVIEW?

[dongre.gaurao1991]

I want to measure RMS value of current and voltage signal which I am getting by using CRIO 9076 analog input card. I have used rms block from electrical power of LabVIEW, but value varries from 0 to rms which is not required. So, suggest me program for measuring rms value measurement. 

[LewisL]

Hi Dongre, What do you mean by "but value varries from 0 to rms which is not required. " If you are using EPS 2014, you should first identify the type of data acquisition cards you are using for your cRIO 9076 (SAR of Delta-Sigma), and then choose the examples with the corresponding type in name in the Power Quality folder. These are more ready-to-run than the examples in Basic Power Measurement which are for DAQmx, but which could also give you a straight forward view of how to measure RMS. You need to check the data acquisition modules on your cRIO for acquisition precision. If they are different from what's used in the examples, you need to manually modify a bit. Refer to the link below for how to adjust precision when you change for another module. http://forums.ni.com/t5/LabVIEW-Electrical-Power-Suite/Wrong-Voltage-Values-using-NI-9225-and-ELectr...

[dongre.gaurao1991]

Dear Levis,

I am using NI 9205 card for measuring volatge, current and power. Here I have attached image of my simulation. Please suggest me what is the problem I have made in it? 

[LewisL]

Dongre,

Please do take the examples as reference first.

<National Instruments>\LabVIEW 2014\examples\Electrical Power\Power Quality\Applications (cRIO) (SAR) or Applications (cRIO) (Delta-Sigma) - depending on the type of the modules you are using . If you do not want to use FPGA to resample the data but to use cRIO CPU instead (which is not recommended), the Applications (DAQmx) folder is a good reference.

[haimo]

Can any one please explain me how to set Sample time in Energy block.
kindly attach .vi file calculating energy from simple simulated sine wave.

It will be great favour 

Thakin you in anticipation

[RavensFan]

Please don't spam the forums by resurrecting multiple old threads and asking the same question.

continue with the post here http://forums.ni.com/t5/LabVIEW-Electrical-Power-Suite/Re-Electrical-power-energy-auditing/td-p/3252...

which I put into its own new message thread.