This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

# MSP430F47187: MSP430F47187

Part Number: MSP430F47187

Helllo Everyone,

i am using MSP430F47187 for our development. i have calculated voltage and current samples ,from these samples ,i have calculated RMS voltage,RMS current ,powers and power factor but these powers are in absolute i.e. no sign  so i need to calculate these powers(active & reactive) with sign(+ & -) . in short i need four quadrant measurement through this MSP430.

kindly revert me proper calculation of powers and angle also in signed form.

• Hi peeyush,

Are you familiar with Energy Measurement Library for MSP430 MCUs Here is the link:

this library makes you able to calculate parameters such as:

• VRMS
• IRMS
• V Peak
• I Peak
• Active Power
• Reactive Power
• Apparent Power
• Power Factor

and so on.

In addition to this software tool, the main idea for calculating reactive power is shifting each voltage sample by 90 degrees.

From the theoretical point of view, the active power is calculated with this formula

And the reactive power is then calculating by a similar formula with a simple difference, which is shifting instantaneous voltage by 90 degrees. Here is the formula

Therefore, in the microcontroller the those integrals are replaced with sigma. I'd recommend that you to take a look at page 8 of this document.

And if you'd like to know how to do this 90 degrees of phase shifting in each voltage sample, look at the image below which I captured from Energy Measurement Design Center API Guide (Result_api module)

If you don't like to work with MCUs and platforms that are supported by Energy Measurement Library for MSP430 MCUs, you can apply a similar idea (shifting voltage samples by 90 degrees) on your device.

I hope this helps.

Hossein

• Hi Hossein,