Hi.I use stpm32 as metering chip.The protocol what I use is SPI.why the sign of reactive energy is wrong but the sign of active energy is correct?

[Mpanj.1]

The amount of reactive energy register is decreased while I expect it to be increased.I use a reference meter" to ensure the sign of reactive energy.what should I do?

Could my stpm32 chip be fake?

[SBEN .2]

Hello @Mpanj.1​ ,

If you suspect that the chip is fake, please provide a high resolution photo of the said chip.

Otherwise, check the value of OFRx[8:0], it might be causing the issue.

 

Best regards,

@SBEN .2​ 

[Mpanj.1]

Hello @SBEN .2 ,

Thank you for your answer.

The value of the active and reactive energy is correct but the sign of reactive energy is wrong.

I tested the chip in 230V and 10A and +45 degrees phase difference with a reference meter.But the problem still remains.

I send a photo of my chip.

Thanks.

[SBEN .2]

Hello @Murtaza Panju​ ,

Are you sure that Phase and Neutral aren't switched up?

Best regards,

@SBEN .2​ 

[Mpanj.1]

Hello @SBEN .2​ 

I am sure because the sign of active power is correct and the value of active energy register is increased as i expect.But the value of reactive energy register is decreased and the sign of reactive power is negative.

The load i was applied is inductive.

The error measurment is less than 0.2%.

Thanks.

[Mpanj.1 · Accepted solution]

Hello @SBEN .2​ 

I changed the chip with a new one that I bought from another online shop.

All problems asked, were resolved.

The old chip was fake.

Best regards.