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STPM34 DC offsets failed to be measured after all HPFs were disabled.

PeterWangPTD
Associate

Hi,

    We try to use STPM34 to measure DC power besides measuring AC power. We had to disable the HPFs of V1,V2/C1,C2 on the EVALSTPM34 board by sending {0x00, 0x010x180x040x88} and {0x02, 0x030x180x240x92} to STPM34 through SPI. When we read Row 0 and Row 1 back, we have {0x04, 0x18, 0x00, 0xA0} and {0x24, 0x18, 0x00, 0xA0} respectively as expected.

    Without inputting any voltage/current, we sent {0x30, 0xFF, 0xFF, 0xFF} and {0xFF, 0xFf, 0xFF, 0xFF} to STPM34 through SPI to read ROW 24 (0x30) (Similarly to read ROW 25- 31 - 0x32 - 0x3E).

    We expect the non-zero DC offsets read out according to your data sheets. However, all zero's were read out in each ROW. Could you explain why and advise us the problem and how to fix? We should read out the non-zero numbers.

   Please see the read outputs below.

  Other question: How stable the DC offset of each channel is in real time? What is the influence by the temperature change?

    Thank you very much for your help,

 

Peter

PeterWangPTD_0-1721696904451.png

 

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