cancel
Showing results for 
Search instead for 
Did you mean: 

STPM34 (EVALSTPM34) - After HPF is disabled, why did we failed to read the V-I channel's DC offset of V / C channels?

PeterWangPTD
Visitor

Hi,

    We try to use STPM34 to measure DC V and I inputs besides measuring AC. The HPFs of V1,V2/C1,C2 on the EVALSTPM34 board were disabled by sending {0x00, 0x01, 0x18, 0x04, 0x88} and {0x02, 0x03, 0x18, 0x24, 0x92} 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 o STPM34 through SPI to read ROW 24 (Similarly to read ROW 25- 31).

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

  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

 

0 REPLIES 0