ADE7758 xWATTHR Measurement:

Hello All,

I have communicated with ADE7758 with my Host MCU.

SPI Works fine and to Read/Write Default Values. From HOST ADE7758 to Host MCU.

I am giving 0 to +/- 500mV to Voltage  and 0 to  +/- 500mV to Current channel(s)

And able to read xVRMS and xIRMS resgiter.

I have able to read xWATTHR with

1) LCYCMODE Register  , RSTREAD =1 Default Mode

2) LCYCMODE Register  , RSTREAD =0, LWATT = 1 and LINECYC  = 0x10.

But I am unable to understand ..

1)How to Convert xWATTHR in to real Watt. With Line Accumulation or With RSTREAD in Default.

2) Or If suppose, AVRMS = 0x1243412 and AIRMS = 0xCBCD12. What should be in AWATTHR Register.

--

Thanks..

  • Hi Karan,

    On doing energy measurements, everything is just proportional and linear, a full scale value of 0.5V in current will give a 0xd7381 IRMS and 0x1902BD for VRMS (see datasheet for the 50 Hz). Also the full scale values will give 0xCCCD WATT going into the AWATTHR register. pls see the integration under steady load section on page 33 for reference.

    Now you are using Line Cycle Accumulation mode, actually you will be talking here of Wh/LSBs. This will depend now on your values. If you use the WATTHR, is is the same proportion since it comes from the same energy loop. You can read the cal section on page 49 for Wh/LSB

    http://www.analog.com/media/en/technical-documentation/data-sheets/ADE7758.pdf 

    Hope this helps.

  • Hello aheredia,

    Thanks for your update... I have read that page(s) from ADE7758 Datasheet Rev. E .

    1) How to Convert xWATTHR in to real Watt. With Line Accumulation or With RSTREAD in Default.

    From which Equation in Datasheet.

    2) How to Convert xVA-Hour in to real Watt. With Line Accumulation or With RSTREAD in Default.

    From which Equation in Datasheet.

    3) How to Convert xVAR-Hour in to real Watt. With Line Accumulation or With RSTREAD in Default.

    From which Equation in Datasheet.

    Line Accumulation or RSTREAD . Which is preferable to induction load.

    I want to measure Power factor of each phase ,(+ Total Power factor) with other  Electrical quantity..

    Any other ADE part no.?

    Thanks

    Karan

  • I want to measure Power factor of each phase ,(+ Total Power factor) with other  Electrical quantity..

    Any other ADE part no.?

    Ideally, in a 3-phase system, PF is the same on all phases.
    Total Power Factor is important when power semiconductors are employes in the system. What you might be looking for are information on phase delay, amplitude and harmonic components (THD) of the input signals. In this case, ADE7880 and ADE9000 could be good candidates for your application.  Which other electrical quantities do you want to measure?

  • ValeriaToff .. Thanks .. to you..

     

    Can you update me as Below ?

    1) How to Convert xWATTHR in to real Watt. With Line Accumulation or With RSTREAD in Default.

    From which Equation in Datasheet.

    2) How to Convert xVA-Hour in to real Watt. With Line Accumulation or With RSTREAD in Default.

    From which Equation in Datasheet.

    3) How to Convert xVAR-Hour in to real Watt. With Line Accumulation or With RSTREAD in Default.

    From which Equation in Datasheet.

     

    With ADE7758.

  • The equations on the DS are linked to the calibration processes and not to conversions (like, for example, xWATTHR =  xWATT*3600/1000 )