Skip to main content
S
sireevenkat1
Explorer II
April 4, 2024
Solved

Pulses to KWh conversion in Energy meter

  • April 4, 2024
  • 2 replies
  • 2821 views

Hi,

I am working with STM32G491RE.I communicating  ATM90E26 single phase energy meter with STM32 through SPI communication.
I can able to read voltage ,current values correctly from the meter.
For KWH calculation, I am reading Absolute active energy register for kwh values. In the datasheet they mentioned the values I receive from the energy register are pulses.
  how can I convert pulses to kwh. can anyone suggest?
my pulse constant value is 1000 imp/kwh.

 

sireevenkat1_0-1712211776138.png

From the datasheet they mentioned register will be cleared after read.
For that I am following below process

 

 

uint16_t Em_kwh=0;
uint16_t Em_kwhcharging=0;
uint8_t kwh_power[2]={0x00,0x00,0x00};
Em_kwh=GetAbsoluteActiveEnergy(); //to read the register its working properly
Em_kwhcharging=Em_kwhcharging+Em_kwh;
// I am converting above decimal value in to hex values 
void ConvertDecimalToHex(int decimalValue, uint8_t* res) {
 res[0] = (uint8_t)((decimalValue >> & 0xFF); // High byte
 res[1] = (uint8_t)(decimalValue & 0xFF); // Low byte

}
ConvertDecimalToHex(Em_kwhcharging,kwh_power);
I am sending the hex value to other mcu using uart.

 

 

Is above way of handling the reset of register is correct. Can anyone suggest.
Is there any possibility Em_kwhcharging overflows. Is it better to take Em_kwhcharging as uint32_t.
Please suggest
Thanks

    This topic has been closed for replies.
    Best answer by Andrew Neil
    @sireevenkat1 wrote:


      how can I convert pulses to kwh. can anyone suggest?
    my pulse constant value is 1000 imp/kwh.

    That's just basic arithmetic, surely?

    "imp/kWh" is, presumably, short for "impulses per kWh" - in other words, "pulses per kWh"

    So "1000 imp/kWh" means that you get 1000 pulses for each kWh

    So 1 pulse is 1/1000 kWh - ie, 1 Wh

     

    @sireevenkat1 wrote:

     

    sireevenkat1_0-1712211776138.png

    So that's telling you that the number in the register is in units of 0.1 pulse;

    eg, if the register value is 65535, that represent 65535 * 0.1 pulses = 6553.5 pulses.

    As we've already established, 1 pulse represents 1 kWh - so 6553.5 pulses represent 6553.5 kWh.

     

    As the others have said, none of this has anything specifically to do with the STM32.

     

    2 replies

    P
    Peter BENSCH
    Technical Moderator
    April 4, 2024

    Well, these are all questions that have little to do with an STM32 as already mentioned before. Only the reading of the ATenergy register, which you read with 8-bit accesses, should be done with a 16-bit access.

    The manufacturer of this component or its forum can (perhaps) help you with the other questions, as already mentioned too.

    Regards
    /Peter

      A
      Andrew NeilAnswer
      Super User
      April 4, 2024
      @sireevenkat1 wrote:


        how can I convert pulses to kwh. can anyone suggest?
      my pulse constant value is 1000 imp/kwh.

      That's just basic arithmetic, surely?

      "imp/kWh" is, presumably, short for "impulses per kWh" - in other words, "pulses per kWh"

      So "1000 imp/kWh" means that you get 1000 pulses for each kWh

      So 1 pulse is 1/1000 kWh - ie, 1 Wh

       

      @sireevenkat1 wrote:

       

      sireevenkat1_0-1712211776138.png

      So that's telling you that the number in the register is in units of 0.1 pulse;

      eg, if the register value is 65535, that represent 65535 * 0.1 pulses = 6553.5 pulses.

      As we've already established, 1 pulse represents 1 kWh - so 6553.5 pulses represent 6553.5 kWh.

       

      As the others have said, none of this has anything specifically to do with the STM32.

       

      Terms & ConditionsAccessibility statement