Measurement Application Questions

Assuming you are using the C-Bus module to send the message, this is the function you use :

Code:

/****************************************************************************
 * This function sends a Measurement Application message.
 *   channel is the measurement channel number
 *   mantissa is the numeric value of the measured parameter.
 *   exponent is the multiplier (power of ten)
 *   units is the units of the measured parameter
 ****************************************************************************/
extern dec_DLL void cbus_measurement_vf_send_data(int8u network,
                                                  int8u device_id,
                                                  int8u channel,
                                                  int32s mantissa,
                                                  int8s exponent,
                                                  cbus_measurement_et_unit_type units);

To convert a real number to the mantissa/exponent format needed by this function, this is the (C) code we use in the CTouch :

Code:

  int32s i_mantissa;
  int8s i_exponent;
  
  float f_temp;

  /* Convert float value to mantissa + exponent */
  
  i_exponent = 0;
  
  /* First, check if it fits in a 16 bit signed integer as-is */
  if ((modff(f_value, &f_temp) == 0) && 
      ((f_value <= 32767) && f_value >= -32768))
    {
      i_mantissa = (int32s)f_temp;
    }
  else
    {
      if (f_value < 0)
        {
          f_value = -f_value;
          i_mantissa = -1;
        }
      else
        {
          i_mantissa = 1;
        }
    
      while (f_value < 32767)
        {
          f_value = f_value * 10;
          i_exponent--;
        }

      while (f_value > 32767)
        {
          f_value = f_value / 10;
          i_exponent++;
        }

      i_mantissa = i_mantissa * (int32s)f_value;
    }
  

Hope this helps.