Library Description

Library performs the communication with the device via uart interface by sending commands and checking response from the device to the host. Commands perform writting to the registers, reading from the registers (data can be 8bit, 16bit, or 32bit), calibration, writting to the EEPROM and reading from the EEPROM. By using functions for reading user can read measurements that include voltage RMS, current RMS, power data (active, reactive, apparent) and many other things. For more details check documentation.

Key functions:

• T_PWRMETER_RETVAL pwrmeter_readRegBytes( uint16_t regAddr, uint8_t nBytes, uint8_t *dataOut ) - Function reads data bytes from registers.

• T_PWRMETER_RETVAL pwrmeter_writeRegWORD( uint16_t registerAddr, uint16_t dataIn ) - Function writes 16-bit data to the register.

• T_PWRMETER_RETVAL pwrmeter_sendCommand( uint8_t commandByte ) - Function sends and performs a determined command.

Example description

The application is composed of three sections :

• System Initialization - Initializes peripherals and pins.
• Application Initialization - Initializes UART interface, puts output of regulator in active state and configures gain channel and uart baud rate.
• Application Task - (code snippet) - Reads voltage, current and power measurements from data registers, converts this values to determined units and all results on uart terminal. Repeats operation every second.

void applicationTask()
{
 responseByte = pwrmeter_readRegWORD( _PWRMETER_VOLT_RMS_REG, &voltageRMS );
 checkResponse();
 responseByte = pwrmeter_readRegDWORD( _PWRMETER_CURR_RMS_REG, ¤tRMS );
 checkResponse();
 responseByte = pwrmeter_readRegDWORD( _PWRMETER_ACTIVE_PWR_REG, &activePower );
 checkResponse();
 responseByte = pwrmeter_readRegDWORD( _PWRMETER_REACTIVE_PWR_REG, &reactivePower );
 checkResponse();
 responseByte = pwrmeter_readRegDWORD( _PWRMETER_APPARENT_PWR_REG, &apparentPower );
 checkResponse();
 responseByte = pwrmeter_readRegSigned( _PWRMETER_PWR_FACTOR_REG, _PWRMETER_16BIT_DATA, &powerFactor );
 checkResponse();

 measData[ 0 ] = (float)voltageRMS / 100;
 measData[ 1 ] = (float)currentRMS / 1000;
 measData[ 2 ] = (float)activePower / 100000;
 measData[ 3 ] = (float)reactivePower / 100000;
 measData[ 4 ] = (float)apparentPower / 100000;
 measData[ 5 ] = (float)powerFactor / 32767;

 responseByte = pwrmeter_getStatus( &statusByte );
 checkResponse();

 if ((statusByte & _PWRMETER_DCMODE_MASK) != 0)
 {
 mikrobus_logWrite( "DC mode", _LOG_LINE );
 }
 else
 {
 mikrobus_logWrite( "AC mode", _LOG_LINE );
 }

 FloatToStr( measData[ 0 ], text );
 floatConv();
 mikrobus_logWrite( "RMS voltage: ", _LOG_TEXT );
 if (((statusByte & _PWRMETER_DCMODE_MASK) != 0) && ((statusByte & _PWRMETER_DCVOLT_SIGN_MASK) == 0))
 {
 mikrobus_logWrite( "-", _LOG_TEXT );
 }
 mikrobus_logWrite( text, _LOG_TEXT );
 mikrobus_logWrite( "[V]", _LOG_LINE );

 FloatToStr( measData[ 1 ], text );
 floatConv();
 mikrobus_logWrite( "RMS current: ", _LOG_TEXT );
 if (((statusByte & _PWRMETER_DCMODE_MASK) != 0) && ((statusByte & _PWRMETER_DCCURR_SIGN_MASK) == 0))
 {
 mikrobus_logWrite( "-", _LOG_TEXT );
 }
 mikrobus_logWrite( text, _LOG_TEXT );
 mikrobus_logWrite( "[mA]", _LOG_LINE );

 FloatToStr( measData[ 2 ], text );
 floatConv();
 mikrobus_logWrite( "Active power: ", _LOG_TEXT );
 if ((statusByte & _PWRMETER_PA_SIGN_MASK) == 0)
 {
 mikrobus_logWrite( "-", _LOG_TEXT );
 }
 mikrobus_logWrite( text, _LOG_TEXT );
 mikrobus_logWrite( "[W]", _LOG_LINE );

 FloatToStr( measData[ 3 ], text );
 floatConv();
 mikrobus_logWrite( "Reactive power: ", _LOG_TEXT );
 if ((statusByte & _PWRMETER_PR_SIGN_MASK) == 0)
 {
 mikrobus_logWrite( "-", _LOG_TEXT );
 }
 mikrobus_logWrite( text, _LOG_TEXT );
 mikrobus_logWrite( "[VAr]", _LOG_LINE );

 FloatToStr( measData[ 4 ], text );
 floatConv();
 mikrobus_logWrite( "Apparent power: ", _LOG_TEXT );
 mikrobus_logWrite( text, _LOG_TEXT );
 mikrobus_logWrite( "[VA]", _LOG_LINE );

 FloatToStr( measData[ 5 ], text );
 floatConv();
 mikrobus_logWrite( "Power factor: ", _LOG_TEXT );
 mikrobus_logWrite( text, _LOG_LINE );
 mikrobus_logWrite( "", _LOG_LINE );

 Delay_ms( 1000 );
}

Additional Functions :

• void checkResponse() - Checks response from the device to the host and logs message if error occurred.
• void floatConv() - Makes the float values be rounded to two decimal places.

Other mikroE Libraries used in the example:

• Conversions
• UART

Additional notes and information

Depending on the development board you are using, you may need USB UART click, USB UART 2 click or RS232 click to connect to your PC, for development systems with no UART to USB interface available on the board. The terminal available in all MikroElektronika compilers, or any other terminal application of your choice, can be used to read the message.