This example Arduino based code implements procedure of reading data( Voltage,Current,Power,Frequency,Total Active Energy) from Energy Meter SDM230 and send it via ESP32 Dev Board to Blynk app. TTL to RS485 adapter is used in that project.UART side pins Rx and Tx are connected respectively to GPIO16 and GPIO17 of ESP32 Dev Board.RS485 side - respectively to the energy meter.Used protcol for reading energy meter data is Modbus. Used Blynk Virtual Pins are V5,V6,V7,V8 and V9. Baudrate and Rx,Tx pins are configured at file SDM_Config_User.h.
For more detailed information about Energy Meters Modbus driver and library: https://github.com/reaper7/SDM_Energy_Meter
It needs to be installed Blynk library in Arduino program. Image of the scheme and connections is shown at /IMG/emeter.jpg