By combining lora and modbus RTU I was able to read data from my slaves remotely. The distance may be up to 15km or more. I tried it in the best condition, on the sea surface the distance I gained was over 11km.
All you need to do is declare the parameters on the tool.
I use an ESP32 module so it can be combined with wifi to race data onto the internet, such as MQTT.
What you can configure in modbus RTU are:
ID slave, baud rate, register, parity, bitstop, databit.
What you can configure in lora are: Transmission power, baud rate, air rate, channel MHz.
And update data time in registers of modbus.
We will have two makeshift components called A and B.
Board A will be the modbus master, it reads your slave device and then transmits data to board B. Board B will be the modbus slave, it simulates registers, and allows the master (maybe PLC, PC..) to read its data.
I finished it and ready to share it for you. Include hardware ang firmware.