Connect 12v DC sensor to Arduino UNO using TTL RS485 I'm trying to connect Arduino Uno with BGT PM2510 sensor (which uses 7-12V DC) by using UART TTL to RS485 Two-way Converter.
The only thing I wonder is can the sensor damage the MCU ?
According to the information on 12v sensor, it says:
Output signal: RS485 (Modbus protocol), I did measurement on A &amp; B port of that sensor, the multimeter shows 3.3V.
My question is, can the sensor damage the MCU. I intend to connect Arduino &amp; sensor as the diagram below:

Thank you,
You should be fine.
RS-485 does specify signal levels of ±1.5V to ±5V, but even so, and even when the sensor would misbehave or when the common mode voltage is low or high, there is still the TTL-to-RS485 converter in the middle that has 5V TTL logic on the Arduino side.
As long as the TTL-to-RS485 converter is properly connected to the Arduino and working as it should, the Arduino is safe.