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 & B port of that sensor, the multimeter shows 3.3V.

My question is, can the sensor damage the MCU. I intend to connect Arduino & sensor as the diagram below:

enter image description here

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.

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