In RS-485 communication, an external power supply is usually not required. RS-485 is A differential signal communication standard that uses two data lines (line A and line B) for data transmission. These two data lines are usually connected directly between the master device (such as a PLC or computer) and the slave device (such as a sensor or actuator).
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The data transmission of RS-485 communication is based on differential signals rather than power supply. The transmission mode of differential signal can effectively resist electromagnetic interference, provide longer communication distance and higher data transmission rate.
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However, it is important to note that each device in RS-485 communication usually requires its own power supply. This means that each device needs a proper power connection to provide the required voltage and current.
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To sum up, RS-485 communication itself does not require an external power supply, but each device needs an appropriate power supply in communication. Ensure that each device is connected to the appropriate power supply to ensure proper communication and operation.
It is necessary to connect to the power supply, because 485 communication is only one of the methods of communication. It communicates without electricity. Therefore, the device is 485 mode of communication must be connected to an external power supply. Otherwise, the device cannot be used.
485 communication uses differential signal transmission signal, 485 transmission of the differential signal is generated by the 485 driver chip only need to supply power to the 485 module.