Why is Modbus ASCII transmission inherently less efficient than Modbus RTU?
Answer
Each byte of data requires two ASCII characters to represent it.
The primary reason for the lower efficiency of Modbus ASCII compared to Modbus RTU is the encoding scheme. RTU transmits data in a highly compact binary format, packing information efficiently. In contrast, ASCII mode transmits data using human-readable characters, meaning that every single byte of data being sent requires representation by two separate ASCII characters. For example, transmitting the hexadecimal value 0xFF requires sending the characters 'F' and 'F' instead of sending a single binary byte, leading to nearly double the transmission bandwidth requirement for the same payload.
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