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Can Sentera products communicate with non-Sentera products via Modbus RTU communication?
Modbus RTU – how to interconnect Sentera devices
Modbus is an open communication protocol, meaning that it's free for manufacturers to build into their equipment without having to pay royalties. The Modbus communication protocol works by the master-slave principle. The Modbus master sends a request, the slave device(s) send their answer back.
Sentera devices use the Modbus RTU transmission mode. All connected devices must also use the Modbus RTU transmission mode to make communication possible. In RTU (Remote Terminal Unit) Mode, each 8-bit message byte contains two 4-bit hexadecimal characters, and the message is transmitted in a continuous stream.
A Modbus message is placed in a message frame by the transmitting device. This message frame is used to mark the beginning and ending point of the message allowing the receiving device to determine which device is being addressed and to know when the message is completed. It also allows partial messages to be detected and errors flagged as a result. Each word of this message (including the frame) is also placed in a data frame that appends a start bit, stop bit, and parity bit. In RTU mode, the word size is 8 bits. Thus, every 8 bits of an RTU message is effectively 11 bits when accounting for the start, stop, and parity bits of the data frame.
All connected devices mustuse the same message frame structure to make communication possible.
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