Protocol Description; Communication Frame - Craftsman G10-0R7G-2SB Manual

(2) Transmission method
Asynchronous serial, half-duplex transmission. At the same time, only one of the
master and slave can send data and the other receive data. In the process of serial
asynchronous communication, data is transmitted in frames and frames.
(3) Topology
Single-master multi-slave system. The slave address is set from 1 to 247, and 0 is the
broadcast communication address. The address of each slave in the network is unique.
This is the basis for ensuring Modbus serial communication.

8.4 Protocol description

The series inverter communication protocol is an asynchronous serial master-slave
Modbus communication protocol. Only one device (host) in the network can establish a
protocol (called "query/command"). Other devices (slave) can only respond to the host's
"query/command" by providing data, or according to the host's "query/command". The
host refers here to a personal computer (PC), an industrial control device, or a
programmable logic controller (PLC). The slave refers to a G10 series inverter or other
control device having the same communication protocol. The host can communicate with
a slave separately and broadcast information to all slaves. For a host "query/command"
that is accessed separately, the slave must return a message (called a response). For the
broadcast message sent by the host, the slave does not need to feed back the response
message to the host.

8.5 Communication frame

The Modbus protocol communication data format of the G10 series inverter is divided
into RTU (Remote Terminal Unit) mode.
In RTU mode, the format of each byte is as follows:
Encoding system: 8-bit binary, each 8-bit frame field contains two hexadecimal
characters, hexadecimal 0~9, A~F.
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