User's Manual

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6 Communication Protocol
To ensure real-time communication, Hesai’s TCP protocol uses binary format and has disabled Nagle’s algorithm.
6.1 Packet Structure
A client can send command messages to the server (LiDAR). Each command message includes a fixed 8-byte header and a variable command-specific
payload. The header describes the command type and payload length.
Table 6.1 Command Message Sent from Client to LiDAR
Type
Length
Field Description
0x47
1 byte
Fixed content
0x74
1 byte
Fixed content
Cmd
1 byte
Command code. See Section 6.2 Command Description
Return Code
1 byte
Useless
Payload Length
4 bytes
Data length for the command 0x00 – no payload
Payload
Indicated in Payload Length
Additional data for the command
The server (LiDAR) outputs a feedback message for every command it receives.
Table 6.2 Feedback Message from LiDAR to Client
Type
Length
Field Description
0x47
1 byte
Fixed content
0x74
1 byte
Fixed content
Cmd
1 byte
Command code
Return Code
1 byte
Return code from server
Data Length
4 bytes
Data length for the command 0x00 – no payload
Payload
Indicated in Payload Length
Additional data for the command