This page describes the packet structure and specifications of two types of communication packets between the robot and cradle, Instruction Packet and Status Packet, respectively.
As briefly described in 1. Communication System Overview, the Instruction Packet is a communication packet sent from the host PC to the cradle. In this packet, various commands and control values for the robot are given as parameters, and the remote robot operates according to these parameters.
The Instruction Packet consists of the following five types of packet blocks:
Table 2-1-1 shows the specific packet structure.
Table 2-1-1 Structure of Instruction Packet
| Header 1 (H1) | Header 2 (H2) | Length (LEN_L) | Length (LEN_H) | Instruction (INST) | Param. 1 (P1) | Param. 2 (P2) | … | Param. X (PX) | Check-Sum (SUM) | | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | | 0xFF | 0xFD | 0xXX | 0xXX | 0xXX | 0xXX | 0xXX | …. | 0xXX | 0xXX |
The first 2 bytes of the Instruction Packet are called the "Header block (H1, H2)". The values of H1 and H2 are always fixed at 0xFF
and 0xFD
. The cradle side detects the start of the Instruction Packet by continuously receiving 0xFF
and 0xFD
on the communication packet.
The 2-byte packet block following the Header block is called the "Length Block (LEN_L, LEN_H)”. The packet length from the "Instruction block" (described below) to the "Check-Sum block" at the end of the packet is expressed as a 2-byte value, with the lower 1 byte set to LEN_L and the upper 1 byte set to LEN_H.