Synria Communication Protocol v1.0.6

caution

Reading Guide

1. All numerical values in this document are uniformly represented in decimal or hexadecimal. Data starting with 0x is hexadecimal; unmarked data is decimal.
2. Multi-byte data uses little-endian order (low byte first, high byte last). The example frames already include the check byte and can be used directly for serial debugging.

Alicia-M Button Functions:

• Single click: Switch motor mode, mit mode ↔ pv mode (saved through power-off)
• Double click: The button light flashes rapidly and plays back the recorded motion (press any key during this time to stop playback)
• Long press: Within 1~2s, switch the gravity compensation mode (only valid in mit mode)
• Extra-long press: More than 2s, the button light flashes slowly and records the motion during the button-light flashing period (press any key during this time to stop recording)

Serial Communication Parameters:

• Frame rate with gravity compensation: 830 Hz
• Frame rate without gravity compensation: 1000 Hz
• Limit frame rate: 1630 Hz (applicable to C/C++)

Last modified: May 21, 2026

Note: The final right of interpretation of this communication protocol document and its related functions belongs to Synria Technology Co., Ltd.

I. Basic Structure of the Synria Communication Protocol

The Synria communication protocol consists of a frame header, command, function code, data length, data, check, and frame tail. The default serial baud rate for users is 1000000.

Field	Length	Description	Fixed Value or Example
Frame header	1 byte	Data frame start marker	0xAA
Command	1 byte	The major category of function to be executed by this frame	0x01, 0x06
Function code	1 byte	Read/write direction, robotic arm selection, or sub-function	0x02, 0x82
Data length	1 byte	The number of bytes in the subsequent "data" field	0x00, 0x10
Data	Variable	Joint, gripper, parameter, or status data	Per each command description
Check	1 byte	The lower 8 bits of the CRC32 check result	Given in the examples
Frame tail	1 byte	Data frame end marker	0xFF

The check calculation range is: command + function code + data length + data. The frame header and frame tail are not included in the calculation.

For example, querying device information:

Frame Header	Command	Function Code	Data Length	Data	Check	Frame Tail
0xAA	0x01	0x7E	0x00	Empty	0x5D	0xFF

Complete frame:

AA 01 7E 00 5D FF

Here, 0x5D is the check byte calculated for 01 7E 00.

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II. Common Conventions

1. Robotic Arm Selection

Most commands use the lower two bits of the function code to select the robotic arm:

Function Code Bit	Meaning
Bit 0	Teaching arm
Bit 1	Follower arm

Common values:

Function Code	Meaning
0x01	Select the teaching arm
0x02	Select the follower arm
0x03	Select both the teaching arm and the follower arm
0x81	Write to the teaching arm
0x82	Write to the follower arm

It is recommended to interface in a "single frame operates only one robotic arm" manner, especially for joint data read/write and motor parameter setting.

2. Joint Numbering

Use Case	Numbering Method
Zeroing, mechanical lock	Numbered starting from 0
Motor parameter setting	Numbered starting from 1
Joint data read/write	No start-joint field; defaults to starting from joint 0

The Alicia-M single arm normally has 7 physical joints. For public interfacing, the 7th joint is the gripper-related joint; when writing the control mode with 0x11, it is skipped, while other already-opened motor parameters such as acceleration, deceleration, velocity loop, and position loop are still processed according to the requested range.

3. Feedback Function Code

Most feedback frames set the highest bit of the request function code to 1. For example:

Request Function Code	Feedback Function Code
0x02	0x82
0x03	0x83
0x7E	0xFE

If the request function code itself is already greater than or equal to 0x80, the feedback function code usually remains the same.

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III. Command ID Overview

Command	Function	Public Description
0x01	Device information read	Open
0x02	User personalization settings	Open
0x03	Protocol-layer zeroing	Open
0x05	Mechanical lock and stiffness switching	Open
0x06	Joint data read/write	Open
0x09	Enable and disable	Open
0x11	Motor parameter setting	Open for control mode, acceleration, deceleration, velocity loop, and position loop parameters
0x15	Clear motor errors	Open
0x16	Control lock	Open
0x17	Gripper gripping parameters	Open
0xFB	Serial frame rate statistics	Open, used for debugging
0xEE	Error feedback	Returned by the lower-level controller

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IV. Command Functions

1. Command ID 0x01: Query Device Information

Command 0x01 is used to read the Alicia-M's product model, serial number, hardware version, and firmware version.

Field	Value
Command	0x01
Request function code	0x7E
Request data length	0x00
Feedback function code	0xFE
Feedback data length	0x18

Example: Query Device Information

Frame Header	Command	Function Code	Data Length	Data	Check	Frame Tail
0xAA	0x01	0x7E	0x00	Empty	0x5D	0xFF

Complete frame:

AA 01 7E 00 5D FF

Example: Device Information Feedback

Frame Header	Command	Function Code	Data Length	Data	Check	Frame Tail
0xAA	0x01	0xFE	0x18	0x41 0x4D 0x58 0x53 0x32 0x35 0x30 0x31 0x30 0x31 0x30 0x31 0x41 0x30 0x30 0x31 0x64 0x00 0x00 0x00 0x6E 0x00 0x00 0x00	0x05	0xFF

Complete frame:

AA 01 FE 18 41 4D 58 53 32 35 30 31 30 31 30 31 41 30 30 31 64 00 00 00 6E 00 00 00 05 FF

The feedback data is 24 bytes in total:

Offset	Length	Meaning	Example
0	4 bytes	Product model	41 4D 58 53
4	12 bytes	Serial number	32 35 30 31 30 31 30 31 41 30 30 31
16	4 bytes	Hardware version	64 00 00 00
20	4 bytes	Firmware version	6E 00 00 00

In the example above, the raw hardware version value is 100, which can be displayed as 1.0.0; the raw firmware version value is 110, which can be displayed as 1.1.0.

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2. Command ID 0x02: User Personalization Settings

Command 0x02 is used to read or write user configuration. After writing, it is saved through power-off.

Function code description:

Function Code Bit	Meaning
Highest bit is 0	Read
Highest bit is 1	Write
Bit 0	Power-on action configuration
Bit 1	Gripper type configuration
Bit 2	Periodic upload switch

Each configuration item occupies 4 bytes, all little-endian.

Configuration Item	Function Code Bit	Data Length	Value Range or Valid Rule	Description
Power-on action configuration	Bit 0	4 bytes	Reserved field; recommended to keep the default value	Reserved configuration
Gripper type configuration	Bit 1	4 bytes	Currently judged by bit1: bit1=0 is the small gripper configuration, bit1=1 is the large gripper configuration; recommended to write 0 or 2	Configuration flag value, not a directly written model number
Periodic upload switch	Bit 2	4 bytes	0 off, 1 on; other values reserved	When enabled, actively uploads follower-arm position data about every 5ms

The gripper type configuration is not a directly written model number; it is currently parsed by bit1:

Configuration Value	Byte Order	Meaning
0	00 00 00 00	bit1=0, select the small gripper configuration
2	02 00 00 00	bit1=1, select the large gripper configuration

After periodic upload is enabled, the lower-level controller will actively upload follower-arm position data about every 5ms. This active upload frame uses command 0x06 with function code 0x04.

Example 1: Read All User Configuration

Frame Header	Command	Function Code	Data Length	Data	Check	Frame Tail
0xAA	0x02	0x07	0x00	Empty	0xBB	0xFF

Complete frame:

AA 02 07 00 BB FF

Send parsing:

Field	Byte	Meaning
Command	02	User personalization settings
Function code	07	Read the three configuration items corresponding to bits 0, 1, and 2
Data length	00	A read request requires no data
Check	BB	This frame's check

Example feedback:

Frame Header	Command	Function Code	Data Length	Data	Check	Frame Tail
0xAA	0x02	0x07	0x0C	0x00 0x00 0x00 0x00 0x02 0x00 0x00 0x00 0x01 0x00 0x00 0x00	0x55	0xFF

Complete frame:

AA 02 07 0C 00 00 00 00 02 00 00 00 01 00 00 00 55 FF

Feedback parsing:

Field	Byte	Meaning
Command	02	User personalization settings
Function code	07	Returns the three configuration items corresponding to bits 0, 1, and 2
Data length	0C	The data area is 12 bytes, with each configuration item being 4 bytes
Data 1	00 00 00 00	The power-on action configuration value is 0
Data 2	02 00 00 00	The gripper type configuration value is 2, bit1=1, indicating a large gripper
Data 3	01 00 00 00	Periodic upload is enabled

Example 2: Modify Gripper Type Configuration

This example writes the gripper type configuration as 2, indicating selection of the large gripper configuration. In the current firmware, bit 1 of this value is used to select the gripper type.

Frame Header	Command	Function Code	Data Length	Data	Check	Frame Tail
0xAA	0x02	0x82	0x04	0x02 0x00 0x00 0x00	0xCF	0xFF

Complete frame:

AA 02 82 04 02 00 00 00 CF FF

Send parsing:

Field	Byte	Meaning
Command	02	User personalization settings
Function code	82	Write the gripper type configuration corresponding to bit 1
Data length	04	Write 1 configuration item, 4 bytes total
Data	02 00 00 00	The target configuration value is 2, bit1=1, select the large gripper configuration

Feedback:

Frame Header	Command	Function Code	Data Length	Data	Check	Frame Tail
0xAA	0x02	0x82	0x01	0x81	0x8E	0xFF

Complete frame:

AA 02 82 01 81 8E FF

Feedback parsing:

Field	Byte	Meaning
Command	02	User personalization settings
Function code	82	Corresponds to this write request
Data length	01	Feedback of 1 status byte
Data	81	The write request has been received

Example 3: Enable Periodic Upload

Frame Header	Command	Function Code	Data Length	Data	Check	Frame Tail
0xAA	0x02	0x84	0x04	0x01 0x00 0x00 0x00	0x3C	0xFF

Complete frame:

AA 02 84 04 01 00 00 00 3C FF

Send parsing:

Field	Byte	Meaning
Command	02	User personalization settings
Function code	84	Write the periodic upload switch corresponding to bit 2
Data length	04	Write 1 configuration item, 4 bytes total
Data	01 00 00 00	Enable periodic upload

Feedback:

Frame Header	Command	Function Code	Data Length	Data	Check	Frame Tail
0xAA	0x02	0x84	0x01	0x81	0x3C	0xFF

Complete frame:

AA 02 84 01 81 3C FF

Feedback parsing:

Field	Byte	Meaning
Command	02	User personalization settings
Function code	84	Corresponds to this write request
Data length	01	Feedback of 1 status byte
Data	81	The write request has been received

Example 4: Write Power-On Action Configuration

This example writes the power-on action configuration as 0. This item currently serves as a reserved configuration, and the tool side can use it to confirm whether the write link is normal.

Frame Header	Command	Function Code	Data Length	Data	Check	Frame Tail
0xAA	0x02	0x81	0x04	0x00 0x00 0x00 0x00	0xEA	0xFF

Complete frame:

AA 02 81 04 00 00 00 00 EA FF

Send parsing:

Field	Byte	Meaning
Command	02	User personalization settings
Function code	81	Write the power-on action configuration corresponding to bit 0
Data length	04	Write 1 configuration item, 4 bytes total
Data	00 00 00 00	The target configuration value is 0

Feedback:

Frame Header	Command	Function Code	Data Length	Data	Check	Frame Tail
0xAA	0x02	0x81	0x01	0x81	0xD7	0xFF

Complete frame:

AA 02 81 01 81 D7 FF

When the feedback data is 0x81, it indicates that the setting has been received.

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3. Command ID 0x03: Protocol-Layer Zeroing

Command 0x03 is used to set the current joint position as the new protocol zero point. It has two methods:

Zeroing Method	Data Value	Description
Soft zeroing	0x00	Only changes the protocol display and protocol control zero point, without changing the motor's underlying zero point
Hard zeroing	0x01	Clears the protocol offset and performs an underlying hard zeroing

The request data is arranged in the order of the selected robotic arms. Each robotic arm occupies 2 bytes:

Byte	Meaning
1st byte	Start joint number, starting from 0
2nd byte	Number of consecutive joints

If 1 more byte is appended at the end, that byte is the zeroing method. When the zeroing method is not included, hard zeroing is processed by default.

Example 1: Soft Zeroing of the 7 Follower-Arm Joints

Frame Header	Command	Function Code	Data Length	Data	Check	Frame Tail
0xAA	0x03	0x02	0x03	0x00 0x07 0x00	0x44	0xFF

Complete frame:

AA 03 02 03 00 07 00 44 FF

Field explanation:

Field	Value
Function code	0x02, follower arm
Start joint	0x00
Consecutive count	0x07
Zeroing method	0x00, soft zeroing

Feedback:

Frame Header	Command	Function Code	Data Length	Data	Check	Frame Tail
0xAA	0x03	0x82	0x01	0x01	0xCB	0xFF

Complete frame:

AA 03 82 01 01 CB FF

Feedback parsing: 0x82 indicates the follower-arm zeroing feedback, and data 0x01 indicates successful reception.

Example 2: Hard Zeroing of the 7 Joints of Both Arms

Frame Header	Command	Function Code	Data Length	Data	Check	Frame Tail
0xAA	0x03	0x03	0x05	0x00 0x07 0x00 0x07 0x01	0x4C	0xFF

Complete frame:

AA 03 03 05 00 07 00 07 01 4C FF

Field explanation:

Field	Value
Function code	0x03, select both the teaching arm and the follower arm
Teaching arm start joint	0x00
Teaching arm consecutive count	0x07
Follower arm start joint	0x00
Follower arm consecutive count	0x07
Zeroing method	0x01, hard zeroing

Feedback:

Frame Header	Command	Function Code	Data Length	Data	Check	Frame Tail
0xAA	0x03	0x83	0x01	0x01	0xFC	0xFF

Complete frame:

AA 03 83 01 01 FC FF

Feedback parsing: 0x83 indicates the dual-arm zeroing feedback, and data 0x01 indicates successful reception.

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4. Command ID 0x05: Mechanical Lock and Stiffness Switching

Command 0x05 is used to make the specified joints enter high-stiffness holding while the remaining joints enter low-stiffness holding. It is not a power-off lock, but rather changes the joint holding strength.

The request data format is the same as zeroing: each selected robotic arm occupies 2 bytes.

Byte	Meaning
1st byte	Start joint number, starting from 0
2nd byte	Number of consecutive joints

Example: The 7 Follower-Arm Joints Enter High-Stiffness Holding

Frame Header	Command	Function Code	Data Length	Data	Check	Frame Tail
0xAA	0x05	0x02	0x02	0x00 0x07	0x2B	0xFF

Complete frame:

AA 05 02 02 00 07 2B FF

Send parsing:

Field	Byte	Meaning
Command	05	Mechanical lock and stiffness switching
Function code	02	Select the follower arm
Data length	02	The follower arm occupies a 2-byte interval description
Data	00 07	Starting from joint 0, 7 consecutive joints enter high-stiffness holding

Feedback:

Frame Header	Command	Function Code	Data Length	Data	Check	Frame Tail
0xAA	0x05	0x82	0x01	0x01	0x17	0xFF

Complete frame:

AA 05 82 01 01 17 FF

Feedback parsing: 0x82 indicates the follower-arm feedback, and data 0x01 indicates successful reception.

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5. Command ID 0x06: Joint Data Read/Write

Command 0x06 is the most commonly used control command of the Alicia-M, used to read joint status and also to write control data such as target position, velocity, and torque.

5.1 Joint Data Address Table

Each address fixedly occupies 2 bytes in the data frame.

Address	Name	Readable	Writable	Effective Bit Width	Unit	Description
0x00	pos	Yes	Yes	16-bit	rad	Joint position affected by zeroing
0x01	vel	Yes	Yes	12-bit	rad/s	Velocity target or feedback
0x02	tor	Yes	Yes	12-bit	N·m	Torque target or feedback
0x03	kp	Yes	Yes	16-bit	dimensionless	Position stiffness coefficient, non-negative
0x04	kd	Yes	Yes	16-bit	dimensionless	Velocity damping coefficient, non-negative
0x05	Linear interpolation velocity	Yes	Yes	12-bit	rad/s	Used for smooth motion to the position target
0x06	Coil temperature	Yes	No	16-bit	°C	Read-only

12-bit data is placed in a 2-byte slot. When writing the 3 types of 12-bit fields (velocity, torque, linear interpolation velocity), if the 2-byte raw value is 0xFFFF (written as FF FF in a little-endian frame), the lower-level controller treats it as the underlying precise zero value 0. This special value is only used for writing 12-bit fields and does not apply to the position, stiffness, damping, or temperature fields.

5.2 Read Joint Data

The data area of a read request is fixed at 2 bytes:

Byte	Meaning
1st byte	Start address
2nd byte	Number of consecutive addresses

The data area format of read feedback:

Field	Length	Description
Reply start address	1 byte	The highest bit of the request start address is set to 1
Address count	1 byte	Consistent with the request
Joint data	2 × address count × 7 bytes	Expanded in joint order
Operating status	1 byte	Button, error, or peripheral status

Example: Read the Protocol Position of the 7 Follower-Arm Joints

Frame Header	Command	Function Code	Data Length	Data	Check	Frame Tail
0xAA	0x06	0x02	0x02	0x00 0x01	0xCE	0xFF

Complete frame:

AA 06 02 02 00 01 CE FF

Example feedback: All 7 joints are near the protocol zero point, and the operating status is 0.

Frame Header	Command	Function Code	Data Length	Data	Check	Frame Tail
0xAA	0x06	0x02	0x11	0x80 0x01 0xFF 0x7F 0xFF 0x7F 0xFF 0x7F 0xFF 0x7F 0xFF 0x7F 0xFF 0x7F 0xFF 0x7F 0x00	0x4D	0xFF

Complete frame:

AA 06 02 11 80 01 FF 7F FF 7F FF 7F FF 7F FF 7F FF 7F FF 7F 00 4D FF

In the feedback data, FF 7F is a 16-bit position value, which can be understood as "an intermediate value close to the zero point".

5.3 Write Joint Data

The data area format of a write request:

Field	Length	Description
Start address	1 byte	The first address to write
Address count	1 byte	How many consecutive addresses to write
Joint data	Variable	By default, written sequentially starting from joint 0

The data area of write feedback is fixed at 3 bytes:

Field	Length	Description
Reply start address	1 byte	The highest bit of the request start address is set to 1
Address count	1 byte	Consistent with the request
Reception status	1 byte	0x01 indicates successful reception

Example 1: The 7 Follower-Arm Joints Target Position Is Zero, Velocity Is Zero

This example writes both address 0x00 and 0x01 simultaneously. Each joint is 4 bytes: position FF 7F, velocity FF FF.

Frame Header	Command	Function Code	Data Length	Data	Check	Frame Tail
0xAA	0x06	0x82	0x1E	0x00 0x02 0xFF 0x7F 0xFF 0xFF 0xFF 0x7F 0xFF 0xFF 0xFF 0x7F 0xFF 0xFF 0xFF 0x7F 0xFF 0xFF 0xFF 0x7F 0xFF 0xFF 0xFF 0x7F 0xFF 0xFF 0xFF 0x7F 0xFF 0xFF	0x35	0xFF

Complete frame:

AA 06 82 1E 00 02 FF 7F FF FF FF 7F FF FF FF 7F FF FF FF 7F FF FF FF 7F FF FF FF 7F FF FF FF 7F FF FF 35 FF

Feedback:

Frame Header	Command	Function Code	Data Length	Data	Check	Frame Tail
0xAA	0x06	0x82	0x03	0x80 0x02 0x01	0x36	0xFF

Complete frame:

AA 06 82 03 80 02 01 36 FF

Example 2: Zero the Linear Interpolation Velocity of the 7 Follower-Arm Joints

Frame Header	Command	Function Code	Data Length	Data	Check	Frame Tail
0xAA	0x06	0x82	0x10	0x05 0x01 0xFF 0xFF 0xFF 0xFF 0xFF 0xFF 0xFF 0xFF 0xFF 0xFF 0xFF 0xFF 0xFF 0xFF	0xEF	0xFF

Complete frame:

AA 06 82 10 05 01 FF FF FF FF FF FF FF FF FF FF FF FF FF FF EF FF

Feedback:

Frame Header	Command	Function Code	Data Length	Data	Check	Frame Tail
0xAA	0x06	0x82	0x03	0x85 0x01 0x01	0x1E	0xFF

Complete frame:

AA 06 82 03 85 01 01 1E FF

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6. Command ID 0x09: Enable and Disable

Command 0x09 is used to enable or disable the specified robotic arm.

Data Value	Meaning
0x00	Disable
Non-0x00	Enable

Example 1: Enable the Follower Arm

Frame Header	Command	Function Code	Data Length	Data	Check	Frame Tail
0xAA	0x09	0x82	0x01	0x01	0xAF	0xFF

Complete frame:

AA 09 82 01 01 AF FF

Send parsing: 0x09 is the enable/disable command, function code 0x82 indicates writing to the follower arm, and data 0x01 indicates enable.

Feedback:

Frame Header	Command	Function Code	Data Length	Data	Check	Frame Tail
0xAA	0x09	0x82	0x01	0x01	0xAF	0xFF

Complete frame:

AA 09 82 01 01 AF FF

Feedback parsing: The function code remains 0x82, and data 0x01 indicates that the lower-level controller has received this enable request.

Example 2: Disable the Follower Arm

Frame Header	Command	Function Code	Data Length	Data	Check	Frame Tail
0xAA	0x09	0x82	0x01	0x00	0x39	0xFF

Complete frame:

AA 09 82 01 00 39 FF

Send parsing: The function code 0x82 still indicates writing to the follower arm, and data 0x00 indicates disable.

Feedback:

Frame Header	Command	Function Code	Data Length	Data	Check	Frame Tail
0xAA	0x09	0x82	0x01	0x01	0xAF	0xFF

Complete frame:

AA 09 82 01 01 AF FF

Feedback parsing: Data 0x01 indicates that the lower-level controller has received this disable request; it does not mean "still enabled".

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7. Command ID 0x11: Motor Parameter Setting

Command 0x11 is used to modify motor control parameters. The public edition opens the control mode, acceleration, deceleration, velocity loop, and position loop parameters. When writing the control mode, the 7th physical joint is skipped; when writing the acceleration, deceleration, velocity loop, and position loop parameters, it is not automatically skipped just because the 7th physical joint is the gripper.

Parameter	Parameter Address	Parameter Value Type	Unit or Attribute	Parameter Description
Acceleration	0x05	32-bit float	rad/s²	The larger the value, the faster the startup and acceleration
Deceleration	0x06	32-bit float	rad/s²	The larger the value, the faster the deceleration and stop
Velocity loop Kp	0x1A	32-bit float	Drive parameter	If velocity following is slow, increase slightly; if velocity jitters, decrease
Velocity loop Ki	0x1B	32-bit float	Drive parameter	If the target velocity is not reached for a long time, increase slightly; if it easily overshoots, decrease
Position loop Kp	0x1C	32-bit float	Drive parameter	If position following is slow, increase slightly; if it jitters after arrival, decrease
Position loop Ki	0x1D	32-bit float	Drive parameter	If there is a position error for a long time, increase slightly; if there is obvious swing-back or trailing, decrease
Control mode	0x0B	32-bit unsigned integer	Enum value	Determines which mode the motor accepts control in

Control mode values:

Mode Value	Meaning
1	Torque-hybrid control mode
2	Position-velocity mode
3	Velocity mode
4	Position-velocity-current hybrid mode

Write data format:

Field	Length	Description
Start motor number	1 byte	Starting from 1
Motor count	1 byte	Consecutive count
Parameter address	1 byte	See the parameter address table above
Parameter value	4 bytes	Low byte first
Save flag	1 byte	0 not saved, non-0 writes and saves

Read data format:

Field	Length	Description
Start motor number	1 byte	Starting from 1
Motor count	1 byte	Consecutive count
Parameter address	1 byte	The public edition opens reading of control mode 0x0B

When debugging, you can first use save flag 0, and after confirming that the action effect is normal, then decide whether to write and save.

Example 1: Switch Follower-Arm Motors 1 to 6 to Position-Velocity Mode, Without Saving Through Power-Off

Frame Header	Command	Function Code	Data Length	Data	Check	Frame Tail
0xAA	0x11	0x82	0x08	0x01 0x06 0x0B 0x02 0x00 0x00 0x00 0x00	0xC4	0xFF

Complete frame:

AA 11 82 08 01 06 0B 02 00 00 00 00 C4 FF

Send parsing:

Field	Byte	Meaning
Command	11	Motor parameter setting
Function code	82	Write to the follower arm
Data length	08	Start motor, count, parameter address, parameter value, save flag, 8 bytes total
Start motor	01	Starting from motor 1
Motor count	06	6 consecutive motors
Parameter address	0B	Control mode
Parameter value	02 00 00 00	Position-velocity mode
Save flag	00	Not saved through power-off

Feedback:

Frame Header	Command	Function Code	Data Length	Data	Check	Frame Tail
0xAA	0x11	0x82	0x04	0x01 0x06 0x8B 0x01	0xD6	0xFF

Complete frame:

AA 11 82 04 01 06 8B 01 D6 FF

Feedback parsing: 01 06 returns this motor range as-is, 8B indicates the feedback for the control mode address, and the trailing data 01 indicates successful reception.

Example 2: Change the Acceleration of Follower-Arm Motors 1 to 6 to 20, Without Saving Through Power-Off

Frame Header	Command	Function Code	Data Length	Data	Check	Frame Tail
0xAA	0x11	0x82	0x08	0x01 0x06 0x05 0x00 0x00 0xA0 0x41 0x00	0xF0	0xFF

Complete frame:

AA 11 82 08 01 06 05 00 00 A0 41 00 F0 FF

Send parsing:

Field	Byte	Meaning
Command	11	Motor parameter setting
Function code	82	Write to the follower arm
Data length	08	Start motor, count, parameter address, parameter value, save flag, 8 bytes total
Start motor	01	Starting from motor 1
Motor count	06	6 consecutive motors
Parameter address	05	Acceleration
Parameter value	00 00 A0 41	32-bit float, representing 20
Save flag	00	Not saved through power-off

Feedback:

Frame Header	Command	Function Code	Data Length	Data	Check	Frame Tail
0xAA	0x11	0x82	0x04	0x01 0x06 0x85 0x01	0x58	0xFF

Complete frame:

AA 11 82 04 01 06 85 01 58 FF

Feedback parsing: 85 indicates the feedback for the acceleration address, and the trailing data 01 indicates successful reception.

Example 3: Change the Deceleration of Follower-Arm Motors 1 to 6 to 20, Without Saving Through Power-Off

Frame Header	Command	Function Code	Data Length	Data	Check	Frame Tail
0xAA	0x11	0x82	0x08	0x01 0x06 0x06 0x00 0x00 0xA0 0x41 0x00	0x5E	0xFF

Complete frame:

AA 11 82 08 01 06 06 00 00 A0 41 00 5E FF

Send parsing:

Field	Byte	Meaning
Command	11	Motor parameter setting
Function code	82	Write to the follower arm
Data length	08	Start motor, count, parameter address, parameter value, save flag, 8 bytes total
Start motor	01	Starting from motor 1
Motor count	06	6 consecutive motors
Parameter address	06	Deceleration
Parameter value	00 00 A0 41	32-bit float, representing 20
Save flag	00	Not saved through power-off

Feedback:

Frame Header	Command	Function Code	Data Length	Data	Check	Frame Tail
0xAA	0x11	0x82	0x04	0x01 0x06 0x86 0x01	0x9B	0xFF

Complete frame:

AA 11 82 04 01 06 86 01 9B FF

Feedback parsing: 86 indicates the feedback for the deceleration address, and the trailing data 01 indicates successful reception.

Example 4: Change the Velocity Loop Kp of Follower-Arm Motors 1 to 6 to 1.0, Without Saving Through Power-Off

Frame Header	Command	Function Code	Data Length	Data	Check	Frame Tail
0xAA	0x11	0x82	0x08	0x01 0x06 0x1A 0x00 0x00 0x80 0x3F 0x00	0x26	0xFF

Complete frame:

AA 11 82 08 01 06 1A 00 00 80 3F 00 26 FF

Send parsing: Parameter address 0x1A indicates the velocity loop Kp, and parameter value 00 00 80 3F indicates the 32-bit float 1.0.

Feedback:

Frame Header	Command	Function Code	Data Length	Data	Check	Frame Tail
0xAA	0x11	0x82	0x04	0x01 0x06 0x9A 0x01	0xC6	0xFF

Complete frame:

AA 11 82 04 01 06 9A 01 C6 FF

Feedback parsing: 0x9A indicates the feedback for the velocity loop Kp address, and the trailing data 0x01 indicates successful reception.

Example 5: Change the Velocity Loop Ki of Follower-Arm Motors 1 to 6 to 1.0, Without Saving Through Power-Off

Frame Header	Command	Function Code	Data Length	Data	Check	Frame Tail
0xAA	0x11	0x82	0x08	0x01 0x06 0x1B 0x00 0x00 0x80 0x3F 0x00	0x83	0xFF

Complete frame:

AA 11 82 08 01 06 1B 00 00 80 3F 00 83 FF

Send parsing: Parameter address 0x1B indicates the velocity loop Ki, and parameter value 00 00 80 3F indicates the 32-bit float 1.0.

Feedback:

Frame Header	Command	Function Code	Data Length	Data	Check	Frame Tail
0xAA	0x11	0x82	0x04	0x01 0x06 0x9B 0x01	0x87	0xFF

Complete frame:

AA 11 82 04 01 06 9B 01 87 FF

Feedback parsing: 0x9B indicates the feedback for the velocity loop Ki address, and the trailing data 0x01 indicates successful reception.

Example 6: Change the Position Loop Kp of Follower-Arm Motors 1 to 6 to 1.0, Without Saving Through Power-Off

Frame Header	Command	Function Code	Data Length	Data	Check	Frame Tail
0xAA	0x11	0x82	0x08	0x01 0x06 0x1C 0x00 0x00 0x80 0x3F 0x00	0x3B	0xFF

Complete frame:

AA 11 82 08 01 06 1C 00 00 80 3F 00 3B FF

Send parsing: Parameter address 0x1C indicates the position loop Kp, and parameter value 00 00 80 3F indicates the 32-bit float 1.0.

Feedback:

Frame Header	Command	Function Code	Data Length	Data	Check	Frame Tail
0xAA	0x11	0x82	0x04	0x01 0x06 0x9C 0x01	0x40	0xFF

Complete frame:

AA 11 82 04 01 06 9C 01 40 FF

Feedback parsing: 0x9C indicates the feedback for the position loop Kp address, and the trailing data 0x01 indicates successful reception.

Example 7: Change the Position Loop Ki of Follower-Arm Motors 1 to 6 to 1.0, Without Saving Through Power-Off

Frame Header	Command	Function Code	Data Length	Data	Check	Frame Tail
0xAA	0x11	0x82	0x08	0x01 0x06 0x1D 0x00 0x00 0x80 0x3F 0x00	0x9E	0xFF

Complete frame:

AA 11 82 08 01 06 1D 00 00 80 3F 00 9E FF

Send parsing: Parameter address 0x1D indicates the position loop Ki, and parameter value 00 00 80 3F indicates the 32-bit float 1.0.

Feedback:

Frame Header	Command	Function Code	Data Length	Data	Check	Frame Tail
0xAA	0x11	0x82	0x04	0x01 0x06 0x9D 0x01	0x01	0xFF

Complete frame:

AA 11 82 04 01 06 9D 01 01 FF

Feedback parsing: 0x9D indicates the feedback for the position loop Ki address, and the trailing data 0x01 indicates successful reception.

Example 8: Read the Control Mode of Follower-Arm Motors 1 to 2

Frame Header	Command	Function Code	Data Length	Data	Check	Frame Tail
0xAA	0x11	0x02	0x03	0x01 0x02 0x0B	0x2E	0xFF

Complete frame:

AA 11 02 03 01 02 0B 2E FF

Send parsing: Function code 0x02 indicates reading the follower arm; data 01 02 0B indicates reading the control mode of 2 motors starting from motor 1.

Example feedback: Both motors are in position-velocity mode.

Frame Header	Command	Function Code	Data Length	Data	Check	Frame Tail
0xAA	0x11	0x02	0x0B	0x00 0x00 0x00 0x02 0x00 0x00 0x00 0x02 0x00 0x00 0x00	0x6E	0xFF

Complete frame:

AA 11 02 0B 00 00 00 02 00 00 00 02 00 00 00 6E FF

In the feedback data, the first 3 bytes can be treated as reserved bytes, and each subsequent 4 bytes represents the mode value of one motor.

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8. Command ID 0x15: Clear Motor Errors

Command 0x15 is used to clear the motor errors of the specified robotic arm. The data area must be 0xFE.

Example: Clear Follower-Arm Errors

Frame Header	Command	Function Code	Data Length	Data	Check	Frame Tail
0xAA	0x15	0x02	0x01	0xFE	0x85	0xFF

Complete frame:

AA 15 02 01 FE 85 FF

Send parsing: Function code 0x02 indicates the follower arm, and data 0xFE is the fixed byte for this command.

Feedback:

Frame Header	Command	Function Code	Data Length	Data	Check	Frame Tail
0xAA	0x15	0x82	0x01	0x01	0x88	0xFF

Complete frame:

AA 15 82 01 01 88 FF

Feedback parsing: 0x82 indicates the follower-arm error-clearing feedback, and data 0x01 indicates successful reception.

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9. Command ID 0x16: Control Lock

Command 0x16 is used to lock all joints to their current positions, or to unlock them.

Function Code	Meaning
0x80	Lock
0x00	Unlock

After locking, the lower-level controller will reject control-type commands that would cause motor motion until an unlock command is received.

Example 1: Enter Control Lock

Frame Header	Command	Function Code	Data Length	Data	Check	Frame Tail
0xAA	0x16	0x80	0x00	Empty	0x9B	0xFF

Complete frame:

AA 16 80 00 9B FF

Send parsing: Function code 0x80 indicates entering control lock, and the data length is 0.

Feedback:

Frame Header	Command	Function Code	Data Length	Data	Check	Frame Tail
0xAA	0x16	0x80	0x01	0x01	0x08	0xFF

Complete frame:

AA 16 80 01 01 08 FF

Feedback parsing: The function code remains 0x80, and data 0x01 indicates that the lock request has been received.

Example 2: Exit Control Lock

Frame Header	Command	Function Code	Data Length	Data	Check	Frame Tail
0xAA	0x16	0x00	0x00	Empty	0xD0	0xFF

Complete frame:

AA 16 00 00 D0 FF

Send parsing: Function code 0x00 indicates exiting control lock, and the data length is 0.

Feedback:

Frame Header	Command	Function Code	Data Length	Data	Check	Frame Tail
0xAA	0x16	0x00	0x01	0x01	0x88	0xFF

Complete frame:

AA 16 00 01 01 88 FF

Feedback parsing: The function code remains 0x00, and data 0x01 indicates that the unlock request has been received.

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10. Command ID 0x17: Gripper Gripping Parameters

Command 0x17 is used to read or set the gripper torque and force-control related parameters. It can only select one robotic arm at a time. This command only modifies the internal parameters of the gripper controller. It does not write to the J7 ESC register, nor does it change the J7 control mode. After a successful write, the parameters are updated into the gripper controller's running configuration and take effect in subsequent gripper control cycles. If you need to save through power-off, you can append 1 save flag byte at the end of the write data area; when the save flag is non-zero, the device saves the current complete gripper parameter configuration.

Function code description:

Function Code	Meaning
0x01	Read the teaching arm
0x02	Read the follower arm
0x81	Write to the teaching arm
0x82	Write to the follower arm

Mask Bit	Value	Parameter Meaning	Unit or Description	Range	Adjustment Direction
Bit 0	0x01	Target gripping force	N, estimated force at the gripper end	Small gripper: [1, 80] N Large gripper: [1, 120] N	Increasing raises the target gripping force, decreasing lowers the gripping strength
Bit 1	0x02	Opening feedforward torque	N·m, feedforward torque on the motor side	Small gripper: [0.2, 3.0] N·m Large gripper: [0.2, 5.0] N·m	Increasing raises the opening assist torque, decreasing lowers the opening impact
Bit 2	0x04	Closing feedforward torque	N·m, feedforward torque on the motor side	Small gripper: [-5.0, -0.2] N·m Large gripper: [-8.0, -0.2] N·m	The closing direction is negative; increasing the absolute value raises the closing assist torque, adjusting toward 0 lowers the closing impact
Bit 3	0x08	Maximum holding torque	N·m, torque upper limit on the motor side	Small gripper: [0.5, 5.0] N·m Large gripper: [0.5, 10.0] N·m	Increasing raises the torque upper limit during the holding phase, decreasing lowers the continuous gripping torque
Bit 4	0x10	Force-control proportion	dimensionless	[0, 2.0]	Increasing raises the force-control response, decreasing lowers the force-control oscillation tendency
Bit 5	0x20	Force-control integral	1/s	[0, 2.0] 1/s	Increasing raises the long-term compensation capability, decreasing lowers the integral trailing
Bit 6	0x40	Integral limiting	N·s	[0, 100] N·s	Increasing raises the integral compensation upper limit, decreasing limits the long-term integral accumulation
Bit 7	0x80	Torque scaling when approaching closure	ratio	[0, 1]	Increasing raises the closing assist torque when approaching the target, decreasing makes the end closure more gentle

When reading, an empty data area means reading all parameters; a single non-zero mask in the data area means reading only the parameters selected by the mask.

When writing, the 1st byte of the data area is the mask, followed by 32-bit floats placed in order of the mask bits from low to high. If you need to save through power-off, you can append 1 save flag byte after all the floats:

Data area length = 1 + number of parameters * 4              // Takes effect immediately
Data area length = 1 + number of parameters * 4 + 1          // Takes effect immediately and saves through power-off depending on the save flag

When the save flag is 0x00, it only takes effect immediately; when the save flag is non-zero, the device saves the complete gripper parameter configuration after writing.

Example 1: Read All Gripper Parameters of the Follower Arm

Frame Header	Command	Function Code	Data Length	Data	Check	Frame Tail
0xAA	0x17	0x02	0x00	Empty	0x65	0xFF

Complete frame:

AA 17 02 00 65 FF

Example feedback (the following data uses the small gripper default parameters as an example):

Frame Header	Command	Function Code	Data Length	Data	Check	Frame Tail
0xAA	0x17	0x82	0x22	0x01 0xFF 0x00 0x00 0x0C 0x42 0x00 0x00 0xA0 0x3F 0x00 0x00 0x20 0xC0 0x00 0x00 0x20 0x40 0x9A 0x99 0x19 0x3F 0xCD 0xCC 0xCC 0x3E 0x00 0x00 0xA0 0x41 0x33 0x33 0xB3 0x3E	0x8C	0xFF

Complete frame:

AA 17 82 22 01 FF 00 00 0C 42 00 00 A0 3F 00 00 20 C0 00 00 20 40 9A 99 19 3F CD CC CC 3E 00 00 A0 41 33 33 B3 3E 8C FF

The meaning of the first 2 bytes of the feedback data:

Byte	Meaning
0x01	Follower arm
0xFF	Returns all 8 parameters

Each subsequent 4 bytes is a 32-bit float, in the same order as the parameter mask table.

Example 2: Set the Follower-Arm Target Gripping Force to 35 N and the Maximum Holding Torque to 2.5 N·m

The mask is 0x09, indicating writing the two parameters at bit 0 and bit 3.

Frame Header	Command	Function Code	Data Length	Data	Check	Frame Tail
0xAA	0x17	0x82	0x09	0x09 0x00 0x00 0x0C 0x42 0x00 0x00 0x20 0x40	0xB3	0xFF

Complete frame:

AA 17 82 09 09 00 00 0C 42 00 00 20 40 B3 FF

Feedback:

Frame Header	Command	Function Code	Data Length	Data	Check	Frame Tail
0xAA	0x17	0x82	0x03	0x01 0x09 0x01	0x74	0xFF

Complete frame:

AA 17 82 03 01 09 01 74 FF

Example 3: Set the Follower-Arm Target Gripping Force to 2 N and Save

The mask is 0x01, indicating writing only the bit-0 target gripping force. The last byte 0x01 of the data area is the save flag, indicating saving the current complete gripper parameter configuration.

Frame Header	Command	Function Code	Data Length	Data	Check	Frame Tail
0xAA	0x17	0x82	0x06	0x01 0x00 0x00 0x00 0x40 0x01	0xBD	0xFF

Complete frame:

AA 17 82 06 01 00 00 00 40 01 BD FF

Here, 00 00 00 40 is the little-endian format of the 32-bit float 2.0f, and the final 01 indicates save.

Feedback:

Frame Header	Command	Function Code	Data Length	Data	Check	Frame Tail
0xAA	0x17	0x82	0x03	0x01 0x01 0x01	0x7C	0xFF

Complete frame:

AA 17 82 03 01 01 01 7C FF

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11. Command ID 0xFB: Serial Frame Rate Statistics

Command 0xFB is used to debug serial communication performance.

Function Code	Meaning
0x00	Start statistics
0x01	Query statistics results
0x02	Stop statistics

The query result is 12 bytes in total, composed of 3 32-bit floats:

Order	Meaning
1st	Total effective frame rate
2nd	0x06 control success frame rate
3rd	Variance of the time interval between adjacent frames

Example 1: Start Statistics

Frame Header	Command	Function Code	Data Length	Data	Check	Frame Tail
0xAA	0xFB	0x00	0x00	Empty	0x23	0xFF

Complete frame:

AA FB 00 00 23 FF

Feedback:

Frame Header	Command	Function Code	Data Length	Data	Check	Frame Tail
0xAA	0xFB	0x80	0x01	0x01	0xED	0xFF

Complete frame:

AA FB 80 01 01 ED FF

Example 2: Query Statistics Results

Frame Header	Command	Function Code	Data Length	Data	Check	Frame Tail
0xAA	0xFB	0x01	0x00	Empty	0x62	0xFF

Complete frame:

AA FB 01 00 62 FF

Example feedback: All three statistics values are 0.

Frame Header	Command	Function Code	Data Length	Data	Check	Frame Tail
0xAA	0xFB	0x81	0x0C	0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00	0x61	0xFF

Complete frame:

AA FB 81 0C 00 00 00 00 00 00 00 00 00 00 00 00 61 FF

Example 3: Stop Statistics

Frame Header	Command	Function Code	Data Length	Data	Check	Frame Tail
0xAA	0xFB	0x02	0x00	Empty	0xA1	0xFF

Complete frame:

AA FB 02 00 A1 FF

Feedback:

Frame Header	Command	Function Code	Data Length	Data	Check	Frame Tail
0xAA	0xFB	0x82	0x01	0x01	0x83	0xFF

Complete frame:

AA FB 82 01 01 83 FF

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12. Command ID 0xEE: Error Feedback

Command 0xEE is returned by the lower-level controller to indicate that a frame sent by the upper computer cannot be processed normally.

An error feedback frame consists of a frame header, 0xEE, error type, length 0x01, additional information, check, and frame tail. Below are two sets of actual feedback frames that can be directly compared.

Error Type	Meaning	Additional Information
0x00	Frame header or frame tail error	The received frame length
0x01	Length error	The received frame length
0x02	Check error	The check byte computed by the lower-level controller
0x04	Angle out of bounds	The out-of-bounds joint number
0x05	Data length error	The current data length or count
0x06	Address error	The illegal address or out-of-bounds value
0x07	The current state does not allow this operation	The request function code
0xEE	Mode switch rejected	The high 4 bits are the current mode, the low 4 bits are the target mode

When the error type is 0xEE, the additional information is the mode flag byte:

Current mode = (additional information & 0xF0) >> 4
Target mode  =  additional information & 0x0F

Mode code meanings:

Mode Code	Meaning
0x0	Normal state
0x1	Control protocol state
0x2	Gravity compensation state
0x3	Dual-arm synchronization state
0x4	Firmware upgrade state
0x5	Control lock state

Common mode flag examples:

Additional Information	Current Mode	Target Mode	Meaning
0x31	0x3 Dual-arm synchronization state	0x1 Control protocol state	Currently in dual-arm synchronization, rejecting entry into the control protocol.
0x51	0x5 Control lock state	0x1 Control protocol state	Currently in control lock, rejecting entry into the control protocol.

Example 1: Check Error

Frame Header	Command	Function Code	Data Length	Data	Check	Frame Tail
0xAA	0xEE	0x02	0x01	0x12	0x70	0xFF

Complete frame:

AA EE 02 01 12 70 FF

Indicates that the correct check byte computed by the lower-level controller is 0x12.

Example 2: A Motion Control Command Received During Control Lock

Frame Header	Command	Function Code	Data Length	Data	Check	Frame Tail
0xAA	0xEE	0xEE	0x01	0x51	0x9E	0xFF

Complete frame:

AA EE EE 01 51 9E FF

Additional information 0x51 indicates: currently in the control lock state, and the target operation is the control protocol state.

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V. Interfacing Workflow

1. First complete the three basic communications: 0x01 query device information, 0x06 read follower-arm position, and 0x09 enable the follower arm.
2. Before controlling the joint positions, first use 0x16 to confirm that the device is not in the locked state, then use 0x06 to write the target position and velocity.
3. If you only want to stop the linear interpolation, prefer writing 0x06 address 0x05 and write each joint as FF FF.
4. If you want to use active upload, enable periodic upload via 0x02, and parse the active frames according to the 0x06 / 0x04 format.