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AX-18A
ax-18a

AX-18F, AX-18A

NOTE : AX-18A is a new version of the AX-18F with the same performance but more advanced external design. {: .notice}

Specifications

Item Specifications
Baud Rate 7843 bps ~ 1 Mbps
Resolution 0.29°
Running Degree 0° ~ 300°
Endless Turn
Weight 54.5g(AX-18F), 55.9g(AX-18A)
Dimensions (W x H x D) 32mm x 50mm x 40mm
Gear Ratio 254 : 1
Stall Torque 1.8 N*m (at 12V, 2.2A)
No Load Speed 97rpm (at 12V)
Operating Temperature -5°C ~ +70°C
Input Voltage 9.0 ~ 12.0V (Recommended : 11.1V)
Command Signal Digital Packet
Protocol Type Half Duplex Asynchronous Serial Communication
(8bit, 1stop, No Parity)
Physical Connection TTL Level Multi Drop Bus
ID 0 ~ 253
Feedback Position, Temperature, Load, Input Voltage, etc
Material Engineering Plastic

NOTE : Stall torque is the maximum instantaneous and static torque. Stable motions are possible with robots designed for loads with 1/5 or less of the stall torque. {: .notice}

{% include en/dxl/warning.md %}

Control Table

The Control Table is a structure of data implemented in the DYNAMIXEL. Users can read a specific Data to get status of the DYNAMIXEL with Read Instruction Packets, and modify Data as well to control DYNAMIXEL with WRITE Instruction Packets.

Control Table, Data, Address

The Control Table is a structure that consists of multiple Data fields to store status of the DYNAMIXEL or to control the DYNAMIXEL. Users can check current status of the DYNAMIXEL by reading a specific Data from the Control Table with Read Instruction Packets. WRITE Instruction Packets enable users to control the DYNAMIXEL by changing specific Data in the Control Table. The Address is a unique value when accessing a specific Data in the Control Table with Instruction Packets. In order to read or write data, users must designate a specific Address in the Instruction Packet. Please refer to [Protocol] for more details about Instruction Packets.

NOTE : Two's complement is applied for the negative value. For more information, please refer to Two's complement from Wikipedia. {: .notice--warning}

Area (EEPROM, RAM)

The Control Table is divided into 2 Areas. Data in the RAM Area is reset to initial values when the DYNAMIXEL is turned on (Volatile). On the other hand, modified data in the EEPROM Area keeps their values even when the DYNAMIXEL is turned off (Non-Volatile). Data in the EEPROM Area can only be changed when the value of Torque Enable(64) is cleared to ‘0’.

Size

The Size of data varies from 1 to 4 bytes depend on their usage. Please check the size of data when updating the data with an Instruction Packet.

Access

The Control Table has two different access properties. ‘RW’ property stands for read and write access permission while ‘R’ stands for read only access permission. Data with the read only property cannot be changed by the WRITE Instruction. Read only property(‘R’) is generally used for measuring and monitoring purpose, and read write property(‘RW’) is used for controlling DYNAMIXEL.

Initial Value

Each data in the Control Table is restored to initial values when the DYNAMIXEL is turned on. Default values in the EEPROM area are initial values of the DYNAMIXEL (factory default settings). If any values in the EEPROM area are modified by a user, modified values will be restored as initial values when the DYNAMIXEL is turned on. Initial Values in the RAM area are restored when the DYNAMIXEL is turned on.

Control Table of EEPROM Area

Address Size
(Byte)
Data Name Description Access Initial
Value
0 2 Model Number Model Number R 18
2 1 Firmware Version Firmware Version R -
3 1 ID DYNAMIXEL ID RW 1
4 1 Baud Rate Communication Speed RW 1
5 1 Return Delay Time Response Delay Time RW 250
6 2 CW Angle Limit Clockwise Angle Limit RW 0
8 2 CCW Angle Limit Counter-Clockwise Angle Limit RW 1023
11 1 Temperature Limit Maximum Internal Temperature Limit RW 75
12 1 Min Voltage Limit Minimum Input Voltage Limit RW 60
13 1 Max Voltage Limit Maximum Input Voltage Limit RW 140
14 2 Max Torque Maximun Torque RW 983
16 1 Status Return Level Select Types of Status Return RW 2
17 1 Alarm LED LED for Alarm RW 36
18 1 Shutdown Shutdown Error Information RW 36

Control Table of RAM Area

Address Size
(Byte)
Data Name Description Access Initial
Value
24 1 Torque Enable Motor Torque On/Off RW 0
25 1 LED Status LED On/Off RW 0
26 1 CW Compliance Margin CW Compliance Margin RW 1
27 1 CCW Compliance Margin CCW Compliance Margin RW 1
28 1 CW Compliance Slope CW Compliance Slope RW 32
29 1 CCW Compliance Slope CCW Compliance Slope RW 32
30 2 Goal Position Target Position RW -
32 2 Moving Speed Moving Speed RW -
34 2 Torque Limit Torque Limit(Goal Torque) RW ADD 14&15
36 2 Present Position Present Position R -
38 2 Present Speed Present Speed R -
40 2 Present Load Present Load R -
42 1 Present Voltage Present Voltage R -
43 1 Present Temperature Present Temperature R -
44 1 Registered If Instruction is registered R 0
46 1 Moving Movement Status R 0
47 1 Lock Locking EEPROM RW 0
48 2 Punch Minimum Current Threshold RW 32

Control Table Description

Model Number (0)

This address stores model number of the DYNAMIXEL.

Firmware Version (2)

This address stores firmware version of the DYNAMIXEL.

ID (3)

{% include en/dxl/control_table_id.md %}

Baud Rate (4)

Baud Rate determines serial communication speed between a controller and DYNAMIXELs.

Value Baud Rate Margin of Error
1(Default) 1M 0.000%
3 500,000 0.000%
4 400,000 0.000%
7 250,000 0.000%
9 200,000 0.000%
16 115200 -2.124%
34 57600 0.794%
103 19200 -0.160%
207 9600 -0.160%

NOTE : Less than 3% of the baud rate error margin will not affect to UART communication. {: .notice}

Return Delay Time (5)

{% include en/dxl/control_table_return_delay_time.md %}

CW/CCW Angle Limit(6, 8)

{% include en/dxl/control_table_angle_limit.md %}

Temperature Limit (11)

|Unit|Value Range| | :---: | :---: | :---: | |About 1°C|0 ~ 99|

CAUTION : Do not set the temperature lower/higher than the default value. When the temperature alarm shutdown occurs, wait 20 minutes to cool the temperature before re-use. Keep using the product when the temperature is high can cause severe damage. {: .notice--warning}

Min/Max Voltage Limit (12, 13)

{% include en/dxl/control_table_volt_limit.md %}

Max Torque (14)

{% include en/dxl/control_table_max_torque.md %}

Status Return Level (16)

{% include en/dxl/control_table_status_return_lv.md %}

Alarm LED(17), Shutdown(18)

{% include en/dxl/control_table_alarm_shutdown.md %}

Torque Enable (24)

{% include en/dxl/control_table_torque_enable.md %}

LED (25)

{% include en/dxl/control_table_led.md %}

Compliance Margin (26, 27)

{% include en/dxl/control_table_compliance_margin.md %}

Compliance Slope (28, 29)

{% include en/dxl/control_table_compliance_slope.md %}

Goal Position (30)

{% include en/dxl/control_table_dx_goal_position.md %}

Moving Speed (32)

{% include en/dxl/control_table_moving_speed.md %}

Torque Limit (34)

{% include en/dxl/control_table_torque_limit.md %}

Present Position (36)

{% include en/dxl/control_table_potentio_present_position.md %}

Present Speed (38)

{% include en/dxl/control_table_present_speed.md %}

Present Load (40)

{% include en/dxl/control_table_present_load.md %}

Present Voltage (42)

{% include en/dxl/control_table_present_volt.md %}

Present Temperature (43)

{% include en/dxl/control_table_present_temp.md %}

Registered Instruction (44)

{% include en/dxl/control_table_reg_instruction.md %}

Moving (46)

{% include en/dxl/control_table_moving.md %}

Lock (47)

{% include en/dxl/control_table_lock.md %}

Punch (48)

{% include en/dxl/control_table_punch.md %}

How to Assemble

Maintenance

{% include en/dxl/horn_bearing_replacement.md %}

Reference

NOTE : Compatibility Guide {: .notice}

Connector Information

{% include en/dxl/molex_ttl.md %}

Drawings

{% include en/dxl/download_center_notice.md %}

{% include en/dxl/485_ttl_connection.md %}