A6 Servo Motor RS485 Operation Instruction
Recently, we have received feedback from many customers who still have questions about using Modbus 485 to control the A6 series servo motors. To help everyone better understand and use the 485 module of the A6, we have decided to create some examples.
- **Initial Connection and Communication Setup **
Required Preparations:
● An A6-RS series servo motor with connected motor and power cables;
● An RJ45 Ethernet cable;
● An RS485-USB adapter cable (If you are unsure which one to choose, we recommend using our product: https://www.omc-stepperonline.com/usb-to-rs422-rs485-serial-port-converter-adapter-cable-rs485-1?search=RS485-1;
● A serial communication software or controller capable of sending 485 commands;
Wiring
Find the definition of the 485 interface in the A6-RS series manual as follows:
Compare with the pinout of the RJ45 Ethernet cable:
As can be seen, we need to select wires 4/5/8 to connect to the RS485-USB adapter cable.
For the RJ45 Ethernet cable:
Keep one end's RJ45 connector intact for insertion into the drive's CN3 port.
Cut off the other end's RJ45 connector.
Strip wires 4/5/8 (blue/blue-white/brown) and connect them in the following order:
485+ ----------------TXD+
485- ----------------TXD-
GND ---------------GND
After wiring, insert both ends into the drive and PC interfaces respectively. Power on the drive and open the serial port software to establish communication. (If communication fails to establish, please refer to this troubleshooting article:
Important Note:
If you need to save the written 485 commands, you must first send the following command:
01 06 0A 05 00 01 CRC CRC
Otherwise, when the drive loses power, all written parameters will revert to their default values!
- Operation Modes
2.1. Speed Control Mode
Commend | Description |
|---|---|
01 06 00 00 00 01 CRC CRC | Set drive control mode to speed mode (C00.00=1) |
01 06 03 20 00 03 CRC CRC | Use internal speed command (C03.20=3) |
01 06 12 00 00 01 CRC CRC | Set speed profile mode to cyclic operation (C12.00=1) |
01 06 12 06 02 58 CRC CRC | Set running speed to 600rpm (C12.06=600) |
01 10 12 0A 00 02 04 00 64 00 00 CRC CRC | Set acceleration time to 100ms (C12.0A=100) |
01 10 12 0C 00 02 04 00 64 00 00 CRC CRC | Set acceleration time to 100ms (C12.0C=100) |
01 06 04 11 00 01 CRC CRC | Enable motor and start operation (C04.11=1) |
01 06 04 11 00 00 CRC CRC | Emergency stop command, disable motor (C04.11=0) |
From the above examples, it can be observed that all parameter register addresses in the A6 no longer require complex conversions. For instance, set C00.00 to 1, the register address in the 485 command is simply 0000. Similarly, setting C03.20 to 3 uses register address 0320.
The only conversion needed is the write value. All values in the manual are in decimal format. The 485 command requires hexadecimal conversion.
One critically important note:
In Chapter 8's parameter table (Data Type column), we can see the data types are not uniform:
Special attention is required here:
U16 indicates 16-bit parameters, using write command 0x06:
Example: 01 06 00 00 00 01 CRC CRC (sets C00.00 to 1)
01: Axis address (default=1 for single-drive testing)
06: Write command (C00.00 is 16-bit parameter)
00 00: Parameter address
00 01: Value to write (hexadecimal of decimal 1)
[CRC][CRC]: Checksum (required by some serial ports, optional for others)
U32 indicates 32-bit parameters, using write command 0x10:
Example: 01 10 12 0A 00 02 04 00 64 00 00 CRC CRC (sets C12.0A to 100)
01: Axis address
10: Write command (C12.0A is 32-bit parameter)
12 0A: Parameter address
00 02: Number of registers to write
04: Byte count
00 64 00 00 is the write value 100 (the hexadecimal of 100 is 0x00000064). Since C0A.06=0, the high-order 8 bits 0064 should be placed first, followed by the low-order 8 bits 0000;
CRC CRC is the checksum;
Finally, the difference between I16 and U16 lies in the presence or absence of signed values. If the parameter can accept negative values, the data type is I. Typically, speed-related parameters may have negative values, where negative and positive speed values indicate opposite rotation directions of the motor.
2.2. Multi-Speed Operation
Commend | Description |
|---|---|
01 06 00 00 00 01 CRC CRC | Set drive control mode to speed mode C00.00=1 |
01 06 03 20 00 03 CRC CRC | Use internal speed command C03.20=3 |
01 06 12 00 00 01 CRC CRC | Set speed profile mode to cyclic operation C12.00=1 |
01 06 12 01 00 01 CRC CRC | Set speed profile starting group to Group 1 C12.01=1 |
01 06 12 02 00 02 CRC CRC | Set speed profile ending group to Group 2 C12.02=2 |
01 06 12 06 00 64 CRC CRC | Set Group 1 speed to 100 RPM C12.06=100 |
01 10 12 080 02 04 00 64 00 00 CRC CRC | Set Group 1 operation time to 15000 ms C12.08=15000 |
01 10 12 0A0 02 04 00 64 00 00 CRC CRC | Set Group 1 acceleration time to 100 ms C12.0A=100 |
01 10 12 0C0 02 04 00 64 00 00 CRC CRC | Set Group 1 deceleration time to 100 ms C12.0C=100 |
01 06 12 10 00 05 CRC CRC | Set Group 2 speed to 5 RPM C12.10=5 |
01 10 12 12 00 02 04 00 64 00 00 CRC CRC | Set Group 2 operation time to 15000 ms C12.12=15000 |
01 10 12 14 00 02 04 00 64 00 00 CRC CRC | Set Group 2 acceleration time to 100 ms C12.14=100 |
01 10 12 16 00 02 04 00 64 00 00 CRC CRC | Set Group 2 deceleration time to 100 ms C12.16=100 |
01 06 04 11 00 01 CRC CRC | Enable motor and start operation C04.11=1 |
01 06 04 11 00 00 CRC CRC | Emergency stop command, disable motor C04.11=0 |
2.3. Absolute Position Movement of 5000 pulses(Default setting: 10000 pulses/rev, C00.02=10000)
Commend | Description |
|---|---|
01 06 00 00 00 00 CRC CRC | Set drive control mode to position mode C00.00=0 |
01 06 11 01 00 00 CRC CRC | Set position profile command to absolute positioning C11.01=0 |
01 06 03 00 00 02 CRC CRC | Set position command source to step increment C03.00=2 |
01 06 03 0D 00 01 CRC CRC | Set running speed to 1 rpm C03.0D=1 |
01 06 03 0C 13 88 CRC CRC | Set displacement to 5000 pulses C03.0C=5000 |
01 06 04 00 00 22 CRC CRC | Configure DI1 as position step increment enable C04.00=34 (0x22) |
01 06 04 11 00 01 CRC CRC | Enable motor and start operation C04.11=1 |
01 06 04 01 00 01 CRC CRC | Trigger DI1 enable C04.01=1 |
01 06 04 11 00 00 CRC CRC | Emergency stop command, disable motor C04.11=0 |
01 06 04 01 00 00 CRC CRC | Disable DI1 C04.01=0 |
2.4. Multi-Position Operation under Absolute Positioning(First segment: 3000 pulses; Second segment: 8000 pulses)
Note: In this mode:
The first segment moves 3000 pulses relative to origin 0
The second segment moves 8000 pulses relative to origin 0
If you need to operate in relative position mode, set C11.01=1. In this mode, the second movement will take the 3000 position as its starting point and move forward by 8000 pulses.
Command | Description |
|---|---|
01 06 00 00 00 00 CRC CRC | Set drive control mode to position mode C00.00=0 |
01 06 03 00 00 01 CRC CRC | Enable multi-segment position command C03.00=1 |
01 06 11 00 00 00 CRC CRC | Set single operation mode C11.00=0 |
01 06 11 03 00 01 CRC CRC | Set position profile starting group to Group 1 C11.03=1 |
01 06 11 04 00 02 CRC CRC | Set position profile ending group to Group 2 C11.04=2 |
01 10 11 06 00 02 04 0B B8 00 00 CRC CRC | Set Group 1 displacement to 3000 pulses C11.06=3000 |
01 06 11 08 00 05 CRC CRC | Set Group 1 running speed to 5 RPM C11.08=5 |
01 10 11 0A 00 02 04 00 64 00 00 CRC CRC | Set Group 1 acceleration time to 100 ms C11.0A=100 |
01 10 11 0C 00 02 04 00 64 00 00 CRC CRC | Set Group 1 deceleration time to 100 ms C11.0C=100 |
01 10 11 0E 00 02 04 13 88 00 00 CRC CRC | Set post-operation delay to 5000 ms for Group 1 C11.0E=5000 |
01 10 11 10 00 02 04 1F 40 00 00 CRC CRC | Set Group 2 displacement to 8000 pulses C11.10=8000 |
01 06 11 12 00 01 CRC CRC | Set Group 2 running speed to 1 RPM C11.12=1 |
01 10 11 14 00 02 04 00 64 00 00 CRC CRC | Set Group 2 acceleration time to 100 ms C11.14=100 |
01 10 11 16 00 02 04 00 64 00 00 CRC CRC | Set Group 2 deceleration time to 100 ms C11.16=100 |
01 10 11 18 00 02 04 13 88 00 00 CRC CRC | Set post-operation delay to 5000 ms for Group 2 C11.18=5000 |
01 06 04 00 00 13 CRC CRC | Configure DI1 as position profile trigger C04.00=19 (0x13) |
01 06 04 11 00 01 CRC CRC | Enable motor and start operation C04.11=1 |
01 06 04 01 00 01 CRC CRC | Trigger DI1 enable C04.01=1 |
01 06 04 11 00 00 CRC CRC | Emergency stop command, disable motor C04.11=0 |
01 06 04 01 00 00 CRC CRC | Disable DI1 C04.01=0 |
- Common Commands
Motor Enable:
01 06 04 11 00 01 CRC CRC
Motor Disable:
01 06 04 11 00 00 CRC CRC
Restore Factory Settings:
01 06 31 02 00 01 CRC CRC
Read Current Motor Speed:
01 03 40 01 00 02 CRC CRC
Read Current Absolute Position:
01 03 40 16 00 02 CRC CRC
Read Current Motor Torque:
01 03 40 03 00 02 CRC CRC
(The read value unit is 0.1%, where 100.0% corresponds to 1× motor rated torque)
Read Drive Temperature (unit: 0.1°C):
01 03 40 30 00 02 CRC CRC
Updated on: 03/06/2025
Thank you!