CAN Communication Function

The CAN interface on this device supports the CANopen SDO data transfer protocol. SDO is mainly used to transmit low-priority objects between devices. This data transfer is similar to MODBUS, i.e. after the master station sends a request, the slave station shall return a data response: Client→Server / Server→Client. This is the basic structure of an SDO. The CAN bus uses termination resistors. A 120Ω termination resistor must be placed between CAN_H and CAN_L at each of the two end nodes of the bus to suppress signal reflections and improve communication stability. Intermediate nodes on the bus should not have termination resistors, as doing so would lower the equivalent bus impedance and compromise communication reliability.

Basic SDO Structure
Byte0	Byte1-2	Byte3	Byte4-7
SDO Command Specifier	Object Index	Object SubIndex	Up to 4-byte Data

The 2-byte Object Index and the up-to-4-byte data are transmitted in little-endian (low-order byte first, high-order byte last).
For example, for an object index of 0x606C, Byte1 = 0x6C, Byte2 = 0x60.

Read Parameters

	Identifier	DLC	Data
			0	1	2	3	4	5	6	7
Transmit SDO Message	0x600+Node_ID	8	Transmit Command Code	Object Index		Object SubIndex	00
Receive SDO Message	0x580+Node_ID	8	Receive Command Code	Object Index		Object SubIndex	Up to 4-byte Data

• Transmit Command Code: Always 0x40
• Receive Command Code: 0x4F- 1-byte data received; 0x4B- 2-byte data received; 0x43- 4-byte data received
• Example: Read the actual position of motor #1 (0x606300) via SDO

  	Identifier	Command Code	Object Index		Object SubIndex	Up to 4-byte Data
  Transmitted Message	0x601	0x40	0x63	0x60	0x00	0x00	0x00	0x00	0x00
  Received Message	0x581	0x43	0x63	0x60	0x00	0xD9	0x05	0x00	0x00

  Actual Position = 0x05D9 (HEX) = 1497 (DEC)

Modify Parameters

	Identifier	DLC	Data
			0	1	2	3	4	5	6	7
Transmit SDO Message	0x600+Node_ID	8	Transmit Command Code	Object Index		Object SubIndex	Up to 4-byte Data
Receive SDO Message	0x580+Node_ID	8	Receive Command Code	Object Index		Object SubIndex	Up to 4-byte Data

• Transmit Command Code: 0x2F- 1-byte transmit data; 0x2B- 2-byte transmit data; 0x23- 4-byte transmit data
• Receive Command Code: 0x60- Message transmitted successfully; 0x80- Message transmission failed
• Example: Control the axis of motor #1 (0x604000) via SDO. First write 0x06 to power-off and release the motor shaft, then write 0x0F to power-on and lock the motor shaft.

  	Identifier	Command Code	Object Index		Object SubIndex	Up to 4-byte Data
  1st Transmitted Message	0x601	0x2B	0x40	0x60	0x00	0x06	0x00	0x00	0x00
  1st Received Message	0x581	0x60	0x40	0x60	0x00	0x06	0x00	0x00	0x00
  2nd Transmitted Message	0x601	0x2B	0x40	0x60	0x00	0x0F	0x00	0x00	0x00
  2nd Received Message	0x581	0x60	0x40	0x60	0x00	0x0F	0x00	0x00	0x00

  

PDO Function

The drive provides a simplified built-in PDO function and requires no configuration from the CAN master station.

PDO1 Message Format
Identifier	DLC	Data
		0	1	2	3	4	5	6	7
0x180+Node_ID	8	Mapped to Object 0x60F919 (Actual Speed, 0.001 rpm)				Mapped to Object 0x606300 (Actual Position)

CAN Communication Examples

Example 1: Read motor actual current Iq
Refer to "Table F1-3 Measured Data" in the Common-use Object List. The object address for "Actual Current Iq" is 0x607800, which is a 16-bit signed number.
Assume the motor actual current is 1 Arms. Conversion formula: [DEC] = [Arms] * 1.414 * 2048 / 15. 1 Arms = 193 (DEC) = 0xC1 (HEX)

	Identifier	Command Code	Object Index		Object SubIndex	Up to 4-byte Data
Host-Sent Message	0x601	0x40	0x78	0x60	0x00	0x00	0x00	0x00	0x00
Drive Response Message	0x581	0x4B	0x78	0x60	0x00	0xC1	0x00	0x00	0x00

Example 2: Write Target Speed (High-resolution speed command)
Refer to "Table F1-2 Operating Modes & Control" in the Common-use Object List. The object address for "Target Speed" is 0x60FF00, which is a 32-bit signed number.
Set the speed command to 150 rpm. Conversion formula U[y,x]: [DEC] = ([rpm] * 512 * [Feedback Resolution]) / 1875
Where [Feedback Resolution] = 4096. [DEC] = (150 * 512 * 4096) / 1875 = 167772 → Hex = 0x28F5C

	Identifier	Command Code	Object Index		Object SubIndex	Up to 4-byte Data
Host-Sent Message	0x601	0x23	0xFF	0x60	0x00	0x5C	0x8F	0x02	0x00
Drive Response Message	0x581	0x60	0xFF	0x60	0x00	0x5C	0x8F	0x02	0x00

Example 3: CAN-PDO Communication Example

• Enable PDO
  Refer to "Table F1-5 Communication Parameters" in the Common-use Object List. The object address for "Enable PDO" is 0x470001, which is an 8-bit unsigned number.
  

  	Identifier	Command Code	Object Index		Object SubIndex	Up to 4-byte Data
  Host-Sent Message	0x601	0x2F	0x00	0x47	0x01	0x01	0x00	0x00	0x00
  Drive Response Message	0x581	0x60	0x00	0x47	0x01	0x01	0x00	0x00	0x00

• The slave drive will actively report actual speed and actual position
  If the motor actual speed = 10 rpm (Hex: 0x2710), and actual position = 1000 DEC (Hex: 0x3E8)
  The drive transmits messages periodically (default interval: 10 ms).

  	Identifier	Command Code	Object Index		Object SubIndex	Up to 4-byte Data
  Drive-Initiated Message	0x181	0x10	0x27	0x00	0x00	0xE8	0x03	0x00	0x00