Sockets: RS-485: molex 5264 (4 pin x 2), motor: molex 5264 (3 pin), sensor: sh1.0 (10 pin)
Download this project:
git clone --recursive https://github.com/dukelec/cdfoc
CDFOC is an open-source Field-Oriented Control (FOC) motor controller that communicates over an RS485 interface.
- Default baud rate: 115200 bps
- Maximum speed: 50 Mbps
- Default address: 0xfe
The underlying protocol is CDBUS, with the following frame format:
src, dst, len, [payload], crc_l, crc_h
Each frame includes a 3-byte header, a variable-length payload, and a 2-byte CRC (identical to Modbus CRC).
For more information on the CDBUS protocol, please refer to:
The payload is encoded using the CDNET protocol. For detailed information, please refer to:
CDBUS GUI Tool: https://github.com/dukelec/cdbus_gui
Example: Upon power-on, first write 5 to state, then write the target position to tp_pos to rotate the motor.
After modifying the configuration, write 1 to save_conf to save the configuration to flash.
If you need to restore the default configuration, change magic_code to another value and save it to flash. Then reapply power.
Plots:
Do not connect any loads to the motor during calibration.
Write 1 to dbg_en to enable debug prints in the GUI.
Start by setting the appropriate value for cali_voltage. A higher value locks the rotor more firmly, but also causes the motor to heat up more quickly.
Also be careful to prevent the motor from overheating.
Write 1 to enc_cali to start the calibration. The firmware automatically enters voltage mode and applies cali_voltage, causing the motor to turn clockwise first, then counterclockwise.
Afterward, the calculated encoder offset value will be printed and written to bias_encoder. Be sure to save it to flash.
Write 1 to state to enter open-loop voltage mode.
Write the output voltage directly to tgt_vq and tgt_vd. The voltage value is represented as a fraction of the bus voltage:
output voltage = target value / 32768 * bus voltage.
The phase-current samples are still available for monitoring, but they do not participate in the control calculation or affect the motor output in this mode.
Write 2 to state to enter torque mode, or current mode.
The motor can then be rotated by writing the appropriate q-axis current value to tgt_iq.
The current-control value uses a signed 15-bit full-scale representation stored in an int16_t field. One raw 12-bit ADC count corresponds to 8 current-control counts. Conversion to physical current depends on the board's current-sense circuit.
Write 3 to state to enter speed mode.
Then write the appropriate speed value to tgt_speed to rotate the motor.
One revolution of the motor is divided into 0x10000 units, e.g. from 0 to 0x10000 is one full revolution.
The unit of speed is: how many position-units / second.
Write 5 to state to enter position mode.
Then just write the appropriate values to tp_pos, tp_speed, tp_accel.
Alternatively these parameters can be updated using the quick-exchange command by default.
Mode 4 of state is a position mode without acceleration or deceleration and is not normally used.
The address of the state itself is 0x0400 and its length is 1 byte.
To lock the motor and enter position mode after power up, send the following data to port 5:
20 00 04 05
20 is the subcommand write, 00 04 is the little-endian for address 0x0400 (little-endian is used unless otherwise noted),
and 05 is the value to be written.
The complete command containing the CRC is (host address defaults to 0, motor address defaults to 0xfe, 3rd byte is data length, last two bytes are CRC):
00 fe 06 40 05 20 00 04 05 e9 fb
The complete response package is:
fe 00 03 05 40 00 crc_l crc_h
The last 0x00 means no error.
qxchg_set uses only one element by default, pointing to the area where the table entries tp_pos, tp_speed and tp_accel are located.
If you want to change the target position parameter tp_pos to 0, you can write data 00 00 00 00 to port 6.
If you need to change both the target position and the target speed, e.g. position to 0x00010000 and speed to 0x00005000, writes: 00 00 01 00 00 50 00 00.
Goes to 0 degrees, full command with CRC:
00 fe 06 40 06 00 00 00 00 64 f8
Goes to 180 degrees, full command with CRC:
(0x10000 units for one revolution, 0x8000 for 180 degrees)
00 fe 06 40 06 00 80 00 00 65 10
Rotates to the 5th revolution position and sends the speed value (0x00140000 or 14 revolutions per second) with the CRC:
00 fe 0a 40 06 00 00 05 00 00 00 14 00 ae c4
Demonstration of return data for the above three commands:
fe 00 0a 06 40 xx xx xx xx yy yy yy yy crc_l crc_h
The xx and yy are defined by qxchg_ret to return 8 bytes of data such as tgt_pos.