Kria™ KD240 Drives Starter Kit
FOC Motor Control Application Tutorial

Known Issues and Debug Help

Known Issues and Limitations

  • QEI reported speed is showing glitches. The QEI library computation of the speed has a known issue and will be addressed with a QEI library update.

  • Motor lower speed mode control capability is approximately 250 rpms.

  • Default motor tuning values are provided for the KD240 Motor Accessory Kit based the Anaheim motor with the plastic disk visual load. This load disk primarily acts as an inertial load and thus if you are connecting other loads to your motor, you should plan on conducting your own tuning process and defining custom tuning defaults based on your load testing.

  • Open-loop control mode is intended as a test mode and thus does not implement any software based ramp control. You will see fault protections triggered if immediately trying to set open-loop mode control with a Vq voltage > ~10V. If using an open-loop, you are responsible for incrementally stepping up the Vq command to your desired voltage setting. Typical use cases of open-loop mode have Vd set to 0V.

  • DC link current reading is limited to reading analog values > ~0.5A due to a limitation in the KD240 hardware. You should not assume the DC link current feedback is accurate until it is > ~0.5A.

  • If the bokeh server is stopped while the motor is running, the motor will not stop. The motor should be stopped through the GUI by switching to Off mode before stopping the bokeh server.

Debugging Motor Control Application

If the motor control application is not functioning as intended, follow these debugging steps to diagnose and resolve issues.

  1. Check Wire Connections

    • Ensure that wire connections matches the configuration shown in the application deployment page.

    • Verify that the 24V DC supply is connected and the wall power is up.

    • Check DS9 LED, which represents the DC link; it should be in a high state.

    • Confirm that the Quadrature Encoder Interface (QEI) encoder from the motor is properly connected to the board.

  2. Read DC Link Voltage

    • If the application repeatedly fails to start with system faults, measure the DC link voltage by reading data from the ADC interface (ADC-HUB voltage channel 6).

    • Use the command iio_attr -c xilinx_adc_hub voltage6 to check the voltage reading and should read around 24V.

      iio_attr -c xilinx_adc_hub voltage6
dev 'xilinx_adc_hub', channel 'voltage6' (input), attr 'input', value '25.116806030'

      A reading significantly lower or higher than the tolerance range of the power supply could indicate a hardware failure on the board.

  3. Debug PL Interfaces

    • If unexpected behavior occurs, start probing different blocks of the programmable logic (PL) interfaces for debugging.

    • Utilize the IIO utilities or the IIO driver sysfs for the specific hardware interface.

    • For detailed information on debugging hardware interfaces, refer to the Device and Channel Attributes section.

  4. Gate Drive Mode

    • Ensure that the software application is set to a valid mode that turns the Gate Drive ON, except for the off mode.

    • Monitor DS10 LED: it should go high in modes other than off.

  5. Observe Errors and Messages from the Application

    • Keep an eye on the serial console for error messages or other relevant information.

    • Review the dmesg logs, which provide valuable information from the respective hardware drivers. These logs can be a helpful source of diagnostic information.

  6. Network Connection

    • If the application does not respond to changes from the GUI, verify the network connection by pinging the host address.

    • Sometimes, a web socket disconnection message may appear, indicating a communication issue. If you encounter such disconnection issues, try killing the Bokeh server and relaunching the server and the dashboard.

    Sample Disconnection Message:

    2023-09-13 18:47:32,361 WebSocket connection closed: code=None, reason=None

CAN bus issue

Sometime, if the CANopen setup is left running for long time, them TX queue of the CAN interface can fillup resulting in the interface hang, especially on KR260. There is no indication for this situation except KR260 and KD240 do not receive can message. To fix this just bring the can interface down and up again.

sudo ip link set can0 down
sudo ip link set can0 up

If this is frequent enough then consider increasing the tx queue length on KR260 with sudo ip link set can0 txqueuelen 10000

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