Hardware connection

Use the matching CAN power cable to connect the [Power] interface of the OnePMU to the [Power1/2] interface of the flight controller, as shown in the figure.

Product light language

PWR： The power indicator is constantly red

CAN communication：The green light flashes rapidly when not communicating with the flight controller. It blinks once per second when the communication is normal

SYS：A three-color light that shows the approximate battery power status

When the green light is on: The voltage of a single battery cell is greater than 4.0V

When the yellow light is on: The voltage of a single battery cell is lower than 4.0V but higher than 3.7V

When the red light is on: The voltage of a single battery cell is lower than 3.5V

How to use the ArduPilot firmware

Under the default parameters, the battery voltage can be directly displayed on the ground station. If the voltage is not shown, search for the following parameters in "Configuration/Debugging >> All Parameter Tables" of the ground station, modify the parameters, and restart the flight controller after writing the parameters.

Set BATT_MONITOR to 8

Set CAN_P1_DRIVER to 1

Set CAN_P2_DRIVER to 1

Battery parameter configuration

The default parameters of the ammeter are suitable for monitoring 6S standard-voltage LiPo batteries. For batteries with other cell counts, parameters need to be modified. The operations are as follows:

After the battery voltage is displayed on the ground station, go to the "Initial Setup >> Optional Hardware >> DroneCAN/UAVCAN" interface, click on "MAVLINK-CAN1", and the list of UAVCAN communication devices will be displayed.
Find "org.ZeroOne.PMU" in the list, click [menu], and then click "parameters". The parameter list of the ammeter will be displayed. The modifiable parameters are as follows:
- BAT_CELL_NUM": the number of battery cells, with a default of 6 cells
- BAT_FULL_VOLTAGE": the full-charge voltage per cell. 4200 represents 4.2V
- BAT_LOW_VOLTAGE": the minimum voltage per cell
- CAN_NODE_ID": the CAN communication node ID. The default value of 0 means that the flight controller automatically assigns an ID to the ammeter. Users can manually assign an ID in the range of 1 - 255.
After modifying the parameters, click "Write Parameters" to complete the configuration.

How to use the PX4 firmware

Connect the battery, connect the flight controller to the QGroundControl ground station, and enter the parameters interface in "Vehicle setup" to search for and configure the following parameters. Set "UAVCAN_ENABLE" to "Sensors automatic config". Generally, no modification is required by default. Set "UAVCAN_SUB_BAT" to "enable" or "RAW data". Set "BAT1_SOURCE" to "disable". After modifying the parameters, restart the flight controller, and the ground station will display the battery voltage, battery percentage, and ammeter temperature data. If you need to modify the parameters of the power module, such as the number of battery cells and the voltage of a single cell, you need to use the ArduPilot firmware to make the modifications.

Firmware upgrade

In the [Optional Hardware] - [DroneCAN/UAVCAN interface], click on [MAVLink-CAN1]. After "org.ZeroOne.pmu" is displayed, click on [menu] and select [update]. When the prompt box pops up, click [No], then select the downloaded local firmware and wait for the firmware upgrade to complete.

OnePMU Power Module