Matek Mateksys AP_PERIPH CAN-L4-BM Digital Power Monitor User Manual

1. Introduction

The Matek Mateksys AP_PERIPH CAN-L4-BM is an ultra-precise digital power monitor designed for applications requiring accurate current and voltage measurements via the CAN bus. It utilizes the TI INA239 IC and runs ArduPilot AP_Periph firmware, supporting the CAN/DroneCAN protocol. This device provides reliable power monitoring without the need for calibration.

2. Features

Ultra-precise digital power monitoring.
Based on TI INA239 and ArduPilot AP_Periph firmware.
Supports CAN/DroneCAN protocol.
No calibration required for accurate current and bus voltage readouts.
Low power loss due to 200µΩ typical conductive path resistance.

3. Specifications

MCU: STM32L431xC, 256KB Flash
Power Monitor IC: INA239 (85-V, 16-Bit, High-Precision)
Battery Voltage Sense Input: 0~85V
Current Sense Range: 0~204.8A
Load Current on Sensing Resistor: 150A (Continuous), 204.8A (Burst)
Voltage Accuracy: 0.1%
Current Accuracy: 2%
Interface: CAN (DroneCAN Protocol), UART2 (spare, DFU), ST debug (SWCLK & SWDIO)
Power Supply: 4.5~5.5V @5V pad/pin
Power Consumption: 10mA
Operating Temperatures: -40~85 °C
Board Size: 30mm x 22mm x 3mm
Weight: 4g
Firmware: ArduPilot AP_Periph (Update via DroneCAN GUI Tool)

4. Product Overview

Component Layout

**Image:** Matek Mateksys CAN-L4-BM Digital Power Monitor with included JST-GH-4P cable. This image displays the compact size of the board and its primary connection interface, along with key specifications like current and voltage ranges.

Matek Mateksys CAN-L4-BM board with dimensions — **Image:** Top-down view of the CAN-L4-BM board with precise dimensions (30mm x 22mm x 3mm) and mounting hole specifications. This illustrates the physical footprint of the device for integration planning.

Matek Mateksys CAN-L4-BM board close-up showing components — **Image:** Close-up view of the CAN-L4-BM board, highlighting the STM32L431xC MCU, INA239 IC, and various connection pads including JST-GH-4P, 5V, CAN-H, CAN-L, and GND. This provides detail on the board's internal layout.

Matek Mateksys CAN-L4-BM integrated with XT60 connectors — **Image:** The CAN-L4-BM power monitor integrated with XT60 connectors, demonstrating a typical wiring configuration for power input and output in a system. This shows a practical application setup.

5. Setup and Installation

Wiring Instructions

Proper wiring is crucial for accurate readings and safe operation of the CAN-L4-BM.

Wiring diagram for CAN-L4-BM with single battery and external BEC — **Image:** Wiring diagram illustrating how to connect the CAN-L4-BM to a flight controller and battery for current and voltage monitoring. This diagram shows a single battery setup with an external BEC for power to the flight controller.

Wiring diagram for CAN-L4-BM with dual battery and built-in BEC — **Image:** Advanced wiring diagram showing connection of the CAN-L4-BM to a flight controller with a built-in 5V BEC, and a dual battery setup for current and voltage monitoring. This configuration allows for monitoring two separate power sources.

General Wiring Tips

Solder the positive wires as close as possible to both sides of the current sensing resistor on the board for optimal accuracy.
Ensure a common ground connection between the flight controller and the ESC/Load to prevent ground loops and ensure stable operation.
If CAN wires are excessively long, bridge the 120R jumper on the CAN-L4-BM board to maintain signal integrity.
The large pad on the bottom side of the board is a dead pad and has no circuit network; it can be used for structural support if needed.
The two mounting ears can be carefully cut off if not required for installation in space-constrained environments.

Firmware Configuration

The CAN-L4-BM runs ArduPilot AP_Periph firmware. Configuration is performed via the DroneCAN protocol through your flight controller's settings.

Connect the CAN-L4-BM to your flight controller's CAN bus port.
Set the appropriate parameter in your flight controller's firmware to enable the CAN driver:
- For CAN bus1: CAN_P1_DRIVER = 1
- For CAN bus2: CAN_P2_DRIVER = 1
Configure battery monitoring by setting: BATTx_MONITOR = 8 (DroneCAN-BatteryInfo), where 'x' corresponds to the battery monitor instance you are configuring.
Firmware updates for the CAN-L4-BM can be performed using the DroneCAN GUI Tool.

6. Operation

LED Indicators

Blue LED (Fast blinking): Indicates the board is in the process of booting up.
Blue LED (Slow blinking): Indicates the board is working correctly and communicating via CAN.
Red LED: Indicates that 3.3V power is present on the board.

Data Monitoring

Once properly configured and powered, the flight controller will receive accurate current and bus voltage data from the CAN-L4-BM via the DroneCAN bus. This data can be logged and monitored through your flight controller's telemetry system or compatible ground station software.

7. Maintenance and Best Practices

Regularly inspect all soldered connections for integrity and signs of wear or corrosion.
Keep the board free from dust, moisture, and debris to ensure optimal performance and longevity.
Ensure proper ventilation if operating the device in enclosed spaces, although the CAN-L4-BM has a wide operating temperature range.
Avoid exposing the board to extreme environmental conditions (e.g., excessive humidity, direct water contact) beyond its specified operating range.

8. Troubleshooting

Common Issues

No data from monitor:
- Verify all CAN bus connections (CAN-H, CAN-L, GND, 5V) are secure and correct.
- Check the LED indicators for proper boot and operation (a slow blue blink indicates normal function).
- Ensure CAN_P1_DRIVER or CAN_P2_DRIVER is set correctly in the flight controller parameters.
- Confirm that BATTx_MONITOR = 8 is set for the correct battery monitor instance.
- Check for any short circuits or incorrect voltage supply to the CAN-L4-BM board.
Inaccurate readings:
- Ensure positive wires are soldered as close as possible to the current sensing resistor on the board.
- Verify common ground connections between all components in the power system.
- Check for any physical damage to the board or its components that might affect sensor accuracy.
Board not powering on:
- Confirm that a stable 4.5~5.5V supply is provided to the 5V pad/pin.
- Check the Red 3.3V indicator LED; if it's off, there might be a power issue.
- Inspect all power supply wiring for breaks or incorrect connections.

9. Contact and Support

For further assistance, technical support, or to access additional resources, please refer to the official Mateksys documentation available on their website or consult relevant community forums for ArduPilot and DroneCAN users.

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Mateksys CAN-L4-BM