Integrating INA3221 with Pixhawk v6X via UART4 (I2C)

IZ0NA · June 13, 2025, 2:02pm

Hi everyone,

I’m trying to connect an INA3221 (current/voltage sensor) to a Pixhawk v6X using the UART4 port in I2C mode. Here’s my setup:

-Wiring: SDA/SCL/GND connected to UART4’s corresponding pins.
Mission Planner Config: *SER4_PROTOCOL = -1 (disables UART to free SDA/SCL).

-Issue : The INA3221 isn’t detected in HW ID.

Any clear steps or advice to setup this ship would be greatly appreciated!

Notes:
I’m using Mission planner * Firmware V4.6.0

idris · June 14, 2025, 10:12pm

Hello.

BATT_MON = ?

BATT_MON_ADDR = ?

What are these?

You can see the connected I2C addresses using the Lua in the link.

github.com/ArduPilot/ardupilot

libraries/AP_Scripting/examples/i2c_scan.lua

master

-- This script scans for devices on the i2c bus

---@diagnostic disable: need-check-nil

local address = 0
local found = 0

local i2c_bus = i2c:get_device(0,0)
i2c_bus:set_retries(10)

function update() -- this is the loop which periodically runs

  i2c_bus:set_address(address)

  if i2c_bus:read_registers(0) then
      gcs:send_text(0, "Found I2C at " .. tostring(address))
      found = found + 1
  end

  address = address + 1

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IZ0NA · June 16, 2025, 7:39am

Thank you for your response! I tried looking for the parameters you mentioned, but I could only find one:

BATT_MONITOR (set to 30 for INA3221)

The other parameters and BATT_MON_ADDR

don’t appear in my parameter list, as you can see in the attached screenshots, I tiped them in the search bar.

Regarding the script, I’m unsure how to execute it—I can’t access the scripting console in Mission Planner (the option seems unavailable). Any guidance would be greatly appreciated!

Thanks again!

IZ0NA · June 17, 2025, 10:26am

Hi there,
For the scripting part, I found 3 addresses none of them are the INA3221’s 0x40, as you can see in the screenshot. Any guidance would be greatly appreciated!

Thanks again!

LupusTheCanine · June 17, 2025, 10:40am

I don’t recall capability to use serial as I2C port. Use I2C port instead.