M5Stack Analog to I2C 4-20mA Input Unit (STM32G030)

M5Stack 4-20mA Analog to I2C Input Unit

The M5Stack AIN4-20mA Unit converts a single industrial 4–20mA current-loop signal into data that an embedded host can read through I2C. It uses an STM32G030F6P6 controller, HCNR200 isolation path, and SGM321YC5/TR op-amp circuitry for current-signal acquisition.

Jumper configuration supports 2-wire or 4-wire sensor wiring and internal or external power arrangements. This makes the unit useful for integrating industrial transmitters into embedded monitoring, energy-management, motor-control, and process-automation prototypes.

Connect Standard 4–20mA Sensors to an I2C Host

Current-loop sensors are common in industrial environments because the signal can remain useful over longer cable runs than many direct voltage interfaces. The unit presents the measured value to the host through I2C at address 0x55.

Isolation and Wiring Configuration

The onboard isolation path improves separation between the field signal and controller side, but complete system safety still depends on power supplies, grounding, surge protection, cable shielding, enclosure design, and the voltage ratings of every connected component.

Verify Loop Power Before Connection

Determine whether the transmitter is 2-wire loop-powered or 4-wire self-powered, then set the jumpers and external supply accordingly. Incorrect loop wiring can prevent measurement or damage equipment. Confirm polarity and current limits before energizing the circuit.

Calibrate the Complete Measurement Chain

For process control or threshold alarms, validate the transmitter, wiring, conversion path, and firmware scaling together. A 4–20mA signal often represents a configured engineering range, so map current to the actual pressure, level, temperature, or other process variable used by the sensor.

Technical setup details are available in the M5Stack AIN4-20mA documentation.