Measuring multiple voltages on a three-phase system stacks up constraints quickly: high signal levels, mandatory isolation, self-powering from the measured bus, and everything has to fit inside a DIN rail enclosure.
Voltage transformers were chosen over resistive dividers — for safety, galvanic isolation, and signal quality. Outputs are conditioned before hitting the STM32G0B0CET6’s ADC. Analog multiplexing lets several channels share a single measurement path, keeping the hardware compact.
The board powers itself via a buck converter fed from the bus it measures. That sounds straightforward, but switching noise on an analog measurement board is a genuine concern — placement, supply separation, grounding strategy, and filtering were all handled carefully. RS485 telemetry for reporting. The DIN rail enclosure imposed mechanical constraints from day one.