The Measurement Core is the essential electronic subsystem of a Power Monitoring Unit responsible for sampling, conditioning, digitizing, and processing electrical signals (voltage, current) to calculate key power parameters such as active power, reactive power, apparent power, power factor, energy consumption, and harmonic distortion. It operates by receiving analog voltage and current signals from sensors (e.g., CTs, PTs). These signals are conditioned (filtered, amplified), then converted to digital values by an Analog-to-Digital Converter (ADC). A digital signal processor (DSP) or microcontroller executes algorithms on this data to perform calculations, apply calibration factors, and generate the final measurement data for display, communication, or control purposes. The component is designed for integration into power monitoring equipment and is characterized by a set of reference parameters that must be verified for the specific model and application. These include a sampling rate of 4000 Hz (minimum for harmonic analysis up to the 50th order, per IEC 62053-22), measurement accuracy for active energy of ±0.5% (Class 0.5S per IEC 62053-22), input voltage range of 57.7–480 V AC (phase-to-neutral, supports LV and MV via PT, per IEC 61000-4-30), input current range of 0.05–6 A (for external CTs, overload 2x continuous, per IEC 62053-22), frequency range of 45–65 Hz (nominal 50/60 Hz, per IEC 61000-4-30), power consumption ≤5 W (auxiliary supply, includes communication), auxiliary supply voltage of 24–230 V AC/DC (wide range, galvanically isolated, per IEC 61010-1), operating temperature of -40–85 °C (extended range for outdoor cabinets, per IEC 60068-2-1/2), humidity of 5–95% RH non-condensing (at 40°C, 48h, per IEC 60068-2-78), ingress protection of IP54 (for panel mounting; IP65 optional, per IEC 60529), isolation voltage of 4000 V AC (1 min, between input and output, per IEC 61010-1), communication interface of RS485 (Modbus RTU; optional Ethernet, per IEC 62056-21), and weight of 0.5–1.2 kg (depending on housing and options). Materials on file include silicon (for integrated circuits), FR-4 (PCB substrate), and copper (for traces and connectors). These values are directory references and must be confirmed with the legal manufacturer or supplier for the actual model.
The Measurement Core receives analog voltage and current signals from external sensors such as current transformers (CTs) and potential transformers (PTs). These signals are first conditioned through filtering and amplification to ensure they are within the ADC's input range and free from noise. The conditioned signals are then sampled and converted to digital values by an Analog-to-Digital Converter (ADC) at a rate of at least 4000 Hz to support harmonic analysis up to the 50th order. A digital signal processor (DSP) or microcontroller executes algorithms on the digital data to compute power parameters such as active, reactive, and apparent power, power factor, energy, and harmonic distortion. Calibration factors are applied to correct for sensor and circuit tolerances. The final measurement data is made available for display, communication via RS485 (Modbus RTU) or optional Ethernet, or for control purposes. The component is designed to operate within specified voltage, current, frequency, temperature, and humidity ranges, and provides galvanic isolation between input and output circuits.
