## Technical Overview: AKW401-R The **AKW401-R** is a high-precision digital power meter (KW monitor) developed by Panasonic. It is designed to be DIN-rail mounted and is primarily used for monitoring power consumption in industrial machinery and electrical panels. --- ### 1. Key Electronic Components & Specifications The AKW401-R consists of several internal modules including a micro-controller, high-speed sampling ADCs, and communication interfaces. | Feature | Specification | | :--- | :--- | | **Input Voltage Range** | 100 to 240 V AC / 440 V AC (Depends on wiring) | | **Phase Support** | Single-phase 2-wire, Single-phase 3-wire, 3-phase 3-wire | | **Output Type** | Relay Output (Contact) + RS485 Communication | | **Display Type** | 4-digit, 2-row LCD (Green/Red backlight) | | **Current Measurement** | External CT (Current Transformer) required (5A / 50A / 100A / 250A / 400A / 600A) | | **Accuracy** | Class 1.0 (IEC62053-21) | --- ### 2. Functional Electronic Blocks 1. **Sensing Circuit:** * **Voltage Sensing:** High-impedance voltage dividers reduce the line voltage to levels manageable by the internal ADC. * **Current Sensing:** Utilizes dedicated external **Current Transformers (CTs)**. The secondary current is converted into a proportional voltage signal across an internal burden resistor. 2. **Processing Unit:** * A dedicated **ASIC/Microcontroller** performs True RMS calculations. It integrates instantaneous power (V x I) over time to calculate Active Energy (kWh). 3. **Output & Interface:** * **RS485 Port:** Uses Modbus RTU or MEWTOCOL protocol for data logging to a PLC or PC. * **Pulse/Alarm Output:** An open-collector or relay output that triggers based on specific power thresholds or integrates energy consumption pulses. 4. **Power Supply:** * An internal switching mode power supply (SMPS) converts the AC input to DC for the logic circuits. --- ### 3. Connection Terminals | Terminal ID | Description | | :--- | :--- | | **L1, L2, L3** | Voltage measurement inputs (Phase lines) | | **N** | Neutral line (for single-phase 3-wire) | | **CT1+, CT1- / CT2+, CT2-** | Secondary side connections for Current Transformers | | **RS485 (+, -)** | Serial communication wires | | **Out (R)** | Relay output for alarms or control signals | --- ### 4. Application Logic The device calculates several electrical parameters simultaneously: * **Active Power (kW)** * **Integrated Energy (kWh)** * **Current (A) and Voltage (V)** * **Power Factor (PF)** * **Frequency (Hz)** ---