The **DRS-3-R** is an industrial-grade, DIN-rail mounted 3-phase energy meter. It is primarily used for monitoring and measuring electrical energy consumption in commercial and industrial environments. Below is an overview of its core electronic components and technical specifications. --- ### 1. Key Electronic Components | Component | Description | | :--- | :--- | | **Current Transformer (CT)** | Internal sensors used to measure the current flowing through each phase without direct series connection for high loads. | | **Microcontroller (MCU)** | The "brain" of the unit that processes analog signals from the voltage and current sensors to calculate energy values (kWh, kVARh). | | **LCD Display** | A digital screen used to visualize energy readings, voltage, current, and power factor. | | **Communication Port** | Usually equipped with an **RS485** interface using the **Modbus RTU** protocol for remote data logging. | | **Pulse Output (SO)** | An opto-isolated transistor output that sends pulses proportional to the energy measured (e.g., 1000 pulses per kWh). | --- ### 2. Technical Specifications | Feature | Specification | | :--- | :--- | | **Connection Type** | 3-Phase 4-Wire (3P4W) | | **Nominal Voltage** | 230V/400V AC (Operating range: 0.8 - 1.2 Un) | | **Current Range** | Usually 5(80)A or 5(100)A (Base current to Max current) | | **Accuracy Class** | Class 1.0 (IEC 62053-21) | | **Frequency** | 50Hz / 60Hz | | **Mounting** | 35mm DIN Rail (Standard EN50022) | --- ### 3. Functional Features #### Data Measurement The electronic circuitry is designed to measure several parameters simultaneously: * **Active Energy (kWh):** Total energy consumed by the load. * **Reactive Energy (kVARh):** Energy stored and discharged by inductive/capacitive loads. * **Real-time Parameters:** Instantaneous values for Voltage (V), Current (I), Power Factor (PF), and Frequency (Hz). #### Security and Durability * **EEPROM Memory:** Non-volatile memory ensures that the cumulative energy data is stored safely even during a power outage. * **Isolation:** High-voltage isolation between the measuring circuits and the communication interface to prevent damage to external monitoring hardware. --- ### 4. Connection Diagram (General) ```text L1 (In) --- [Sensor] --- L1 (Out) L2 (In) --- [Sensor] --- L2 (Out) L3 (In) --- [Sensor] --- L3 (Out) N (In) ---------------- N (Out) Terminals: [ 20 / 21 ] -> RS485 (A / B) [ 22 / 23 ] -> Pulse Output (SO) ```