1. Introduction
The EARU Three-Phase Multifunctional Electric Energy Meter is an advanced electronic energy meter designed for accurate measurement of AC voltage and energy consumption. Utilizing microelectronic technology, imported large-scale integrated circuits, digital acquisition, and SMT processes, these meters meet national standards GB/T117215.321-2008 (IEC 62053-21:2003, IDT) and GB/T17215.322-2008 (IEC 62053-22:2003, IDT).
These meters offer reliable performance, compact size, light weight, and flexible installation, making them suitable for various applications requiring precise energy monitoring.
2. Key Features
- DIN Rail Mounting: Designed for 35mm DIN standard rail installation, compliant with DIN EN-50022.
- High Accuracy: Achieves Level 1 accuracy for active electric energy and Level 2 for reactive electric energy (or Level 0.5 for active energy in some models).
- LCD Display: Clear 6+1 digit LCD display (999999.9 kWh) for easy reading.
- Pulse Output: Passive pulse output conforming to DIN43864 standard, with LED indication.
- Power-off Memory: Data is retained even in the event of a power failure, preventing measurement errors.
- Parameter Query: Quick query function for various parameters.
- RS485 Communication (EA777 only): Equipped with an RS485 communication interface, supporting Modbus communication protocol for remote meter reading and centralized management.
- Comprehensive Measurement (EA777 only): Measures and displays total active/reactive energy, input/output active/reactive energy, three-phase voltage, current, total/phase active power, total/phase power factor, and frequency.
- Bi-Directional Measurement (EA777 only): Capable of measuring energy flow in both directions.
Figure 1: Feature Comparison between EA771 and EA777 Models
3. Technical Specifications
3.1. Model EA771
Figure 2: EA771 Dimensions and Key Parameters
| Parameter | Value |
|---|---|
| Model Number | EA771 |
| Material | Metal + ABS |
| Reference Voltage | 3 X 127/220V, 3 X 220/380V, 3 X 230/400V |
| Reference Current | 3 X 10(100A) |
| Accuracy Level | 1.0 |
| Rated Frequency | 50/60 Hz |
| Constant Pulse | 400 imp/kWh |
| Display Type | LCD 6+1 (999999.9 kWh) |
| Power Consumption | ≤2W, 10VA |
| Starting Current | 0.004Ib |
| Operating Temperature | -20°C ~ +55°C |
| Storage Temperature | -25°C ~ +70°C |
| Operating Voltage Range | 0.9-1.1 Rated Voltage |
| Utmost Voltage Range | 0.7-1.2 Rated Voltage |
| Average Humidity Value | ≤75% |
| Type | Three Phase Four Wire Electronic Type |
| Degree of Protection | IP20 |
| Dimensions | 100mm x 76mm x 65mm |
3.2. Model EA777
Figure 3: EA777 Dimensions and Key Parameters
| Parameter | Value |
|---|---|
| Model Number | EA777 |
| Material | Metal + ABS |
| Rated Voltage | 3 X 127/220V, 3 X 230/400V |
| Max Operating Current | 3 X 5(80)A |
| Accuracy Class | Level 1 and 0.5s |
| Input Frequency | 50/60 Hz |
| Pulse Frequency | 400 imp/kWh |
| Display Type | LCD 6+1 (999999.9 kWh) |
| Power Waste | <2W/10VA Each phase |
| Starting Current | 0.4%Ib |
| Operating Temperature | -10°C ~ +55°C |
| Installation Mode | 35mm standard guide rail installation |
| Phase | Three Phase |
| Power Supply | AC |
| Certification | CE |
4. Installation
4.1. Mounting
The energy meter is designed for 35mm DIN standard rail installation. It can be directly installed in a household lighting distribution box or similar electrical enclosures.
Figure 4: Example of DIN Rail Installation
4.2. Wiring
Ensure all power is disconnected before attempting any wiring. Follow the appropriate wiring diagram for your specific model (EA771 or EA777) and electrical system configuration.
4.2.1. EA771 Wiring
The EA771 model supports both 'Up IN Down Out' and 'Up Out Down In' wiring configurations for the main power lines (A, B, C, N phases).
Figure 5: EA771 Main Power Wiring Options
4.2.2. EA777 RS485 Communication Wiring
For the EA777 model, RS485 communication allows for remote meter reading and centralized management. Connect the RS485 cables to terminals 17 (485B) and 18 (485A) as shown in the diagram. Terminals 15 (P1-) and 16 (P1+) are for pulse output.
Figure 6: EA777 RS485 Communication Wiring
Note: Each RS485 collector can typically collect data from up to 32 meters for centralized management.
Figure 7: Remote Meter Reading Centralized Management
5. Operation
5.1. Display Modes
Both EA771 and EA777 models feature an LCD display that cycles through various measurement parameters. The EA777 model offers a more comprehensive display of parameters due to its advanced features.
Figure 8: EA777 Display Parameters Cycle
Watch the video below for a demonstration of the display cycling and basic operation for both models:
Video 1: Display Cycling and Basic Operation for EA771 and EA777
5.2. Programming Menu (EA777 only)
The upgraded multifunctional EA777 version allows setting parameters such as communication address, baud rate, data format, and current magnification using the integrated buttons.
Figure 9: EA777 Programming Menu and Button Functions
To access and navigate the programming menu:
- Press and hold the 'SET' button for 5 seconds to enter the programming menu.
- Use the 'SET' button to switch between parameters (Address, Baud Rate, Data Format, Current Magnification).
- Use the 'PRESS' button to adjust the value of the selected parameter.
- Long press 'SET' to save the data and exit the programming menu.
6. Maintenance
- Cleaning: Use a soft, dry cloth to clean the meter's exterior. Do not use abrasive cleaners or solvents.
- Inspection: Periodically check for any visible damage to the casing or terminals. Ensure all connections are secure.
- Environment: Ensure the meter is operated within its specified operating temperature and humidity ranges to maintain optimal performance and longevity.
- Calibration: For critical applications, periodic calibration by a qualified technician may be required to ensure continued accuracy.
7. Troubleshooting
7.1. No Display / Meter Not Powering On
- Check the power supply to the meter. Ensure the correct voltage (e.g., 3X230/400V) is applied to the appropriate terminals.
- Verify all wiring connections are secure and correctly installed according to the wiring diagrams.
- Ensure the circuit breaker or fuse protecting the meter is not tripped or blown.
7.2. Incorrect Readings
- Double-check the wiring connections for phase and neutral lines. Incorrect wiring can lead to inaccurate measurements.
- Ensure the meter's specifications (voltage, current) match your electrical system.
- For EA777, verify the current magnification setting in the programming menu is correct if applicable.
- If the issue persists, contact technical support.
7.3. RS485 Communication Issues (EA777 only)
- Verify the RS485 wiring (A and B terminals) is correct and secure.
- Check the communication settings (address, baud rate, data format) in the meter's programming menu and ensure they match the settings of your RS485 collector or master device.
- Ensure there are no conflicts with other devices on the RS485 bus (e.g., duplicate addresses).
8. User Tips
- Remote Monitoring: For the EA777 model, the RS485 interface enables remote monitoring. While the meter itself doesn't connect directly to a mobile phone, it can be integrated into a system with an RS485 collector and a server. This setup allows for data access and control via a computer or a mobile application connected to that server.
- Data Retention: Both models feature power-off memory, ensuring that your energy consumption data is not lost during power outages.
9. Warranty and Support
For warranty information, technical support, or service inquiries, please refer to the product packaging or contact your authorized EARU dealer or customer service representative. Keep your purchase receipt as proof of purchase.
