Application of Hangjing HCI 32.768kHz Crystal Oscillator in the Electricity Meter Industry

With the development of smart grid and IoT technology, modern electricity meters are gradually shifting from traditional mechanical to electronic and intelligent. In smart meters, crystal oscillators are one of the core components widely used in system clocks and communication modules, providing critical support for the stable operation of the meter.

1、 The main role of crystal oscillator in electric meters
1. System clock source
The microcontroller (MCU) and metering chip inside the smart meter require a high-precision clock source to ensure the accuracy of data acquisition, metering calculation, and control. As a stable clock source, crystal oscillators can provide accurate frequency signals, ensuring the reliability of data processing.
2. Communication module support
Smart meters typically integrate multiple communication modules, such as RS-485, Zigbee, LoRa, or NB IoT, for data transmission with other devices or backend systems. These modules have strict requirements for the frequency stability and phase noise of clock signals, and crystal oscillators can provide high-quality reference frequencies to ensure communication quality and efficiency.
3. Time synchronization function
Smart meters require recording of electricity usage time and quantity, which places high precision demands on time synchronization. Through the accurate clock signal provided by the crystal oscillator, the electric meter can achieve long-term time measurement stability and avoid data deviation.

2、 The specific application frequency of crystal oscillator in electric meters
The frequency of crystal oscillators used in electric meters depends on their specific functions and application requirements. The following are several commonly used crystal oscillator frequencies in electric meters and their corresponding uses:
1.32.768 kHz
(1) Purpose:
01 is used as a time base for real-time clock (RTC).
02 provides time synchronization function for recording electricity consumption time, calculating electricity consumption, etc.
(2) Characteristics:
01 Low power consumption, high precision, suitable for long-term timing needs.
2.8 MHz / 16 MHz / 20 MHz
(1) Purpose:
01 provides the main clock signal for the microcontroller (MCU), which is used for core functions such as data processing and metering calculations.
(2) Characteristics:
01 intermediate frequency range, suitable for processing data and performing logical operations.
3.26 MHz / 40 MHz
(1) Purpose:
01 is used to provide reference frequency signals for communication modules such as LoRa, Zigbee, NB IoT.
02 Ensure the stability and data transmission efficiency of wireless communication.
(2) Characteristics:
01 High frequency, with good stability and low phase noise.
4.12 MHz / 25 MHz / 50 MHz
(1) Purpose:
01 is used for high-speed data interfaces (such as SPI, UART) or Ethernet modules.
02 supports more multifunctional applications in electricity meters, such as smart home integration or advanced data collection functions.
(2) Characteristics:
01 is suitable for high bandwidth and high-speed data transmission requirements.

3、 Key requirements for crystal oscillator selection
1. Frequency stability
Electricity meters require long-term stable operation, thus requiring crystal oscillators with low frequency drift. Typically, temperature compensated crystal oscillators (TCXOs) or crystal oscillators (XOs) with high stability are used.
2. Operating temperature range
Smart meters may be installed outdoors and must withstand complex environmental tests such as high and low temperatures, as well as changes in humidity. Crystal oscillators need to have a wide temperature range performance (such as -40 ℃ to+85 ℃) to ensure stable operation of the meter under harsh conditions.
3. Anti interference capability
The working environment of electric meters may have strong electromagnetic interference (EMI), requiring crystal oscillators to have high anti-interference performance to avoid signal distortion and data errors.
4. Low power consumption
Smart meters are typically powered by batteries and require the crystal oscillator to have the lowest possible power consumption to extend battery life.
5. Small size
The main board of the electric meter is highly concentrated, and the crystal oscillator is mainly packaged in small-sized SMD3225/3215/2016 sizes
These crystal oscillator frequencies and related functions support the metering, communication, and intelligent functions of the electricity meter, ensuring its stable operation and efficient data processing in complex environments.

4、 32.768kHz domestically produced high stability crystal oscillator
Due to the high requirements for clock stability and consistency in electricity meters, which are used to record electricity consumption time, calculate electricity consumption, etc., clock deviations have a significant impact on users and power companies. Therefore, the majority of the current electricity meter industry still uses Seiko 32.768kHz products.
To solve the problem of domestic substitution, starting from 2023, Hangjing has launched a high stability 3215 32.768kHz crystal oscillator, model: FC31M2-PM-NTLLLDT（Tuning Fork 3.2x1.5 SMD for electricity meter）， It has been tested and verified by multiple electricity meter customers and delivered in bulk.
If you need samples, please contact us at Hangjing!

5、 Future Development Trends
As the electricity meter industry develops towards higher precision and intelligence, crystal oscillator products will pay more attention to miniaturization, low power consumption, high stability, and anti-interference ability. Especially in the context of the increasing demand for intelligent monitoring in the power grid, crystal oscillators will play a more important role in ensuring the stability and reliability of the electricity meter system.
As one of the core components of smart meter systems, crystal oscillators are helping the meter industry move towards a higher quality and higher efficiency future.