Remote automatic meter reading systems are an important indicator of building intelligence. Due to industry barriers and other factors, most residential buildings in Chinese cities still rely on door-to-door meter reading, which wastes a lot of manpower, causes time delays in billing for electricity, water, and gas companies, increases the burden on property management departments, and causes inconvenience to residents. Remote automatic meter reading systems effectively solve these problems. The design uses digital pulse meters for electricity, water, and gas to achieve automatic on-site data collection. The home smart controller collects the pulses emitted by each meter, converts them into actual meter data, and stores it in an e2prom. When the property management center's monitoring computer queries the data, the home smart controller transmits the data to the monitoring computer via the LON network. The LONworks automatic meter reading node and system 's LONworks control unit uses a LONworks main control module based on the Neuron chip. The main control module includes a transceiver, address decoding circuit, reset circuit, crystal oscillator circuit, and e2prom, etc. The main control module transmits data via the Lontalk protocol and performs network message processing, user-defined calculations, and I/O event processing for event scheduling. A schematic diagram of the Lonworks node is shown in Figure 1. The main control module is used for communication and control; the 89C51 microcontroller processes and drives input/output data, counts pulse input signals, and completes data transmission with the main control module. The transceiver in the main control module connects the node to the network. Figure 1: Lonworks node structure diagram. In the meter reading module, an FFT-10 transceiver (Figure 2) can be used, suitable for twisted-pair media; or a PLT22 transceiver (Figure 3) can be used, suitable for power line communication media. Figure 2: Connection diagram of the Neuron chip and FFT-10 transceiver. Figure 3: PLT22 transceiver. The meter reading module collects the output signals of each pulse meter in real time, accumulates the pulse count in the meter reading module's RAM, and accumulates them into different time periods according to the set segment time and the current time, achieving time-segmented counting. The meter reading module's memory has a power-off protection function to prevent the loss of pulse accumulation values ​​in case of power failure. The data concentrator repeatedly polls and collects data from each meter reading module, storing it in the corresponding memory. It automatically filters out illegal data and handles communication anomalies accordingly. The automatic meter reading system has numerous and dispersed data acquisition modules, and the real-time requirements for data transmission are not high, requiring only that each transmitted and received data be error-free. When the host computer collects data, it can directly send the data stored in the concentrator to the computer, without needing to directly read the meter reading data from the meter reading modules. This meter reading module is specifically designed for the automatic reading of water, electricity, and gas meters. Each module reads 24 analog quantities, analyzes their A/D sampling values, identifies the status of the pulse meter, and detects the continuity of the circuit. The communication between the Lonworks bus control module and the 89C51 uses a synchronous serial I/O method, employing a Neurowire master control mode. This means the master control module drives the synchronous clock input and chip select signal output, and the 89C51 receives the synchronous clock input. In the master control module, the Neuron chip's IO8 pin outputs the synchronous clock; IO9 is the serial data output; IO10 is the serial data input; and IO5 is the chip select signal output. The 89C51 uses interrupt mode to transmit data and adds a checksum to the protocol frame to ensure the correctness of the communication data, as shown in Figure 4. Figure 4 Communication wiring diagram between 89C51 and main control module Conclusion The automatic meter reading system consists of a two-level network composed of a community management computer and an automatic meter reading module. It adopts a free topology structure. The real-time readings of water meters, electricity meters and gas meters of each household can be queried on the management microcomputer. The three meters can also be opened and closed at the management center. References: 1. Ma Li, Intelligent Control and LON Network Development Technology, Beijing University of Aeronautics and Astronautics Press, 2003 2. Peng Haixia, Design and Development of Smart Home Network Nodes Based on LONWorks Technology, Modern Electronics Technology, 2005(12): 45-47