Based On The Low Voltage Power Line In The Ward Call System Design

Ward Calling System, consisting of the Alarm-device in the nurse station and the calling-devices in the ward, is an important tools for patients asking doctors or nurses for help. The PLC(Power Line Communication), a telecommunication technology which is developed so fast in the last 20 years, has many advantages such as low-cost, always on-line. So the ward calling system based on PLC, which is proposed in this paper, also has the same advantages as the PLC, and it's capability is also better than the traditional ward calling system.The paper describes the basic concept of ward calling system, the development of PLC and its basic principles(Spread Spectrum Communication Technology), and then shows the hardware design and some software design of the ward calling system based on low-voltage power line communication. Finally, the experimental results and expectation are on the paper. The MCU of the system is AT89S52, and PLC chip is SC1128, which is specially designed for low-voltage power network in China. The system uses the master-slave structure design, and the slave has the function of call, the host has the function of alarm, LED display, and USB communication, both the master and slave can receive and transmit the signal.After schematic design, PCB design, plate making, welding, programming and debugging process, finally the system was tested. on a summary of all the work, the whole system design has achieved the desired results.