Design Of Far Field Multi-communication System For Static Load Testing Instrument

Static load testing is the most efficient way to measure the pressure of pile foundation in engineering geology experiment. To protect the operators against danger, the concentrator and controller of static load testing system is parted up to 1km. Traditional systems using wire communication way has the disadvantages of using heavy transmission line, difficult to detect and maintain as it has gone wrong, and also some other difficulties. The efficiency and convenience will be promoted greatly if we have changed to wireless way.After analyzing the far field communication technology, this thesis proposes some improvement for the P2P wireless network developed in the last project, and finally designs a communication system suited for static load testing system. In this design, we add a power amplifier circuit to increase the signal transmit distance up to 1km with the power allowed by law, and also achieve the multi-communication purpose with the help of CSMA/CA multi-access method and random back-off algorithm.Besides that, this thesis has also creatively proposed an adaptive protocol of multi-channel network constructing, which solve the problem of multi-system coexistence and spread the scope of usage. The sleep/awake function decreases power consumption and extend the active time of node. Specifically, we solve the second order harmonic interfering problem, which improve the system's performance and stability.At the end of this thesis, we give the detail test result of the system function and performance. The test result indicates that, the system has fully filled the design requirement. The system has already been used successfully in static load testing system, and it can also be applied to power control, water conservancy, traffic, meteorological and industrial control with a brightly future.