Designment And Implementation Of Smart Microwave Switch

Smart microwave switch is a non-contact material level meter, providing control signals for PLC or SCAD A systems to realize production automation. The paper discusses the designment and implementation of smart microwave switch on both hardware and software in detail.Smart microwave switch is mainly composed of microwave transmitter and microwave receiver.The microwave transmitter uses multi-level modulation,sents microwave signal intermittently and the total duty cycle is less than2%, relatively to continuous-wave mode it reduces the total work time and increases the life of microwave transmitter module. By adding the feedback circuit microwave signal is controlled by feedback, the output of microwave signal is highly stable. The low-frequency signal of transmitter is adjusted by eight leves, receiver intelligently recognizes the different switch signals.It can solve the problem of mutual interference among many smart microwave switches of the scene.The signal amplification circuit of the receiver uses the three programmable gain amplifier and the optimization algorithm to select the best gain from the224kinds of gain allocation scheme, in order to remove interference of dust and others on detection and detect better of different materials.Receiver demodulates the amplified signal to microwave amplitude signal, low frequency signal,the IF signal and sends them to MSP430F149control core for measuring, measurement results compares with the nominal values respectively, under the minimum risk, by a vote of three judgments (a total of eight kinds of combinations) using valuation theory to determine the path of the microwave beam unblocked/blocked. The experimental results show that the method can accurately identify the microwave signal, provide a reliable basis for output of smart microwave switch.The designment of smart microwave switch can fully meet the design requirements, which was validated by site running test.