To solve the problems of the traditional RS485 isolation repeater and the features of RS485 communication in coal mine,a RS485 isolation repeater was designed based on magnetic coupling isolation technology and the technology of automatic control between receiving and transmitting was designed.A signal transmission theoretical model of the repeater was established to analyze the principle of data transmission,which proved that signal transmission mechanisms in two cases of the low-frequency and high-frequency were different and both cases can achieve Zero Delay transmission of the RS485 communication. The performance test platform of the repeater was set up to study its data transmission,power and delay characteristics.Through the waveform test,the above theoretical model was verified, through the tests of the power characteristics and the delay time characteristics, the power characteristics and delay characteristics of the repeater were studied in-depth. Through experimental communication tests, the re-peater realized the function of isolated relay RS485 communication.%针对煤矿井下RS485通信特点及传统的RS485隔离中继器存在的问题,研制了基于磁隔离技术及收发自动转换控制技术的RS485隔离中继器.建立了该中继器信号传输理论模型,分析了数据传输状态工作原理,证明其在低频与高频信号传输两种情况下存在不同的机理,但均可实现RS485通信信号的零延时传输.搭建了该中继器性能测试平台,研究了其数据传输、功率及延迟时间特性,通过波形测试,验证了上述理论模型;通过功率特性测试及延迟时间特性测试,深入研究了该中继器的功率特性与延迟时间特性.通过实际通信测试,证明该中继器实现了RS485隔离中继通信功能.
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