单总线多点测温系统的器件遗漏研究

采用C8051F340为核心,实现一个I/O对多个单总线温度器件DS18B20的测温系统时,发现离主机较远的测温点器件信息未能获取,产生器件遗漏的现象。实验分析发现单总线多点温度测量系统中,总线分布电容和电阻引起单总线上信号衰减,导致离主机较远的温度器件收到的主机指令出现错误。经过大量测试实验,提出改变总线拓扑结构和提升总线电平两种可行方案,有效的解决了多点测温系统中温度器件漏读问题,并且增加了系统单总线长度和温度器件接入数量。

Missing Research of Multipoint Temperature Detecting System by 1-Wire bus

When we take C8051F340 as the core to realize multipoint temperature detecting by DS18B20 through one I/O port. Found that temperature measuring point sensor information not far away from the host access, generating sensor missing phenomenon. It causes the further temperature sensors do not correctly identify the host command that the bus distributed capacitance and resistance damp the bus signal, through the experimental analysis, which result in the missing of sensor. After a lot of tests, Finding that system can improve the voltage increasing the attenuation redundancy and change the network topology declining the Signal attenuation to solve the problem of omission from sensor. Then increase the 1-wire bus length and the number of the connected temperature sensors.