总线式温湿度变送器的开发

Exploitation of Bus Temperature-humidity Transmitter

总线式温湿度变送器采用总线式结构,在温湿度采集点数多、分布散、距离监控中心较远的场合,具有较高的性能价格比。系统用一台专用采集器通过一条双绞线可在长达2km的范围内连接多达255只变送器,变送器采用线性标定。模/数转换电路采用精密线性PWM(Pulse Width Modulation)电路,可直接完成模数转换,省去了A/D转换器,提高了系统的精度和可靠性,同时降低了设计成本。系统在仓储、农业种植养殖等领域具有广阔的前景。

The temperature-humidity transmitter adopts bus structure.It has better function and low price when many temperature and humidity spot which need data collection are disperse and far from the control center.The system can connect two hundred and fifty-five transmitters to the twisted-pair within two kilometers through a special collection instrument.The transmitter can be demarcated linearly.The Pulse-Width-Modulation circuit can complete directly A/D transmition,saving the A/D transmitter instrument.The circuit has better linearity,precision and low cost.The system will have wide foreground in storage and breed aquatics about agricultural and so on.