基于总线的温度传感网络采集系统设计

Design of temperature sensor network acquisition system based on bus

针对小飞行器狭小空间多温度点高精度测量存在布线复杂和线缆过重的问题,设计了串联总线温度传感网络。温度测量点、中央采集单元和遥测单元均属于总线中的一个节点,该总线满足RS485电气规范。使用恒流源对Pt100进行激励,AD7711实现温度的高精度A/D转换,转换结果经由I2 C总线给MCU进行身份标识和时间标识。中央采集单元获取每个温度测量点的温度进行存储,并和遥测单元进行信息交换,打包各个被测点的温度信号给遥测单元。在不改变中央采集单元的情况下,可在总线上灵活的增减温度测量点。测试结果表明,温度测量节点精度在±0.6℃范围内。线缆重量是星形网络的2/n。

In order to solve the problems of complex wiring and heavy cable in the high-precision measurement of multiple temperature points in the narrow space of small aircraft,a series bus temperature sensor network is designed.Temperature measurement point,central acquisition unit and telemetry unit are all nodes in the bus,which meet the RS485 electrical specifications.Using constant current source to excite PT100,AD7711 realizes high precision A/D conversion of temperature,and the conversion result is identified by I2 C bus to MCU.The central acquisition unit acquires the temperature of each temperature measurement point for storage,exchanges information with the telemetry unit,and packages the temperature signals of each measured point to the telemetry unit.Without changing the central acquisition unit,the temperature measurement points can be added and subtracted flexibly on the bus.The test results show that the accuracy of temperature measurement node is within±0.6℃.The cable weight is 2/n of the star network.