基于RS-485通信的温度水位远程测控系统
为满足太阳能热水工程远距离测控的需要,设计了一个基于单片机控制的温度和水位远程测控系统。系统的主机和从机均以ATmega16为控制器,二者通过RS-485通信,距离可以超过1 km。用NTC热敏电阻作测温元件,使用单片机内置的10位A/D转换模块实现多路温度的测量。通过非对称式多谐振荡器电路把水位转换为振荡频率,再用计数器测量频率来实现水位的测量。给出了主机和从机的完整电路及功能,较详细地介绍了水位和温度的测量电路以及传感器参数。
Abstract:
To saTIsfy the demand of long-distance control of solar hot water project, a remote measurement and control system of temperature and water level was introduced. ATmega16 was applied as controller in both master and slaver which communicated by RS-485. The communicaTIon distance can exceed 1km. With NTC thermistor as temperature sensor, mulTI-channel water temperature was measured by a 10 bit A/D convertor embedded in ATmega16. An unsymmetrical oscillator was uTIlized to convert the water level to oscillating frequency which was measured by a counter. In this paper, the circuit diagrams and function of master and salver were given, the measurement circuit of water level and temperature and sensors parameters were also introduced in detail.