為滿足太陽能熱水工程遠距離測控的需要，設計了一個基于單片機控制的溫度和水位遠程測控系統。系統的主機和從機均以ATmega16為控制器，二者通過RS-485通信，距離可以超過1 km。用NTC熱敏電阻作測溫元件，使用單片機內置的10位A/D轉換模塊實現多路溫度的測量。通過非對稱式多諧振蕩器電路把水位轉換為振蕩頻率，再用計數器測量頻率來實現水位的測量。給出了主機和從機的完整電路及功能，較詳細地介紹了水位和溫度的測量電路以及傳感器參數。

　　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.

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