基于RS-485通信的溫度水位遠(yuǎn)程測(cè)控系統(tǒng)

　　為滿足太陽(yáng)能熱水工程遠(yuǎn)距離測(cè)控的需要，設(shè)計(jì)了一個(gè)基于單片機(jī)控制的溫度和水位遠(yuǎn)程測(cè)控系統(tǒng)。系統(tǒng)的主機(jī)和從機(jī)均以ATmega16為控制器，二者通過(guò)RS-485通信，距離可以超過(guò)1 km。用NTC熱敏電阻作測(cè)溫元件，使用單片機(jī)內(nèi)置的10位A/D轉(zhuǎn)換模塊實(shí)現(xiàn)多路溫度的測(cè)量。通過(guò)非對(duì)稱式多諧振蕩器電路把水位轉(zhuǎn)換為振蕩頻率，再用計(jì)數(shù)器測(cè)量頻率來(lái)實(shí)現(xiàn)水位的測(cè)量。給出了主機(jī)和從機(jī)的完整電路及功能，較詳細(xì)地介紹了水位和溫度的測(cè)量電路以及傳感器參數(shù)。

　　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.

?