The Design And Implementation Of The Monitor System Of Temperature And Humidity Based On PIC16F877

In terms of on analyzing the development and tendency of the technique of humidity checking and micro controller unit(MCU) and intelligent measurement, the monitor system of temperature and humidity based on MCU PIC16F877 is designed. The principle of system design is convenience, good practicability, high reliability and low cost. And then hardware structure and software design of the system are also introduced in detail. A kind of high accuracy process method that be applied in the enviroment temperature and relative humidity measure is proposed in this system. In the range of 1%RH~100%RH the system implement high accuracy measure between ±2%RH on environment humidity,so that the distinguish reach 0.1%RH. To input signal, moving average smoothing is used in order to heighten the lever of confidence of input signal. Moreover we realized humidity autocontrol by means of the parameter optimization of PID, make system control prompt, supertune small, and stable. Using serial communication mode though RS485 interface,we can do communicate with the upper microcomputer(PC) or MCU,whereby measured system can be monitored on real-time.By means of the integrated development environment MPLAB-IDE software, assembling program and off-circuit simulation can be made. Together with using the online-circuit debugger, we can make the system realize the fuctions of in-circuit programming, in-circuit debugging, and down-loading the assembling program, which makes the design and development of the device easier.The result of testing on every section of the system shows that the system can operate in good order, and meet a demand for designing.