In some temperature control system circuits, widely used is through the thermocouple, RTD or PN junction temperature measurement circuit through the appropriate signal conditioning circuit, converted into A / D converter can receive analog, and then through the sample / hold circuit Perform A/D conversion, and finally send it to the SCM and its corresponding peripheral circuits to complete monitoring. However, traditional signal conditioning circuits are complex, susceptible to interference, difficult to control and have low precision. This paper introduces the design of SCM and DS18B20 water temperature control system. Therefore, the system uses a new type of programmable temperature sensor (DS18B20), which can complete data acquisition and processing directly with SCM without complex signal conditioning circuit and A/D conversion circuit. Easy to implement, high precision, can be used for various occasions according to different needs.
table of Contents
one. introduction
two. aim of design
three. System functions
four. System equipment
Fives. Overall plan and principle of temperature control
1. System module diagram
2. System module total diagram
six. Temperature conversion core and its algorithm
1. Principle and characteristics of temperature sensor DS18B20
Pins and Characteristics of DSl8B20
The internal structure of DS18B20
DS18B20 memory structure
DS18B20 temperature measurement function
DSl820 working process agreement
Temperature sensor and microcontroller communication timing
2. Temperature conversion algorithm and analysis
Seven. Hardware design instructions
1. Overall system circuit diagram
2. Each module circuit diagram
Input system
Output system
Chip system
Eight. Software Design Description
1. General module flow chart
2. The flow chart of each module
Reading the temperature of the DS18B20 module
Keyboard scan processing flow
nine. Operating instructions
Key Function
Display temperature
set temperature
ten. references
Program source code
two. aim of designDesign and produce a water temperature automatic control system, the control object is 1 liters of clean water, the container is enamelware. The water temperature can be manually set within a certain range, and can be automatically controlled when the ambient temperature decreases to keep the set temperature substantially constant.
The use of single-chip AT89S52 intelligent control of water temperature, so that the water temperature can be achieved in the 40-90 degrees control temperature adjustment. Use the instrument to read the water temperature, and adjust the water temperature to the temperature that we input through the keyboard (in the form of heating or cooling) and display the temperature on our seven-segment LED board.
three. System functions1. The temperature can be set freely. At that time, it must be within 0-100 degrees Celsius. When setting, it can display the set temperature value in a timely manner. The temperature can be freely set, the sensor's detection value and setting. The temperature comparison can be displayed on seven segments of light emitting diodes.
2. The temperature is achieved by a 1000w electric furnace. If the temperature is not between 40-90 degrees, "8888" is displayed on the LED, indicating an error.
3. The water temperature can be continuously displayed, and the number of digits displayed is four hundred, one hundred, one, ten, and decimal digits. (But because the rule does not exceed 90 degrees, 100 is not implemented, the default 100 is not displayed)
four. System equipmentME300B Minimum System Board
DS18B20 Digital Temperature Sensor (Integrated A/D Conversion Function)
1000W electric furnace
thermometer
Relay
fan
Water container
Disposable Vape,Disposable Vape Flavours,Disposable Vape Fume,Disposable Vape Flum
Lensen Electronics Co., Ltd , https://www.lensenvape.com