Design And Implementation Of The Multi-channel Temperature Measuring Instrument

With the development of society and science technology, many products raise more strict requirements on the temperature range and people gradually realize the importance of temperature factors. There are more demands for high precision, quick response and multi point temperature measurement instruments to satisfy the industrial development needs. In view of this situation, this thesis developed a multi-point measurement, real-time, high accuracy temperature measurement instrument; the measurement system can deal with multiple point temperature measurement and will perfectly satisfy the market demand.The design in this thesis is based on the DS18B20and the multi-point temperature measurement system chooses AT89S52single chip microcomputer system as the core. They can conduct the simultaneous measurement of multiple point temperature. Each detection unit acquires the corresponding temperature according to instruction from the main control machine. The measurement results are displayed on the LED digital tube. The main control machine and other units in the whole system can contact and coordinate with each other. The whole temperature measurement system reaches a harmonious, unified status and function of each unit can be independently completed. This thesis gives hardware and software flow of the whole system.The temperature signal can be directly converted into serial digital signals for the further processing conducted by the single chip microcomputer by using DS18B20single line digital temperature sensor. Because each DS18B20has unique64-bit sequence number which cannot be changed, the sequence provides the address of each sensor node, so any number of DS18B20chips can be mounted on a single bus. Only single port interface is needed when reading or writing temperature information from the DS18B20. The power for reading and writing is also supplied from the data bus, so the bus itself can also supply the power for the DS18B20, and no additional power supply is needed. The power can also be supplied by the local3.0V to5.5V power supply. DS18B20provides9to12bit temperature readings, and the lowest weight equivalent to0.5℃to0.0625℃. DS18B20can constitute a multi-point temperature detection system without any external hardware.