Research And Development Of Portable Temperature Logger And Its Monitoring System

With the rapid economic development, the scale engineering construction is becoming larger and larger. Meanwhile, the mass concrete arises in quantity in the normal industrial and civil construction buildings. When the mass concrete engineering is under construction, the mass concrete occurs crack because of its acute internal temperature and temperature stress changes caused by cement's heat of hydration. The cracking will either affect the durability of the concrete structure, or even influence the mechanics performance of theconcrete. Thus, To avoid the harmful crack (including concrete shrinkage) through controling the temperature rise temperature differences and the speed of temperature drop is a key problem in construction. The research has indicated that we can control the concrete temperature to prevent the thermal crack. The task is to find how to measure the temperature of the mass concrete.Considering the construction craft and the actuality of monitoring and controling technology of the mass concrete, this work designs a portable thermal monitor as well as its monitoring system.This system which possesses the functions of data memory,print and thermal field assisted analyses can monitor the temperature of concrete reliably, exactly in good time so that the builders can control the concrete crack effectively. Meanwhile, it can provide reliable data for the futureanalysis for controlling temperature and avoiding crack.The paper introduces the origin, monitor meaning and research state of monitoring temperature on mass concrete. Then, presents detailed expatiate on system constructor, hardware and software design. System hardware mostly includes seven parts:SCM, power supply,temperature acquisition, man-machine interface,real-time clock, memory and communication interface. The sensor adopts 1-wire DS18B20; The core of the data acquisition is STC89LE58AD MCU which implements the operation of data acquisition, programmed in assemble language. The monitoring system includes five parts:entry,parameter setting, data acquisition,temperatur reports, system maintenance.programmed in Visual Basic. At last, it summarizes limitations present in the system and presents how to improve the system.The portable logger of temperature and its monitoring system has some features as follows:(1) Itineratly measure to many points and design thousands of test pathways.(2) Having dynamic code function of temperature sensor, the serial points of sensors are easily setted.(3) Automatically identify the number of measurement point and record measurement time of every independent measurement point.(4) The way of independent temperature compensation for sensor can achieve higher measurement accuracy in a greater range.