Research On Temperature System Of Precast Beam Based On ZigBee Technology

Precast box girders are widely used in important transportation facilities such as passenger dedicated lines and bridges.In order to ensure the comfort and safety of trains,strict requirements for the quality of precast box girders are put forward.In order to further improve the safety and durability of the box girder,after concrete pouring of box girder,it is necessary to carry out the steam curing for 72 hours.In the process of maintenance,steam volume should be adjusted according to temperature information.If the temperature is not well controlled,it is easy for the box girder to produce different degrees of cracks,which cannot meet the engineering requirements.Therefore,temperature control is very important in the steam curing process of precast box girder.It is necessary to measure the core,surface and ambient temperature of the beam in real time and accurately.In this paper,a wireless temperature monitoring system for precast beam is designed by using ZigBee technology.It can transmit the temperature information to the monitoring center in real time,and facilitate the staff to monitor the temperature at any time.The hardware circuit of wireless node is designed with STM32 processor and AT86RF212 RF chip as the center;The DS18B20 temperature sensor is used to collect key point temperature information and send the temperature data to the coordinator through the wireless node.The coordinator sends the temperature data to the host computer through the serial port;The host computer monitoring interface is programmed by Kingview software,and the collected temperature information is analyzed and processed to realize real-time monitoring,data storage and alarm functions.The design uses the open source Contiki operating system and the FreakZ protocol stack to build a wireless sensor network and transplant it into a wireless node.Then,according to the Zigbee standard protocol,temperature measurement program was added,and Contiki and FreakZ protocol stack codes were modified,which made the modified protocol stack more stable through debugging and completed the wireless transmission of data.By analyzing the Zigbee routing protocol,the routing algorithm of the wireless network is improved and the algorithm is simulated.Use the terminal simulation software to analyze the network command call and network topology,the network test of ZigBee wireless network;Analysis of node transmission path to complete routing algorithm test;After testing,the temperature measurement system has realized the upper computer's processing of uploaded information,real-time display,record preservation and other functions,meeting the design requirements of multi-point wireless temperature measurement of prefabricated box girder.