Data Acquisition System Of The Wind Tunnel Designing With MSP430

A data acquisition system (DAS) of the wind tunnel was studied in this paper. The original data acquisition system had a lot of limitation, so the task was to design a new data acquisition system and overcome the limitation, and to ensure the accuracy of the acquired data.The measurement system is the core of the tunnel system, so the accuracy of the result is affected by the data acquisition system immediately. The metrical equipment is the strain gauge balance and the signal sent by the strain gauge balance is at millivolt level. In the original data acquisition system, the signal was transmitted to the data acquisition card in the computer in distance. In the signal transfer process, it was easy to cause interference, so the result was not exact and could not correctly reflect the actual cases. So a new data acquisition system must be designed to eliminate the interference and improve the accuracy of the system.As the development of the computer technique and communications technique, the singlechip-computer mode has been used usually in the data acquisition system. In this way, the system has the merit of redundant reliability, high accuracy and easy operation. Especially the more advanced module type structure is used. Through simply changing modules and programming, a new system can be recomposed according to different application request. Therefore, this method was also selected to design the recent data acquisition system in this research.The singlechip is the core of the system, and it is very important to select a suitable one. In this research, MSP430F149 was selected. With high operational capability and nice hardware disposition, the singlechip can be matched with the system. The serial communication modules of MSP430F149 are powerful. Compared with the traditional serial communication, high-speed service can be realized even in the low clock rate. The singlechip has two serial communication modules: USART0 and USART1. The function of the serial communication modules is very strong and the operation is also convenient.In the new data acquisition system, the signal sent by the strain gauge balance was magnified at 1000 times. Then the signal was sent to MSP430F149 after the A/D transformation. The data was sent to the computer by MSP430F149 through the serial communication modules. In this way, the weak voltage signal was sent in a very short distance. Instead of the weak voltage signal, the digital signal was transmit in the long distance. Therefore the interference of the original system was well controlled, and the stability and accuracy of the data acquisition system was also well ensured.After the new data acquisition system was completed, the practical application test was carried out. The result confirmed that the new system operated steadily, reliably, exactly and meet the actual requirements completely. A set of suitable program was compiled for the recent data acquisition system. The program for the MSP430F149 and the computer was included in the set of program. This part was also introduced in details in this paper.