Journal of South China University of Technology (Natural Science Edition) ›› 2010, Vol. 38 ›› Issue (1): 113-118.doi: 10.3969/j.issn.1000-565X.2010.01.022

• Mechanical Engineering • Previous Articles     Next Articles

Modeling of Time Property and Analysis of Real-Time Optimization for Virtual Instruments

Xu Qin-gui  Liu Gui-xiong  Gao Fu-rong   

  1. 1. School of Mechanical and Automotive Engineering, South China University of Technology, Guangzhou 510640, Guangdong, China; 2. Guangdong Institute of Metrology, Guangzhou 510405, Guangdong, China
  • Received:2009-02-12 Revised:2009-04-02 Online:2010-01-25 Published:2010-01-25
  • Contact: 徐钦桂（1967-），男，在职博士生，东莞理工学院副教授，主要从事仪器仪表和嵌入式系统技术研究． E-mail:xqg@dgut．edu．cn
  • About author:徐钦桂（1967-），男，在职博士生，东莞理工学院副教授，主要从事仪器仪表和嵌入式系统技术研究．
  • Supported by:

    广东省科技攻关重点项目(2007A060304003)；东莞市科技计划项目(2007108101012)

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Abstract:

In multitasking environment, the response time is unpredictable because the execution speed of measurement and control tasks is uncertain. In order to solve this problem, first, a response time model is put forward based on the virtual instrument architecture and the real-time working conditions. Next, real-time measuring indicators are exactly computed via the timing measurement at a microsecond level. Then, the main approaches to real- time performance optimization are proposed and experimentally verified based on the derivation of data-processing delay formula. Finally, an estimation formula for the highest data acquisition frequency is presented based on the analysis of experimental results, which enables virtual instruments to maintain stable response time under the system load as high as that with 80% CPU usage, and thus realizes the constrained optimization of real-time performance.

Key words: virtual instrument, real-time system, constrained optimization, multitasking environment, response time