功能安全浮筒液位变送器可靠性设计与评估

  功能安全仪表对工业生产的安全运行至关重要，根据功能安全相关标准，设计了1001D结构的功能安全浮筒液位变送器。对其硬件电路进行FMEDA分析，得到各模块失效率及安全失效分数SFF，并针对不同的故障模式设计相应的诊断方法，提高了变送器的诊断覆盖率。通过建立马尔可夫模型，对变送器的可靠性进行评估。结果表明，液位变送器安全完整性等级为SIL2，满足功能安全仪表对相关指标的可靠性要求。

 

Reliability Design and Assess of Functional Safety Float Liquid Level Transmitter
 
MA Ben1, SUN Zi-qiang1, LI Qian-ru2
 
1. Key Laboratory of advanced chemical process control and optimization technology of Ministry of Education, East China University of Science and Technology, Shanghai, 200237
 
2. Shanghai automation instrument co., LTD, Shanghai, 200072
 
Abstract ： Functional safety instrument is very important to the operation safety of industrial production ， according to the functional safetyrelated standards, a functional safety float liquid level transmitter with 1oo1D architecture is designed. The failure rate and SFF of each module are obtained by adopting FMEDA for hardware circuits, and for different failure mode, it designs corresponding diagnosis methods to improve diagnostic coverage of the transmitter. The Markov model was established to access the reliability of transmitter. The results show that the Safety Integrity Level of liquid level transmitter is SIL2, meets the reliability requirements of relevant indicators of functional safety instrument.
 
Keywords：Functional Safety Instrument; Liquid Level Transmitter; FMEDA; Markov model; Safety Integrity Level