功能安全儀表對(duì)工業(yè)生產(chǎn)的安全運(yùn)行至關(guān)重要，根據(jù)功能安全相關(guān)標(biāo)準(zhǔn)，設(shè)計(jì)了1001D結(jié)構(gòu)的功能安全浮筒液位變送器。對(duì)其硬件電路進(jìn)行FMEDA分析，得到各模塊失效率及安全失效分?jǐn)?shù)SFF，并針對(duì)不同的故障模式設(shè)計(jì)相應(yīng)的診斷方法，提高了變送器的診斷覆蓋率。通過建立馬爾可夫模型，對(duì)變送器的可靠性進(jìn)行評(píng)估。結(jié)果表明，液位變送器安全完整性等級(jí)為SIL2，滿足功能安全儀表對(duì)相關(guān)指標(biāo)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