现场总线协议在安全仪表系统中的应用

Field Bus Protocol in Safety Instrument System

安全仪表系统通常设置为独立的系统,并作为生产过程的安全保障被广泛应用在制造、机械、食品加工、化工等行业中。国家及国际标准对组成安全仪表系统的软件及硬件有严格的设计原则,并要求其到达一定的安全完整性等级。为了将现场总线应用到安全仪表系统中,国际电工委员会制定标准规定了一些措施来保证信息传递的完整及可靠,并采用在现场总线原有的OSI参考模型之上增加安全层的软件方式,以符合安全仪表系统的设计原则及安全完整性等级。

Safety instrument system is generally set up as an independent system, and it is taken as the safe guard of production has been widely used in manufacturing, mechanical, food industry and chemical. There are some strict design principles its software and hardware and measure up the given safety integrated level. In order to make field bus used in safety instrument system,International Electrotechnical Commission issued code IEC-61508 which includes some approaches to ensure integrality and reliability of communications, and also includes adding extra safety layer above the original open system interconnection of field bus to accord with the design principles and safety integrated level.