学习安全仪表系统(SIS)，IEC的相关标准首先要熟读和掌握。IEC的相关标准是鼻祖，其他组织引用、借鉴，甚至是直接翻译。下表列出了IEC/ISA/GB的SIS相关标准。英语水平良好的话，可以读IEC原汁原味标准，然后再拓展到ISA标准。英语费劲的话，读GB标准吧，反正是直接翻译过来的，和IEC标准没有什么大的区别。

IEC(国际电工委员会)
◆IEC 61511-2016
Functional Safety-Safety Instrumented Systems for the Process Industry Sector
◆IEC 61508-2010
Functional safety of electrical/electronic/programmable electronic safety-related systems

ISA(国际自动化协会)
◆ANSI/ISA-61511-2018
Functional Safety-Safety Instrumented Systems for the Process Industry Sector
◆ISA-TR84.00.02-2015
Safety Integrity Level(SIL)Verification of Safety Instrumented Functions

GB(中国国家标准)
◆GB/T 21109-2007
过程工业领域安全仪表系统的功能安全
◆GB/T 20438-2017
电气/电子/可编程电子安全相关系统的功能安全

在IEC官网可查询IEC 61511和IEC 61508版本变更记录，从侧面见证了过程控制的功能安全的一个发展史。其中，IEC 61511-2016=ANSI/ISA-61511-2018=GB/T 21109-2007，也就是说“过程工业领域安全仪表系统的功能安全”方面，我们选取一个熟读即可。ISA旧版“ISA-84.00.01 (IEC 61511: Mod)”已经完全被“ANSI/ISA-61511-2018”取代。

那么“电气/电子/可编程电子安全相关系统的功能安全”方面，IEC 61511-2016=GB/T 21109-2007，我们选取一个熟读即可。ISA 2015年发布的“ISA-TR84.00.02-2015”代替了之前的旧版本，不区分Part，旧版本的Part如下表，我们也了解下。无论新旧版本，ISA和IEC都有不少区别，比如在计算PFD数值方面，采用简化计算公式，应用也很广泛。

ISA旧版本(Part1-5)
Part 1: Introduction
Part 2: Determining the SIL of via Simplified Equations
Part 3: Determining the SIL of a via Fault Tree Analysis
Part 4: Determining the SIL of a via Markov Analysis
Part 5: Determining the PFD of Logic Solvers via Markov Analysis

标准框架
下表列出了两个标准的各个部分，了解其基本内容框架。
1、“过程工业领域安全仪表系统的功能安全”方面
在过程工业中，用来执行仪表安全功能的安全仪表系统已使用了多年。如果要使用仪表能有效地用于仪表安全功能，最重要的是该仪表应达到某些最细标注和性能水平。GB/T 21109-2007包含了作为应用基础的两个概念：安全生命周期和安全完整等级。针对基于使用电气、电子、可编辑电子技术的安全仪表，在逻辑解算器使用其他技术的情况下，须应用GB/T 21109-2007的基本原则。还涉及安全仪表系统的传感器和最终原件，而不管它们所使用的技术。

Safety instrumented systems(SISs)have been used for many years to perform safety instrumented functions (SIFs) in the process industries. If instrumentation is to be effectively used for SIFs, it is essential that this instrumentation achieves certain minimum standards and performance levels.The IEC 61511 series addresses the application of SISs for the process industries. The IEC 61511 series also addresses a process Hazard and Risk Assessment (H&RA) to be carried out to enable the specification for SISs to be derived. Other safety systems' contributions are only considered with respect to the performance requirements for the SIS.The SIS includes all devices necessary to carry out each SIF from sensor(s) to finalelement(s).The IEC 61511 series has two concepts which are fundamental to its application: SIS safety life-cycle and safety integrity levels (SILs).The IEC 61511 series addresses SISs which are based on the  use of electrical/electronic/programmable electronic technology. Where other technologies are used for logic solvers, the basic principles of the IEC 61511 series should be applied to ensure the functional safety requirements are met. The IEC 61511 series also addresses the SIS sensors and final elements regardless of the technology used. The IEC 61511 series is process industry specific within the framework of the IEC 61508 series.

IEC 61511-2016分为三个部分
◆IEC 61511-1:2016+AMD1:2017 CSV
Part 1: Framework, definitions, system, hardware and application programming requirements
◆IEC 61511-2:2016
Part 2: Guidelines for the application of IEC 61511-1:2016
◆IEC 61511-3:2016
Part 3: Guidance for the determination of the required safety integrity levels

ISA ANSI/ISA-61511-2018分为三个部分
◆ANSI/ISA-61511-1-2018 / IEC 61511-1:2016+AMD1:2017 CSV
Part 1: Framework, definitions, system, hardware and application programming requirements
◆ANSI/ISA-61511-2-2018 / IEC 61511-2:2016
Part 2: Guidelines for the application of IEC 61511-1:2016
◆ANSI/ISA-61511-3-2018 / IEC 61511-3:2016
Part 3: Guidance for the determination of the required safety integrity levels

GB/T 21109-2007分为三个部分
◆GB/T 21109.1-2007
第1部分：框架、定义、系统、硬件和软件要求
◆GB/T 21109.2-2007
第2部分：GB/T 21109.1的应用指南
◆GB/T 21109.3-2007
确定要求的安全完整性等级的指南

2、“电气/电子/可编程电子安全相关系统的功能安全”方面
由电气和电子器件构成的系统，多年来在许多应用领域中执行其安全功能。以计算机为基础的系统(一般指可编程电子系统)在其应用领域中用于执行的安全功能，并且也越来越多的用于执行安全功能。GB/T 20438 针对电气、电子、可编程电子组件构成的。用来执行安全工功能的系统安全生命周期的所有活动，提出了一个通用方法。其第六部分，有PFD计算公式。

Systems comprised of electrical and/or electronic elements have been used for many years to perform safety functions in most application sectors. Computer-based systems (generically referred to as programmable electronic systems) are being used in all application sectors to perform non-safety functions and, increasingly, to perform safety functions. If computer system technology is to be effectively and safely exploited, it is essential that those responsible for making decisions have sufficient guidance on the safety aspects on which to make these decisions.This International Standard sets out a generic approach for all safety lifecycle activities for systems comprised of electrical and/or electronic and/or programmable electronic(E/E/PE)elements that are used to perform safety functions. This unified approach has been adopted in order that a rational and consistent technical policy be developed for all electrically-based safety-related systems. A major objective is to facilitate the development of product and application sector international standards based on the IEC 61508 series.

IEC 61508-2010分为七个部分
◆IEC 61508-1:2010
Part 1: General requirements
◆IEC 61508-2:2010
Part 2: Requirements for electrical/electronic/programmable electronic safety-related systems
◆IEC 61508-3:2010
Part 3: Software requirements
◆IEC 61508-3-1:2016
Part 3-1: Software requirements - Reuse of pre-existing software elements to implement all or part of a safety function
◆IEC 61508-4:2010
Part 4: Definitions and abbreviations
◆IEC 61508-5:2010
Part 5: Examples of methods for the determination of safety integrity levels
◆IEC 61508-6:2010
Part 6: Guidelines on the application of IEC 61508-2 and IEC 61508-3
◆IEC 61508-7:2010
Part 7: Overview of techniques and measures

ISA-TR84.00.02-2015不区分Part
Safety Integrity Level (SIL) Verification of Safety Instrumented Functions

GB/T 20438-2017分为七个部分
◆GB/T 20438.1-2017
第1部分：一般要求
◆GB/T 20438.2-2017
第2部分：电气/电子/可编程电子安全相关系统的要求
◆GB/T 20438.3-2017
第3部分：软件要求
◆GB/T 20438.4-2017
第4部分：定义和缩略语
◆GB/T 20438.5-2017
第5部分：确定安全完整性等级的方法示例
◆GB/T 20438.6-2017
第6部分：GB/T 20438.2和GB/T 20438.3的应用指南
◆GB/T 20438.7-2017
第7部分：技术和措施概述

【经验分享】SIS的学习步骤
1、先学习GB/T 21109-2007和GB/T 20438-2017
2、再学习IEC 61511-2016和IEC 61508-2010
3、加强学习ISA-84.00.01和ISA-84.00.02
4、自我总结，同行交流

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