IEC 60987:2021提供了仪控系统硬件方面的要求和建议，无论采用何种技术，并以分级方式适用于所有安全等级（如IEC 61513所定义）。本文件指南中定义的要求，尤其是现有组件的选择、系统详细设计和实施的硬件方面以及设备制造。 第三版取消并取代2007年出版的第二版。本版本包括与前一版本相比的以下重大技术变更: a） 修改标题； b） 考虑到硬件要求适用于所有仪控技术，包括传统硬接线设备、可编程数字设备或通过使用这两种设备的组合； c） 使本标准与原子能机构文件SSR-2/1的新修订版保持一致，其中尽可能包括对定义的修改； d） 尽可能替换自第2.1版以来发布的标准相关要求，尤其是IEC 61513、IEC 60880、IEC 62138、IEC 62566和IEC 62566-2； e） 审查现有要求并更新术语和定义； f） 将本标准的范围扩大到所有硬件（计算机化和非计算机化）以及所有安全等级1、2和3； g） 完成、更新IEC和IAEA参考资料和词汇； h） 检查考虑扩展SC 45A范围的其他IAEA要求和建议可能产生的影响； i） 强调IEC 62566和IEC 62566-2在HPD开发中的使用； j） 为预先存在的项目引入具体活动（选择、可接受性和/或缓解）； k） 对电子模块级设计、制造和控制提出更明确的要求； l） 完整的可靠性评估方法； m） 在使用自动化测试或控制活动时引入要求； n） 完整描述制造控制活动（控制过程、制造设备评估、产品保存）； o） 定义并确保包含处理3种不同类别设备和相关要求的分级方法。

IEC 60987:2021 provides requirements and recommendations for the hardware aspects of I&C systems whatever the technology and applies for all safety classes in a graded manner (as defined by IEC 61513). The requirements defined within this document guide, in particular, the selection of pre-existing components, hardware aspects of system detailed design and implementation and equipment manufacturing. This third edition cancels and replaces the second edition published in 2007. This edition includes the following significant technical changes with respect to the previous edition: a) Title modified; b) Take account of the fact that hardware requirements apply to all I&C technologies, including conventional hardwired equipment, programmable digital equipment or by using a combination of both types of equipment; c) Align the standard with the new revisions of IAEA documents SSR-2/1, which include as far as possible an adaptation of the definitions; d) Replace, as far as possible, the requirements associated with standards published since the edition 2.1, especially IEC 61513, IEC 60880, IEC 62138, IEC 62566 and IEC 62566‑2; e) Review the existing requirements and update the terminology and definitions; f) Extend the scope of the standard to all hardware (computerized and non-computerized) and to all safety classes 1, 2 and 3; g) Complete, update the IEC and IAEA references and vocabulary; h) Check possible impact of other IAEA requirements and recommendations considering extension of the scope of SC 45A; i) Highlight the use of IEC 62566 and IEC 62566-2 for HPD development; j) Introduce specific activities for pre-existing items (selection, acceptability and/or mitigation); k) Introduce clearer requirements for electronic module-level design, manufacturing and control; l) Complete reliability assessment methods; m) Introduce requirements when using automated tests or control activities; n) Complete description of manufacturing control activities (control process, assessment of manufactured equipment, preservation of products); o) Define and ensure the inclusion of a graded approach for dealing with the 3 different classes of equipment and related requirements.