IEC 60947-5-8:20 20 RLV包含官方IEC国际标准及其红线版本。Redline版本不是官方文档，它只有英文版本，为您提供了一种快速简单的方法来比较IEC官方标准与其以前版本之间的所有变化。 IEC 60947-5-8:20 20规定了三位使能开关的要求。这些开关被用作使能装置的部件以提供信号， -当被激活时，允许通过单独的启动控制来启动机器操作，以及 -当去激活时， --启动停止功能，以及 ——防止启动机器操作。 这第二版取消并取代了2006年出版的第一版。本版构成技术修订版。与上一版相比，此版本包括以下重大技术变更:-由于三位置使能开关的有用应用范围不断扩大，因此对范围说明、操作特性和测试进行了审查； -在附录A中添加了包含使能开关的设备的示例图； -增加了新的附录B，用于确定功能安全应用中使用的开关的可靠性数据的程序。

IEC 60947-5-8:2020 RLV contains both the official IEC International Standard and its Redline version. The Redline version is not an official document, it is available in English only and provides you with a quick and easy way to compare all the changes between the official IEC Standard and its previous edition.

IEC 60947-5-8:2020 specifies requirements for three-position enabling switches. These switches are used as components of enabling devices to provide signals that,
- when activated, allow machine operation to be initiated by a separate start control, and
- when de-activated,
-- initiate a stop function, and
-- prevent initiation of machine operation.
This second edition cancels and replaces the first edition published in 2006. This edition constitutes a technical revision. This edition includes the following significant technical changes with respect to the previous edition:
- due to the increasing range of useful applications of three-position enabling switches, note of scope, operational characteristics and tests are reviewed;
- figures for example of devices incorporating enabling switch are added in Annex A;
- new Annex B for procedure to determine reliability data for the switch used in functional safety applications is added.