ISO 21919描述了通过使用机器维护设备对至少一台计算机数控（CNC）机器进行自动机器维护的接口。这些接口是自动化机器维护设备和用于生产的机器之间的链接。自动机器维护由机器维护系统或机器启动。 本文档概述并定义了如何设置接口的基本原则。它定义了必要的词汇并设置了信号结构的语法。它区分了安全接口、控制接口和项目特定扩展。 本文档定义了三个一致性类和专用一致性选项。 类别和选项由多个信号组成，可同时: -允许根据项目特定功能范围灵活调整接口； -将信号组绑得足够紧，以避免机器维护设备和机器供应商之间不必要的协调工作。 ISO 21919专注于控制相关和安全相关连接。它不描述机械连接，不确定传输物理、引脚分配、接口硬件或通信措施，例如协议，也不用于与MES（制造执行系统）的通信。 注意ISO 219192涉及安全接口和控制接口，将信号分配给一致性类别和/或一致性选项，描述每个信号的详细功能，在流程图中描述和显示信号之间的时序交互，并显示安全矩阵和安全示例- 相关的功能关系。

ISO 21919 describes interfaces for automated machine tending of at least one computer numerically controlled (CNC) machine by using a machine tending device. These interfaces are the link between automated machine tending devices and machines used for production. The automated machine tending is initiated by either the machine tending system or by the machine. This document gives an overview and defines the fundamental principles on how the interfaces are set up. It defines the necessary vocabulary and sets the syntax for the structure of signals. It distinguishes between the safety interface, the control interface and project specific extensions. This document defines three conformance classes and dedicated conformance options. Classes and options consist of a number of signals to simultaneously: — allow a flexible adaptation of the interface(s) to a project-specific scope of functions; — tie sets of signals tight enough to avoid unnecessary coordination efforts between suppliers of the machine tending devices and machines. ISO 21919 concentrates on the control-related and safety-related connections. It does not describe the mechanical connections, it does not determine the transfer physics, a pin assignment, the hardware of the interfaces or measure of communication, e.g. protocol, and it is not intended to be used for communication to a MES (Manufacturing Execution System). NOTE ISO 21919？2 deals with the safety interface and control interface, allocating signals to a conformance class and/or conformance option, describing the detailed functions of each signal, describing and displaying the timing interactions between signals in flow charts and showing examples for safety matrices and safety-related functional relationships.