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.