Overview
ISO 21919-2:2021 defines the safety and control interface for automated machine tending - the electrical and logical link between machine tending systems (robots, gantries, AIV/AGV, handling systems) and production machines (CNC machine tools, CMM, 3D scanners, X‑ray machines). The standard allocates signals to conformance classes and conformance options, describes each signal’s function, and displays timing interactions and flow charts to support consistent, safe integration.
Key deliverables in the document include:
- Allocation of interface signals to conformance classes/options
- Detailed signal function descriptions
- Timing and interaction flow charts (Annex C)
- Examples of safety matrices and safety‑related functional relationships (Annex B)
- A normative list of signals (Annex A)
Key topics and technical requirements
- Conformance classes: Three classes are defined to cover different functional scopes-
- Class 1: Minimum set of signals for simple loading/unloading and basic safety
- Class 2: Extended set including coherent/non‑coherent transfer, clamping, guard door functions, and richer status info
- Class 3: Extended set with process optimization features
- Conformance options and project extensions: Options let integrators tailor interfaces to project‑specific functions while keeping interoperability.
- Signal allocation and timing: Signals are grouped and assigned to classes/options; the standard defines signal semantics and timing interactions to avoid supplier coordination issues.
- Safety engineering support: Includes examples of safety matrices and distribution of performance levels (references to PFHD/performance considerations) to help design safety‑related control systems.
Applications and who should use it
ISO 21919-2 is intended for:
- Machine builders and machine tending system suppliers - to implement interoperable safety and control interfaces
- System integrators - to reduce project‑specific interface design and commissioning time
- Plant operators and automation engineers - to specify interface requirements and verify safety behavior
- Functional safety engineers - to map signals to safety functions and evaluate performance levels
Typical use cases:
- Integrating robots or gantries to load/unload CNC machines
- Coordinating clamping and coherent transfer operations
- Standardizing interfaces across multi‑vendor production lines to shorten commissioning and reduce errors
Related standards
ISO 21919-2 references and complements:
- ISO 21919-1 - overview and fundamental principles for automated machine tending interfaces
- ISO 13849-1 and IEC 62061 - safety of machinery and functional safety of control systems
Keywords: ISO 21919-2, safety and control interface, automated machine tending, conformance class, signals, safety matrices, flow charts, CNC integration, machine tending standard.