The ABB FPNO-21 is a specialized safety relay module designed to enhance electrical safety in industrial automation systems. Part of ABB's Safety product range, this module provides critical protection against hazardous machine movements by monitoring safety circuits and enforcing safe states during emergencies. Engineered for flexibility, it supports configurable safety functions (e.g., emergency stop, light curtains, two-hand control) and integrates seamlessly with programmable logic controllers (PLCs) and other safety devices. Its compact design, combined with robust diagnostics, makes it suitable for applications requiring compliance with global safety standards, including machinery, material handling, and process industries.