Here are some key features of the AB Safety Relay 440R-S12R2:

Safety Function: The relay is designed to perform safety functions such as monitoring emergency stop circuits, two-hand control circuits, and guard interlock circuits.

Inputs and Outputs: The relay has four input channels and two normally-open safety outputs. The inputs can accept a variety of input types, including dual-channel inputs and inputs with cross-monitoring capabilities.

Diagnostic Features: The relay includes built-in diagnostics and monitoring capabilities to help detect faults and ensure the integrity of the safety system. It can monitor devices connected to the input channels for faults like wiring errors, short circuits, and open circuits.

Safety Integrity Level (SIL): The 440R-S12R2 safety relay is SIL 3 certified according to the IEC 61508 standard and can be used in safety applications up to SIL 3.