safetyrelay

A safety relay is a specialized electrical relay designed to monitor and control safety-related circuits in machinery. It acts as an interface between protective devices—such as emergency stop devices, safety interlocks, light curtains, and safety mats—and the machine control system, ensuring that a hazardous condition triggers a safe shutdown or other protective action.

Safety relays are built to fail safe. They often feature redundancy, self-diagnosis, and contact configurations that promote safe behavior. Many units use forced-guided or positive-opening contacts so that when a fault or power loss occurs, the safety contacts are guaranteed to open, interrupting dangerous current paths. Some models employ two-channel arrangements to monitor signals from separate protective devices, providing improved fault detection and safer final outputs. Auxiliary contacts and status indicators are common to help confirm safe operation.

Standards and performance: Safety relays are designed to meet safety standards such as IEC 62061 and ISO 13849-1, with performance levels or safety integrity considerations appropriate to the application. They undergo testing for electrical and mechanical durability, short-circuit protection, and contact wear. Selection typically depends on the required safety category, response time, load current, and the type of protective device being monitored.

Applications: They are widely used to implement emergency stop circuits, door interlocks, safety gates, light curtains, and safety mats in industrial automation. By converting safe input signals into a clearly defined safe output, safety relays help ensure that machinery de-energizes or enters a safe state when a fault or dangerous condition is detected, and can be integrated with safety controllers or programmable logic controllers to form a broader safety system.