The LOVATO Electric SR series is a modular family of safety relays launched in 2023, designed to cover the most common risk categories in industrial machinery safeguarding. The series comprises two sub-families: the SRB series, engineered for emergency stops, safety switches, magnetic sensors, and mechanical safety interlocks; and the SRA series, which extends this coverage to two-hand control devices and safety devices with OSSD outputs such as photoelectric barriers, RFID tags, and laser scanners. The SRA series also includes a multifunctional code with a front-panel selector, capable of managing all primary safety functions in a single device. This modular approach, combined with certifications up to PLe/Category 4 (EN/ISO/BS 13849-1) and SIL 3 (IEC 61508), ensures compliance with the most stringent machinery safety regulations.

For two-hand control applications, the SRATH21 model within the SRA series is purpose-built to meet Type IIIC requirements according to EN 574. This function requires that two independent control buttons be pressed synchronously (within 0.5 seconds) to initiate a machine cycle, ensuring that the operator's hands are safely positioned away from the hazardous area. The relay monitors both input channels for consistency and timing. Upon valid synchronous actuation, the two redundant, force-guided normally open (NO) safety outputs are energized. The force-guided contact design ensures that a welded contact on one channel will be detected via the associated PNP auxiliary output, preventing the system from being reset and maintaining the integrity of the safety function. The device provides both automatic and manually monitored reset modes.

The SR series is engineered for practical installation and maintenance. All modules feature special removable screw terminals, which significantly speed up wiring, reduce cabling errors, and simplify module replacement. Front-panel LED indicators provide immediate visual diagnostics for power supply and safety output status, enabling rapid fault-finding on the factory floor. The SRA series modules maintain a slim 22.5mm profile, while the SRB series achieves an ultra-compact 17.8mm width, both optimized for space-saving DIN rail mounting in dense control panels. The front panel is rated IP40 and the terminals IP20, with a pollution degree of 2. The module weighs approximately 0.15kg.

The SR series safety relays operate on a 24VDC auxiliary supply (for SRA series) and carry international homologations, including cULus for the North American market and TÜV for conformity with the Machinery Directive 2006/42/EC. They are ideal for a wide range of industrial safety applications, including emergency stop circuits, safety gate access monitoring, magnetic safety switch integration, and two-hand control stations for presses, stamping machines, and injection molding equipment. By covering numerous applications with a small number of individual codes, the SR series simplifies inventory management while providing uncompromising safety performance.

Technical Specifications