The Input Expanders by Schmersal are engineered to provide scalable and reliable expansion of safety input channels in machine safety systems. These modules are part of the PROTECT SRB-E series, designed to connect multiple safety devices such as emergency stop switches, safety sensors, guard switches, and interlocks to a central safety controller.
In complex automation environments, connecting each safety device individually can increase wiring complexity and installation time. Input expanders solve this by enabling series connection of multiple safety devices via a single interface, reducing wiring effort while maintaining high safety integrity.
These modules evaluate signals from both electromechanical contacts and electronic OSSD outputs, ensuring accurate and reliable signal processing. The integrated electronics safely combine (AND-link) multiple input signals, ensuring that machine operation is permitted only when all safety conditions are satisfied.
Schmersal input expanders are designed for installation in control cabinets (DIN rail mounting) and offer flexible configuration options for different machine safety requirements. With high safety ratings up to Category 4 / Performance Level e (PL e) / SIL 3, they are suitable for critical safety applications in industrial automation.
Advanced variants also support multiple sensor connections (e.g., monitoring up to 4 safety devices), signalling outputs, and easy integration with PLCs and safety controllers, making them ideal for both simple and complex automation systems.
Key Features & Specifications
• Expansion of safety inputs for machine safety systems
• Series connection of multiple safety devices via a single interface
• Compatible with safety switches, sensors, interlocks, and E-STOP devices
• Supports both contact outputs and electronic OSSD signals
• Safe signal evaluation and AND-linking of inputs for reliable operation
• High safety performance (up to Cat. 4 / PL e / SIL 3)
• Available in SRB-E multifunctional safety relay modules
• Multiple input and signalling output options (model dependent)
• Reduced wiring complexity and installation time
• DIN rail mounting for easy panel installation
• Compatible with PLC and safety control systems
Applications
Input Expanders by Schmersal are widely used in:
• Industrial automation and machine safety systems
• Conveyor and material handling equipment
• Robotic work cells and automated production lines
• Packaging and processing machinery
• Machine guard and safety door monitoring
• Complex systems requiring multiple safety inputs
The Input Expanders by Schmersal provide a flexible and efficient solution for expanding safety systems, enabling reliable connection of multiple safety devices while reducing wiring effort and ensuring high-performance safety compliance in modern industrial automation environments.
