SR3D Safety Control Unit – Maximum Safety for Machines and Systems

The SR3D safety control unit allows for the quick and safe shutdown of moving parts of a machine or system in the event of a hazard. With its three safe relay outputs and one auxiliary contact (monitoring contact), it meets the highest safety requirements and is ideal for monitoring emergency stop systems and protective doors.

Applications of the SR3D
The SR3D safety control unit is used in various safety-critical applications, including:

• Emergency stop circuits (single or dual-channel)
• Safety guard monitoring on machines and systems
• Combustion plants in continuous operation according to EN 50156-1 and EN 746-2
• Maritime applications (certified by Germanischer Lloyd)

Key Features and Benefits

• Start behavior:
- Monitored manual start
- Automatic start

• Safety category: Up to PL e, SILCL 3, Category 4
• Cross-fault and ground-fault monitoring to ensure line integrity
• Redundant, diverse relay outputs – 3 safe relay outputs plus 1 auxiliary contact (monitoring contact)
• Connection options:
- Emergency stop buttons
- Safety switches
- Contactless safety switches
- Safety components with OSSD outputs

Functionality and Safety Concept
The SR3D ensures the safe separation of safety circuits according to EN 60204-1. It performs the safety-related stop function up to PL e / SIL 3 according to EN ISO 13849-1 and IEC 61508. In the event of an emergency stop (e.g., triggered by an emergency stop button or an opened protective door), the SR3D immediately interrupts the enabling current paths and stops the machine. Thanks to the force-guided relays, the safety function is maintained even if a failure occurs in the device.

Additional Safety Functions

• Cyclic monitoring of output contacts to detect faults or contact welding
• Feedback loop to monitor downstream contactors or expansion modules
• LED display of the switching state for quick diagnosis and maintenance

Technical Specifications

• Protection class: IP54 (installation in control cabinets required)
• Operating voltage: AC 115 V / 230 V – Maintain a minimum distance of 10 mm to adjacent devices
• Mounting: On a 35 mm DIN rail according to EN 60715 TH35
• Climatic conditions: Ensure heat dissipation in the control cabinet to prevent overheating
• Accessories: Spacers from ZANDER AACHEN (Art.-No. 472596) for defined distance control

Standards and Certifications
The SR3D meets the following standards and safety requirements:

• EN ISO 13849-1 (PL e)
• IEC 61508 (SIL 3)
• EN 60204-1 (safe separation of safety circuits)
• EN 50156-1 / EN 746-2 (combustion plants)
• Certified by TÜV Rheinland and Germanischer Lloyd (Certificate TAE00003JF)

Installation and Setup

• Mounting on a 35 mm DIN rail according to EN 60715 TH35
• Ensure heat dissipation in the control cabinet to prevent overheating
• Maintain a minimum distance of 10 mm to adjacent devices for the AC 115 V / 230 V version

Conclusion
The SR3D safety control unit offers a comprehensive safety solution for machines, systems, combustion plants, and maritime applications. It meets the highest safety standards according to SIL 3 and PL e, ensuring flawless operation with redundant architecture and force-guided relays.