SR3D Safety Control Unit – Maximum Safety for Industrial Applications

The SR3D is a universally applicable safety control unit designed to quickly and safely shut down moving parts of machines or systems in the event of a hazard. With its three safe, redundant, and diverse relay outputs and an additional auxiliary contact, it provides maximum safety and flexibility in safety architecture.

Applications of the SR3D
The SR3D is used in:

• Single or dual-channel emergency stop circuits
• Safety guard monitoring
• Combustion plants in continuous operation in accordance with EN 50156-1 and EN 746-2
• Maritime applications (certified by Germanischer Lloyd)

Functional Features of the SR3D

• 2 possible start behaviors:
- Monitored manual start
- Automatic start

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

Safety Concept
The SR3D allows for 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. If the emergency stop circuit (e.g., triggered by a guard door contact or emergency stop button) is opened, the SR3D immediately interrupts the enabling current paths, safely stopping the machine. Thanks to the redundant design with force-guided relays, the safety function is maintained even in the event of a single failure.

Safety Functions of the SR3D

• Feedback loop to monitor downstream contactors or expansion modules
• Cyclic monitoring of output contacts to detect welded contacts or malfunctions
• LED status display for quick diagnosis and maintenance
• Redundancy through force-guided relays – safety functions remain intact even with a single fault

Technical Specifications

• Protection class: IP54 (installation in control cabinets required)
• Mounting: On a 35 mm DIN rail according to EN 60715 TH35
• Operating voltage: AC 115 V / 230 V – Minimum distance of 10 mm to adjacent devices must be maintained
• Accessories: Spacers from ZANDER AACHEN (Art.-No. 472596) for defined distance control

Certifications and Standards
The SR3D meets the highest safety requirements and is certified according to:

• EN ISO 13849-1 (PL e)
• IEC 61508 (SIL 3)
• EN 60204-1
• Certification by TÜV Rheinland and Germanischer Lloyd

Installation and Setup

• Mounting on 35 mm DIN rail according to EN 60715 TH35.
• Ensure heat dissipation in the control cabinet to avoid 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 comprehensive safety functions, reliability, and easy maintenance. It meets the highest safety standards according to SIL 3 and PL e, making it essential for applications in machine monitoring, combustion plants, and maritime environments. With the SR3D, you are on the safe side – flexible, reliable, and easy to maintain.