Safety Relays

Part Number	Description / PDF	Quantity
56.OA44.6022C Altech Corporation	OA5644 48VDC2NO/2NC CONTACTS AGS	0
56.OA01.1131N Altech Corporation	OA5601110V3NO/1NC AGNI10+2UMAU I	0
256.OA02.1242C Altech Corporation	2 CHANNEL MODULE 6P10A 12V 4NO/2	0
2903261 Phoenix Contact	PSR-SPP-24DC/MXF4/4X1/2X2/B	0
8949.2N Altech Corporation	SAFETY RELAY CONTACT N	0
8951.2S Altech Corporation	SAFETY RELAY 1CH DPDT 24VDC CONT	0
8956.2S Altech Corporation	RM2G4 4 CHANNEL SAFETY RELAY MOD	0
56.OA43.2121N Altech Corporation	OA5643 21VDC2NO/1NC CONTACTS AGN	0
456.OA01.1222C Altech Corporation	SAFETY MODULE 4 CH 4P10A 12V 2NO	0
56.OW70.1231C Altech Corporation	OW5670 12VDC3NO/1NC CONTACTS AGS	0
56.OA67S.1100N Altech Corporation	OA5667S 110V 2CO CONTACTS AGNI10	0
56.OA02.0624N Altech Corporation	OA5602 6V 2NO/4NC AGNI10+2UMAU I	0
1304040000 Weidmuller	SCS 24VDC P1SIL3DS MG3	16
256.OA02.2424C Altech Corporation	2 CHANNEL MODULE 6P10A 24V 2NO/4	0
56.OA44.6031S Altech Corporation	OA5644 60VDC3NO/1NC CONTACTS AGN	0
8924.4C Altech Corporation	SAFETY RELAY 24V DPDT BUSSED CON	0
56.OA43.2421S Altech Corporation	OA5643 24VDC2NO/1NC CONTACTS AGN	0
56.OA22.1233C Altech Corporation	OA5622 12VDC3NO/3NC CONTACTS AGS	0
56.OA01.1122S Altech Corporation	OA5601110V2NO/2NC AGNI10+5UMAU I	0
2903258 Phoenix Contact	PSR-SPP-24DC/MXF3/4X1/2X2/B	0

Safety Relays

1. Overview

Safety relays are specialized control devices designed to ensure fail-safe operation in industrial systems. They monitor safety-related inputs (e.g., emergency stops, light curtains) and trigger protective actions by cutting power to machinery. Compliant with international standards like IEC 61508 and ISO 13849-1, these relays form the backbone of safety instrumented systems (SIS) across automation sectors.

2. Major Types and Functional Classification

Type	Functional Characteristics	Application Examples
Electromagnetic Safety Relays	Mechanical contact-based design with physical separation	Machinery emergency stops, simple safety circuits
Solid-State Safety Relays	Zero-contact semiconductor switching with vibration resistance	Precision equipment, explosive atmosphere environments
Programmable Safety Relays	Configurable logic with diagnostic capabilities	Robotic cells, complex safety interlocking systems
Monitoring Safety Relays	Continuous circuit integrity verification	Safety door interlocks, two-hand control systems

3. Structure and Components

Typical safety relay construction includes:

Enclosure: Flame-retardant polymer housing (UL94 V-0 rated)
Coil System: 24V DC/AC operating with bifilar winding for failure detection
Contact Arrangement: Gold-plated contacts with positive-guided mechanism
Diagnostic Circuitry: Built-in semiconductor for contact state monitoring
Mounting Options: DIN rail or PCB mount with screw/clamp terminal connections

4. Key Technical Parameters

Parameter	Typical Value	Importance
Safety Integrity Level (SIL)	SIL 3 (IEC 61508)	Determines risk reduction factor
Response Time	5-50 ms	Affects machine safe stop performance
Contact Rating	6A @ 250V AC	Dictates load switching capability
MTBF	500,000 hours	System uptime prediction
Environmental Temp	-20 C to +55 C	Operational reliability factor

5. Application Areas

Primary industries include:

Industrial Automation: CNC machines, assembly lines
Energy Systems: Wind turbine safety circuits
Transportation: Rail vehicle door control systems
Medical Equipment: MRI machine emergency cutoffs

Case Study: Automotive Press Line Safety

A major automotive manufacturer implemented safety relays in 1200-ton press machines, achieving PLc (EN ISO 13849-1) compliance through dual-channel emergency stop circuits with 35ms response time.

6. Leading Manufacturers and Products

Manufacturer	Representative Product	Key Features
Siemens	3SK1 Safety Relay	Modular design, PROFINET integration
Schneider Electric	XPSM Safety Relay	Multi-sensor monitoring, SIL3 capable
Omron	G9SP-N Safety Controller	Programmable with 30 pre-defined safety functions
Phoenix Contact	PSR-SCP-24DC-PO Safety Relay	Plug-in module with status visualization

7. Selection Guidelines

Critical selection factors:

Safety Category: Match to application risk assessment (Cat. 2/3/4)
Environmental Conditions: Consider temperature, vibration, and EMC
Certifications: Required standards (CE, UL, T V)
Expansion Capability: Future system scalability
Diagnostic Coverage: Minimum 90% recommended

8. Industry Trends

Emerging developments include:

Integration with Industry 4.0 through IO-Link interfaces
Functional safety for collaborative robots (cobots)
Wireless safety communication protocols
Miniaturization while maintaining IP67 ratings
AI-enhanced predictive maintenance capabilities