Safety Relays

Part Number	Description / PDF	Quantity
56.OA03.0635S Altech Corporation	OA5603 6V 3NO/5NC AGNI10+5UMAU I	0
8951.3N Altech Corporation	SAFETY RELAY 2CH DPDT 24VDC CONT	0
56.OA70.1222N Altech Corporation	OA567012VDC2NO/2NC CONTACTS AGNI	0
56.OA43.1221N Altech Corporation	OA5643 12VDC2NO/1NC CONTACTS AGN	0
2702924 Phoenix Contact	1 OR 2-CH EXPANSION MOD DIN RAIL	0
56.OW69.1100S Altech Corporation	OW5669110V 2CO AGNI10+5UMAU IP67	0
456.OA01.2422C Altech Corporation	SAFETY MODULE 4 CH 4P10A 24V 2NO	0
7S.34.9.012.4310 Finder Relays, Inc.	SFTY RLY GUIDE 3NO+1NC 6A 12VDC	0
ISS-102ACI-MC Wickmann / Littelfuse	RELAY SAFETY SPST/SPDT 5A 120V	11
56.OA11.2431C Altech Corporation	OA561124V 3NO/1NC AGSN02+02UMAU	2430
56.OA01.1122N Altech Corporation	OA5601110V2NO/2NC AGNI10+2UMAU I	0
8923.3N Altech Corporation	SAFETY RELAY 12V DPDT BUSSED CON	0
56.OW69.2011S Altech Corporation	OW566920V 1NO/1NC AGNI10+5UMAU I	0
2981512 Phoenix Contact	EXTENSION MODULE DIN RAIL	0
56.OW70.1222S Altech Corporation	OW5670 12VDC2NO/2NC CONTACTS AGN	0
8951.4N Altech Corporation	SAFETY RELAY 3CH DPDT 24VDC CONT	0
56.OW70.2431C Altech Corporation	OW5670 24VDC3NO/1NC CONTACTS AGS	0
7S.32.9.024.5110 Finder Relays, Inc.	SFTY RLY GUIDE 1NO+1NC 6A 24VDC	0
456.OA01.1231C Altech Corporation	SAFETY MODULE 4 CH 4P10A 12V 3NO	0
UE23-3MF2A3 SICK	RELAY SAFETY 4PST 8A 230V	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