Safety Relay – A Safety Solution That Meets Most Automation Industry Requirements
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- Zoe
- Issue Time
- Mar 4,2025
Summary
Utilize safety relays to achieve the safety control functions of the machine, providing real-time monitoring of emergency stop buttons, safety gates, safety light curtains, two-hand control buttons, safety mats, magnetic switches, and reset buttons.
Safety Relay – A Safety Solution That Meets Most Automation Industry Requirements
Functional Definition of Safety Relays
Safety relays are critical execution units in functional safety systems. Through redundant circuit design, real-time self-testing, and force-guided contact mechanisms, they ensure reliable disconnection of equipment power sources and activation of a safe shutdown when hazardous events (e.g., emergency stop activation, safety light curtain interruption) or internal faults are detected. They support multi-channel inputs (e.g., dual-contact emergency stop buttons, safety door interlocks) and logical combinations (e.g., two-hand control, zone interlocking), complying with the Performance Level (PL) requirements defined in ISO 13849-1.
With the advancement of industrial networking, safety relays integrated with protocols such as PROFIsafe and EtherNet/IP CIP Safety enable real-time data exchange with higher-level control systems. They provide fault diagnostics, event logging, and predictive maintenance support, aligning with the dual demands of safety and availability in smart manufacturing applications (e.g., automotive welding lines, safety control systems for packaging machinery).
Relying on Safety Technology Standards
Our safety relays are engineered for the highest level of industrial safety, meeting stringent global standards.
For Example: Safety Relay Module LS-2A4S
Performance Level (PL): PL e, compliant with EN ISO 13849.
Safety Category (Cat.): Cat. 4, compliant with EN ISO 13849.
MTTFd: ≥ 20 years, compliant with EN ISO 13849.
Diagnostic Coverage (DC): ≥ 99%, compliant with EN ISO 13849.
Safety Integrity Level (SIL): SIL 3, compliant with IEC 61508 and IEC 62061.
Hardware Fault Tolerance (HFT): 1, compliant with IEC 61508 and IEC 62061.
Safe Failure Fraction (SFF): ≥ 99%, compliant with IEC 61508 and IEC 62061.
PFHD: ≤ 1.86E-9/h, compliant with IEC 61508 and IEC 62061.
Stop Category: 0, compliant with EN 60204-1.
Safety Relay Wiring Diagram
Quickly and easily integrate various safety sensors into the safety circuits of machines and systems.
Typical Safety Relay Wiring Diagrams：
Safety Relay LS-2A4S
Safety Relay LS-3A1B.C
Four Emergency Stop Button Inputs with Safety Relay Module
Description:
Input Components: CH1 (Emergency Stop Button); CH2 (Emergency Stop Button); CH3 (Reset Button)
Input Components: CH4 (Emergency Stop Button); CH5 (Emergency Stop Button); CH6 (Reset Button)
Control Logic: CH1 & CH2, CH4 & CH5
Reset Mode: Manual Reset
Output Delay: 0 s
Safety Category: Cat. 4
Performance Level: PL e
Safety Integrity Level: SIL 3
Dual-Channel Emergency Stop Button Input with Safety Relay
Description:
Dual-Channel Emergency Stop Button Input
Short-Circuit Monitoring Between Channels
Manual Reset
With Output Contact Feedback
Suitable for the Highest Safety Category 4
Components:
S1: Dual-Channel Emergency Stop Button
S3: Reset Button
K7, K8: Contactors
F1: External Fuse Protection
M1: Motor
How to Find the Right Safety Relay for Your Application
1️⃣Safety Zones/Number of Safety Functions
2️⃣Expandable Safety Relays
3️⃣Power Supply Voltage
4️⃣Configurable Parameters
5️⃣Compact Design
DADISICK Safety Relay Features Overview
LS-3A1B.C – Cost-effective solution
Suitable for various machinery, compatible with emergency stop buttons, safety doors, and PNP-type safety light curtains.
▪️Dimension: 114.5 × 99 × 22.5 mm
▪️Outputs: 3 NO (Normally Open) safety outputs, 1 NC (Normally Closed) auxiliary output
▪️Functions: Supports single/dual-channel operation, manual/automatic reset, and short-circuit monitoring between channels
▪️Key Feature: Economical and efficient, ideal for standard machine safety applications
LS-2A4S – Safety relay module
Designed for intelligent safety control, supporting multiple switching-type safety device inputs.
▪️Dimension: 114.5 × 99 × 45 mm
▪️Inputs: Supports up to 6 safety device inputs (such as emergency stop buttons, safety doors, two-hand switches, etc.)
▪️Outputs: 2 relay safety outputs, 4 semiconductor safety outputs
▪️Functions: Safety logic can be configured via software to meet various application requirements
▪️Key Feature: Flexible and expandable, suitable for complex safety systems
Ter-A – Multi-Type Safety Sensor Compatibility
Supports a wide range of safety sensors, making it ideal for multi-sensor applications.
▪️Dimension: 112 × 99.5 ×22.6 mm
▪️Compatible Devices: Emergency stop buttons, Safety switches, Safety door locks, Safety light curtains, Safety scanners, Safety sensors, Safety edges, Safety mats, Two-hand switches
▪️Key Feature: Highly compatible with various safety detection devices, suitable for complex industrial safety control
LS-A – Economical Safety Relay
Designed for basic safety control, compatible with standard safety devices such as emergency stop buttons and safety door locks.
▪️Dimension: 114.5 × 99 × 22.5 mm
▪️Compatible Devices: Emergency stop buttons, Safety switches, Safety door locks, Safety light curtains, Safety scanners, Two-hand switches, Safety sensors
▪️Key Feature: High cost-performance ratio and simple design, ideal for standard safety applications
QSRN – Specifically designed for safety light curtains
Specifically designed for monitoring safety light curtains, ensuring reliable detection performance.
▪️Dimension: 117 × 100 × 22.5 mm
Recommended Safety Relays
Supports up to 6 safety device inputs, 2 relay safety outputs, and 4 semiconductor safety outputs. Configurable via setup software to define safety control logic, meeting various on-site application requirements.
A safety relay with 3 NO (normally open) safety output contacts and 1 NC (normally closed) auxiliary output contact. It supports single or dual-channel operation, manual or automatic reset, and features short-circuit monitoring between channels.
3NO + 1NC safety contacts
Auto/manual reset option
Redundant self-monitoring circuit ensures reliability
Automatic contact testing in each cycle
3NO + 1NC safety contacts
Auto/manual reset option
Configurable for E-stop, light curtains, door locks, and two-hand control switches
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Beam spacing: 30mm
Number of optical axes: 42
Protection height: 1230mm
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