How to Choose the Right Safety Relay Brand?
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- Zoe
- Issue Time
- Apr 28,2025
Summary
In the field of industrial automation, safety relays are the core components that protect both equipment and personnel. When an existing-brand safety relay needs replacement, how do you choose a compatible substitute? This article will provide you with a systematic selection guide—examining technical compatibility, cost-effectiveness, and after-sales service—while highlighting the characteristics of the market’s leading brands.
Four Common Needs for Replacing Safety Relays
1. Relay Failure
:When the original relay fails during equipment operation, it must be promptly replaced to restore safety functions.2. Discontinued Models
If the originally purchased brand or model has been discontinued, a functionally equivalent replacement is needed.3. Budget Reduction
With tighter procurement budgets, there is a need to lower costs while maintaining safety standards.4. Pursuit of High Cost-Performance
By comparing multiple brands, it’s possible to balance functionality and price to achieve the best return on investment.Four Key Factors in Choosing a Safety Relay Brand
1. Technical Compatibility: Ensure Seamless Integration with Existing Systems
The core function of a safety relay is to monitor safety input signals such as emergency stop buttons, safety door switches, safety light curtains, and two-hand control buttons. Upon detecting any abnormality, it promptly cuts off the power to prevent accidents.
Different brands may vary in functional module design, input/output interface standards, communication protocols, and programming logic, making technical compatibility the primary consideration.
Case Example: If the original system uses a modular safety control system such as the Pilz PNOZ X series expansion modules, the new relay (e.g., DADISICK LS-2A4S) must support similar expansion capabilities and connection methods to ensure seamless functional replacement.
Recommendation: Prioritize brands that:
• Support standardized interfaces (e.g., compliant with IEC 61131 programming standards and EN ISO 13849-1 safety standards)
• Offer flexible input/output configurations
• Are compatible with existing devices like emergency stops, safety doors, and light curtains This minimizes retrofit costs and debugging risks.
2. Cost-Effectiveness: Balance Performance, Functionality, and Budget
• Purchase Cost: Different brands have varying pricing strategies. Modular designs (such as Phoenix Contact's modular relays) allow on-demand function expansion, avoiding unnecessary features and reducing initial investment.
• Functionality Matching: If only basic functions like emergency stop and door monitoring are needed, a single-function relay is sufficient. For more complex needs like speed monitoring or delayed shutdown, a multifunctional relay is necessary—though it comes at a higher price.
• Total Cost of Ownership (TCO): Consider not only the initial purchase cost but also maintenance expenses, spare parts replacement, and potential downtime costs due to failures.
Recommendation: Choose products that offer sufficient functionality and stable performance at a reasonable total cost, instead of blindly pursuing the cheapest or the most feature-rich options.
3. Brand Reliability: Select Brands Proven by the Market and Trusted by the Industry
Since safety relays are directly linked to equipment and personnel safety, brand reliability is crucial. Key points to evaluate:
• Industry History and Experience: For example, Pilz, the inventor of the safety relay, has over 30 years of market validation for its PNOZ series and is highly recognized in industrial automation fields.
• Extensive Application Cases: High-quality brands typically have a wide range of successful applications in industries like automotive manufacturing, packaging machinery, robotics, and electronics manufacturing.
• Certification and Compliance: Check if the products are certified by reputable third parties (such as TÜV) and comply with international safety standards like ISO 13849-1, IEC 62061, SIL3, or PL e.
Recommendation: Choose brands with rich industry experience, complete certifications, and mature technologies to significantly reduce risks associated with product quality issues.
4. After-Sales Service and Technical Support: Ensure Long-Term Reliability
Excellent after-sales service and technical support are critical for smooth project execution and long-term system stability, especially during emergency troubleshooting or system upgrades.
• Delivery and Spare Parts Support: Evaluate whether the brand has a global supply chain network for fast delivery and spare parts availability.
• Technical Documentation and Consultation Services: Check if comprehensive manuals, wiring diagrams, and selection guides are available, and whether one-on-one technical consulting is provided during the selection phase.
• Training and Remote Support: Determine if the manufacturer or distributor offers installation and commissioning training, as well as online remote troubleshooting services, helping customers quickly master product usage.
• Recommendation: Prioritize brands that offer localized technical support and rapid global response services to minimize extra costs caused by delayed after-sales assistance.
Comparison Between Mainstream Safety Relay Brands and DADISICK Safety Relays
DADISICK provides transparent and comprehensive performance comparisons between its safety relays and those of leading brands, assisting customers in making well-informed and objective procurement choices.
Brands | Safety Relay Series | Safety Certification Levels | Features | Monitoring |
| Pilz | PNOZ X series | PL e of EN ISO 13849-1 SIL CL 3 of IEC 62061 ... | Proven reliability and durability in industrial environments; One relay per safety function; Uses voltage-free, dual electromechanical relay technology; Widths from 22.5 mm to 90 mm; Available with 2 to 8 contacts; | Two-Hand Control Button, E-STOP, safety gates, light barriers, Pressure-sensitive mat, Muting controller, Standstill and voltage, Some of the units are suitable for use as safe timer relays |
| Allen Bradley | Guardmaster 440R series | IEC 60204-1
EN ISO 13849-1 (PLe / CAT4) EN ISO 12100
IEC 61508 (SIL CL3) ... | — | Safety Interlock Switches, Pressure-Sensitive Safety Mats, Emergency Stop Devices, OSSD Devices (e.g., Safety Light Curtains), SensaGuard Safety Sensors |
| Phoenix Contact | PSR classic series | EN ISO 13849 (PL e) IEC 61508 (SIL 3) ... | Supports single-channel or dual-channel operation; Automatic or manual reset; Equipped with monitoring start/restart interlock Provides 3 safety output contacts (NO) and 1 signaling output (NC) 24 V DC Operating voltage; | Emergency Stop, Safety Door Switches, Light Grids, Two-Hand Control Devices, Electro-sensitive Protective Equipment, Zero-Speed and Over-Speed Monitoring |
DADISICK | LS-2A4S | EN ISO 13849-1:2015 (PL e / Cat 4)
EN 61508 Parts 1-7:2010 (SIL 3)
EN ISO 13851:2019 (Type IIIC)
EN IEC 60664-1:2020 + AC:2020-12
EN 61326-3-1:2017
EN IEC 62061:2021
EN 61511-1:2017 + A1:2017
EN 60204-1:2018
IEC 60204-1:2021 + AMD1:2021 | 2NO Relay + 4 PNP Transistor Outputs; 24V DC Power Supply; Safety Inputs: 6 (Redundant Safety Inputs); Reset Method: auto/manual reset, configurable via software | Emergency Stop Button, Safety Gate, Safety Mat, Magnetic Switch, Two-Hand Control Button, Safety Light Curtain, Reset Button, Safety switch, Safety sensor, Proximity Switches, Encoders, Encoder Direction, Heartbeat Sensors |
LS-3A1B.C | 3NO + 1NC Relay Outputs; 24V AC/DC Power Supply; Dual-channel safety Inputs; Configurable auto/manual reset; | Emergency Stop Button, Safety Gate, Safety Light Curtain | ||
Ter-A | EN IEC 60947-1:2021
EN 60947-5-1:2017
EN ISO 12100:2010
EN 60204-1:2018
EN 13856-1:2013
EN 62061:2015
EN 13849-1:2015 (Cat 4 / PL e) EN 61496-3:2019 TYPE4 EN IEC 61000-3-2:2019+A1:2021
EN 61000-3-3:2013+A2:2021
EN IEC 61000-6-1:2019
EN IEC 61000-6-3:2021 | 3NO + 1NC Relay Outputs; 24V DC Power Supply; Dual-channel with self-monitoring safety Inputs; Configurable auto/manual reset; Multi-function DIP switch for mode selection; | Emergency Stop Button, Safety Mat, Safety Edge, Two-Hand Control Button, Safety Light Curtain, Safety switch, Safety sensor, Safety laser scanner | |
LS-A | 3NO + 1NC Relay Outputs; 24V DC Power Supply; Dual-channel safety Inputs; Configurable auto/manual reset; | Emergency Stop Button, Two-Hand Control Button, Safety Light Curtain, Safety switch, Safety sensor, Safety laser scanner | ||
QSRN | Designed for safety light curtain; | Safety Light Curtain |
In addition to the major safety relay brands mentioned above, the following brands and product series can also serve as valuable reference points when evaluating the safety relay market:
OMRON G9SX Safety Modules
Schneider Electric Preventa XPS Series
Siemens SIRIUS 3SK Safety Relay Portfolio
Schmersal SRB-E Series Safety Relay Modules
These options offer diverse features, safety functions, and integration capabilities, making them relevant benchmarks during brand or product selection.
DADISICK Industrial Safety Relays for Equipment Monitoring
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For PILZ PNOZ X Series Replacement 24V DC, 24V/115V/110V/230V AC Supply Voltage P2HZ X1 Safety Relay
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Disclaimer: The brands and specifications shown on this page are for product comparison and selection purposes only. Our safety relays are manufactured by DADISICK and are not official products of the listed brands. DADISICK offers replacements compatible with these brands' products. We do not own the rights to any of the mentioned brands. If you need to purchase official brand products, please contact the brand official representative.