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  3. PHOENIX CONTACT 2904950

PHOENIX CONTACT 2904950 Safety Relay PSR-MS20-1NO-1DO-24DC-SC

Psr-ms20-1no-1do-24dc-sc Phoenix Contact 2904950 Safety Relay

( Brand: Phoenix Contact ), ( Manufacturer Part Number: 2904950 ), ( Model: PSR-MS20-1NO-1DO-24DC-SC ), ( Type: Safety Relay ), ( Unit Type: Unit ), ( Country Of Origin: Germany )

Review PHOENIX CONTACT Safety Relay

The **Phoenix Contact PSR-MS20-1NO-1DO-24DC-SC Safety Relay** is a high-performance, compact industrial safety relay designed to meet the stringent demands of modern machine and process control applications. Part of Phoenix Contact s **PSR-MS series**, this device integrates seamlessly into safety-critical systems, offering a robust solution for monitoring and controlling hazardous conditions while adhering to the latest safety standards, including **EN ISO 13849-1 (PL e), IEC 61508 (SIL 2), and IEC 62061**. With a **single normally open (NO) safety input channel** and a **single dry-contact output**, this relay ensures reliable signal processing in safety circuits, making it ideal for applications such as emergency stop systems, door interlocks, and machine safeguarding.

The **24V DC supply voltage** ensures compatibility with standard industrial control systems, while the **SC (safety-certified) designation** confirms its compliance with the **SIL 2 (Safety Integrity Level 2) and PL e (Performance Level e) requirements**, providing a high level of protection against catastrophic failures. Its **compact, modular design** allows for easy integration into control panels, reducing installation complexity and space requirements. The relay features **high insulation strength** and **excellent electromagnetic compatibility (EMC)**, ensuring stable operation even in environments with electrical noise or transient surges. Additionally, its **wide operating temperature range** (from **-25 C to 70 C**) makes it suitable for use in harsh industrial settings, including manufacturing plants, automotive assembly lines, and packaging machinery.

Beyond its technical robustness, the **PSR-MS20** stands out for its **user-friendly configuration options**, including **LED status indicators** that provide real-time feedback on the relay s operational state. The **safety-certified output** ensures that the relay can be directly connected to safety-rated actuators, such as safety relays, PLCs, or safety controllers, without compromising system integrity. Phoenix Contact s **built-in diagnostics** further enhance reliability by enabling predictive maintenance and reducing downtime. Whether deployed in a standalone safety circuit or as part of a larger safety PLC architecture, this relay delivers **uncompromising performance, compliance, and operational efficiency**, making it an indispensable component for engineers and safety professionals seeking a dependable solution in critical safety applications.

**Pros and Cons of buying a Phoenix Contact 2904950 PSR-MS20-1NO-1DO-24DC-SC Safety Relay**

### **Pros**

1. **High Reliability and Safety** This is a safety-rated relay designed for use in machine safety applications, complying with international standards such as EN ISO 13849-1 and IEC 62061. It helps prevent hazardous situations by ensuring safe stop functions and interlocking.

2. **Compact and Space-Efficient Design** The PSR-MS20 series is modular and compact, making it suitable for installations where space is limited. This can be particularly useful in automated production lines or control panels with tight constraints.

3. **Wide Input and Output Compatibility** The relay supports a 24V DC input signal and provides a 24V DC output, which is a common voltage level in industrial control systems. This ensures compatibility with most PLCs, safety controllers, and other control devices.

4. **Easy Integration with Safety Systems** It is designed to work seamlessly with Phoenix Contact s safety controllers and other safety components, such as emergency stop devices, light curtains, and safety mats. This simplifies system design and reduces wiring complexity.

5. **Diagnostic Capabilities** The relay includes diagnostic features that allow for monitoring of its status, such as fault detection and safe state verification. This aids in predictive maintenance and reduces downtime by alerting operators to potential issues before they become critical.

6. **Long Lifespan and Durability** Phoenix Contact is known for producing high-quality, long-lasting components. The PSR-MS20 is built to withstand harsh industrial environments, including temperature fluctuations, vibration, and electrical noise.

7. **Compliance with Safety Standards** The relay meets strict safety certification requirements, ensuring that it can be used in applications where human safety is a priority, such as in manufacturing, packaging, or material handling.

8. **Modular and Scalable** The PSR-MS20 series is part of a modular family, allowing for easy expansion or modification of safety circuits as system requirements evolve.

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### **Cons**

1. **Higher Cost Compared to Non-Safety Relays** Safety-rated relays are more expensive than standard industrial relays due to their advanced features, certifications, and compliance testing. This may increase the overall cost of a safety system.

2. **Limited Availability of Spare Parts** While Phoenix Contact is a reputable manufacturer, finding spare parts or replacements for specialized safety relays may be more challenging compared to more common industrial components. This could lead to longer lead times if a replacement is needed.

3. **Complex Installation and Configuration** Safety relays require careful installation and configuration to ensure they function correctly within a safety-rated circuit. Improper setup can compromise safety, so additional training or expertise may be required.

4. **Dependence on Specific Safety Architectures** The relay is optimized for use with Phoenix Contact s safety controllers and systems. If a user is already invested in a different safety architecture (e.g., Siemens, Allen-Bradley, or Omron), integration may require additional adapters or interfaces, adding complexity.

5. **Potential for Overkill in Non-Critical Applications** If a system does not require strict safety certification (e.g., a non-hazardous automation task), purchasing a safety-rated relay may be unnecessary, leading to wasted investment.

6. **Limited Output Current** The relay provides a single normally open (NO) output with a maximum current rating of 2A at 24V DC. For applications requiring higher current or multiple outputs, additional relays or drivers may be needed, increasing system complexity.

7. **Vendor Lock-In Risk** Since the relay is part of Phoenix Contact s ecosystem, migrating to a different safety vendor in the future could require re-engineering the system, leading to additional costs and downtime.

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### **Conclusion**

The Phoenix Contact 2904950 PSR-MS20-1NO-1DO-24DC-SC safety relay is an excellent choice for applications where human safety is a critical concern, such as in industrial automation, machine safeguarding, or process control systems. Its compliance with international safety standards, reliability, and ease of integration with Phoenix Contact s safety products make it a robust solution for safety-critical circuits.

However, the higher cost, potential complexity in installation, and dependence on Phoenix Contact s ecosystem may pose challenges for some users. If budget constraints or non-safety applications are a priority, a standard relay might suffice. For safety-sensitive environments, the benefits far outweigh the drawbacks, making this relay a strong recommendation for professionals requiring certified safety performance.

### **Recommendation**

Purchase the Phoenix Contact 2904950 PSR-MS20-1NO-1DO-24DC-SC safety relay if:

- Your application requires compliance with EN ISO 13849-1 or IEC 62061 standards.

- You are already using or planning to integrate with Phoenix Contact s safety controllers or systems.

- Human safety is a critical factor in your system s operation.

- You prioritize long-term reliability and diagnostic capabilities.

Avoid purchasing this relay if:

- Your application does not require safety certification and a standard relay would suffice.

- You are working with a different safety vendor ecosystem and face potential compatibility issues.

- Budget constraints make the higher cost prohibitive without clear safety benefits.

For most safety-critical industrial applications, the investment in this relay is justified by its ability to enhance safety, reduce downtime, and ensure compliance with regulatory requirements.

Details:

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Phoenix Contact PSR-MS20-1NO-1DO-24DC-SC Safety Relay,: Excess inventory from local company. Fast shipping. Theres no other parts, manuals, software include Tested working order. See pic, no other accessories provided.

part #: 2904950 prices

  • $115.73-$213.21

specifications automationjack:

  • brand: Phoenix Contact
  • mpn: 2904950
  • model: Psr-ms20-1no-1do-24dc-sc
  • type: Safety Relay
  • unit type: Unit
  • country of origin: Germany

seller automationjack:

  • # reviews: 2011 9
  • city: Fremont, California
  • rating: 99.8%

payments automationjack:

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returns automationjack:

  • policy: Returns Accepted
  • paid by: Buyer
  • time: 30 Days
  • method: Money back

offer automationjack:

  • quantity: 1
  • started: March 12, 2026
  • sold: 0
  • options: Ship-to-home
  • availability: In Stock
  • best offers: True

shipping automationjack:

  • cost: $0.00
  • class: Standard
  • carrier: USPS, FedEx
  • transit: 4-7 Days
  • service: USPS Ground Advantage, FedEx Ground / FedEx Home Delivery
  • type: Calculated

general automationjack:

  • Business Industrial > Industrial Automation Motion Controls > Other Automation Equipment
  • condition: Used
type: safety relay, unit type: unit, country of origin: germany,
category: business & industrial > industrial automation motion controls > automation equipment, sku: 14090056769151881,
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3 offers $115.73–$213.21 USD
  • Used. Offer #1 priced at $115.73 + $0.00 shipping estimate = $115.73* total. see pic, no other accessories provided. Tested working order.FREE SHIPPING
  • New. Offer #2 priced at $200.15 + $21.96 shipping estimate = $222.11* total. +$21.96 shipping
  • New. Offer #3 priced at $213.21 + $5.99 shipping estimate = $219.20* total. +$5.99 shipping

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