Siemens 6EP1961-2BA21 SITOP Redundancy Module for Power Systems

The Siemens 6EP1961-2BA21 SITOP Redundancy Module is a vital component for ensuring uninterrupted power supply in critical industrial applications. This module significantly enhances system reliability by providing seamless power transfer and effective load sharing between multiple SITOP power supplies. Its core advantages lie in its ability to prevent single points of failure, maintain operational continuity during power source anomalies, and offer advanced diagnostics for proactive maintenance. Key technical parameters include its input and output voltage ranges, current carrying capacity, and operating temperature, all designed to meet the stringent demands of industrial environments.

Product Specifications

| Feature                  | Specification                               |

| :----------------------- | :------------------------------------------ |

| Product Type             | SITOP Redundancy Module                     |

| Siemens Order Number     | 6EP1961-2BA21                               |

| Input Voltage            | 24-28 V DC                                  |

| Output Voltage           | 24 V DC                                     |

| Max. Input Current       | 40 A                                        |

| Max. Output Current      | 40 A                                        |

| Module Width             | 50 mm                                       |

| Operating Temperature    | -25 to +70 °C                               |

| Protection Class         | IP20                                        |

| Mounting Type            | DIN rail                                    |

| Status Indication        | LEDs for DC OK, Buffering, Input 1/2        |

| Communication Interface  | None (direct connection)                    |

Core Features & Market Positioning

The Siemens 6EP1961-2BA21 stands out in the power system market due to its robust design and seamless integration capabilities with the broader SITOP power supply portfolio. Its primary function is to enable the parallel connection of two SITOP power supplies to an equally rated load, thereby creating a redundant system that is resilient to individual power supply failures. This redundancy is crucial for applications where downtime is not an option, such as in process automation, manufacturing lines, and critical infrastructure. The module's sophisticated internal circuitry ensures that if one power supply fails, the other immediately takes over the full load without interruption, a feature highly valued in demanding industrial settings. Unlike simpler diode-based solutions, SITOP redundancy modules offer active monitoring and status indication, providing valuable insights into system health.

Key Application Scenarios

This SITOP redundancy module is engineered for industrial environments requiring high power availability. It is commonly deployed in manufacturing facilities to safeguard automated production lines, preventing costly interruptions due to power supply malfunctions. In the chemical and petrochemical industries, where continuous process control is paramount, the 6EP1961-2BA21 ensures that critical control systems remain powered. Furthermore, it finds extensive use in water treatment plants, transportation systems, and building automation, wherever reliable power is essential for safety, operational efficiency, or regulatory compliance. Users frequently search for solutions to protect PLCs, SCADA systems, and other sensitive control equipment from power disturbances.

Practical System Integration Guidance

Integrating the Siemens 6EP1961-2BA21 into a power system is straightforward. It requires the parallel connection of two identical SITOP power supplies to the module's input terminals, with the load connected to the output. For optimal performance and redundancy, it's recommended to use two SITOP power supplies with the same voltage and current rating. The module utilizes integrated diodes to prevent reverse current flow, ensuring proper load sharing and isolation between the power supplies. Wiring should adhere to standard industrial electrical practices, ensuring secure connections for both power input and load output. Status LEDs on the module provide immediate visual feedback on the operational status of each input power supply and the overall DC OK status, simplifying troubleshooting and commissioning.

Operation and Risk Mitigation

The primary operational function of the 6EP1961-2BA21 is to passively monitor the input voltages from two connected power supplies and direct the combined current to the load. In the event of a failure in one input, the module automatically isolates the faulty supply and routes all power through the remaining operational supply. Risk mitigation is inherent in its design; by eliminating a single point of failure at the power supply level, it significantly reduces the probability of system downtime. Potential issues typically relate to incorrect wiring or exceeding the module's current limits. Users should ensure that the total load current does not surpass the 40A rating of the module. The clear LED indicators for "DC OK," "Buffering," and "Input 1/2" statuses provide immediate alerts for abnormal conditions, allowing for timely intervention.

Scalability & Long-Term Value

The Siemens 6EP1961-2BA21 SITOP Redundancy Module offers excellent long-term value through its robust construction and compatibility within the extensive Siemens SITOP power supply ecosystem. While the module itself is not directly scalable in terms of its core function, its value is realized through the ability to easily upgrade or expand the underlying redundant power supplies as power demands increase. The modular design allows for straightforward replacement of individual power supplies without affecting the redundancy setup. Furthermore, its integration with other Siemens industrial automation components facilitates its inclusion in broader digital transformation initiatives, supporting the move towards Industry 4.0 by providing a highly reliable foundation for networked and intelligent systems.

Frequently Asked Questions

What is the primary function of the Siemens 6EP1961-2BA21?

The Siemens 6EP1961-2BA21 SITOP Redundancy Module primarily ensures high power availability by enabling two SITOP power supplies to operate in parallel. It automatically takes over the full load if one power supply fails, preventing system downtime.

This module acts as a crucial safeguard against single points of failure in critical industrial power systems. Its design allows for seamless transition between power sources, maintaining continuous operation of connected equipment. It is a key component for enhancing system reliability and operational uptime.

The redundancy provided by this module is essential for applications where even brief power interruptions can lead to significant financial losses or safety hazards. It is designed for robust performance in demanding industrial environments.

How do I connect two SITOP power supplies to the 6EP1961-2BA21 module?

Connect the positive output terminals of two identical SITOP power supplies to the "DC INPUT 1" and "DC INPUT 2" terminals of the module. Ensure that both power supplies are set to the same output voltage and are rated for sufficient current for the load.

The negative outputs of both power supplies should be connected to a common ground or the negative terminal of the load. The load is then connected to the "DC OUTPUT" terminals of the redundancy module. Always follow proper electrical wiring codes for secure connections.

Double-check all connections before energizing the system. Ensure that the power supplies are correctly phased and that the total load current does not exceed the module's specified maximum output current of 40A.

What happens if one of the connected SITOP power supplies fails?

If one SITOP power supply fails, the Siemens 6EP1961-2BA21 module will automatically detect the loss of voltage or current from that input. It then seamlessly switches the entire load to the remaining operational power supply without interruption.

The module isolates the faulty power supply internally, preventing reverse current from flowing back into it. This ensures that the good power supply can handle the full load independently. The status LEDs on the module will indicate which input has failed.

This automatic failover capability is the core benefit of using a redundancy module, significantly enhancing the reliability of your power system and minimizing the impact of component failure on your operations.

Can I use SITOP power supplies with different current ratings with the 6EP1961-2BA21?

Siemens strongly recommends using two SITOP power supplies with identical voltage and current ratings for optimal performance and load sharing with the 6EP1961-2BA21. Using different current ratings can lead to uneven load distribution.

While the module may technically function with dissimilar supplies, one power supply could be consistently overloaded while the other is underutilized. This reduces efficiency and can shorten the lifespan of the power supplies.

For guaranteed redundancy and longevity of your power system, always select identical power supplies. Consult the SITOP product catalog for compatible models and configurations.

What are the key benefits of using this redundancy module over basic diode OR-ing?

The Siemens 6EP1961-2BA21 offers active monitoring and status signaling, unlike passive diode OR-ing. This provides crucial diagnostic information through LEDs for "DC OK," "Buffering," and input status.

This module provides superior thermal management and efficiency compared to simple diodes, which can generate significant heat and cause voltage drops. The SITOP module is designed for reliable operation across a wide temperature range.

Its intelligent design ensures proper load sharing and minimizes voltage drops, offering a more robust and reliable solution for critical applications where system uptime and diagnostics are paramount.

What is the maximum load current this module can handle?

The Siemens 6EP1961-2BA21 SITOP Redundancy Module is rated for a maximum continuous output current of 40A. It is designed to handle the combined output of two 20A SITOP power supplies or two 40A SITOP power supplies if configured for load sharing.

It's crucial not to exceed this 40A limit, as doing so could lead to module overheating, premature failure, or damage to connected equipment. Always consider the peak load requirements of your application when selecting power supplies and the redundancy module.

Ensure that the total current drawn by your load is always within the specified 40A rating for safe and reliable operation of the entire redundant power system.

How do the status LEDs on the 6EP1961-2BA21 indicate system status?

The "DC OK" LED indicates that the output voltage is within the acceptable range, meaning the load is receiving stable power. "Buffering" typically illuminates when the module is actively balancing current or during a transient condition.

The "Input 1" and "Input 2" LEDs provide direct visual feedback on the status of each connected SITOP power supply. If an input LED is off or red, it signifies a fault or issue with that specific power supply.

These LEDs are essential for quick troubleshooting. They allow operators to immediately identify which power supply, if any, has failed or is experiencing issues, facilitating faster response times.

What is the operating temperature range for this module?

The Siemens 6EP1961-2BA21 SITOP Redundancy Module is designed to operate reliably within a wide ambient temperature range of -25°C to +70°C. This broad range makes it suitable for diverse industrial environments, including those with extreme conditions.

Maintaining operation within this specified temperature range is critical for ensuring the longevity and performance of the module. Avoid exposing it to temperatures outside these limits, which could cause malfunction or permanent damage.

Ensure adequate ventilation around the module and the connected power supplies to help dissipate heat, especially in enclosed control cabinets or when operating near the upper limit of the temperature range.

Can this module be used with other brands of power supplies?

The Siemens 6EP1961-2BA21 is specifically designed and optimized for use with Siemens SITOP power supplies. While it might technically accept inputs from other 24V DC power sources, using non-SITOP power supplies is not recommended.

Using other brands may lead to unpredictable performance, incorrect load sharing, or failure to activate the redundancy function correctly. The module's internal circuitry is calibrated to work with the specific output characteristics of SITOP power supplies.

For guaranteed reliability, safety, and performance, always pair the 6EP1961-2BA21 with genuine Siemens SITOP power supplies that meet the specified voltage and current requirements.

Is programming required to set up this redundancy module?

No, the Siemens 6EP1961-2BA21 SITOP Redundancy Module does not require any programming or complex configuration. It is a plug-and-play device designed for straightforward installation and operation.

Its functionality is based on direct electrical connections and internal circuitry that automatically manages the redundancy logic. The setup involves correct wiring of the input power supplies and the output load.

The module's intelligent design ensures automatic load sharing and failover, making it an easy-to-implement solution for enhancing power system reliability without the need for software or configuration tools.