DSSR122 48990001-NK ABB DCS Power Supply Unit

• Brand
  ABB
• Model
  DSSR122
• Product Name
  Power Supply Unit / Voltage Regulator
• Place of Origin
  Sweden
• Customs HS Code
  85043180
• Part number
  48990001-NK
• Dimensions
  238.5mm × 162mm × 72mm
• Weight
  2.35 kg
• Operating Temperature
  -20°C ~ +70°C
• Storage Temperature
  -60°C ~ +90°C
• Warranty
  12 month
• Product Status
  brand new

Advantages of ABB DSSR122 (48990001-NK)

The DSSR122 is a rack-mounted regulated power supply module engineered exclusively for ABB INFI90 / Symphony DCS and Advant Controller 450 platforms.

Native System Compatibility

It is fully compatible with the backplane of ABB Symphony / INFI90 DCS and supports plug-and-play mounting. It provides stable 5V DC power supply for controllers and I/O modules, avoiding compatibility risks introduced by third-party power units. The module supports both redundant and non-redundant power configurations to satisfy high availability demands for critical process control systems.

Stable High-Current Output

It provides regulated 5V DC output with a maximum current of 40A and high conversion efficiency. It maintains constant voltage output amid load variations, making it suitable for 24/7 continuous operation of high-load DCS racks across process industries.

Comprehensive Built-in Protection

Multiple protective functions are integrated, including overcurrent, overvoltage, undervoltage and overtemperature protection. 1500VDC galvanic isolation is implemented between the input and output sides, which effectively suppresses ground loop interference and protects core DCS hardware against surges and electrical noise from field circuits.

Convenient Diagnosis & Maintenance

LED indicators on the front panel display real-time operating status and fault alarms. Maintenance personnel can rapidly identify abnormal conditions without additional test equipment. Its rack-mounted modular design enables quick replacement to minimize system downtime during maintenance work.

Rugged Industrial Environmental Adaptability

It features a wide operating temperature range of 0°C ~ +60°C. Robust mechanical construction offers resistance to vibration and temperature fluctuations, fitting harsh working environments in power plants, petrochemical plants, pulp & paper mills and metallurgical facilities.

Long-term Field Proven Reliability

It has decades of proven operational history at process control sites worldwide. It qualifies for ABB’s 10-year preventive maintenance scheme, delivering low failure rates and extended service life to cut spare parts expenditure and overall lifecycle maintenance costs.

Compact Modular Structure

Adopting standard rack form factor for easy installation inside control cabinets. Optimized weight and layout simplify cabinet assembly and field wiring work.

Redundant Power Architecture of ABB DSSR122 (48990001-NK)

1. Overall Topology

The system applies a 1+1 hot-standby parallel redundant configuration. Two identical DSSR122 modules are mounted in the same DCS rack with independent 24VDC field power inputs. Both modules convert voltage separately and connect their 5VDC outputs to the unified rack backplane power bus through built-in decoupling diodes. All rack control and I/O loads are powered by the shared backplane bus to implement redundant power backup.

2. Input Side Redundancy Design

Each DSSR122 module is equipped with an independent 24VDC input channel. The two modules can be powered by two isolated upstream power sources such as independent UPS systems or battery groups. This dual-input design eliminates single-point failure of the front-end power supply. If one 24VDC power source fails, the other intact input channel continues normal power supply, ensuring uninterrupted power delivery for the entire DCS rack.

3. Output Diode Decoupling Principle

The integrated decoupling diode serves as the core of the redundant architecture.

Normal operation: Two DSSR122 modules operate in parallel with automatic load sharing, jointly bearing the overall 5V bus load.

Single module fault: When one module fails due to overvoltage, overcurrent, overtemperature or internal hardware abnormality, its internal decoupling diode automatically cuts off reverse current transmission. This isolates the faulty module completely, preventing bus voltage drop or damage to the healthy module. The remaining normal module instantly takes over the full rack load to maintain continuous and stable 5VDC power output.

The diode isolation design thoroughly avoids cross-interference and fault propagation between dual power modules, achieving genuine fault-tolerant power redundancy.

4. Hot-Swap Support

The DSSR122 features a pluggable rack-mounted structure. Under 1+1 redundant operation, individual modules support online hot swapping. Faulty modules can be removed and replaced without powering off the rack or shutting down the DCS system. The standby module maintains full-load power supply throughout the maintenance process, enabling non-stop maintenance and maximizing the continuous operation capability of process production lines.

5. Module Self-Diagnosis and Fault Alarm

Each DSSR122 supports real-time comprehensive monitoring of input voltage, output voltage, load current and internal operating temperature. Front-panel LED indicators intuitively display operating status and fault information. Once a module fails, it triggers local LED alarm signals and uploads fault messages to the DCS controller. The system keeps normal operation while outputting maintenance prompts, and the faulty module is automatically isolated by the decoupling circuit to ensure system safety and stability.

6. Working Modes

Dual-module normal mode: Two modules work in parallel and share the load simultaneously for high-reliability power supply.

Single-module fault mode: The faulty module is electrically isolated; the healthy module bears full load independently with system alarms triggered.

Non-redundant single mode: A single DSSR122 can be used for non-critical racks to meet basic power supply demands.

7. Key Constraints

Redundant parallel operation is only allowed with two identical DSSR122 modules; mixed use of different power module models is prohibited.

The total rack load current must be limited within the 40A rated capacity of a single module, ensuring the standalone module can fully support all loads after single-module failure.

Backplane bus and field wiring must be standardized to minimize 5V bus voltage drop and power loss.

Each module retains 24V input and 5V output galvanic isolation to effectively suppress ground loop interference.

8. Core Advantages of Redundant Architecture

Switch-free seamless switching ensures zero power interruption during single-module failure.

Diode decoupling structure prevents mutual interference and fault coupling between dual power supplies.

Dual independent input channels realize dual-layer redundancy of upstream power source and terminal module.

Hot-swap function eliminates system downtime caused by module maintenance.

Native compatibility with ABB Symphony/INFI90 rack backplanes requires no additional external redundant accessories, simplifying system configuration.

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