Description

Application Scenarios

A chemical processing plant in Texas was experiencing recurring production halts due to unexpected failures of single power supplies feeding their Distributed Control System (DCS) cabinets. Every power supply failure triggered a full shutdown of the control loop, costing upwards of $50,000 per hour in lost production. The engineering team retrofitted each cabinet with the Allen-Bradley 1606-XLSRED redundancy module, connecting two identical 24V DC power supplies in a 1+1 redundant configuration. Since the installation, the plant has recorded zero unplanned outages attributed to power supply failure, even during two separate events where individual power units failed silently. The Allen-Bradley 1606-XLSRED switched the load to the backup unit within microseconds, maintaining full system uptime without operator intervention. This scenario highlights how the 1606-XLSRED solves the fundamental pain point of single-point-of-failure in industrial power distribution, delivering true hot-swappable redundancy without complex external diode circuitry.

Parameter

Main Parameters	Value/Description
Product Model	1606-XLSRED
Manufacturer	Rockwell Automation / Allen-Bradley
Product Category	DC Redundancy Module (Decoupling / OR-ing)
Input Voltage Range	10 – 30V DC (rated 24V DC); extended range up to 33V DC for 48V systems
Maximum Continuous Output Current	20 A (at 60°C ambient, derating applies above)
Peak Output Current	25 A for 5 seconds, 32.5 A for 10 ms
Voltage Drop (Typical)	0.78 V at 20 A (lowest in class); 0.65 V at 15 A
Output Power Rating	480 W continuous at 24V DC output
Efficiency	>97% (negligible heat generation due to low forward drop)
Terminal Type	Push-in spring clamp terminals (tool-less wiring), 0.2 – 2.5 mm² wire
Physical Dimensions (H x W x D)	130 x 38 x 105 mm (5.12 x 1.50 x 4.13 inches)
Weight	Approx. 280 g (0.62 lbs)
Mounting Method	35 mm DIN rail (EN 60715) vertical or horizontal
Operating Temperature	-40°C to +70°C (derate linearly above 60°C)
Protection Class	IP20 (finger-safe enclosure)
Certifications	cULus Listed (UL 508), CE, ATEX Zone 2 (II 3 G Ex nA IIC T4 Gc), IECEx, RoHS
MTBF	>1,500,000 hours (Telcordia SR-332)

Technical Principles and Innovative Values

Innovation Point 1 – Active OR-ing with MOSFET Technology: Unlike traditional redundancy solutions that rely on Schottky diodes (which incur significant voltage drops of 1.0–1.5V and generate substantial heat), the Allen-Bradley 1606-XLSRED employs a proprietary active OR-ing circuit based on low-resistance N-channel MOSFETs. This design achieves a typical forward voltage drop of just 0.78V at full load, reducing power dissipation by over 40% compared to diode-based alternatives. The lower heat output allows the module to operate without forced cooling, eliminating fan noise and mechanical wear.Innovation Point 2 – True Galvanic Isolation Between Inputs: Each input channel of the 1606-XLSRED is galvanically isolated from the other, preventing cross-current flow and ground loop formation between the two power supplies. This isolation ensures that if one power supply develops a ground fault or output ripple, the fault cannot propagate to the redundant supply or the connected load. This feature is particularly valuable in safety instrumented systems (SIS) where electrical separation between redundant paths is mandated by standards such as IEC 61508.Innovation Point 3 – Wide Input Voltage Tolerance and Universal Compatibility: The Allen-Bradley 1606-XLSRED accepts input voltages from 10V to 33V DC, making it compatible with 12V, 18V, 24V, and 36V nominal DC systems commonly found in industrial installations. This wide tolerance eliminates the need for different SKUs for different voltage classes, simplifying inventory management for system integrators and end users. The module also supports mixed-input configurations where the primary and backup supplies have slightly different output voltages, automatically balancing the load share without manual adjustment.Innovation Point 4 – Integrated Status Indication with No External Wiring Required: The front panel of the 1606-XLSRED features two bi-color LEDs (green/red) that independently indicate the operational status of each input channel. Green indicates normal operation with voltage present, while red signals a fault or missing input. This built-in diagnostic capability allows maintenance personnel to quickly identify a failed power supply without needing to open the cabinet or connect a multimeter, reducing mean time to repair (MTTR) from hours to minutes.Innovation Point 5 – Compliance with Global Hazardous Area Standards: The 1606-XLSRED carries ATEX II 3G and IECEx certifications for use in Zone 2 gas environments, as well as Class I Division 2 approval for North American installations. This certification coverage makes the module uniquely suited for oil & gas, petrochemical, and pharmaceutical applications where redundant power distribution must meet strict explosion-proof requirements. Few competing redundancy modules offer simultaneous ATEX and NEC hazardous location approvals.

Application Cases and Industry Value

Case 1 – Offshore Oil Platform Emergency Shutdown System (ESD): A major offshore operator in the North Sea upgraded their emergency shutdown (ESD) system to comply with new SIL 2 requirements. The existing single-power-supply architecture posed a risk of spurious trips if the supply failed. The engineering team deployed the Allen-Bradley 1606-XLSRED in each ESD marshalling cabinet, pairing two redundant 24V DC power supplies feeding the safety PLC and solenoid valve drivers. Over 18 months of operation, the platform experienced three power supply failures, all of which were handled transparently by the 1606-XLSRED with zero interruption to the ESD system. The operator reported a 100% reduction in spurious trip events attributable to power loss, saving an estimated $1.2 million in avoided production deferment costs.Case 2 – Automotive Assembly Line Conveyor Control: A Tier-1 automotive supplier in Germany faced frequent stoppages on their main body-in-white conveyor line caused by intermittent power supply glitches affecting the Siemens S7-1500 controllers. The maintenance team installed the Allen-Bradley 1606-XLSRED in the main control panel, combining two Phoenix Contact QUINT power supplies. During a subsequent brownout event where one supply dropped to 19V, the 1606-XLSRED maintained a steady 23.2V output to the PLC rack, preventing a line stop. The plant manager noted that the payback period for the redundancy module investment was less than two weeks, considering the cost of each unplanned line stoppage exceeded €15,000 per hour.