Siemens 6EP1961-3BA20 SITOP Modular Redundancy Module

6EP1961-3BA20 is a Siemens SITOP modular redundancy module for two stabilized 24 V DC supplies. It decouples the feeds so the remaining supply can continue powering the load if one supply fails.

6EP1961-3BA20 takes the positive outputs from the two supplies at In 24V-1 and In 24V-2, their negative outputs at Gnd, and feeds the load from Out 24V. Follow the Siemens wiring diagram and size the output conductor for the total current.

6EP1961-3BA20 supports two supplies rated up to 20 A each with one module. Siemens requires two redundancy modules for redundant arrangements using two supplies rated 30 A or 40 A, with one module assigned to each supply.

6EP1961-3BA20 has a rated 24 V DC input, a 22–28.8 V DC operating range and a maximum total output current of 40 A. Siemens gives the output voltage as approximately 0.5 V below the input voltage.

6EP1961-3BA20 uses green and red LEDs plus a floating relay contact to indicate whether both feed voltages exceed the switching threshold. The response threshold can be adjusted from approximately 20 V to 25 V on the module.

6EP1961-3BA20 mounts vertically on a standard DIN rail with its terminals at the bottom. Siemens calls for at least 50 mm clearance above and below the module for cooling, and installation work by qualified personnel with power isolated.

6EP1961-3BA20 should be specified by its complete Siemens order number. Provide the two supply ratings, load current, intended redundancy arrangement, installed cabinet conditions and quantity; confirm whether one or two modules are required for the supply currents.