Siemens 6EP1961-3BA21 SITOP Redundancy Module

Overview

Core Specifications

• System voltage: DC 24 V (input range 18–30 V DC)
• Input capacity: 2 independent channels, each supports max 20 A power supply input
• Total rated output current: 40 A
• Diode forward voltage drop: Typical 0.45 V, low power loss (approx 34 W at full load)
• Voltage alarm threshold: Adjustable 20–25 V DC for diagnosis signal
• Mounting: Standard 35 mm DIN rail, dimension 70 × 125 × 125 mm
• Protection class: IP20 (cabinet installation only)
• Operating temperature: -25 ℃ ~ +70 ℃ (derate 3%/K above 60 ℃)
• Terminals: Screw-type wiring terminals
• Weight: About 300 g
• Certifications: CE, UL/cUL, ATEX, DNV GL marine certification

Built-in Diagnosis Functions

1. Dual-path LED status indicator
   • Green light: Both input power supplies normal
   • Red light: Single or dual power supply undervoltage/fault
2. Isolated relay changeover contact (8 A / 240 VAC): Remote fault signal output to PLC/HMI, used for upper system alarm monitoring

Key Features

1. High-current decoupling isolation, one power supply short-circuit/failure will not drag down the other power source, bumpless switching without load power loss
2. Low-loss Schottky diode design, less heat generation, no extra cooling fan required, maintenance-free
3. Flexible matching: Supports two 20A SITOP power supplies for 40A total load; parallel multiple modules for higher current expansion
4. Adjustable undervoltage detection threshold, adapts to different on-site power fluctuation environments
5. Reverse current protection, avoids damaged power supply charging back to the intact power unit
6. Compact housing, can be side-by-side installed with SITOP switching power supplies to save cabinet space

Applications

• Redundant power for S7-400H / S7-1500R/F redundant PLC systems
• Process industry: Chemical, thermal power, water treatment, metallurgy continuous production lines
• Heavy machinery: Mine hoists, papermaking main drives, packaging automation
• Safety-related equipment, industrial communication switches, IPC, precision detection instruments, marine automation control cabinets