Allen‑Bradley 1756-RM2 – Enhanced ControlLogix Redundancy Module

Specifications

• Interfaces: Dual SFP fiber optic ports (LC duplex connector)
• Fiber Speed: 1000 Mbps (1Gbps) single-mode fiber
• Max Transmission Distance: Up to 10 km with matched SFP transceivers
• Sync Switchover Time: ≤20 ms typical bumpless failover
• Backplane Current Draw: 1.16 A @ 5.1 VDC; 3.4 mA @ 24 VDC
• Max Power Dissipation: 6 W (21 BTU/h)
• Compatible Controllers: ControlLogix 5560 / 5570 series (1756-L7x CPU)
• Matching Fiber Cables: 1756-RMC1 (1m), 1756-RMC3 (3m), 1756-RMC10 (10m)
• Status Display: 4-character alphanumeric readout + multi-function diagnostic LEDs
• Slot Requirement: Occupies one standard slot on any 1756 chassis
• Operating Temperature: 0 °C to +60 °C
• Humidity: 5%–95% RH, non-condensing
• Dimensions: 145 × 35 × 120 mm; Weight: ~0.29 kg
• Certifications: UL/cULus, CE, Class A industrial emissions

Key Features

• Enables primary/secondary dual-chassis redundant ControlLogix architecture
• High-speed fiber link synchronizes logic, I/O tags and runtime data between two chassis
• Seamless bumpless switchover without process interruption upon primary chassis/CPU fault
• SFP modular design supports short jumper cables and long-distance remote redundant chassis layouts
• Built-in comprehensive diagnostics for fiber link health, sync status and fault alarms
• Hot-swappable module for maintenance without full system power-down
• Fully configured via Studio 5000 Logix Designer software
• Immune to electrical interference via fiber optic isolation, eliminates EMI sync errors
• One module required per chassis to form a complete redundant pair

Applications

• Mission-critical high-availability industrial control systems
• Oil & gas, power generation, pharmaceutical continuous production
• Water/wastewater treatment, large packaging and automotive assembly lines
• Processes requiring zero downtime and uninterrupted control logic execution