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Phone: +86 16626708626Description
Real-World Use & Application Scenarios
In industries where continuous process control and zero downtime are crucial, such as oil and gas, refining, power generation, and pharmaceuticals, the Allen-Bradley 1756-RM2 redundancy module provides a robust solution. It enables two ControlLogix controllers to operate in active-active redundancy, ensuring seamless switchover without interruption in control or data loss. This capability is essential in high-availability systems where any process downtime leads to significant operational or safety risks.
The module is applicable in facility automation systems that require fault-tolerant controllers with high-speed synchronization over distances up to 10 kilometers. It addresses challenges such as rapid channel switchover, data integrity maintenance, and interference-resistant communication between redundant controllers. The 1756-RM2 enhances system durability and operational continuity in mission-critical environments.
Product Introduction & Positioning
The Allen-Bradley 1756-RM2 is an enhanced redundancy module that pairs with another 1756-RM2 module installed in a separate ControlLogix chassis. It facilitates high-speed (up to 1000 Mbps) fiber-optic communication between controllers, supporting synchronization of controller state and I/O data. The module supports controllers in the 5560 and 5570 series and fits in any standard ControlLogix chassis slot.
Engineers value the 1756-RM2 for its advanced features, including low controller switchover times (~20 ms), redundant fiber ports eliminating single points of failure, and interference-free diagnostics. This module enables quick recovery from controller faults and maintains control reliability—key attributes in stringent industrial automation and safety systems.
- 1756-RM2
- 1756-RM2
Key Technical Features & Functional Benefits
The 1756-RM2 supports single-mode 8.5/125 micron fiber-optic LC-type connectors with cable options of 1 m, 3 m, and 10 m lengths, allowing flexible deployment over distances up to 10 kilometers. Its 1000 Mbps transmission rate ensures fast and reliable synchronization of multiple nodes and I/O modules.
The module’s power consumption is approximately 1.16 A at 5.1 V DC and 3.4 mA at 24 V DC, with a maximum power dissipation of 6 W. It provides an open enclosure format and can be installed in any ControlLogix slot, supporting up to seven Ethernet/IP or ControlNet communication modules within the system.
Enhanced diagnostics monitor communication health and fault status continuously, minimizing false alarms and network interference. The module’s thermal dissipation is rated at 21 BTU/hr, manageable in typical industrial cabinet cooling setups.
Detailed Technical Specifications
| Parameter | Value |
|---|---|
| Model | 1756-RM2 |
| Brand | Allen-Bradley |
| Product Type | Enhanced Redundancy Module |
| Compatible Controllers | ControlLogix 5560, 5570 |
| Communication Technology | Fiber-optic single-mode, LC-type connectors |
| Cable Type | 8.5/125 micron single-mode fiber-optic cable |
| Transmission Speed | 1000 Mbps |
| Maximum Distance | Up to 10 kilometers |
| Channels | 1 (transmit and receive fiber) |
| Power Consumption | 1.16 A at 5.1 V DC; 3.4 mA at 24 V DC |
| Power Dissipation | 6 Watts |
| Thermal Dissipation | 21 BTU/hr |
| Dimensions (L x W x H) | 5.51 in x 4.41 in x 5.71 in |
| Operating Temperature | 0 to 60 °C (32 to 140 °F) |
| Enclosure | Open type |
Related Modules or Compatible Units
1756-RM2K – Extended range redundancy module designed for up to 10 km fiber distance.
1756-RM2XT – Extended temperature range redundancy module suited for harsh environments.
1756-L71 – ControlLogix redundant controller module compatible with 1756-RM2.
1756-EN2TR – Ethernet communication module supporting ControlLogix systems.
1756-RMC1/3/10 – Fiber-optic cables of various lengths for redundancy module connections.
Installation Notes & Maintenance Best Practices
Install the 1756-RM2 redundancy module into any slot in a ControlLogix chassis, ensuring proper fiber-optic cable connections with LC-type connectors. Use recommended 1 m, 3 m, or 10 m single-mode fiber cables to establish communication between redundant controllers. Ensure the installation environment complies with temperature and humidity specifications to maintain optimal performance.
Regular maintenance should include visual inspection of fiber connections for cleanliness and integrity and monitoring of module diagnostics through ControlLogix or Studio 5000 software. Prompt troubleshooting of any fault indicators will minimize system downtime. Use authorized replacement cables and modules to preserve communication reliability and adherence to warranty terms.
