Allen-Bradley 1756-RM Redundancy Module | ControlLogix Redundancy, Hot Backup, IP20 Specs

Allen-Bradley 1756-RM Redundancy Module | ControlLogix Redundancy, Hot Backup, IP20 Specs

Allen-Bradley 1756-RM ControlLogix redundancy module specifications. Hot backup redundancy, 1.5 Gbps sync link, IP20 protection. For high-availability industrial control systems.

Product Overview

The Allen-Bradley 1756-RM​ is a redundancy module​ from the ControlLogix series, designed to provide high-availability, fault-tolerant control systems. This module enables hot backup redundancy​ for ControlLogix processors, allowing automatic switchover between primary and secondary controllers with zero or minimal process interruption. The "1756" designation indicates the ControlLogix module series, "RM" specifies the redundancy module function. This module is essential for critical applications requiring continuous operation, such as power generation, oil and gas, chemical processing, and other process industries where system downtime is unacceptable.

Technical Specifications

Note: Specifications are based on Allen-Bradley 1756 series technical documentation. The "1756-RM" model specifically indicates the redundancy module for ControlLogix systems. Actual specifications may vary slightly depending on production batch.

Model Number Decoding (1756-RM)

• 1756:​ Series designation (ControlLogix module series)

• RM:​ Module type (RM = Redundancy Module)

Note:​ The "RM" designation specifically indicates the redundancy module function. This module works in pairs (one in each redundant chassis) and requires specific ControlLogix processors that support redundancy (1756-L6x, L7x series). It is not a standalone module and is always used in redundant system configurations.

Key Features

• Hot Backup Redundancy:​ Active/standby configuration with automatic failover

• High-Speed Synchronization:​ 1.5 Gbps fiber optic synchronization link

• Zero Data Loss:​ Maintains process data during switchover (properly configured)

• Fast Switchover:​ 20-200 ms typical switchover time

• Automatic Fault Detection:​ Continuous monitoring of primary controller health

• Synchronized I/O:​ Maintains I/O state consistency between controllers

• Diagnostic Indicators:​ Comprehensive LED status for system health monitoring

• Industrial Grade:​ Designed for harsh industrial environments

• Fiber Optic Isolation:​ Electrical isolation between chassis via fiber optic link

• International Certifications:​ Multiple agency approvals for critical applications

• Easy Configuration:​ Configured through Studio 5000 software

System Configuration Requirements

Typical Applications

• Power Generation:​ Turbine control, boiler control, generator protection

• Oil and Gas:​ Pipeline control, refinery processes, offshore platforms

• Chemical Processing:​ Continuous process control, reactor control

• Pharmaceutical:​ Batch process control, critical manufacturing

• Water/Wastewater:​ Plant-wide control, pumping stations

• Nuclear Power:​ Safety systems, auxiliary control

• Metals Processing:​ Continuous casting, rolling mill control

• Pulp and Paper:​ Continuous process lines

• Food and Beverage:​ Critical process control

• Transportation:​ Tunnel control, bridge operations

Important Technical Notes

1. System Requirements:​ Requires matched pair of ControlLogix processors (1756-L6x or L7x) that support redundancy. Both processors must have identical firmware and memory configuration.

2. Chassis Configuration:​ Primary and secondary chassis must have identical module configuration (type, slot position, and firmware).

3. Fiber Optic Cable:​ Use specified 50/125 µm multimode fiber with SC connectors. Maximum length 300m. Protect from physical damage.

4. Module Placement:​ RM module must be installed immediately to the left of the processor in the chassis.

5. Power Supplies:​ Each chassis requires independent, reliable power sources. Consider UPS for critical applications.

6. I/O Configuration:​ I/O modules should be configured for redundant operation where supported. Non-redundant I/O will experience brief interruption during switchover.

7. Network Configuration:​ Network modules should be configured for redundancy where supported (ControlNet, EtherNet/IP).

8. Programming:​ System programmed as single controller. Redundancy configuration done in Studio 5000.

9. Testing:​ Regular testing of redundancy switchover recommended. Test under controlled conditions.

10. Maintenance:​ Monitor system health through diagnostic indicators. Keep firmware updated on both systems.

Note: For complete installation guidelines, wiring diagrams, configuration instructions, and detailed technical data, consult the official Allen-Bradley ControlLogix Redundancy System User Manual. Always verify the exact model number configuration with the manufacturer, as notation variations may occur.