The Core Hardware for Mission-Critical Control System Redundancy

Technical Specifications

Main Features and Advantages

Engineered for Maximum System Availability: The primary advantage of the HONEYWELL 900RR0-0101​ is its fault-tolerant architecture. It is specifically designed to facilitate a true 1:1 hot-backup redundancy scheme. Within this assembly, the primary and secondary CPU modules operate in lockstep, with the standby unit continuously synchronizing its memory and process image with the active unit via a dedicated, high-speed synchronization link. The 900RR0-0101 Rack Assembly​ contains the necessary hardware and firmware to constantly monitor the health of both CPUs. If a fault is detected in the active controller—whether a processor failure, memory error, or power issue—the assembly’s control logic orchestrates a sub-second, bumpless transfer of control to the healthy standby CPU. This process is transparent to the plant process, preventing trips or disruptions and delivering exceptional availability.Integrated and Simplified Redundancy Deployment: The HONEYWELL 900RR0-0101​ provides a fully integrated solution that dramatically simplifies the engineering, installation, and maintenance of a redundant control system. Instead of sourcing and wiring individual components like separate power supplies, synchronization modules, and complex cabling, this assembly comes as a cohesive, pre-configured unit. This integration reduces design complexity, minimizes wiring errors, and cuts commissioning time. The robust chassis offers superior protection against electromagnetic interference (EMI) and provides organized cable management. Furthermore, the assembly supports online maintenance; components like power supplies and, in some designs, fan trays can be replaced without powering down the entire 900RR0-0101​ rack, supporting the goal of continuous operation. This holistic approach ensures reliability is built into the system’s foundation from the ground up.

Application Field

The HONEYWELL 900RR0-0101​ Redundant CPU Rack Assembly is deployed in industries where the cost of control system failure—whether in safety, production, or financial terms—is exceptionally high. In the Oil & Gas sector, it is the control core for critical installations such as Offshore Platforms, where it manages Emergency Shutdown (ESD) and Fire & Gas (F&G) systems. Its fault-tolerant design ensures that safety functions remain online and operational even during a controller hardware fault. In Refineries and Chemical Plants, the HONEYWELL 900RR0-0101​ oversees complex, continuous processes like catalytic reforming or distillation. An unplanned shutdown in these facilities can result in days of lost production and costly restart procedures; the redundancy provided by this assembly makes such events due to controller failure virtually impossible.Within Power Generation, especially in large Combined-Cycle Gas Turbine (CCGT) or coal-fired plants, the 900RR0-0101 Rack Assembly​ is used for critical Balance of Plant (BOP) controls, such as boiler feedwater systems and flue gas treatment. Its high availability is crucial for grid stability and plant efficiency. In the Pharmaceutical and Biotechnology industries, where batch processes are governed by stringent FDA regulations, the assembly ensures the uninterrupted execution of complex recipes, protecting batches worth millions of dollars from being lost due to a control system hiccup. Furthermore, it is ideal for infrastructure applications like Large Water Treatment Facilities and Pipeline Compressor Stations, where remote or unattended operation is common, and system reliability is essential for public service and environmental protection. The HONEYWELL 900RR0-0101​ is the hardware of choice for any application demanding the highest level of control system resilience.