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The TK-PRR021 is a conformal-coated redundancy module (Part No: 51309288-275 or 51309288-475) primarily used in the Honeywell C200/C300 Control System. It handles power and signal redundancy, operating at 7mA @ 1.2VDC and 0.75A @ 3.3VDC.
Holds Class I Division 2 hazardous location explosion-proof certification aligned with T4A thermal ratinge
Supports online hot-swapping maintenance on the redundant backup chassis side without shutting down the system
Triggers self-healing logic within microseconds to transfer control if the primary card encounters power loss or hardware failure
The foundational mission of the Honeywell TK-PRR021 is to deliver bumpless, hot standby redundancy with automatic, deterministic fault transfer. During normal operations, the module coordinates a continuous data-mirroring cycle between the primary and secondary units, copying control loop variables, PID parameters, timer states, and I/O status tables via dedicated high-speed fiber-optic linkages. If the primary controller experiences a catastrophic hardware malfunction, abrupt power loss, communication link flash, or an unexpected firmware shutdown, the redundancy modules instantly detect the deviation. Within milliseconds, the module initiates a seamless switchover, transferring absolute process control to the backup controller without packet drops, signal distortion, or valve position jumps, satisfying the strict continuity demands of automated process lines that cannot tolerate unscheduled downtime.
Important Notice: Other accessories, manuals, cables, calibration data, software, etc. are not included with this equipment unless listed in the above stock item description.
Honeywell TK-PRR021 Redundancy Module Coated Manuals, Datasheets, Drivers, Link
Important Notice: Other accessories, manuals, cables, calibration data, software, etc. are not included with this equipment unless listed in the above stock item description.
Oil & Gas Extraction
Used in offshore drilling platforms or onshore gas wellhead control systems to ensure millisecond switchover between hot-standby controllers during lightning strikes or brief power dropouts, preventing accidental wellhead closure due to control interruption.
Petrochemical & Refining
Synchronizes real-time PID loop data between primary and backup controllers in high-temperature, high-pressure continuous refining units like hydrocracking, ensuring smooth valve outputs during switchover to prevent unit overpressure.
Coal Chemical & Gasifier Control
Applied to the core interlock protection systems of large coal gasification processes; if the primary CPU suffers an occasional fault, this redundancy module guarantees that the backup CPU takes over instantly, preventing unscheduled shutdowns of high-risk gasifiers.
Nuclear & Large-scale Thermal Power Generation
Used in steam turbine Digital Electro-Hydraulic (DEH) and Boiler Burner Management Systems (BMS) to maintain strict data synchronization, guaranteeing a continuous response to grid load dispatching and eliminating single-point failure risks.
Metallurgy & Iron and Steel Industry
Deployed in the main control networks of blast furnaces, converters, and continuous casting lines to prevent system paralysis from a single CPU freeze, which could otherwise cause catastrophic molten iron solidification inside kilns or piping.
The modules in the two redundant chassis must be directly and peer-to-peer connected using original, dedicated fiber-optic patch cables, and passing through any intermediate network switches is strictly prohibited. Prior to powering up, it is critical to verify that the firmware revisions of both the primary and backup controllers are identically matched. otherwise, the system will fail to synchronize.
Although the module features a protective conformal coating, it occupies two chassis slots and generates significant internal heat during high-frequency memory mirroring. Therefore, it must be installed in a well-ventilated standard industrial enclosure with ambient temperatures strictly maintained between 0°C and 60°C.
Furthermore, never disconnect fiber cables or extract the module while the system is live without first confirming that the backup chassis is fully healthy and synchronized, as this can trigger an unscheduled production shutdown.
Alternative Names
Alternative Names
TK PRR021TK-PRRO21TK-PRR02ITK-PRRO2I
Technical notes
Technical notes
Honeywell TK-PRR021 Coated adopts a single-wide plug-in structure for Series-A chassis slots, synchronizing memory data and logical states of primary and backup processors in real time over a high-speed fiber-optic link to trigger microsecond-level seamless physical switchovers when the primary card encounters power interruptions or hardware failures. Its circuit board features a conformal coating for wide-temperature operations from -20 °C to +60 °C while holding Class I, Division 2 hazardous location explosion-proof certification, serving as the physical hub to guarantee high-availability hot-standby communications for controllers in continuous production industries such as petrochemical and chemical processing.
It is a chassis-based Redundancy Module manufactured by Honeywell, belonging to the Series-A (CIOM-A) platform of the Experion PKS automation system, primarily responsible for coordinating and managing the seamless primary/backup switchover between dual controllers.
How should the TK-PRR021 product be used correctly?
The hardware features a slide-in design and must be installed in pairs within the designated slots of the primary and backup chassis, with both modules connected via a dedicated fiber-optic redundancy cable to establish a high-speed synchronization channel between the two processors.
What is the core operating principle of the TK-PRR021?
It synchronizes the internal memory data, process variables, and execution states of the primary and backup control processors (such as TK-PRS022 C200E) in real time over a high-speed fiber link, instantly triggering microsecond-level switchover logic if a primary processor hardware failure is detected.
What is the purpose of the physical interfaces configured on the TK-PRR021 module?
The module panel is equipped with dedicated high-performance fiber-optic physical interfaces used to plug in redundancy communication fiber patch cords, ensuring the data synchronization between primary and backup chassis has maximum physical isolation and immunity to interference.
Under what conditions will the system trigger a primary/backup switchover via the TK-PRR021?
When the primary processor experiences a hardware freeze, a backplane power failure, or a physical interruption in its chassis-side network communication link, this module instantly detects the fault and transfers control to the backup unit.
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Disclaimer: We are not an authorized distributor or distributor of the product manufacturer of this website, The product may have older date codes or be an older series than that available direct from the factory or authorized dealers. Because our company is not an authorized distributor of this product, the Original Manufacturer`s warranty does not apply.While many DCS PLC products will have firmware already installed, Our company makes no representation as to whether a DSC PLC product will or will not have firmware and, if it does have firmware, whether the firmware is the revision level that you need for your application. Our company also makes no representations as to your ability or right to download or otherwise obtain firmware for the product from our company, its distributors, or any other source. Our company also makes no representations as to your right to install any such firmware on the product. Our company will not obtain or supply firmware on your behalf. It is your obligation to comply with the terms of any End-User License Agreement or similar document related to obtaining or installing firmware.
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