Honeywell TK-PRR021 Redundancy Module

Technical Specifications Overview

The table below details the core technical parameters of this redundancy module.

Parameter	Specification
Model Number	TK-PRR021
Product Type	Redundancy Module
Compatible System	Honeywell Experion PKS Series
Redundancy Type	1:1 (primary/backup) with automatic failover
Synchronization Method	Dedicated high-speed sync link
Sync Link Type	RS-422 (isolated)
Failover Time	≤ 50 ms (typical)
Voting Mechanism	2-out-of-2 with diagnostic comparison
Internal Power Draw	5 VDC, 350 mA
Dimensions (W x H x D)	45 mm x 130 mm x 120 mm
Weight	0.26 kg
Connector Type	9-pin D-sub (sync link)
Indicators	4 LEDs (PRIMARY, BACKUP, SYNC, and FAULT)
Operating Temperature	0°C to +60°C

Automatic System Redundancy for High Availability

The TK-PRR021 redundancy module enables automatic failover between primary and backup controllers in Honeywell Experion PKS systems. This redundancy module implements a 1:1 architecture, where a secondary controller stands ready to assume control within milliseconds. A dedicated RS-422 sync link maintains constant communication between the two controllers, ensuring seamless data synchronization.

The module achieves a failover time of 50 ms or less, minimizing process disruption during controller switching. This rapid response protects critical process operations from extended downtime. The TK-PRR021 continuously monitors both controller health and communication integrity, triggering failover only when necessary.

Robust Synchronization and Voting Mechanism

This redundancy module uses a sophisticated 2-out-of-2 voting mechanism with diagnostic comparison to ensure system integrity. The TK-PRR021 compares the operational status of both controllers and validates data consistency between them. This approach eliminates the risk of split-brain scenarios, where both controllers mistakenly attempt to act as the primary.

The sync link operates over an isolated RS-422 connection, providing robust noise immunity for high-integrity communication. The module supports synchronization of all application data, including process variables, setpoints, and alarm statuses. This comprehensive data synchronization ensures a seamless transfer of control during failover events.

Physical Design and Status Indication

This redundancy module occupies a single slot in the Experion 13-slot chassis and measures 45 mm in width. The module weighs 0.26 kg, making handling straightforward during installation and replacement. A 9-pin D-sub connector on the front panel provides the dedicated sync link interface, requiring only a shielded twisted-pair cable for connection.

Four LEDs deliver comprehensive status indication: a green PRIMARY LED shows active control status, an amber BACKUP LED indicates standby mode, a green SYNC LED confirms synchronization, and a red FAULT LED signals any error condition. These indicators enable rapid assessment of the redundancy system health without requiring diagnostic software.

Power and Environmental Specifications

The TK-PRR021 draws 350 mA from the 5 VDC backplane, ensuring stable operation in fully populated racks. This redundancy module operates reliably across a temperature range of 0°C to +60°C. It also withstands humidity from 5% to 95% (non-condensing) and resists vibration up to 2G at 10-150 Hz.