Overview
Manuals
Operating principle
System Integration Note
Features:
- 3BSE057021R1 TK856 RCU Control Link Cable, 1m
- Used as RCU Control Link Cable with PM891 pre-fabricated Redundant Control
- DCS AC 800M Distributed Control System (DCS) processors system
The TK856 is a core connection component in ABB's industrial automation control systems, specifically designed for RCUs (Redundant Control Units) and used as a control link cable. This 1-meter cable primarily serves as the physical connection and signal transmission between two independent PM891 CPU controllers.
With its highly stable data channel, the control system achieves seamless hardware-level interconnection, ensuring extremely high fault tolerance of the control core in automated production lines or high-risk industrial environments. Functionally, the TK856 cable carries the most critical "heartbeat" and status communication between redundant systems.
The TK856 ABB RCU Control Link Cable may still be available for purchase and support from Moore Automated Company beyond End-Of-Life (EOL) by the manufacturer (OEM).
ABB TK856 RCU Control Link Cable maunal(Datasheets), 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. All prices are shown in USD.
Redundancy in the control system is maintained by establishing a dedicated physical control link. After the system is operational, the two PM891 units continuously send mutual check signals through this cable to confirm each other's health status. If the primary CPU fails, an interrupt signal in the cable will immediately trigger a hardware-level state change, notifying the backup CPU to immediately take over control of the entire system. Its physical layer employs high-performance shielded twisted-pair cable and dedicated connectors, effectively suppressing complex electromagnetic interference in industrial environments, thereby ensuring absolute accuracy and extremely low latency in dual-unit identification and data mirroring transmission.
The TK856 RCU link is entirely different from standard ControlNet/Ethernet cables. It is responsible for redundancy arbitration at the core processor hardware level. If this cable is disconnected or damaged during redundant system operation, it will trigger an "RCU link disconnected" hardware error, which can lead to a split-brain scenario, where two processors attempt to compete for master control or force a safe system shutdown.
