ABB TK850 CEX-Bus Extension Cable

The ABB TK850V007 (TK850 CEX-Bus Extension Cable), also cataloged as the 3BSC950192R1 CEX-Bus Extension Cable, operates as a dedicated hardware component for extending the CEX-Bus backplane link within ABB AC 800M controller architectures. It establishes high-integrity data paths between AC 800M processor units and adjacent expansion modules or communication interface cards. In redundant controller setups, it connects dual CPUs to shared CEX-Bus units alongside the TK851 RCU-Link Cable. Featuring DB-25 male-to-female connectors over a 0.7 m length, the cable requires a TK851 CEX-Bus terminator to maintain signal integrity across deterministic control networks.

Hardware Specifications

CEX-Bus Deterministic Backplane Communication and Signal Integrity

The TK850 extension cable maintains backplane bus communication velocity across expanded AC 800M CPU stacks without introducing transmission latency or frame jitter. Digital communication lines within the cable assembly carry high-frequency deterministic data packets between the processor core and downstream CEX-Bus interface modules. Shielded DB-25 connectors minimize ground-loop noise and electromagnetic interference, preserving deterministic bus cycle times across redundant processor configurations.

Frequently Asked Questions

Q: Is the TK850 cable hot-swappable during active system operation?

A: Disconnecting the TK850 cable during active controller operation breaks the CEX-Bus continuity, which will cause communication failure to all downstream interface units. Cable replacement requires powering down the affected CEX-Bus segment or transitioning the controller pair to a stopped state.

Q: Can the TK850 cable operate without a TK851 CEX-Bus terminator?

A: No. The CEX-Bus line requires proper impedance matching at its physical endpoints. Utilizing the TK850 cable without the TK851 terminator causes signal reflections on the bus lines, resulting in backplane communication errors and dropped packets.

Q: How does the cable integrate into redundant CPU configurations?

A: In redundant AC 800M controller setups, the two CPU units communicate directly via the TK851 RCU-Link Cable while both connect to the common CEX-Bus expansion segment through TK850 extension cables or BC810/BC820 interconnection units.

Field Installation Guidelines

1. Power Verification: Turn off power to the AC 800M CPU base units and attached CEX-Bus expansion modules before attaching or removing the interconnecting bus cable.
2. Connector Alignment: Align the DB-25 male connector on the TK850 cable with the female CEX-Bus port on the AC 800M processor unit or BC810 module. Push straight in to avoid bending the interface pins.
3. Mechanical Fastening: Tighten the captive jack-screws on both DB-25 connector shells using a flathead screwdriver. Ensure hand-tight torque to maintain ground shell continuity and prevent accidental disconnection from cabinet vibration.
4. Terminator Installation: Attach the mandatory TK851 CEX-Bus terminator to the last open CEX-Bus port on the extended segment to complete the impedance termination loop.
5. Bend Radius and Cable Routing: Maintain a minimum bend radius of 50 mm along the 0.7 m cable run inside the control cabinet. Route the cable separately from high-voltage AC power lines and drive output cables to suppress induced noise.