ABB BC820K01 3BSE071501R1 Kit

The ABB BC820K01 is a critical hardware component within the ABB Ability™ System 800xA® control system architecture, specifically engineered to enhance the communication reliability, scalability, and availability of AC 800M controller systems. As a CEX-Bus Interconnection Unit, the BC820K01's primary function is to segment the local CEX-Bus from the processor unit into two physically separate, electrically isolated segments. This architectural approach is fundamental for building robust, high-availability control systems that support redundant communication interfaces, thereby minimizing single points of failure and ensuring operational continuity.

In mission-critical industrial automation environments where unplanned downtime carries significant cost and safety implications, the BC820K01 provides a vital layer of protection. It ensures that a fault occurring on a communication interface unit within one CEX-Bus segment is contained, preventing it from cascading to affect the central Processor Unit (CPU) or disrupting operations on the other, independent CEX-Bus segment. This design philosophy directly contributes to increased system Mean Time Between Failures (MTBF) and reduced recovery times.

The BC820K01 is supplied as a comprehensive kit (Product ID: 3BSE071501R1), containing all essential hardware required for deploying a redundant interconnection configuration. This turnkey approach facilitates efficient integration into both new AC 800M system installations and existing system upgrades or expansions.

II. Key Features and Benefits

1. CEX-Bus Segmentation & Electrical Isolation: The core capability of the BC820 unit is to bifurcate a single CEX-Bus connection from the processor baseplate into Segment A and Segment B. This creates two distinct communication domains, providing physical and electrical isolation that is essential for fault containment and high system availability.

2. Foundation for Redundant Communication Architectures: The segmented bus structure natively supports the implementation of fully redundant communication interfaces. Critical network modules (e.g., PROFIBUS, PROFINET, Ethernet) can be installed in a cross-coupled manner across the two segments, establishing primary and backup paths to guarantee uninterrupted data flow even if one module or segment fails.

3. Long-Distance Extension Capability: Beyond segmentation, the BC820K01 enables the extension of both the CEX-Bus and the RCU (Redundant Control Unit) Link over distances up to 200 meters using fiber optic and copper cables. This flexibility is crucial for distributed control architectures, allowing remote I/O clusters or communication cabinets to be placed at optimal locations throughout a plant.

4. Online CPU Replacement (Hot Swap) Support: In a fully configured system utilizing redundant controllers (Primary/Backup CPUs) interconnected via BC820 units, a failed CPU module (including its baseplate) can be replaced while the system remains operational. This hot-swap capability, performed under specific procedures, dramatically reduces planned and unplanned maintenance windows.

5. Dual Power Supply Options for Enhanced Reliability: The unit receives primary power via the CEX-Bus from its host processor. Additionally, it features an external 24V DC power input connector. Utilizing this external source allows for the implementation of a redundant power scheme for the CEX-Bus segments, safeguarding against power supply failures.

6. Comprehensive System Availability Enhancement: By integrating segmentation, interface redundancy, online maintainability, and optional power redundancy, the BC820K01 delivers a multi-faceted solution for maximizing overall system uptime and resilience in demanding automation applications.

7. Hardware Safety and Configuration Integrity: The accompanying TP850 baseplate incorporates a mechanical keying system (alpha code lock) to prevent accidental installation of incompatible units. Furthermore, paired BC820s in a redundant setup must be configured with opposite toggle switch states (Upper/Lower), which is critical for the system to correctly identify and manage the roles of primary and backup controller CPUs.

III. Installation and Configuration Key Points

1. Mounting: BC820 units are designed to be mounted directly onto the CEX-Bus connector located on the processor unit's baseplate (e.g., TP830 for PM8xx).

2. Redundant Configuration: A typical high-availability setup involves two BC820K01 kits. One BC820 connects to the primary CPU's CEX-Bus, the other to the backup CPU's CEX-Bus. These two BC820s are then interconnected via user-provided fiber optic (RCU Data Link) and crossover Ethernet cables (RCU Control Link), creating two independent CEX-Bus segments (A & B) that span both controllers.

3. Bus Termination: Each physical CEX-Bus segment must be properly terminated at its end to ensure signal integrity. The kit-supplied TB850 male terminators are used for this purpose. If a TK850 extension cable is employed in the configuration, a TB851 female terminator is required instead.

4. Power Supply Strategy: For maximum reliability, connecting an external 24V DC redundant power supply to the BC820's terminals is recommended. Advanced configurations can cross-connect power sources (e.g., Source 1 powers CPU A and BC820 B; Source 2 powers CPU B and BC820 A) or employ a single source with an SS82x voting unit.

5. Critical Switch Configuration: In a paired redundant setup, the toggle switches on the two BC820 units must be set to opposite positions (one "Upper," one "Lower"). This is a mandatory step for correct system initialization and role management between the redundant CPUs.

6. User-Supplied Cable Requirements:

• RCU Control Link: Requires shielded, twisted-pair crossover Ethernet cables (RJ45) built to the EIA/TIA-568B crossover pinout (all four pairs crossed), with a maximum length of 200m.

• RCU Data Link: Requires 50/125μm OM3 grade multimode fiber optic cables with LC Duplex connectors, with a maximum length of 200m.

7. Safety Prohibition: Never attempt to manipulate, install, or remove CEX-Bus baseplates (TP850) while the system is powered on and operating. All CEX modules on a segment must be removed before its baseplate can be safely handled.

IV. Maintenance and Troubleshooting

1. Online CPU Replacement: This operation is possible in a fully redundant BC820 configuration where the BC820s are powered from an external source. It requires a precise sequence: powering down the faulty CPU, replacing it and its baseplate, then restarting. The healthy segment continues operation undisturbed during this process.

2. Online Cable Replacement: Replacement of RCU link cables may be performed online if supported by the specific system's software and hardware revision levels. The procedure typically mandates working on the backup/standby side of the system, following a strict power-disconnect-replace-reconnect-power sequence.

3. Replacing a BC820 Unit: To replace a faulty BC820 unit itself, it is necessary to power down both the adjacent Controller CPU and disconnect the external DC power supply feeding that specific BC820.

4. Diagnostic Aids: The BC820's LED panel is the primary tool for initial fault diagnosis:

• Solid Red Fault LED: Check external 24V power supply voltage and connections. If power is confirmed, the unit likely has an internal hardware fault and requires repair.

• Run Green LED Off: Indicates a fundamental hardware failure; the unit should be sent for repair.

• Blinking Yellow RCU LED: Use the blink code (1, 2, or 3 times) to direct troubleshooting efforts toward switch configuration, fiber optic links, or Ethernet control links, respectively.

V. Typical Application Scenarios

The BC820K01 is deployed in industrial sectors where system reliability, safety, and continuous operation are non-negotiable, including:

• Oil & Gas: Offshore drilling platforms, pipeline transmission monitoring and control (SCADA), refinery process units.

• Chemical & Pharmaceutical: Batch and continuous reaction processes, where interruption can lead to significant product loss or safety events.

• Power Generation & Distribution: Control systems for conventional thermal power plants, hydroelectric plants, and electrical substations.

• Metals, Mining & Pulp & Paper: Automation of large-scale, continuous production lines like rolling mills or paper machines.

• Marine: Integrated vessel control systems for propulsion, power management, and dynamic positioning.