ABB BC820K02 3BSE071500R1 Kit

The ABB BC820K02 is a key hardware component within the ABB Ability™ System 800xA® control system architecture, specifically designed to enhance the communication reliability, scalability, and availability of AC 800M controller systems. As a CEX-Bus Interconnection Unit, the core function of the BC820K02 is to segment the local CEX-Bus from the processor unit into two physically separate segments and support long-distance extension, thereby building a robust control system with high availability and support for redundant communication interfaces.

In complex industrial automation environments, the continuous and stable operation of the control system is paramount. Through its unique architectural design, the BC820K02 ensures that a failure of a communication interface unit on one CEX-Bus segment is isolated within that segment, preventing impact on the Processor Unit (CPU) or devices on the other CEX-Bus segment. This design significantly improves the overall availability and fault tolerance of the controller system.

The BC820K02 is supplied as a complete kit, containing the core hardware necessary for deploying a redundant interconnection configuration, facilitating rapid integration into existing or new AC 800M systems.

II. Key Features and Benefits

1. CEX-Bus Segmentation & Isolation: The BC820 can divide a single CEX-Bus from the processor baseplate into two independent segments (Segment A and B). This physical isolation is fundamental to improving system availability, preventing the propagation of local failures.

2. Support for Redundant Communication Interfaces: Segmentation allows for the straightforward implementation of redundant communication interface configurations. Critical communication modules (e.g., various network interfaces) can be installed across the two segments to form primary/backup redundancy, ensuring uninterrupted communication links.

3. Long-Distance Extension Capability: The BC820 not only segments the bus but also extends the CEX-Bus and RCU (Redundant Control Unit) Link distances up to a maximum of 200 meters via fiber optic and copper cables. This enables more flexible layout of remote I/O cabinets or distributed communication interfaces.

4. Support for Online CPU Replacement (Hot Swap): In a fully redundant system employing redundant controllers (Primary/Backup CPUs) coupled with BC820 units, online replacement of a faulty CPU module is supported without interrupting ongoing CEX-Bus traffic. This greatly reduces unplanned downtime.

5. Redundant Power Supply Support: The BC820 can be powered either via the CEX-Bus from the Processor Unit or through its external 24V DC power supply connector. Using the external power connection allows for providing redundant power to the CEX-Bus segments, further safeguarding system power supply reliability.

6. Enhanced System Availability: Combining segmentation, redundant interfaces, online replacement, and redundant power supply features, the BC820K02 provides multiple layers of protection for critical control processes, making it an ideal choice for building High Availability automation systems.

7. Clear Hardware Lock and State Setting: The BC820's TP850 baseplate features a preset two-letter alpha code lock to prevent the installation of incorrect unit types. Furthermore, paired BC820 units must be set to different states (Upper/Lower) via a toggle switch to coordinate with the primary/secondary role selection of redundant CPUs, ensuring proper system identification and operation.

III. Installation and Configuration Key Points

1. Installation Location: BC820 units must be mounted directly onto the CEX-Bus of the processor unit baseplate (e.g., PM866).

2. Segment Configuration: One BC820 manages one CEX-Bus segment. A typical redundant configuration uses two BC820s, each connected to a primary/backup CPU, and interconnected via user-supplied fiber optic and crossover Ethernet cables, forming two independent physical segments.

3. Termination: Each CEX-Bus segment must be terminated at its end with a terminator (e.g., the TB850 included in the kit). If a TK850 extension cable is used, a TB851 (female) terminator is required.

4. Power Connection: For improved reliability, it is recommended to connect an external 24V redundant power supply to the BC820. Power can be allocated per segment (e.g., one supply for CPU on Segment A and BC820 on Segment B, another for CPU on Segment B and BC820 on Segment A), or a common supply can be used with an SS82x voting unit.

5. State Setting: The toggle switches on a pair of BC820s must be set to different states (one Upper, one Lower) to correctly match the primary/backup roles of the redundant CPUs.

6. Cable Requirements:

• RCU Control Link: User-supplied shielded twisted pair crossover Ethernet cable (RJ45), following EIA/TIA-568 T568A to T568B crossover standard with all four pairs crossed, max 200m.

• RCU Data Link: User-supplied 50/125μm OM3 multimode fiber, LC Duplex connectors, max 200m.

7. Prohibited Actions: Manipulating or removing CEX-Bus baseplates in a powered and running system is strictly prohibited. Before replacing or removing a baseplate, all CEX modules on that segment must first be removed.

IV. Maintenance and Troubleshooting

1. Online CPU Replacement: In a full BC820 redundant configuration where the BC820s are externally powered, a halted CPU (including its baseplate) can be replaced online following strict procedures without interrupting normal CEX-Bus communication.

2. Online Cable Replacement: Provided the software version and hardware product revision levels support it, RCU link cables can be replaced online. The operation typically needs to be performed at the backup CPU end, following a power-off, replace, power-on sequence.

3. Replacing the BC820 Unit Itself: If a BC820 unit needs replacement, it is necessary to power off both the adjacent Controller CPU and the external DC power supply for that BC820.

4. Fault Diagnosis: Common issues can be quickly diagnosed via the unit's LED indicators. For example:

• Red Fault LED steady ON: Check external 24V power or send unit for repair.

• Green Run LED OFF: Hardware fault, requires repair.

• Yellow RCU LED Blinking: Refer to the blink count (1,2,3) to check Upper/Lower switch settings, fiber optic link, or control network copper link accordingly.

V. Typical Application Scenarios

The BC820K02 is widely used in industrial sectors with extremely high demands for system reliability and continuity, such as:

• Oil & Gas: Redundant control for offshore platforms, pipeline SCADA systems.

• Chemicals & Pharmaceuticals: Continuous process control, preventing production stoppages or safety incidents due to single-point failures.

• Power & Energy: Automation control for power plants (especially conventional islands in nuclear plants), substations.

• Metals & Paper: Main control systems for large production lines.

• Marine & Shipbuilding: Ship propulsion control systems, power management systems.