CI867K01 is a high-performance Modbus TCP communication interface module designed by ABB for its AC 800M series of Programmable Logic Controllers (PLCs) and Distributed Control Systems (DCS). The product features a modular design, consisting of the CI867 Communication Interface Unit and the TP867 Mounting Baseplate, with the part number 3BSE043660R1. It is specifically used to provide standard Ethernet-based Modbus TCP protocol communication capability for AC 800M controllers within industrial automation networks, enabling efficient and reliable data exchange with third-party devices supporting Modbus TCP (such as sensors, meters, drives, HMIs, or upper-level monitoring systems).
As a key component on the AC 800M Communication Expansion Bus (CEX-Bus), the CI867K01 significantly expands the controller's connectivity and interoperability, allowing it to integrate seamlessly into broader Industrial Internet of Things (IIoT) and factory automation architectures.
II. Detailed Functional Features
The CI867K01 is designed to provide a stable, flexible, and easily integrable communication solution for demanding industrial environments. Its core functional features are as follows:
1. Dual Ethernet Port Design:
The module provides two independent Ethernet physical ports (CH1 and CH2). CH1 supports 10/100M auto-negotiation and can be used to connect to the main control network or high-speed devices. CH2 is a fixed 10M port, which can be used for lower-speed devices or as a redundant/diagnostic network. This dual-port design increases network connection flexibility and reliability, facilitating network segmentation or cascading.
2. Full Modbus TCP Protocol Stack Support:
The CI867K01 has a built-in full Modbus TCP server and/or client functionality. The AC 800M controller can use this module to act as a Modbus TCP master, actively reading from or writing to slave devices on the network, or as a slave to respond to data requests from other masters (e.g., SCADA systems). It strictly adheres to the Modbus TCP standard, ensuring broad compatibility with numerous third-party devices.
3. Plug-and-Play & Hot-Swap Support:
The module supports hot-swap functionality. It can be installed on or removed from the CEX-Bus while the system is running (following safe operating procedures and disconnecting communication cables first). This greatly facilitates system maintenance, expansion, and upgrades, reducing planned downtime.
4. Redundancy Configuration Support:
In systems requiring high availability, the CI867K01 supports redundant configuration. Two CI867 modules can operate in parallel, one as the primary module and the other as the backup. If the primary module fails, the backup module can take over communication tasks seamlessly, ensuring continuity of control network communication. The PRIM (Primary) and DUAL (Redundant) LED indicators on the front panel clearly show the module's role and status in a redundant system.
5. Mechanical Key Locking Mechanism (Alpha Code Lock):
The TP867 baseplate is equipped with a pre-set two-letter mechanical key lock. The CI867 communication unit has a matching key. This design is a physical error-proofing mechanism that ensures only the correct type of communication interface unit (CI867) can be installed on the corresponding baseplate (TP867), preventing hardware damage or system failure caused by installing incompatible modules. The key code for CI867/TP867 is D-B.
6. Comprehensive Status Diagnostic Indicators:
The module front panel is equipped with a set of multi-color LED indicators providing intuitive status and diagnostic information:
- F (Red): Fault indicator. Lights up when a severe hardware or communication error is detected in the module.
- R (Green): Run indicator. Steady on when the module is operating normally.
- RxTx1 / RxTx2 (Yellow): Data transmit/receive indicators. Correspond to CH1 and CH2 ports. Flash when Ethernet packets are being sent or received, facilitating network traffic monitoring and troubleshooting.
- PRIM (Yellow): Primary module indicator (lights up in redundant configuration).
- DUAL (Yellow): Redundant mode indicator (lights up when the module is operating in a redundant configuration).
7. Seamless Integration into the AC 800M Architecture:
The CI867K01 is an integral part of the AC 800M hardware platform. It connects to the AC 800M processor unit (e.g., PM851, PM856, PM860, PM861, PM864, PM865, PM866, PM891, etc.) via the standard CEX-Bus (Communication Expansion Bus). The CEX-Bus provides communication modules with power, a high-speed data channel, and a synchronization clock, ensuring real-time and deterministic communication.
8. Broad System Compatibility:
The module is compatible with various AC 800M system versions, including:
- Control Systems: 800xA, Compact Product Suite.
- Controller Hardware Versions: AC 800M Hardware 5.0, 5.1.
- System Version: 800xA 6.0 System.
This ensures its applicability in both existing system upgrades and new projects.
III. Working Principle and Architecture
The functionality of the CI867K01 is based on its sophisticated hardware architecture and close collaboration with the AC 800M controller. Its working principle can be broken down as follows:
1. Hardware Architecture Layers:
The CI867K01 system is physically divided into two layers:
TP867 Baseplate: This is the fixed mounting base and external connection hub of the module. It is permanently mounted on the DIN rail and carries all external connection terminals, including:
Two RJ45 Ethernet sockets (CH1, CH2).
CEX-Bus connectors for connecting to the AC 800M processor unit and other CEX modules.
Mechanical key lock and DIN rail locking device.
The baseplate houses a termination board internally, responsible for signal conditioning, isolation, and routing.
CI867 Communication Unit: This is the pluggable module containing the core electronics. It connects electrically to the TP867 baseplate via connectors at its bottom. Its interior mainly includes:
CEX-Bus Interface Circuitry: Responsible for high-speed, parallel data exchange with the AC 800M processor, adhering to the CEX-Bus communication protocol and timing.
Main CPU and Memory: Executes the Modbus TCP protocol stack, handles data encapsulation/decapsulation, manages communication sessions, and runs necessary diagnostic routines.
Ethernet Transceivers (PHY): Two independent chips drive CH1 and CH2 respectively, implementing Ethernet physical layer signal encoding, decoding, and driving.
DC/DC Power Converter: Converts the 24V DC power from the CEX-Bus into the low voltages (e.g., +3.3V) required by the module's internal circuits (CPU, memory, PHY).
2. Data Communication Flow:
3. Integration Principle with AC 800M System:
Address Mapping: The CI867 module is assigned a logical station address within the system. The AC 800M control software (Control Software), through engineering configuration, maps the Modbus TCP communication data areas (e.g., coils, discrete inputs, holding registers, input registers) to specific memory addresses in the controller or directly to channels of connected S800 I/O modules. This mapping is transparent to the application program; programmers can access remote Modbus data as if they were local variables.
Real-time Performance and Determinism: The CEX-Bus is a high-speed dedicated internal bus in the AC 800M, and its communication cycle is synchronized with the controller scan cycle. This ensures that data exchange between the CI867 and the processor has high real-time performance and determinism, allowing Modbus TCP communication to meet the timing requirements of most industrial control scenarios.
Redundancy Mechanism: In a redundant configuration, the two CI867 modules share the same IP and MAC addresses (managed by the system software through address swapping). The primary module handles all communication traffic and synchronizes key status information with the backup module through internal mechanisms (potentially coordinated with the controller redundancy link). Once a primary module failure is detected, the backup module immediately activates its network ports and takes over communication using the same network identity, achieving bumpless switching at the network level.
4. Network Connection Practices:
The module's two RJ45 ports are typically connected to an industrial Ethernet switch via shielded twisted pair cables (recommended CAT5e or higher). The switch provides a star topology for the entire control system network, ensuring stable communication and isolating collision domains. Proper grounding, cable shield handling, and adherence to EMC installation guidelines (e.g., maintaining sufficient distance from power cables) are crucial for ensuring communication reliability in industrial electromagnetic interference environments.
IV. Application Scenarios
The CI867K01 is suitable for all industrial automation fields requiring the integration of AC 800M controllers into networks based on the Modbus TCP protocol. Typical applications include:
Process Industries: Oil & gas, chemicals, power generation, water/wastewater treatment, pharmaceuticals, for connecting third-party smart meters, analyzers, gas chromatographs, flow computers, etc.
Manufacturing Automation: Automotive, food & beverage, packaging, material handling production lines, for data exchange with robots, vision systems, smart sensors, specialized machine tool controllers.
Building Automation: Integrating HVAC systems, lighting control, security systems, etc.
Energy Management: Connecting smart meters, PV inverters, energy storage systems for data acquisition and monitoring.
Acting as a Gateway: In some architectures, the AC 800M with CI867K01 can serve as a protocol gateway, consolidating data from devices on the Modbus TCP network and uploading it via other buses (e.g., PROFIBUS DP, FF HSE) to higher-level DCS or SCADA systems.
