AC 800M Communication Protocols Explained: Ethernet, PROFIBUS, and More
Introduction
In modern industrial automation, communication is the lifeline between controllers, field devices, and supervisory systems. The ABB AC 800M controller, part of ABB’s 800xA platform, is designed to be flexible, modular, and scalable — but its true power comes from the range of communication protocols it supports.
Whether you’re integrating intelligent field devices, connecting to SCADA systems, or linking multiple controllers, understanding AC 800M communication protocols is essential for designing reliable, high-performance automation solutions.
1. Why Communication Protocols Matter in AC 800M Systems
The AC 800M controller can be customized with different communication interface modules (CI modules), allowing it to connect to virtually any industrial network. These protocols determine:
Speed of data exchange
Reliability under harsh conditions
Compatibility with existing devices
Scalability for future expansion
Diagnostics and maintenance capabilities
Choosing the right protocol means balancing these factors for your specific application.
2. Overview of Supported Protocols
2.1 Ethernet-Based Protocols
Ethernet communication is one of the most common and flexible options for AC 800M.
Common modules:
Built-in Ethernet port
CI867 Ethernet/IP module
CI871 for PROFINET
Key features:
High-speed data transfer (10/100 Mbps)
Supports TCP/IP, UDP, and industrial variants
Easy integration with IT systems
Long cable runs via fiber optics
Typical use cases:
Controller-to-controller communication
SCADA integration via OPC
Remote monitoring over plant networks
2.2 PROFIBUS (DP and PA)
Module: CI854A PROFIBUS-DP interface
Key features:
Deterministic, cyclic data exchange
Robust against electrical noise
Supports up to 126 devices per segment
PROFIBUS-DP for high-speed discrete control
PROFIBUS-PA for process automation (intrinsically safe)
Typical use cases:
Distributed I/O systems
Process instrumentation in oil & gas, chemical, or water treatment
Harsh industrial environments with long cable distances
2.3 Modbus (TCP/IP and RTU)
Modules:
Modbus TCP/IP via built-in Ethernet
Modbus RTU via CI853 module
Key features:
Open, widely adopted protocol
Simple master/slave communication
Works over Ethernet (TCP/IP) or serial lines (RS-232/RS-485)
upports both modern and legacy devices
Typical use cases:
Integrating third-party PLCs and HMIs
Connecting older drives and instrumentation
Retrofitting existing plants
2.4 FOUNDATION Fieldbus
Module: CI860 FOUNDATION Fieldbus interface
Key features:
True distributed control at the device level
Advanced diagnostics for predictive maintenance
Single cable for power and data (bus-powered devices)
Supports multiple function blocks per device
Typical use cases:
Chemical and petrochemical plants
Continuous process industries
Systems requiring device-level intelligence
2.5 Serial Communication
Module: CI853 or third-party serial interface
Key features:
RS-232 or RS-485 communication
Low cost and simple to configure
Suitable for point-to-point or multi-drop networks
Typical use cases
Legacy device integration
Laboratory and test equipment connections
Low-speed sensor data acquisition
2.6 IEC 61850
Module: CI869 interface
Key features:
Designed for electrical substation automation
Standardized communication for protection relays and IEDs
Supports high-speed GOOSE messaging
Typical use cases:
Power generation plants
High-voltage substations
Grid automation systems
3. Choosing the Right Protocol for Your Application
When deciding which protocol to use with AC 800M, consider the following:
3.1 Device Compatibility
Check the communication capabilities of all devices you plan to connect. This is the first filter in protocol selection.
3.2 Data Requirements
High-speed, large-volume data exchange → Ethernet-based protocols
Slow, stable, and noise-resistant → Fieldbus protocols like PROFIBUS or FOUNDATION Fieldbus
3.3 Physical Environment
For high-EMI areas, shielded twisted-pair or fiber-based Ethernet is ideal. PROFIBUS also offers strong noise immunity.
3.4 System Architecture
Centralized vs. distributed control will influence whether you choose Ethernet, Fieldbus, or serial.
3.5 Future Scalability
Protocols like PROFINET and Ethernet/IP offer easier expansion compared to serial networks.
4. Real-World Examples
Example 1: Oil Refinery Instrumentation
An oil refinery uses AC 800M with PROFIBUS-PA for hazardous area instrumentation, ensuring intrinsic safety, and Ethernet/IP for control room integration.
Example 2: Power Plant Automation
In a power plant, IEC 61850 connects the AC 800M to protection relays for fast substation communication, while Modbus TCP/IP links to the turbine governor.
Example 3: Water Treatment Facility
A municipal water treatment plant uses FOUNDATION Fieldbus to connect smart flow and pressure transmitters, with OPC over Ethernet to transmit data to the SCADA system.
5. Best Practices for Implementing Communication Protocols
1. Plan the Network Layout– Topology affects performance and reliability.
2. Use Redundancy Where Necessary– Critical systems benefit from dual communication paths.
3. Standardize Protocols– Minimize the number of protocols to reduce complexity.
4. Test in a Staging Environment– Identify configuration issues before live deployment.
5. Document the Configuration– Maintain clear records for maintenance and troubleshooting.
Conclusion
The AC 800M controller offers an impressive range of communication protocols, enabling it to integrate seamlessly into virtually any industrial automation environment.
