Commonly Used Industrial Communication Protocols: Challenges and Things to Look For

In automated systems, communication is key to establishing a coordinated transmission of data. Data is from sensing systems can be transmitted via a communication protocol to a controller unit then to the actuator where it goes as an output signal. In this article, we are going to explore some of the commonly used industrial communication protocols, what to consider when choosing one for your system and some of the challenges associated in the communication protocols 

Commonly Used Industrial Communication Protocols 

Modbus 

Modbus is a widely adopted serial communication protocol used in industrial automation for communication between devices such as programmable logic controllers (PLCs), remote terminal units (RTUs), and human-machine interfaces (HMIs). It is a master-slave protocol, where a master device (such as a PLC) initiates communication with one or more slave devices (such as sensors or actuators).  

Modbus supports two main transmission modes: Modbus RTU (Remote Terminal Unit) and Modbus ASCII (American Standard Code for Information Interchange). In Modbus RTU mode, data is transmitted in binary format with error checking using a cyclic redundancy check (CRC) algorithm. In Modbus ASCII mode, data is transmitted as ASCII characters with error checking using LRC (Longitudinal Redundancy Check). Modbus TCP/IP (Transmission Control Protocol/Internet Protocol) is another variant of the Modbus protocol that encapsulates Modbus messages within TCP/IP packets for communication over Ethernet networks. 

Profibus 

Profibus (Process Field Bus) is a fieldbus protocol widely used in industrial automation for communication between field devices and control systems. It is based on the OSI model and operates at the physical layer (PROFIBUS DP), data link layer (PROFIBUS FDL), and application layer (PROFIBUS PA). Profibus supports both process automation (Profibus PA) and factory automation (Profibus DP) applications, making it versatile for various industrial settings.  

Profibus DP is commonly used for high-speed data exchange in factory automation applications, while Profibus PA is used for process automation applications such as chemical processing and water treatment. Profibus employs cyclic and acyclic data exchange modes for real-time and non-real-time communication, along with diagnostic and monitoring features for system maintenance and troubleshooting. 

Ethernet/IP 

Ethernet/IP is an Ethernet-based industrial communication protocol that combines standard Ethernet communication with the Common Industrial Protocol (CIP) for seamless integration with existing Ethernet networks. It is widely used in industrial automation for applications such as motion control, machine vision, and distributed control systems. Ethernet/IP defines an object-oriented data model for representing industrial data, known as the EtherNet/IP object model.  

This model consists of assemblies, connections, and services for data exchange and device configuration. Assemblies define the structure of industrial data, connections establish communication paths between devices, and services provide methods for accessing and manipulating data. Ethernet/IP devices communicate using explicit messaging (point-to-point communication) and implicit messaging (multicast communication), allowing for real-time and non-real-time data exchange between devices. 

Key Considerations for Selecting Communication Protocols 

1. Speed and Bandwidth Requirements

When selecting a communication protocol for industrial applications, it is essential to consider the speed and bandwidth requirements of the system. Factors such as data volume, update rate, and network latency determine the required bandwidth for the communication protocol. High-speed communication protocols such as Ethernet-based protocols are suitable for applications requiring fast data transmission and high bandwidth, while serial communication protocols may be sufficient for slower-speed applications with lower bandwidth requirements. 

2. Determinism and Real-Time Communication

Real-time communication is critical for industrial automation applications that require precise control and timely response. Determinism refers to the ability of a communication system to guarantee that data is transmitted and received within a specified time frame. Real-time communication protocols such as Profinet RT (Real-Time) and EtherCAT (Ethernet for Control Automation Technology) offer deterministic communication with low latency and jitter, ensuring timely data exchange and control in industrial systems. 

3. Interoperability with Existing Systems

Interoperability is essential for integrating new communication protocols with existing industrial systems and devices. Compatibility with existing infrastructure, devices, and software ensures seamless integration and interoperability within the industrial network. Standardized communication protocols and interfaces facilitate interoperability between devices from different manufacturers, enabling plug-and-play connectivity and data exchange. 

4. Scalability and Future-Proofing

Scalability refers to the ability of a communication protocol to accommodate future expansions and technological advancements. A scalable communication protocol should support a wide range of devices, network topologies, and applications, allowing for flexible and efficient system design. Future-proofing strategies such as modular design, open standards adoption, and support for emerging technologies (such as 5G and edge computing) ensure long-term viability and investment protection for industrial communication systems. 

5. Security and Reliability

Security and reliability are paramount for industrial communication protocols to safeguard against cyber threats, ensure data integrity, and maintain uninterrupted operation of critical processes. Robust security measures such as encryption, authentication, and access control mechanisms protect industrial networks from unauthorized access, data breaches, and cyber-attacks. Redundancy and fault tolerance techniques such as network redundancy protocols (e.g., RSTP, HSR) and device-level redundancy (e.g., hot standby) enhance the reliability and availability of industrial communication systems, minimizing downtime and maximizing productivity. 

Challenges and Solutions in Industrial Communication Protocols 

Legacy System Integration 

Integrating legacy systems with modern communication protocols can be challenging due to differences in communication standards, data formats, and network protocols. Legacy systems may use proprietary communication protocols or outdated hardware that is incompatible with newer technologies.  

To overcome this challenge, organizations can employ protocol conversion techniques such as protocol gateways, protocol converters, and protocol mediation solutions. These devices translate data between different communication protocols, allowing legacy systems to communicate with modern devices and systems seamlessly. 

Protocol Interoperability Issues 

Protocol interoperability refers to the ability of different communication protocols to exchange data and communicate with each other effectively. In heterogeneous industrial environments, interoperability between disparate protocols can be challenging due to differences in data formats, message structures, and network architectures.  

Standardization efforts and industry initiatives aim to address these interoperability challenges by defining common communication standards, protocols, and data models. For example, OPC UA (Unified Architecture) is an open, interoperable communication standard that enables seamless data exchange between devices and systems from different vendors. 

Addressing Cybersecurity Concerns 

Cybersecurity is a major concern for industrial communication protocols, as industrial networks are increasingly vulnerable to cyber-attacks, data breaches, and unauthorized access. Common cybersecurity threats include malware, ransomware, denial-of-service (DoS) attacks, and insider threats.  

To mitigate these risks, organizations can implement robust security measures such as network segmentation, access control, encryption, intrusion detection systems (IDS), and security information and event management (SIEM) solutions. Compliance with cybersecurity standards such as IEC 62443 and ISO/IEC 27001 ensures that industrial networks adhere to best practices and regulatory requirements for cybersecurity. 

Ensuring Robustness in Harsh Environments 

Industrial communication networks often operate in harsh environments characterized by temperature extremes, humidity, vibration, and electromagnetic interference (EMI). These environmental factors can degrade the performance and reliability of communication systems, leading to data loss, signal degradation, and system failures. To ensure robustness in harsh environments, organizations can deploy ruggedized hardware solutions, such as industrial-grade switches, routers, and connectors, designed to withstand harsh operating conditions. Additionally, shielding techniques, surge protection devices, and redundant communication paths enhance the resilience and reliability of industrial communication networks, minimizing downtime and ensuring continuous operation in challenging environments. 

Trends and Future Directions 

 Adoption of IIoT and Industry 4.0 Standards 

The integration of Industrial Internet of Things (IIoT) technologies and Industry 4.0 standards is driving the adoption of open, interoperable communication protocols for seamless connectivity and data exchange across interconnected devices and systems. IIoT protocols such as MQTT (Message Queuing Telemetry Transport), CoAP (Constrained Application Protocol), and OPC UA PubSub (Publisher-Subscriber) enable efficient communication and data sharing in distributed industrial environments. 

Shift Towards Standardization and Interoperability 

Industry initiatives such as Time-Sensitive Networking (TSN) and Advanced Physical Layer (APL) are driving standardization efforts to define common communication standards and protocols for industrial automation. These initiatives aim to ensure interoperability between different devices and systems, enabling seamless integration and data exchange in industrial environments. Standardized communication profiles and interfaces facilitate plug-and-play connectivity and interoperability between devices from different vendors, reducing integration costs and complexity. 

Emergence of Edge Computing 

Edge computing technologies are gaining traction in industrial communication networks, enabling real-time data processing and analysis at the network edge. Edge computing platforms such as Kubernetes and Docker enable the deployment and management of containerized applications at the edge of the network, reducing latency and bandwidth usage. Edge analytics and machine learning algorithms enable real-time insights and decision-making in industrial environments, improving operational efficiency and responsiveness. 

Integration of AI and Machine Learning 

AI (Artificial Intelligence) and machine learning techniques are being integrated into industrial communication protocols to optimize performance and efficiency. AI-driven optimization techniques such as reinforcement learning and genetic algorithms enable dynamic adjustment of communication parameters based on network conditions and traffic patterns. Predictive maintenance and anomaly detection applications leverage AI and machine learning to detect and mitigate network failures and performance degradation proactively, improving reliability and uptime in industrial communication networks. 

Key Takeaways of Commonly Used Industrial Communication Protocols 

By incorporating these detailed explanations, the article provides a comprehensive understanding of industrial communication protocols, addressing technical aspects, challenges, and future trends in industrial automation. Readers gain insights into the commonly used industrial communication protocols, along with strategies for selecting, implementing, and managing robust and reliable communication networks in industrial environments.