Black Channel

Black channel communication is a concept within communication technology that involves the transmission of data through a communication channel with unsecured or non-application-specific properties. This type of communication channel is a fundamental element of the black channel principle, which aims to ensure secure communication. In functional safety technology, black channels are primarily used for transmitting safety-related signals via standardized communication media like Ethernet. 

Secure communication via the black channel works by transmitting safety-related signals from one point to another, ensuring that critical information reaches its destination reliably. The black channel principle allows for the combined transmission of safety and standard signals over various channels, enabling functional safety technology to integrate into existing networks without the need for extensive additional wiring. 

To maintain the integrity of data transmission via the black channel, error-detecting measures are implemented. These measures include mechanisms like consecutive telegram counters or checksums like the Cyclic Redundancy Check (CRC) for preventing data corruption, and "watchdogs" to detect delays. In case of errors, substitute values are used for calculations or outputs to ensure functional safety. 

The black channel approach offers advantages such as cost-effective transportation of safety-related data using readily available components and technologies like industrial Ethernet and field buses. While it also allows for flexible architectures and versatile devices. 

It ensures that the transmission medium itself is secure from eavesdropping or tampering. This may involve the use of dedicated communication lines, secure networks, or encrypted communication protocols (e.g., SSL/TLS for internet communications). 

Black channel communication provides a practical and efficient means of transmitting safety-related data by leveraging existing components and technologies while ensuring a certain level of security and reliability in data transmission processes. 

The black channel principle offers specific technical features that enhance safety, reliability, and efficiency in transmitting safety-related data alongside standard signals. It refers to characteristics of a communication pathway that poses challenges to monitoring, verifying, and ensuring the integrity of data transmission. 

Cost-Effectiveness

One significant advantage of the black channel is its cost-effectiveness. It allows for the use of common network hardware without requiring special equipment. This cost-effective approach enables organizations to implement safety measures without significant additional expenses or complexity. 

Error Detection and Correction

The black channel employs mechanisms to identify and eliminate possible errors in data transmission, ensuring the integrity of communication operations. These mechanisms include detecting errors like incorrect message addressing, data insertion, corruption, or masquerading, enhancing the reliability of data transmission. 

Deterministic Performance

Leveraging network technologies that offer deterministic performance is crucial for effective black channel setups in industrial communication. Technologies like time-sensitive networking (TSN) improve determinism in standard Ethernet, ensuring reliable data transmission with minimal impact on system performance. 

Reliable Communication

The black channel ensures reliable communication by incorporating a safety layer between the OSI model's last layer and the application. This safety layer allows for the transmission of both standard and safety data fail-safe through the same network or bus line, ensuring that safety-critical information is transmitted reliably. 

Data Integrity

By implementing safety checks for data integrity, reliability, fault detection, and authentication of identity and origin, the black channel ensures that transmitted data is accurate and trustworthy. This feature is crucial for maintaining system integrity and preventing accidents resulting from random faults or data corruption. 

The technical features of the black channel include secure communication which helps the machines and devices to communicate with each other without any hindrance.  

IEC 61508 is a safety standard that focuses on functional safety of electrical, electronic, and programmable electronic safety-related systems. It uses a risk-based approach to ensure safety by design, aiming to prevent systematic failures like electromagnetic interference (EMI) that can impact safety-critical systems. It also provides guidelines for the development and maintenance of such systems to ensure they meet specified safety integrity levels (SILs). The standard sets requirements for the entire safety lifecycle, from concept to decommissioning, emphasizing the need for rigorous testing and verification to achieve these levels. SILs are a measure of the reliability of safety functions within a system, ranging from SIL 1 (lowest) to SIL 4 (highest). 

Under IEC 61508, the black channel refers to a communication principle that allows the transmission of both safe and non-safe process data over the same network or bus line. Safety components can transmit data using an isolated safe protocol that tunnels through the underlying network channel. This approach ensures that safety data is transmitted securely, independent of the underlying transmission medium, and does not require a separate safety-specific bus. The black channel principle enhances safety by ensuring that data sent between safety devices is secured and does not pose any harm to the communication system. 

To mitigate the risks associated with black channels, IEC 61508 emphasizes the importance of designing safety-related systems with transparent and verifiable communication pathways. This might involve implementing mechanisms for error detection, fault tolerance, redundancy, and other safety measures to ensure the integrity of data transmission, even in channels where direct observation is limited. 

By adhering to IEC 61508 standards and implementing the black channel approach, organizations can achieve a high level of functional safety in their systems by ensuring that safety-critical data is transmitted securely and reliably within their networks. 

Functional safety protocols are an essential component of industrial automation and communication systems. These protocols are designed to ensure the safe and reliable operation of industrial equipment, machinery, and processes, even in the event of a failure or malfunction. 

It is typically implemented as an additional layer on top of the standard industrial communication protocols, such as PROFIBUS, EtherNet/IP, and EtherCAT. These protocols are responsible for ensuring the integrity and reliability of safety-critical data, allowing for the integration of safety-related devices and systems into a single network. 

PROFIsafe

It is a functional safety protocol that is used in conjunction with the PROFIBUS and PROFINET industrial communication protocols. PROFIsafe provides a high-speed, reliable, and deterministic communication channel for safety-related data, ensuring that critical information is transmitted without errors or delays. It supports safety integrity levels up to SIL 3 according to IEC 61508 standards.  

Safety over EtherCAT (FSoE)

Also known as Fail-Safe over EtherCAT (FSoE), this protocol is a functional safety protocol that is integrated with the EtherCAT industrial Ethernet protocol. FSoE provides a high-performance, deterministic communication channel for safety-related data, allowing for the integration of safety devices and systems into an EtherCAT network. 

CIP Safety

It is a functional safety protocol that is built on top of the Common Industrial Protocol (CIP), which is used in industrial Ethernet networks such as EtherNet/IP and DeviceNet. CIP Safety provides a scalable and flexible solution for integrating safety-related devices and systems into a single network. 

Functional Safety protocols play a critical role in ensuring the safe and reliable operation of industrial automation and communication systems. By providing robust, high-integrity data transmission and fail-safe behavior, these protocols help to minimize the risk of accidents, injuries, and equipment damage, while also improving overall system performance and efficiency. 

Hilscher recognizes the importance of functional safety in modern automation processes, especially in complex industrial environments where adherence to safety standards like IEC 61508 is crucial. Black channel communication plays a significant role in ensuring secure communication between devices, which aligns perfectly with Hilscher's commitment to providing solutions that comply with security-relevant standards. By leveraging black channel protocols, Hilscher offers products that meet the stringent requirements of safety integrity levels (SIL) up to SIL 3, providing a solid foundation for the development of functionally safe systems. 

Hilscher integrates black channel communication technology into their netX hardware and firmware solutions to enhance the reliability and security of industrial communication tasks. The netX communication solution serves as a backbone for secure communication in various machines and systems, enabling compliance with all security-relevant standards such as IEC 61508. The netX hardware includes integrated monitoring and diagnostic functions, while the firmware supports black channel protocols, which transmit safety data independently of non-critical channels. By incorporating black channel communication into their products, Hilscher ensures that critical data is transmitted securely and reliably within control systems, contributing to improved safety and efficiency metrics in industrial environments. 

Their solutions are designed to integrate seamlessly with existing industrial automation systems and devices. By supporting widely used communication protocols and standards, Hilscher facilitates interoperability between disparate components within industrial networks, contributing to the establishment of black channel communication pathways across the system.