Beuster, Henry

Modern manufacturing is characterized by a high degree of automation, with autonomous systems also frequently being used. In such environments human intervention in the event of malfunctions or maintenance becomes a rare but also necessary task. When human workers are no longer an integral part of the production process, but only intervene when necessary, e.g., in the case of unexpected machine behavior, appropriate safety solutions will become even more important. This work describes a wireless communication system enabling a flexible and safe emergency stop function for multiple automation cells. A portable emergency stop switch allows seamless transition between different wireless cells, ensuring functional safety. The communication protocol combines IO-Link Wireless features with the safety requirements already implemented in IO-Link Safety. Security requirements are fulfilled through encryption and authentication. The IO-Link Wireless roaming functionality is used to extend the system across several manufacturing cells. An experimental setup confirms the suitability of the system for various applications. The results demonstrate the effectiveness of the handover mechanism and evaluate the potential of the system to improve flexibility, availability and security in dynamic production environments. Future extensions could include the use of AI based evaluation of the radio signals for an intelligent cell handover.

This paper descibes an enhancement of IO-Link Wireless with an additional safety and security communication layer employing the black channel principle to fulfill safety requirements with respect to IEC 61784-3:2021. An extended channel model based on uniformly distributed segments (UDS) superimposed with the binary symmetric channel (BSC) is applied to simplify the residual error probability (REP) calculation, to detect additional error patterns, and to consider BSC-preserving cryptographic algorithms. Also, the REP with respect to the underlying security layer as well as the probability of failure per hour (PFH) are quantified.

A new FPGA-based approach for a data diode transmitting data unidirectionally from a high security zone to a lower security zone is evaluated and implemented. With the FPGA implementation, the need of additional hardware could be minimized compared to most state-of-the-art data diode realizations. The proposed data diode is designed to use the available backplane bus communication protocol between the programmable logic controller (PLC) and its connected peripherals. To demonstrate the universal approach an open-source platform based on the Revolution Pi (RevPi) and its backplane bus is used. Principally the data diode behaves as a mirror presenting the complete protected system behind the high security zone including the RevPi controller and its devices to the information technology (IT) network. Another controller within the lower security zone is used to imitate the operational technology (OT) process. Our approach is not limited to the above controller and can be applied to any type of PLC. The only requirement is that the communication protocol on the backplane bus is known and can be modified for this purpose.

In the context of Industry 4.0 and the Industrial Internet of Things, an exponential increase in the interconnection of machines and smart devices can be observed together with an increase of interconnections between Operation Technology (OT) and Information Technology (IT) networks as well as Cloud systems. This development is linked to the user's expectation for suitable security solutions, where it remains a challenging task to ensure that, e.g. a specific Safety Integrity Level (SIL) level can be maintained in view of possible potential cyberattacks. In this case, a data diode can be a suitable solution. In this paper a data diode prototype is presented being integrated into an industrial network analyzing the communication on the backplane bus of an Open Source Industrial PC called Revolution Pi. The advantage of our approach is that the data diode is totally transparent from the IT to the OT network, because all process data behind the data diode are mirrored into the IT network within a few system cycles. The security and reliability issues related with this approach are also discussed and evaluated.