Dynamic Adaption to Permanent Memory Faults in Industrial Control Systems

Industrial control systems are making increased use of commercial off-the-shelf hardware components. One such component is memory based on DRAM technology. As pointed out by others, DRAM memory can experience permanent hardware errors, e.g. a memory cell can be permanently stuck-at zero or one. In the worst case, such a fault may have serious safety-related consequences. In this work, we present the application of a self-adaptive software system named Scari that detects erroneous datapoints, analyzes them concerning permanent stuck-at faults, and adapts to them by masking defect memory areas. Crucial for this to work is a hot-standby device that takes over the control loop during the detection and adaption phases. The goal of the mechanism presented here is automatic self-repair of a faulty control device to increase its service life and to strengthen overall resilience. The industrial setting of the presented approach is that of control devices for hydropower plant units.