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Creators/Authors contains: "Ugalde, Ines"

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  1. Programmable Logic Controllers are an established platform used throughout industrial automation, but rather poorly understood among researchers in the control systems community. This paper gives an overview of the state of the practice in industrial control systems while presenting a critical analysis of the dominant programming styles used in today's automation systems. We describe the patterns standardized loosely in IEC 61131-3 and, where there are ambiguities in the standard, realized in concrete vendor implementations. Ultimately, we suggest directions for further research towards enabling increasingly complex industrial control applications subject to the novel requirements of Industry 4.0 settings without compromising the safety and reliability guaranteed by the current industrial automation stack. 
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  2. Programmable Logic Controllers (PLCs) are an established platform, widely used throughout industrial automation but poorly understood among researchers. This paper gives an overview of the state of the practice, explaining why this settled technology persists throughout industry and presenting a critical analysis of the strengths and weaknesses of the dominant programming styles for today's PLC-based automation systems. We describe the software execution patterns that are standardized loosely in IEC 61131-3. We identify opportunities for improvements that would enable increasingly complex industrial automation applications while strengthening safety and reliability. Specifically, we propose deterministic, distributed programming models that embrace explicit timing, event-triggered computation, and improved security. 
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