Benchmarking of OpenPLC Runtime on C-DAC VEGA RISC-V Microcontroller

Modern industrial automation systems are no longer restricted to proprietary Programmable Logic Controllers (PLC). They can be designed, developed, and commissioned on inexpensive yet powerful open-source microcontroller hardware. Open-source control software and communication protocols used in such systems provide increased protection against cyberattacks compared to proprietary controllers.1,2,3 OpenPLC1 is an open-source programming environment developed by Autonomy Logic that provides a platform for deploying industrial automation codes on hardware from different vendors. This work demonstrates the testing and benchmarking of OpenPLC functional blocks, ladder diagrams, etc., on common commercially available microcontroller boards and particularly on the indigenously developed C-DAC ARIES v2 microcontroller board with the THEJAS32 VEGA processor as a PLC. The RISC-V Processor Core and instruction set that run on the VEGA processor support a wide range of applications, including AI-based real-time process automation solutions.4 This work leads to the establishment of a solution framework powered by modular hardware with support for software that uses an extendable RISC-V Instruction Set to build more optimized industrial control system applications5,6,7 using Ladder Logic. This work demonstrates complex tasks such as fast data movement within internal memory, matrix multiplications, and crypto-computations in real-time on the microcontroller hardware, thus conveying that the solution is even capable of hosting an edge-level AI system for modern-day industrial applications. The tasks involved include a benchmarking algorithm that is executed on a candidate microcontroller hardware board. In addition to bare benchmarking using a C-code emulator for the respective boards, an extended version of the benchmarking was also carried out by encapsulating the benchmark algorithm as a PLC Ladder block. The benchmarking block helps control system designers select the right microcontroller unit for automation controllers at the field level, considering the availability of boards, cost, performance, security, and ease of integration.