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The industrial control and automation sector has invested in the development and standardization of new wireless (WirelessHART, ISA 100.11a, and WIA-PA) and wired (Profibus/Profinet, Modbus, and LonWORK) solutions aimed at automating processes to support standard monitoring and control functions from the perspective of addressing critical applications, as well as those integrated within the Building Internet of Things (BIoT) concept. Distributed data acquisition and control systems allow modern installations to monitor and control devices remotely. Various network protocols have been proposed to specify communication formats between a client/gateway and server devices, with Modbus being an example that has been widely implemented in the latest industrial electrical installations. The main contribution made in this paper concerns the completion of the Modbus Extension (ModbusE) specifications for the server station in the classical Modbus communication architecture, as well as their implementation and testing in an STM32F4 kit. A general-purpose control architecture is proposed for BIoT sector, comprising both intelligent touch switches and communication protocols of which the Modbus protocol is used extensively for the monitoring and control part, especially between clients, smart switches, and devices. The specific contributions concern the presentation of a scientific and practical implementation of improved specifications and their integration as software modules on ModbusE protocol server stations. A client station with a VirtualComm USB PC connection is also implemented in the lab to test the operation of the proposed server with specific Modbus applications.

This paper presents the relevant aspects regarding the experimental implementation and performance evaluation of an Internet of things (IoT) gateway for the Modbus extension. The proposed Modbus extension specifications are extended by defining the new optimized message format, and the structure of the acquisition cycle for obtaining a deterministic temporal behavior and solutions are presented for the description of devices at the MODBUS protocol level. Three different implementations are presented, and the Modbus extension’s performance is validated regarding the efficiency in the use of the acquisition cycle time. The software and hardware processing time and the importance and effect of the various components are analyzed and evaluated. They all support the implementation of an Internet of things gateway for Modbus extension. This paper introduces solutions for the structure of the acquisition cycle to include other valuable extensions, discusses the performance of a real implementation in the form of a gateway, adds new features to the Modbus extension specification, and strengthens some of the existing ones. In accordance with the novelty and contribution of this paper to the field of local industrial networks, the results obtained in the analysis, testing, and validation of the Modbus extension protocol refer to the extending of the Modbus functions for industrial process monitoring and control management.

In the context of real-time control systems, it has become possible to obtain temporal resolutions of microseconds due to the development of embedded systems and the Internet of Things (IoT), the optimization of the use of processor hardware, and the improvement of architectures and real-time operating systems (RTOSs). All of these factors, together with current technological developments, have led to efficient central processing unit (CPU) time usage, guaranteeing both the predictability of thread execution and the satisfaction of the timing constraints required by real-time systems (RTSs). This is mainly due to time sharing in embedded RTSs and the pseudo-parallel execution of tasks in single-processor and multi-processor systems. The non-deterministic behavior triggered by asynchronous external interrupts and events in general is due to the fact that, for most commercial RTOSs, the execution of the same instruction ends in a variable number of cycles, primarily due to hazards. The software implementation of RTOS-specific mechanisms may lead to significant delays that can affect deadline requirements for some RTSs. The main objective of this paper was the design and deployment of innovative solutions to improve the performance of RTOSs by implementing their functions in hardware. The obtained architectures are intended to provide feasible scheduling, even if the total CPU utilization is close to the maximum limit. The contributions made by the authors will be followed by the validation of a high-performing microarchitecture, which is expected to allow a thread context switching time and event response time of only one clock cycle each. The main purpose of the research presented in this paper is to improve these factors of RTSs, as well as the implementation of the hardware structure used for the static and dynamic scheduling of tasks, for RTOS mechanisms specific to resource sharing and intertask communication.

Considering human influence and its negative impact on the environment, the world will have to transform the current energy system into a cleaner and more sustainable one. In residential as well as office buildings, there is a demand to minimize electricity consumption, improve the automation of electrical appliances and optimize electricity utilization. This paper describes the implementation of a smart switch with extended facilities compared to traditional switches, such as visual indication of evacuation routes in case of fire and acoustic alerts for emergencies. The proposed embedded system implements Modbus RTU serial communication to receive information from a fire alarm-control panel. An extension to the Modbus communication protocol, called Modbus Extended (ModbusE), is also proposed for smart switches and emergency switchboards. The embedded smart switch described in this paper as a scientific and practical contribution in this field, based on a performant microcontroller system, is integrated into the Building Internet of Things (BIoT) concept and uses the innovative ModbusE protocol. The proposed smart lighting system integrates building lighting access control for smart switches and sockets and can be extended to incorporate functionality for smart thermostats, access control and smart sensor-based information acquisition.

The primary function of a distributed bus is to connect sensors, actuators, and control units that are used for an acquisition process. Application domains, such as industrial monitoring and control systems, manufacturing processes, or building automation, present different requirements that are not exactly invariable and coherent. Updating data from Modbus-type devices involves updating data through a technique called polling, which involves repeatedly scanning the registers from each device. This paper highlights the performance of Modbus communication, considering scenarios in which distributed devices are integrated and accessed registers are or are not at consecutive addresses. The Modbus protocol allows reading one or more holding-type data registers. If the registers are not at consecutive addresses, multiple requests are required, with implications for the real-time characteristics of the data acquisition system. We studied the data update times within the SMARTConvert application when variable numbers of registers are accessed, and we designed an extension for the Modbus protocol. The major reason Modbus is used in current research is that no assumptions are required about application semantics, and the performance/resource ratio for generic services is excellent.

The general evolution of fieldbus systems has been variously affected by both computer electrical engineering and science. First, the main contribution undoubtedly originated from network IT systems, when the Open Systems Interconnection model was presented. This reference model with seven layers was and remains the foundation for the development of numerous advanced communication protocols. In this paper, the conducted research resulted in a major contribution; specifically, it describes the mathematical model for the Modbus protocol and defines the acquisition cycle model that corresponds to incompletely defined protocols in order to provide a timestamp and achieve temporal consistency for proposed Modbus Extension. The derived technical contribution of the authors is to exemplify the functionality of a typical industrial protocol that can be decomposed to improve the performance of data acquisition systems. Research results in this area have significant implications for innovations in industrial automation networking because of increasing distributed installations and Industrial Internet of Things (IIoT) applications.

One of the fundamental requirements of a real-time system (RTS) is the need to guarantee re-al-time determinism for critical tasks. Task execution rates, operating system (OS) overhead, and task context switching times are just a few of the parameters that can cause jitter and missed deadlines in RTS with soft schedulers. Control systems that are susceptible to jitter can be used in the control of HARD RTS as long as the cumulative value of periodicity deviation and worst-case response time is less than the response time required by that application. This artcle presents field-programmable gate array (FPGA) soft-core processors integration based on different instruction set architectures (ISA), custom central processing unit (CPU) datapath, dedicated hardware thread context, and hardware real-time operating system (RTOS) implementations. Based on existing work problems, one parameter that can negatively influence the performance of an RTS is the additional costs due to the operating system. The scheduling and thread context switching operations can significantly degrade the programming limit for RTS, where the task switching frequency is high. In parallel with the improvement of software scheduling algorithms, their implementation in hardware has been proposed and validated to relieve the processor of scheduling overhead and reduce RTOS-specific overhead.

The current trend in real-time operating systems involves executing many tasks using a limited hardware platform. Thus, a single processor system has to execute multiple tasks with different priorities in different real-time system (RTS) work modes. Hardware schedulers can greatly reduce event trigger latency and successfully remove most of the scheduling overhead, providing more computing cycles for applications. In this paper, we present a hardware-accelerated RTOS based on the replication of resources such as program counters, general purpose registers (GPRs) and pipeline registers. The implementation of this new concept, based on real-time event handling implemented in hardware, is intended to meet the current rigorous requirements imposed by critical real-time systems. The most important attribute of this FPGA implementation is the time required for task context switching, which is only one clock cycle or three clock cycles when working with the atomic instructions used in the case of inter-task synchronization and communication mechanisms. The main contribution of this article is its focus on mutexes and the speed of response associated with related events. Thus, fast switching between threads is also validated, considering the handling of events in the hardware using HW_nMPRA_RTOS (HW-RTOS). The proposed architecture implements inter-task synchronization and communication mechanisms with high performance, improving the overall response time when the mutex or message is expected to relate to a higher-priority task.

The expansion of the concept of the Internet of Things (IoT), together with wireless sensor networks, has given rise to a wide range of IoT applications. This paper presents and describes the concept, theory of operation, and practical results of a Telecare-ECG (Electrocardiogram) Monitoring device, designed for the remote monitoring of out-of-hospital cardiac patients. ECG monitoring using the Telecare-ECG Monitor system ensures a better quality of life for patients and greater possibilities for the real-time monitoring and signaling of sporadic cardiac events, by recording instantaneous cardiac arrhythmias captured during certain activities or in the daily environment of the patient; furthermore, hospital resources are less impacted by this device than other devices. In accordance with the novelty and contribution of this paper to the field of ECG investigations, the results obtained in the analysis, testing, and validation of the Telecare-ECG Monitor system refer to the optimization of the functionality of the mobile ECG device under conditions that were as similar to reality as possible.