João Cesar Netto

WirelessHART field devices

In this paper, the Wireless Highway Addressable Remote Transducer (WirelessHART, WH) Protocol which has evolved from the HART Protocol is presented. It is one of the most prominent industrial wireless mesh network communications protocols for process automation applications. We describe how the protocol copes with RF link difficulties. A case study of the network behavior is given using a previously developed FD with commercial tools and analysis software developed by the authors for use in industry to obtain network data.

Development of a WirelessHART compatible field device

The use of wireless industrial field devices (sensors and actuators) is gradually increasing. The easy installation and repositioning of these devices are the greatest motivators of this tendency. On the other hand, wave propagation phenomena, radio frequency coexistence and energy consumption are inherent difficulties that must be taken into account. The applied wireless communication protocol must cope with these difficulties and avoid or minimize them. In this paper, the WirelessHART protocol is introduced as well as the development of a compatible field device. A data logger software and firmware are developed to test the system. The results are presented at the end and can be used to help in the development of new devices.

Study of routing mechanisms in a WirelessHART network

The use of wireless communication for industrial applications provides several advantages over a wired system. However, an industrial wireless protocol must cope with a great number of challenges in order to assure reliability and safety for these communications. The WirelessHART protocol is the first one developed to cope with industrial environments and is the most accepted by the factory managers nowadays. In this protocol, the route and link scheduling policy is dependent on the centralized network management algorithms and these algorithms may not be optimal. This paper presents an analysis of routing and scheduling data, obtained from a network deployed in laboratory. The acquired data allows to check message paths and the employed routing mechanisms. Temporal data for multi-hop message transmissions are also analyzed. The results revealed problems concerning temporal schedules due to the use of the first available but not optimal link for message transmission. This problem may lead to unnecessary latencies in the network since the manager routing and scheduling algorithms may not ensure the best path between the devices through the links.

WirelessHART localization algorithm

The growth in the use of wireless sensor networks has made possible the development of improvements that meet the needs of the communication industry, including several devices with to low cost, low power consumption, mobility and ease of integration, installation and configuration advantages. Not only that but they also create additional functionalities, such as showing the location of field engineers who are active in industrial environments. The WirelessHART protocol is an open standard for wireless communication that seeks to meet these qualities. This study presents a development of an application for the localization of a mobile device via the WirelessHART network. Different methods are analyzed to estimate the distance between the mobile node and the other fixed elements of the wireless sensor network, such as deployment topologies and algorithms, which are used to compute the data and determine the location in a coordinate plane. The operation of the proposed system and the location method were evaluated by means of simulations and practical tests. Due to the conditions used for the installation of the devices, it was possible to obtain a range of radio transmission over 100 m, which allowed to determine an area of monitoring system of about 100 m × 100 m. The results obtained from the error location reached between a 72% and 80% of the estimated localization that was less than 5 meters.

Coexistence issues in wireless networks for factory automation

The adoption of dense industrial wireless network technologies in industrial plants is mandatorily paired with the development of methods and tools for connectivity prediction. These can be used to certify the quality (or reliability) of network information flow in industrial scenarios characterized by harsh propagation environments. Connectivity prediction must account for possibly coexisting heterogeneous radio access technologies as part of the internet of things (IoT) paradigm and easily allow post layout validation steps. The goal of the paper is to provide a practical evaluation of relevant coexistence problems between IEEE 802.15.4 and IEEE 802.11 networks, adopted here as widely used industry standards. Two different scenarios are tested with different radio platforms. Experimental results highlight the tolerable interference levels and sensitivity thresholds under different channel overlapping scenarios.

Research activities on industrial wireless instrumentation: Brazilian perspective

Brazilian research activities in industrial wireless instrumentation have proven to be advanced and compelling, with papers being accepted in important journals, symposiums around the world, such as IFAC, ETFA, INDIN, I2MCT, ICIT, selected journals, and national conferences. This paper provides a glimpse of the research in industrial wireless instrumentation analysis over the past few years, and focuses on papers published by Brazilian researchers from the Federal University of Rio Grande do Norte, Federal University of Rio Grande do Sul and University of São Paulo.

Energy consumption estimation for TDMA-based industrial wireless sensor networks

Industrial wireless sensor networks make use of batteries to provide mobility and low maintenance. The available energy depends of battery specification, electrical characteristics of the device, communication protocol and process variable update rate. The development of industrial field devices and communication protocols demands solutions to verify the expended energy along the time which can be used to predict battery life and to provide a balanced network for messages routing. In this work, an energy measurement circuit is developed for TDMA-based industrial wireless field devices such as WirelessHART and ISA SP100.11 and it is used as a reference to correct an embedded energy estimation algorithm. The overall idea is to certify the algorithm embedded by the electronic measurement, further substituted by simple functions that calculate the expended energy. The results presented a 2.5% in most cases and 3.5% worst case errors by the estimation algorithm when compared to the reference circuit, used for measuring the total energy of the sensor node during a predefined communication period.

Wireless coexistence and spectrum sensing in industrial internet of things: an experimental study

The adoption of dense wireless sensor networks in industrial plants is mandatorily paired with the development of methods and tools for connectivity prediction. These are needed to certify the quality (or reliability) of the network information flow in industrial scenarios which are typically characterized by harsh propagation conditions. Connectivity prediction must account for the possible coexistence of heterogeneous radio-access technologies, as part of the Industrial Internet of Things (IIoT) paradigm, and easily allow postlayout validation steps. The goal of this paper is to provide a practical evaluation of relevant coexistence problems that may occur between industrial networks employing standards such as WirelessHART IEC 62591, IEEE 802.15.4, and IEEE 802.11. A number of coexistence scenarios are experimentally tested using different radio platforms. For each case, experimental results are analyzed to assess tolerable interference levels and sensitivity thresholds for different configurations of channel overlapping. Finally, the problem of over-the-air spectrum sensing is investigated in real scenarios with heterogeneous industrial networks to enable a cognitive resource allocation that avoids intolerable interference conditions.

Wireless communication for IEC61850: A WirelessHART gateway proposal

Power substations have received significant improvements in automation systems through the implementation of IEC 61850 standard. Interoperability between multi-vendor devices and costs reduction by cabling suppression where brought as main advantages. Though, there is yet a gap in the usage of wireless communication systems, which are not covered by the current standard. A wireless solution could further reduce the cabling and installation costs and provide portability. In order to attend the requirements of reliability and security intrinsic to power substations systems, a solution is proposed by integrating industrial wireless communication technologies within the IEC 61850 standard.

Towards WirelessHART Protocol Decentralization: A Proposal Overview

Wireless industrial equipments for monitoring and process control are being widely adopted nowadays. Their main advantage lies in the ease of installation when compared with wired devices. However, link reliability and the strict real time communication requirements are frequently cited as real obstacles. To cope with this, adequate wireless protocols for industrial automation must present features such as deterministic temporal behavior, clock synchronization, and mesh topology. These characteristics lead to the adoption of centralized architectures such as the WirelessHART, the most relevant wireless communication protocol for industrial automation commercially available. By means of thorough analysis of this protocol and the current state of the art, several improvements can be proposed. This paper proposes a decentralized network manager, which should be able to coordinate with other network managers in order to perform a distributed message scheduling. This brings up several advantages such as the faster join and leave of field devices, faster and efficient scheduling schemes, increase of overall reliability and new possible mixed topologies. On the other hand, the proposal raises issues that must be solved in order to obtain practical results. The proposal is introduced in this paper as well as the first evaluations.