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Process industries cover a wide set of industries, in which the processes are controlled by a combination of distributed control systems (DCSs) and programmable logic controllers (PLCs). These control systems utilize various measurements such as pressure, flow, and temperature to determine the state of the process and then use field devices such as valves and other actuating devices to manipulate the process. Since there are many different types of field devices and since each device is calibrated to its specific installation, when monitoring devices, it is important to be able to transfer not only the device measurement and diagnostics but also characteristics about the device and the process in which it is installed. The current monitoring architecture, however, creates challenges for continuous monitoring and analysis of diagnostic data. In this paper, we present the design of an Industrial Internet-of-Things (IIoT) system for supporting large-scale and continuous device condition monitoring and analysis in process control systems. The system design seamlessly integrates existing infrastructure [e.g., highway addressable remote transducer (HART) and WirelessHART networks, and DeltaV DCS] and newly developed hardware/software components (e.g., one-way data diode and IoT cellular architecture) together for control network data collection and streaming of the collected device diagnostic parameters to a private cloud to perform streaming data analytics designed for fault identification and prediction. A prototype system has been developed and supported by Emerson Automation Solutions and deployed in the field for design validation and long-term performance evaluation. To the best of our knowledge, this is the first ever publicly reported effort on IoT system design for process automation applications. The design can be readily extended for condition monitoring and analysis of many other industrial facilities and processes.

RPL, the IPv6 Routing Protocol for Low-Power and Lossy Networks (LLNs), is widely used in resource-constrained wireless sensor networks. RPL is, however, vulnerable to internal routing attacks where compromised nodes may seek to exploit the vulnerability of the Rank value that represents the node’s position relative to the root in the RPL graph. The impact of such attacks can be devastating, especially for real-time wireless networks where network-wide time synchronization needs to be maintained during system operation. In this paper, we present a distributed detection system FORCE to protect the RPL topology from Rank-related attacks. In FORCE, each node locally analyzes the received control messages from its neighbors and generates alerts upon the discovery of an intrusion. We evaluate the performance of proposed IDS using extensive simulations. The findings demonstrate that it can effectively detect Rank-related attacks with a high detection rate, yet incurring only moderate computation and communication overheads.

Blockchain is a distributed and decentralized ledger for recording transactions. It is maintained and shared among the participating nodes by utilizing cryptographic primitives. A consensus protocol ensures that all nodes agree on a unique order in which records are appended. However, current blockchain solutions are facing scalability issues. Many methods, such as Off-chain and Directed Acyclic Graph (DAG) solutions, have been proposed to address the issue. However, they have inherent drawbacks, e.g., forming parasite chains. Performance, such as throughput and latency, is also important to a blockchain system. Sharding has emerged as a good candidate that can overcome both the scalability and performance problems in blockchain. To date, there is no systematic work that analyzes the sharding protocols. To bridge this gap, this paper provides a systematic and comprehensive review on blockchain sharding techniques. We first present a general design flow of sharding protocols and then discuss key design challenges. For each challenge, we analyze and compare the techniques in state-of-the-art solutions. Finally, we discuss several potential research directions in blockchain sharding.

In modern flow control settings, a slow controller sampling rate is often much slower than a flowmeter response, and flowmeters are often selected without consideration of the dynamic response characteristics. However, for fast loops which necessitate a high control sampling frequency, negligence in flowmeter selection might result in an undesirable control performance degradation. Such associated research is expected to be critical to design and evaluation of new flowmeters, i.e., wedge flowmeters in this study, but little work has been found in the public domain to address this issue. In this paper, a new way of calculating process variability is proposed to fast-track the evaluation of flow control performance and cost saving. In addition, based on frequency response analysis, a systematic study of how dynamic response characteristics of flowmeters impact flowmeter accuracy and process variability is presented. Moreover, the impact of controller sampling rate on process variability is researched. Last, the closed-loop stability of the flow control loop with new wedge flowmeters is evaluated for a wide range of its targeted applications. The results demonstrate that a flowmeter with a faster response will always lead to process variability reduction for a given controller sampling rate, and that with careful controller set up, a flow loop with wedge flowmeter is still stable despite relatively slow dynamics.

The fast developing Industrial Internet of Things (IIoT) technologies provide a promising opportunity to build large-scale systems to connect numerous heterogeneous devices into the Internet. Most existing IIoT infrastructures are based on a centralized architecture, which is easier for management but cannot effectively support immutable and verifiable services among multiple parties. Blockchain technology provides many desired features for large-scale IIoT infrastructures, such as decentralization, trustworthiness, trackability, and immutability. This paper presents a blockchain-based IIoT architecture to support immutable and verifiable services. However, when applying blockchain technology to the IIoT infrastructure, the required storage space posts a grant challenge to resource-constrained IIoT infrastructures. To address the storage issue, this paper proposes a hierarchical blockchain storage structure, \textit{ChainSplitter}. Specially, the proposed architecture features a hierarchical storage structure where the majority of the blockchain is stored in the clouds, while the most recent blocks are stored in the overlay network of the individual IIoT networks. The proposed architecture seamlessly binds local IIoT networks, the blockchain overlay network, and the cloud infrastructure together through two connectors, the \textit{blockchain connector} and the \textit{cloud connector}, to construct the hierarchical blockchain storage. The blockchain connector in the overlay network builds blocks in blockchain from data generated in IIoT networks, and the cloud connector resolves the blockchain synchronization issues between the overlay network and the clouds. We also provide a case study to show the efficiency of the proposed hierarchical blockchain storage in a practical Industrial IoT case., Comment: 10 pages, 5 figures, 2019 IEEE International Conference on Blockchain (Blockchain) 978-1-7281-4693-5/19/$31.00 \c{opyright}2019 IEEE

Plant-wide oscillations generated in a single unit can negatively affect the overall control performance of the process; thus, it is necessary to detect them and diagnose their root cause. However, the interference of noise and the need for oscillation propagation routes pose more challenges for process engineers. In this paper, the concept spectral transfer entropy is proposed and its connection to the spectral Granger causality is derived. Moreover, an information transfer method incorporating spectral envelope algorithm and spectral transfer entropy is applied to provide new diagnostic guidance, whose feasibility and effectiveness have been demonstrated by both simulated and industrial case studies. Compared with current methods, the new procedure enjoys the following advantages: (a) performing oscillation detection and diagnosis within a targeted frequency range and mitigating the effects of measurement noise outside the bandwidth; (b) provides an nominal causal map reflecting the oscillation propagat...

A demonstration of a field gateway design that can be configured through a web interface to collect data from multiple data sources using different protocols and stream to cloud based analytics platform

Common application layers are the key to advanced communication and true network integration. ODVA's four best-in-class networks—EtherNet/IP, DeviceNet, ControlNet, and CompoNet—all are linked by one of the industrial automation's most versatile protocols: the Common Industrial Protocol, known as CIP. CIP encompasses a comprehensive suite of messages and services for the collection of industrial automation applications—control, safety, energy, synchronization and motion, information, and network management. CIP allows users to integrate these applications with enterprise-level Ethernet networks and the Internet. IP allows users to benefit today from the many advantages of open networks and protects their existing automation investments, while providing an extensible and upgradable communication architecture. As a single, media-independent platform that is shared by a variety of networking technologies, CIP provides the interoperability and interchangeability that is essential to open networks and open systems. The Base Energy Object acts as an Energy Supervisor for energy implementations in CIP.

WirelessHART™ was released in September 2007 and became IEC standard in April 2010 (IEC 62591). It is the first open wireless communication standard specifically designed for real-time process control applications. It is designed to the same standard as its wired counterpart for reliability and interoperability . To ensure the compliance with the HART™ communication protocol and the adherence to its strict timing requirements, all WirelessHART devices must be thoroughly tested and registered with the HART Communication Foundation (HCF). In this paper, we present Wi-HTest, the test suite developed to exercise WirelessHART devices, thus facilitating compliance assessment . We discuss the detailed architecture of Wi-HTest and highlight several critical features like packet handling with accurate timing control, fault data injection, and the virtual network approach for scalable test setup. We also describe a sniffer called Wi-Analys for capturing WirelessHART packets along with their timing information and a post process suite for analyzing the packets. These three tools together provide the complete compliance verification environment for WirelessHART. Based on the test specification developed by HCF, we presented several representative test cases for examining WirelessHART devices' behaviors in different layers. These test cases in turn show that Wi-HTest is a novel and efficient test suite for verifying the compliance of WirelessHART devices .

6TiSCH network architecture has recently been introduced to combine the high reliability and low-power consumption of the TSCH (Time-Slotted Channel Hopping) mode of IEEE 802.15.4e MAC with the ease of integration offered by the IP-enabled upper layer protocols. 6TiSCH network uses RPL (Routing Protocol for Low Power and Lossy Networks) as its routing protocol to manage the network layer functionalities. RPL however is vulnerable to internal routing attacks such as Rank attack where a malicious node multicasts a fake position (Rank) or a fake path cost toward the sink node to lure nearby nodes to forward their packets through it. In this paper, we propose a hybrid specification-based intrusion detection system (IDS) that consists of centralized and distributed modules installed on the sink and RPL nodes respectively to prevent nodes from selecting an intruder as their successors. The proposed method also eliminates intruders' chances of becoming a time source and disrupt the synchronization of 6TiSCH networks. The results from our extensive simulations show that compared with existing countermeasures, the proposed IDS can effectively protect RPL topologies while only incurring limited network management overhead.

This paper discusses the techniques necessary to implement the InES Linux based IEC 62439-3 (PRP) protocol as a software module within the QNX networking driver environment, which also supports non-PRP traffic simultaneously. Comparisons to other implementations of the PRP stack are discussed. We leverage the NetBSD-based network stack implementation of QNX, and discuss common API calls which are suitable to implement a dual-mode PRP driver for QNX. The software behavior for ingress, egress, and management traffic specific to PRP is discussed at the API level. We show the CPU utilization performance of the PRP network as compared to non-PRP networks, along with QNX microkernel specific concerns. Caveats to this approach and mitigations are discussed.

Many mission-critical and safety-critical applications in networked wireless sensing and control systems have stringent reliability requirements and timing constraints on end-to-end ( E2E ) packet delivery. Late arrivals of packets could severely degrade overall system performance and cause serious problems in system operation. In this paper, we study the data link layer scheduling problem to maximize the reliability of E2E packet delivery in TDMA-based wireless sensing and control networks ( WSCNs ) subject to specified delay constraints. We propose to organize the physical network nodes into logical hypernodes and form a hypergraph for improved scheduling flexibility. Based on the hypergraph, we introduce two data link layer scheduling schemes to maximize the E2E reliability in packet delivery without violating any delay constraints of the packets. The first scheme, named dedicated scheduling , decides how many time slots (TSs) for each hypernode along the path to the destination should be allocated to transmit a packet, and the packets are only transmitted in their scheduled TSs. The second scheme, named shared scheduling , allows the packets to share their scheduled TSs, and thus further improve the E2E reliability. We apply these two schemes in both single-path routing and any-path routing in WSCNs. Asymptotic analysis of the proposed schemes is provided and extensive simulation experiments are performed to illustrate their effectiveness in improving the E2E reliability of packet delivery under different network settings.

Localization in wireless sensor networks is an important functionality that is required for tracking personnel and assets in industrial environments, especially for emergency response. Current commercial localization systems such as GPS suffer from the limitations of either high cost or low availability in many situations (e.g., indoor environments that exclude direct line-of-sight signal reception). The development of industrial wireless sensor networks such as WirelessHART provides an alternative. In this article, we present the design and implementation of ColLoc: a collaborative location and tracking system on WirelessHART as an industrially viable solution. This solution is built upon several technological advances. First, ColLoc adds the roaming functionality to WirelessHART and thus provides a means for keeping mobile WirelessHART devices connected to the network. Second, ColLoc employs a collaborative framework to integrate different types of distance measurements into the location estimation algorithm by weighing them according to their precision levels. ColLoc adopts several novel techniques to improve distance estimation accuracy and decreases the RSSI presurvey cost. These techniques include introducing distance error range constraints to the measurements, judiciously selecting the initial point in location estimation and online updating the signal propagation models in the anchor nodes, integrating Extended Kalman Filter (EKF) with trilateration to track moving objects. Our implementation of ColLoc can be applied to any WirelessHART-conforming network because no modification is needed on the WirelessHART field devices. We have implemented a complete ColLoc system to validate both the design and the effectiveness of our localization algorithm. Our experiments show that the mobile device never drops out of the WirelessHART network while moving around; with the help of even one dependable anchor, using RSSI can yield at least 75% of distance errors below 5 meters, which is quite acceptable for many typical industrial automation applications.

Wireless sensing and networking technologies have taken a strong foothold in the process control industry. The focus has now shifted towards applying control with wireless technology. As such, the current industrial wireless sensor network architectures are under increased scrutiny about their real-time, reliability, and security performances. In this paper, we take a renewed look at network synchronization, the basic building block to support real-time activities. We present our analysis, key observations, and recommendations. We also get into the depth of WirelessHART, the most deployed industrial wireless network architecture, and affirm that, with good practice, we could achieve highly reliable synchronization to provide guaranteed packet deliveries. The correctness of the time synchronization analysis in both line and mesh network topologies is verified through extensive simulation experiments.

Parallel coordinates is a recognized visualization technique in which data points, each defined by multiple coordinates, are represented by an unlimited number of adjoining parallel axes. This type of visualization technique is suitable for process monitoring applications in industrial facilities where a significant number of sensors are used to detect and identify abnormal operating conditions. This work makes use of principal component monitoring methods implemented in parallel coordinates plots, named PC2. The PC2 capabilities to visualize confidence regions of operations, evaluate models with different number of principal components, compare faulty events and determine the frequency of false alarms are here demonstrated. The monitoring visualization technology presented by PC2 was successfully used for early detection of compressor surge and column flooding using actual process data. © 2012 American Institute of Chemical Engineers AIChE J, 59: 445–456, 2013

Wireless technologies have been successfully applied in the process industry since the creation of the first international standard IEC62591 WirelessHART. Applications started in areas where wireless sensors provide rich process information to the automation systems. Although real and demonstrated control applications are advertised, wireless-for-control is still in the initial stage and faces a lot of challenges. In particular, feedback latency and battery longevity, which are also problems for wireless-for-sensing, are even more critical when wireless actuators are applied. There are additional challenges in using wireless actuators because they actively affect the process. This paper lays the foundation for control using a wireless actuator. It demonstrates how traditional control methodologies can be modified to effectively work with general wireless communication. The innovations are tested with simulations and experimentations, both on commercial distributed control systems.

Using wireless communication for sensor networks in industrial settings is now common practice. There are now thousands of industrial wireless sensor and control networks deployed. So the next questions are, “How far can we extend the reach of wireless technologies?” and “Can we utilize the same wireless technology to facilitate the coming of IoT in the industrial settings?” To address both of these questions wireless needs to leverage the wide range of existing sensors and devices that are already in the market. The solution should also be flexible. We report in this paper WirelessCHARM that enables different sensors and actuators to communicate wirelessly in an industrial setting. We describe the design and implementation of WirelessCHARM. A demonstration is built to integrate various types of devices into a commercial distributed control system.

This work demonstrates that parallel coordinates is a recognized visualization technique suitable for process monitoring applications in industrial facilities, where a significant number of sensors are used to detect and identify abnormal operating conditions. Principal Component monitoring methods implemented in Parallel Coordinates, named PC 2 , permits to compare faulty events and determine the frequency of false alarms. The monitoring visualization technology presented by PC 2 was successfully applied to column flooding using actual process data.

WirelessHART™ was released in September 2007 and became an IEC standard in April 2010 (IEC 62591). It is the first open wireless communication standard specifically designed for process measurement and control applications deployed in harsh and noisy environments. WirelessHART distinguishes itself from other public standards by maintaining a central Network Manager. The Network Manager is responsible for maintaining up-to-date routes and communication schedules for the network, thus guaranteeing the reliable and real-time network communications. To deal with the intensive computation requirement in a centralized WirelessHART Network Manager, particularly of middle or large scale network sizes, in this article, we utilize parallelization techniques to implement the Network Manager on embedded multicore architectures. By leveraging the multicore capabilities of the AMD Embedded G-Series Dual-Core processor, we utilize the Texas Multicore Technologies' (TMT) SequenceL™ language and runtime environment to parallelize the algorithms proposed in our previous work for constructing reliable routing graphs and real-time communication schedule. Our experiments show that AMD Embedded G-Series is an ideal platform for medium to large size WirelessHART network and SequenceL™ language can help significantly reduce the development cycle and further improve the algorithm efficiency and system performance in embedded multicore architectures.

Security has become a key consideration in industrial settings. Newer technologies, such as wireless sensor networks, have adopted the position that security is mandatory. For wireless sensor applications it is important to secure data in transit in the air, to authenticate data originating from, or arriving at the wireless devices and applications, and, most important, to protect the safety and integrity of the legacy process control and plant safeguarding systems that the new wireless world interconnects into. Current industrial wireless mesh networks, such as WirelessHART™, ISA100.11a, and WIA-PA, have adopted AES 128 bit encryption for both securing communications and data. To ensure that devices and applications are authenticated special join keys are used. The process of loading these keys is called provisioning. To ensure that join keys remain secret they are loaded offline through special wired interfaces or provisioned over the air using less secure mechanisms. What is needed is a low cost efficient public key mechanism that can be utilized over the air while not compromising security. This paper examines the use of elliptic curve cryptography for this purpose. We realize this technique on a WirelessHART mesh network. Efforts are underway to incorporate this approach as an addition to the WirelessHART standard.

Unlike wired networks, the configuration and the behavior of wireless networks are heavily dependent on many environmental factors. While this makes it more difficult to build a wireless network testbed whose behavior is controllable, it also makes the availability of such a testbed all the more desirable. Indeed, the difficulties in building a good wireless mesh testbed belie the fact that most research work on mesh network performance is backed up only by computer simulations. In this paper, we present a practical design philosophy in which a realistic and controllable wireless mesh network testbed is built with a relatively small deployment of physical equipments by exploiting the idea of a virtual network. Specifically, we simulate a virtual network within the testbed and use one physical wireless transceiver to simulate multiple virtual devices. An observer who only reads the transmitted wireless messages will not be able to tell the difference from a real wireless mesh. Our approach has been adopted in a recent industry-standard testing suite, namely, Wi-HTest. In this paper, we shall discuss our experience in building Wi-HTest by applying the virtual network approach.

There are different kinds of applications running in a process plant, ranging from auxiliary to critical. They are categorized into three groups, Class C applications for monitoring, Class B applications for control, and Class A applications for safety. As a new technology, wireless sees its early deployment in monitoring rather than controlling. And the early wireless devices are sensors rather than actuators. Most of the wireless network applications at the device level are sensing for logging and monitoring. Although work is underway to apply wireless to control applications, wide spread use of wireless in control applications and safety systems is still some time off. While wireless technology needs to advance to tackle the industrial real-time challenges, the traditional process control application also deserve a second look. In this chapter we discuss the challenges of applying wireless in process control in general, and our preliminary study on adapting closed-loop control for wireless communications.

In this chapter we discuss general topics related to the WirelessHART standard. They are grouped into the relationship with OSI network layers, radio basics, centralized control, field survey, relationship with the IEEE 802.15.4 standard, coexistence, other fieldbuses, the limitations, security and reliability, and what it means to the user. The topics are listed as section titles.

The network community has done a lot of research work on wireless mesh networks. Many of them are theoretical. They are validated through simulations or in limited test environments. Wireless mesh in the industrial settings, especially in a process plant, is getting more and more interests. Different from mobile ad hoc meshes in offices or homes, a wireless mesh in a process plant must satisfy real-time requirements, sometimes even hard real-time requirements in which missing a deadline may have catastrophic consequences. Real-time or embedded applications are considered far more difficult than PC based applications. Likewise, real-time wireless network is also very difficult. The time is ripe for the research into industrial wireless mesh networks. Many topics throughout this book are worth studying by the academia. This chapter will re-emphasize some of them. process control industry embrace wireless technology accelerates wireless technology development. The process industrial setting provides a real world test environment for any theories and ideas developed over the past decade by the network research community.

WirelessHART conformance testing requires test specifications and test tools. The test tools include the Wi-HTest tool, the Wi-Analys tool, and a post process suite for analyzing the packets captured by the Wi-Analys tool. The post processing utilities also summarize test results and generate the final compliance report. The Wi-Analys tool is a passive packet sniffer that captures all WirelessHART messages for analysis; The Wi-HTest tool provides a combination of network management, gateway, access point, script execution, and communications. The Wi-HTest tool joins the device under test then supports test script execution by allowing the test to introduce perturbations. The Network communications are captured by the Wi-Analys tool and sent to the post-processor for evaluation. Combined the number of wired and wireless tests totals over 200. These tests cover hundreds of different testing scenarios and thousands of different failure points. Each test script entails an execution of the Wi-HTest tool. To better manage the overall test process, special messages intended for the Wi-Analys tool are emitted as part of the Wi-HTest scripts.

Most of the device attribute values could be set by the network manager. Here we list some default values when they are not configured.

The WirelessHART standard extends the traditional HART standard with wireless capabilities. It is important for existing HART devices to support WirelessHART. The WirelessHART adapter is specially defined to connect wired HART device to host applications via the WirelessHART network. In this chapter we follow the principle of a WirelessHART adapter and suggest a fast solution to equip HART devices with wireless capability without much change to the existing HART devices. This could serve as an intermediate solution before a fully integrated WirelessHART device is developed. In many cases this might also be the final solution for the HART device vendors.

In this chapter we delve into some details of selected topics on the network. They are grouped into device life cycle, routing, host communication, network management, redundancy, scalability, battery consumption, interoperability, and unwanted access. The topics are listed as section titles.

In the ISO™ OSI™ 7 level network design the network layer is responsible for network routing functions. It handles the addressing and delivery of data. The transport layer controls the reliable and timely transmission of data between two network nodes through flow control, segmentation and desegmentation, and error control. The session layer manages the dialogue, session, and connections between two network nodes. In WirelessHART standard the network layer encompasses all three OSI layers. It is the point of convergence for traditional HART Token-Passing Networks and WirelessHART TDMA-based networks. This chapter lists the services that the network layer provides to the upper application link layer. It talks about the communication traffic, routing, and security. It also describes the format of the network layer PDU. Please refer to the Network Management Specification (HCF_SPEC-85) for more details.

The data link layer provides the reliable means to transfer data between network nodes by detecting and possibly correcting errors that may occur in the physical layer. This layer has the important task of creating and managing data frames. There are usually two sublayers, Logical Link Control (LLC) layer and Medium Access Control (MAC) layer. LLC layer defines the service to the network layer and MAC defines how the communication medium is accessed by multiple nodes. This chapter lists the services that the WirelessHART data link layer provides to the upper network layer. It further describes in more detail the LLC and MAC layers. We describe the message format and its flow control, error detection, and security. We also describe how to maintain slot synchronization with TDMA, schedule slots to listen for packets from neighbors and propagate packets from the network layer. Please refer to the TDMA Data Link Layer Specification (HCF_SPEC-75) for more details.

This chapter consists of four sections. In section 18.1 we discuss areas where a wireless application has advantages and where wireless applications could be used to replace existing wired applications. We also list new applications that have not been addressed, or have been poorly addressed, with wired applications. In section 18.2 we discuss location awareness applications and techniques. Location tracking will be a major component of wireless plant applications in the future. A location-determination application in the WirelessHART standard is also described. Section 18.3 talks about cyberphysics for which wireless sensor network could be the immediate interface to the physical world. And the last Section 18.4 reveals the future directions of wireless and offers some thoughts on how the WirelessHART standard will evolve to meet these directions.

WirelessHART was released in September 2007 and is the first open wireless communication standard specifically designed for real-time process control applications. It is designed to the same standards as its wired counterpart for reliability and interoperability. To ensure the compliance with the HART Communication Protocol and the adherence to its strict timing requirements, all WirelessHART devices must be thoroughly tested and registered with the HART Communication Foundation (HCF). In this paper, we present Wi-HTest, the test suite designed to exercise WirelessHART devices, thus facilitating compliance assessment. We discuss the detailed architecture of Wi-HTest and highlight several critical features like packet handling with accurate timing control and fault data injection. We also describe a sniffer called Wi-Analys for capturing WirelessHART packets along with their timing information and a post process suite for analyzing the packets. These three tools together provide the complete compliance verification environment for WirelessHART. Based on the test specification developed by HCF, a representative test case is conducted for the purpose of demonstration. This test case in turn shows that Wi-HTest is a novel and efficient test suite for verifying the compliance of real-time WirelessHART devices.

WirelessHART is the first open wireless standard for the process control industry. Previously we demonstrated a three-node prototype network based on an early release of the protocol stack. In this demonstration we build a fully operational WirelessHART sensor network of multiple nodes. We show the creation of the network and the execution of process monitoring applications on the network. This new demonstration network serves as a proof of concept for the revised WirelessHART standard and as a platform for our future research and experiments.

Wireless technology has been regarded as a paradigm shifter in the process industry. The first open wireless communication standard specifically designed for process measurement and control applications, WirelessHART was officially released in September 2007 (as a part of the HART 7 Specification). WirelessHART is a secure and TDMA- based wireless mesh networking technology operating in the 2.4 GHz ISM radio band. In this paper, we give an introduction to the architecture of WirelessHART and share our first-hand experience in building a prototype for this specification. We describe several challenges we had to tackle during the implementation, such as the design of the timer, network wide synchronization, communication security, reliable mesh networking, and the central network manager. For each challenge, we provide a detailed analysis and propose our solution. Based on the prototype implementation, a simple WirelessHART network has been built for the purpose of demonstration. The demonstration network in turn validates our design. To the best of our knowledge, this is the first reported effort to build a WirelessHART protocol stack.