Industrial wireless sensor networks (IWSNs) have mainly been used to monitor applications, but recently an interest in control and safety applications has emerged. Functional safety and communication in open transmission systems have been laid down in the IEC 61784-3-3 standard. The standard is based on a cyclic polling mechanism, which consumes a considerable amount of bandwidth; since existing IWSNs are very resource-constrained, this becomes a major challenge. To overcome this problem, this paper proposes a novel framework that uses an event-triggered failsafe mechanism based on synchronous wired polling and wireless time-slotted time division multiple access. We analytically derive the minimum and maximum bound for the most important metric for safety-critical applications, safety function response time (SFRT). A new metric, normal state interrupt time (NSIT), is proposed in this paper. Furthermore, we also implement the proposed framework by using the WirelessHART standard. The results are compared to the classical time-triggered approach used in the IEC 61784-3-3 standard. The obtained results show that the proposed framework can reduce the bandwidth usage by 90% and support safety-critical applications that require a SFRT less or equal to 150 ms.

中文翻译：

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Safe-WirelessHART：一种新型框架，可在工业 WSN 上实现安全关键型应用


工业无线传感器网络 (IWSN) 主要用于监控应用，但最近出现了对控制和安全应用的兴趣。 IEC 61784-3-3 标准规定了开放式传输系统中的功能安全和通信。该标准基于循环轮询机制，会消耗大量带宽；由于现有的 IWSN 资源非常有限，这成为一个重大挑战。为了克服这个问题，本文提出了一种新颖的框架，该框架使用基于同步有线轮询和无线时隙时分多址的事件触发故障安全机制。我们通过分析得出安全关键应用最重要指标安全功能响应时间 (SFRT) 的最小和最大界限。本文提出了一种新的度量标准，即正常状态中断时间（NSIT）。此外，我们还使用 WirelessHART 标准实现了所提出的框架。将结果与 IEC 61784-3-3 标准中使用的经典时间触发方法进行比较。获得的结果表明，所提出的框架可以减少 90% 的带宽使用，并支持需要 SFRT 小于或等于 150 ms 的安全关键型应用。