Wireless sensor network (WSN) devices are one of the key components of the latest, in a long line, of bleeding edge technology trends. The Internet of Things (IoT) is a new design paradigm which emphasizes ubiquitous network connection and data acquisition among global networked machines and physical objects e.g. sensors, actuators, machine-to-machine (M2M) devices using wireless sensor networks.
The IoT is composed of four layers, the application layer, service layer, network layer and device layer. The application layer is the real application system; the service layer is now defined as cloud computing; the network layer is the wired/wireless network infrastructure whilst the device layer connects everything to the Internet and is the key infrastructure of the IoT.
The WSN fits in with the network and devices layers. From a device layer point of view, it consists of a wireless technology and sensor solution/interface to collect and transmit analog/digital signals to the main controller. The wireless technology is based on IEEE 802.15.4 and its many protocols, such as ZigBee, 6LoWPAN and WirelessHART. Using a variety of I/Os and sensors, signals can be measured everywhere through the wireless network. For example, balance of bridges can be measured through strain gauges sensors, and energy consumption in the buildings can be measured using a wide range of sensors such as power, water and gas meters. Wireless Sensor Networks can be built using a few or a lot of “nodes”. Each node can be connected to one or several sensors; the network topology is composed of three components: Coordinator/Gateway which is the data collection center and transfers and translates wireless data to other devices; Router which enhances the wireless signal and a wireless router is used to select the optimal path for wireless communication between the coordinator and the end nodes; and End Device (aka End Node) which is a wireless remote I/O for data acquisition. The data is acquired from sensors and then transmitted through the nodes and coordinator directly or via a router.
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| Figure 1: Three components of a wireless sensor network |
Advantech’s ADAM-2000 series is an industrial grade Wireless Sensor Network I/O solution which utilizes IEEE 802.15.4 wireless technology and supports star, tree and mesh topologies. ADAM-2000 series provides a low-power consuming, cost-efficient and reliable wireless network for remote monitoring applications. Once the modules are configured, the ADAM-2000 series will automatically construct the most suitable network topology for your control system without further setting. There are several models in the series, including coordinator/gateway ADAM-2520Z; router ADAM-2510Z; digital input ADAM-2051Z and ADAM-2051PZ; relay output and sensor modules ADAM-2031Z. To perform as a Wireless Sensor Network, a gateway ADAM-2520Z is essential for collecting data from end nodes. With the supported Modbus RTU protocol, the ADAM-2000 series can be easily integrated into any SCADA or Modbus RTU compliant system to extend the coverage of the control system.
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| Figure 2: Advantech’s wired and wireless solutions |
