What Is A Wireless Sensor Network?
With the NI wireless sensor network (WSN) platform, you easily can monitor your assets or environment with reliable, battery-powered measurement nodes that offer industrial ratings and local analysis and control capabilities. Each wireless network can scale from tens to hundreds of nodes and seamlessly integrate with existing wired measurement and control systems.
Understanding the WSN Architecture
A wireless sensor network consists of three main components: nodes, gateways, and software. The spatially distributed measurement nodes interface with sensors to monitor assets or their environment. The acquired data wirelessly transmits to the gateway, which can operate independently or connect to a host system where you can collect, process, analyze, and present your measurement data using software. Routers are a special type of measurement node that you can use to extend WSN distance and reliability. Learn more about each of these components in the sections below.
WSN Architecture
WSN Architectures
Combine different types of nodes and gateways to meet the unique needs of your application. Create a simple, PC-based wireless sensor network (WSN) monitoring system with the NI WSN-9791 Ethernet gateway, or a headless, embedded monitoring system with the NI 9792 programmable gateway, which can run deployed NI LabVIEW Real-Time applications. For applications that require the combination of high-speed I/O (or control) and distributed wireless monitoring, take advantage of the NI 9795 C Series WSN gateway.
Gateways
In a WSN system, the gateway acts as the network coordinator in charge of node authentication and message buffering. The gateway collects measurement data from distributed nodes and bridges to the enterprise network, where you can collect, process, analyze, and present your measurement data using a variety of NI software. In your WSN, you can use multiple gateways, each communicating on a different, nonoverlapping software-selectable wireless channel.
Programmable Gateway
The NI 9792 is a LabVIEW Real-Time controller and a WSN gateway, making it an ideal product for embedded wireless data logging. With dual Ethernet ports, you can communicate with a variety of devices from your LabVIEW Real-Time application, such as enterprise level networks or cellular modems. This high-performance industrial controller features a 533 MHz processor, 2 GB of onboard storage, and a 2.4 GHz IEEE 802.15.4 radio to communicate with up to 36 distributed NI WSN measurement nodes (in a mesh configuration). Take advantage of the integrated Web server to remotely access WSN system data.
C Series Gateway
The NI 9795 delivers tight integration between the NI WSN and CompactRIO platforms. This NI C Series gateway plugs into any available slot in your CompactRIO system so you can complement existing measurement and control systems with wireless I/O. The gateway can communicate with up to 36 distributed NI WSN measurement nodes (in a mesh configuration), delivering wireless measurement data to the LabVIEW Real-Time application running on the CompactRIO system.
Ethernet Gateway
Unlike the NI 9792 programmable gateway that operates headlessly by running deployed LabVIEW Real-time applications, the NI WSN-9791 Ethernet gateway is a pass-through device that must be connected to a host system. This gateway has a 2.4 GHz, IEEE 802.15.4 radio to collect measurement data from the sensor network and a 10/100 Mbit/s Ethernet port to provide flexible connectivity to a Windows or LabVIEW Real-Time host controller.
Measurement Nodes
NI WSN measurement nodes feature direct sensor connectivity, reliable communication, and industrial ratings. The devices are battery-powered, offering up to a three-year lifetime on four AA batteries, and you can combine them with NI outdoor enclosures for long-term outdoor deployment. With the programmable nodes, you can use the LabVIEW WSN Module to customize node behavior, adding intelligence to perform local analysis and control. See the software section to learn more about programmable nodes and LabVIEW WSN capabilities.
NI WSN-3202 Analog Input Measurement Node
The NI WSN-3202 measurement node offers four ±10 V analog input channels with selectable input ranges and four bidirectional digital channels that you can program for event detection or local control. The 18-position screw-terminal connector delivers direct connectivity to sensors and offers a 12 V, 20 mA sensor power output that you can use to drive sensors that require external power.
NI WSN-3212 Thermocouple Measurement Node
The NI WSN-3212 measurement node provides four 24-bit thermocouple input channels and four bidirectional digital channels that you can program for event detection or local control. The node supports J, K, R, S, T, N, B, and E thermocouple types, and you also can use each thermocouple input channel as a ±73mV analog input channel.
NI WSN-3226 Voltage/RTD Combination Node
The NI WSN-3226 measurement node adds resistance-based measurements, such as resistance temperature detectors (RTDs) and potentiometers, to the NI WSN platform. The WSN-3226 has four analog input channels that you can configure on a per-channel basis for ±10 V measurements or resistance-based measurements, so you can combine temperature and voltage measurements on a single device. The device also features two bidirectional digital channels with industrial voltage ranges that you can program for event detection or local control. The WSN-3226 has 50/60 Hz noise rejection and a 12 V, 50 mA sensor power output that you can use to drive sensors requiring external power.
NI WSN-3214 Strain/Bridge Completion Node
The NI WSN-3214 strain/bridge completion node, which brings waveform acquisition capabilities to the WSN product line, is ideal for wireless structural health monitoring applications. The node features four analog channels that support quarter-, half-, and full-bridge completion, as well as two digital I/O channels for event detection and programmatic control. With the LabVIEW WSN Module, you can process and analyze strain data on the node to determine or predict the presence of fault conditions. You can then choose to transmit the entire waveform or only meaningful, analyzed data, which reduces the amount of wirelessly transmitted data, thereby prolonging WSN measurement node battery life.
NI WSN-3230 RS-232 Serial Node
The WSN-3230 features one RS232 port to communicate with serial-based sensors and instruments. This programmable-only node functions as an autonomous serial interface. Using the LabVIEW WSN Module, you can embed query and parse algorithms directly on the WSN nodes to create a remote, programmable interface to a variety of serial devices. The node also features two digital I/O channels for event detection and programmatic control.
NI WSN-3231 RS-485 Serial Node
The WSN-3231 features one RS485 port to communicate with serial-based sensors, instruments, and control boards. This programmable-only node functions as an autonomous serial interface. Using the LabVIEW WSN Module, you can embed query and parse algorithms directly on the WSN nodes to create a remote, programmable interface to a variety of serial devices. The node also features two digital I/O channels for event detection and programmatic control.
Software
LabVIEW is a graphical development environment with configuration-based tools and powerful programming capabilities for developing measurement, analysis, and control applications with professional user interfaces. You can use LabVIEW and a variety of add-on modules to configure and program your WSN for functions such as data logging, event detection, alarming, short message service notifications, and Web-based network data visualization.
LabVIEW WSN Module
The LabVIEW WSN Module can help you create and deploy embedded applications to programmable NI WSN measurement nodes using the LabVIEW graphical development environment – no embedded programming knowledge is required. Use the LabVIEW WSN Module to:
- Extend battery life by optimizing node sample and transmit behavior
- Preprocess acquired data before transmitting it to a gateway
- Perform on-node thresholding or dead-band data analysis
- Respond to digital value changes
- Programmatically respond to acquire data by adapting sample and transmission rates or triggering digital lines to turn devices on or off
- Send and receive messages to and from the gateway
- Detect and react to network status changes
LabVIEW Real-Time Module
NI real-time technology offers reliable, deterministic performance for your time-critical applications. Use the LabVIEW Real-Time Module to develop and deploy embedded applications to the NI 9792 programmable gateway.
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