NI WSN Product and Configuration Guide

Publish Date: Aug 24, 2011 | 18 Ratings | 3.83 out of 5 |  PDF

Overview

Wireless measurement systems can overcome power and network infrastructure limitations and meet new and previously difficult application challenges. They deliver reduced costs and increased flexibility compared to traditional wired measurement systems, and they offer the ability to achieve long-term deployments with reliable, battery-powered devices. This white paper examines the NI wireless sensor network (WSN) product offering, which delivers seamless NI LabVIEW integration as well as advanced customization options. The paper also describes WSN architecture options that you can choose from to meet your application needs.

Table of Contents

  1. Wireless Sensor Networks
  2. NI WSN Products
  3. WSN Architectures
  4. Additional Resources

1. Wireless Sensor Networks

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.  Each wireless network can scale from tens to hundreds of nodes and seamlessly integrate with existing wired measurement and control systems.

The NI WSN platform provides options in each of these categories so that you can customize your WSN to meet the unique needs of your application.  This whitepaper describes the different NI WSN hardware and software products and provides architecture examples that can get you going in the right direction for your application.  

Back to Top

2. NI WSN Products

Gateways

In an NI WSN system, the gateway acts as the network coordinator in charge of node authentication, message buffering, and bridging from the IEEE 802.15.4 wireless network to the wired ethernet network, where you can collect, process, analyze, and present your measurement data using a variety of NI software.  You can use multiple gateways in your WSN, each communicating on a different, non-overlapping wireless channel, which is selectable in software.  You can connect 8 WSN end nodes (in a star topology) or up to 36 WSN nodes (in a mesh topology) to each WSN gateway.  There are three gateway options for your NI wireless sensor network.


Figure 1. NI 9792 Programmable Gateway
  • LabVIEW Real-Time Target
  • 533MHz processor
  • 2GB Onboard Storage
  • Integrated Web Server
  • 2.4 GHz, IEEE 802.15.4 radio to communicate with NI WSN measurement nodes
  • Dual Ethernet ports
  • -40 to 70°C temperature rating
  • 9 to 35 VDC redundant power inputs
  • Panel & DIN-Rail Mounting options

The NI 9792 is a LabVIEW Real-Time controller and a WSN gateway, meaning this gateway can operate independently, without a connection to a host machine.  Deployed LabVIEW Real-Time applications can run locally on the gateway, collecting WSN data and interfacing with other devices in the system, such as cell modems or enterprise networks.  With the serial ports and 10/100 Mbit/s and 10/100/1000 Mbit/s Ethernet ports, you can communicate via TCP/IP, UDP, Modbus/TCP, and serial protocols.

With 2GB of onboard storage, the NI 9792 is perfect for embedded monitoring applications in which you would like to aggregate data from distributed wireless measurement nodes. The NI 9792 also features integrated Web (HTTP) and file (FTP) servers so that you can host measurement data for remote access anywhere with an Internet connection. 

 


Figure 2. NI WSN-9791 Ethernet Gateway
  • 2.4 GHz, IEEE 802.15.4 radio to communicate with NI WSN measurement nodes
  • Ethernet connectivity to Windows or LabVIEW Real-Time host controllers
  • -30 to 70°C temperature rating
  • 9 to 30 VDC powered

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, where you can process and visualize data with LabVIEW.

 


Figure 3. NI 9795 C Series Gateway
  • Direct integration with NI CompactRIO
  • Seamlessly combine wired and wireless systems
  • Communicate with up to 36 distributed nodes per NI CompactRIO chassis

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. 

Measurement Nodes

NI WSN measurement nodes feature direct sensor connectivity, reliable communication, and industrial ratings.  The devices are battery powered, offering up to a 3-year lifetime on 4AA batteries, and can be combined with NI outdoor enclosures for long-term outdoor deployment.  

You can use the LabVIEW WSN Module and graphical programming to customize node behavior, adding intelligence to extend battery life, perform local control, increase acquisition rates, log data locally, and interface with custom sensors. You can download LabVIEW WSN applications wirelessly to NI WSN measurement nodes, allowing seamless updates to deployed nodes.  See the software section of this document to learn more about the capabilities of LabVIEW WSN (Note that you must purchase the programmable version of NI WSN nodes to take advantage of these capabilities).

Figure 4. NI WSN-3202 Four-Channel, 16-Bit,
±10 V Analog Input Measurement Node

  • Battery-powered by 4 AA alkaline cells, with up to three-year battery life
  • Four analog input channels
  • Selectable input ranges – ±10, ±5, ±2, and ±0.5 V
  • Sensor power output, up to 20mA at 12 V
  • Four digital channels, configurable per channel for input, sinking output, or sourcing output
  • -40 to 70°C temperature rating

 

Figure 5. NI WSN-3212 Four-Channel, 24-Bit, Thermocouple Input Measurement Node

  • Battery-powered by 4 AA alkaline cells, with up to three-year battery life
  • Four thermocouple input channels
  • Support for J, K, R, S, T, N, B, and E thermocouple types
  • Four digital channels, configurable per channel for input, sinking output, or sourcing output
  • -40 to 70°C temperature rating

 

Figure 6. NI WSN-3226 Four-Channel, 20-Bit, Voltage/RTD Combination Node

  • Adds support for RTDs, potentiometers and other resistance-based measurements
  • Battery-powered by 4 AA alkaline cells, with up to three-year battery life
  • Supports battery back-up
  • 5 - 30V external power input, ideally suited for energy harvesting applications
  • Four analog input channels, selectable per channel for ±10V or resistive measurements
  • 50/60 Hz filtering
  • Two digital channels, configurable per channel for input, sinking output, or sourcing output
  • -40 to 70°C temperature rating

 

Figure 7. NI WSN-3214 Four-Channel, 20-Bit, Strain Gauge/Bridge Completion Node

  • Four analog input channels that support quarter/half/full bridge completion, strain gauge, and ratiometric measurements
  • Hardware-time waveform acquisition, with sample rates up to 1kS/s/channel
  • Ideal for wireless structural health monitoring applications
  • Battery-powered by 4 AA alkaline cells, with up to three-year battery life
  • Supports battery back-up
  • 5 - 30V external power input, ideally suited for energy harvesting applications
  • Two digital I/O channels
  • -40 to 70°C temperature rating

 

Figure 8. NI WSN Serial Nodes 

(WSN-3230 & WSN-3231)

  • Create a wireless, autonomous interface to serial-based sensors, instruments, and control boards
  • RS-232 and RS-485 variants
  • One serial port per node
  • Requires the use of the LabVIEW WSN Module to embed serial communication programs onto the node
  • Battery-powered by 4 AA alkaline cells, with up to three-year battery life
  • Supports battery back-up
  • 5 - 30V external power input, ideally suited for energy harvesting applications
  • Two digital I/O channels
  • -40 to 70°C temperature rating

The high-accuracy NI WSN measurement nodes provide four analog input channels (or a single serial port) and up to four digital input/output channels for easy sensor connectivity, and you can configure each digital channel as input, sinking output, or sourcing output. The WSN-3202 and WSN-3226 also offer a 12 V, 20-50 mA sensor power output line that draws from the battery or external power supply to drive external sensors. 

These rugged devices feature industrial shock and vibration specifications and -40 to 70 °C temperature ratings. A 2.4 GHz, IEEE 802.15.4 radio provides a 300 m outdoor range with line of sight and allows the measurement nodes to form a reliable mesh network. When you configure the nodes as mesh routers, they must remain on at all times to send and receive data across the network. In this case, it is recommended that you power them with an external source such as a DC supply, energy harvesting source, or larger battery. 

Software

NI-WSN

NI-WSN software that ships with NI WSN gateways allows you to quickly and easily extract measurement data from your wireless sensor network. After you add a WSN gateway to a LabVIEW Project, the nodes configured with the gateway in MAX automatically populate in the LabVIEW Project, giving you instant access to their I/O and properties. Simply drag and drop I/O variables from the LabVIEW Project to a LabVIEW block diagram for data extraction, analysis, and presentation. You can also use I/O variables to monitor node attributes such as link quality and battery voltage and determine if a node is configured as an end device or mesh router. You can create a simple data extraction program or integrate your WSN LabVIEW code into a complete wired and wireless measurement and analysis program.

Figure 9. A Host Controller VI Programmed Using NI-WSN Software

NI-WSN software also delivers easy network configuration using the NI Measurement & Automation Explorer (MAX) utility. MAX provides an intuitive user interface to add and remove measurement nodes and configure wireless settings. You can also use MAX to view all of the nodes in your WSN and their last communication time, battery status, and link quality. In addition, MAX provides an interface to set the wireless communication channel, configure the Gateway IP address, wirelessly update firmware on the measurement nodes, and configure a node to act as an end node or router.

LabVIEW WSN Module

Using the LabVIEW WSN Module you can wirelessly download graphical code to run on WSN measurement nodes.  This allows you to customize node firmware and optimize the node for your unique application.  You can use LabVIEW WSN to perform local data logging and processing, configure node properties, respond to digital value changes, turn on and off relays connected to digital lines, and respond to network status changes.

In addition, one of the most important benefits of LabVIEW WSN is that it allows you to optimize node behavior in terms of sample rate vs. battery life.  The default behavior of an NI measurement node is to sample all channels and transmit every sample acquired to the gateway; however, this is not a requirement for many applications. In some applications, battery life is more important.  In this case, you can use LabVIEW WSN to only sample the channels you want to sample, instead of all channels using the factory-default firmware.  Furthermore, you can transmit only meaningful data, say temperature above a certain threshold, to keep the radio off and preserve battery power.  In applications where sample rate is more important, you can customize the node to change sample interval based on certain conditions or events, or sample faster locally and transmit the data to the gateway in chunks at a later time.  

Figure 10.  Configuring Node Properties and Performing Threshold Analysis Using LabVIEW WSN

 

Note that you must purchase the programmable versions of the measurement nodes along with the LabVIEW WSN software to obtain these capabilities.  Read the whitepaper to learn more about the LabVIEW WSN Module.

Back to Top

3. WSN Architectures

NI WSN systems offer you the flexibility to create a simple, stand-alone wireless monitoring network or a completely integrated wired and wireless measurement solution, with access to the full breadth of NI platforms through LabVIEW. 

As described above, each WSN gateway provides different connectivity options.  The WSN-9791 Ethernet Gateway must be connected to a host machine (Windows PC or LabVIEW Real-Time controller), while the NI 9792 can operate independent of a host and run deployed LabVIEW Real-Time applications.   The NI 9795 must be combined with an NI CompactRIO chassis, delivering an ideal platform for combining high-speed local I/O, FPGA analysis, and distributed wireless monitoring. 

Figure 11.  Choose a WSN architecture that meets the unique needs of your application

Back to Top

4. Additional Resources

With LabVIEW and the NI platform, there are countless ways to customize and enhance your WSN system. To get started today, order an NI WSN Starter Kit, which contains all the hardware and software you need to evaluate NI WSN technology and LabVIEW.

Learn more about the benefits of NI Wireless Sensor Networks

Read about WSN applications and customers using NI Wireless Sensor Networks

Use solar and vibration energy harvesting to power NI WSN nodes

Tutorial:  Getting Started with NI Wireless Sensor Networks

Back to Top

Bookmark & Share


Ratings

Rate this document

Answered Your Question?
Yes No

Submit