Wireless Data Acquisition in. LabVIEW

Transcription

1 Telemark University College Department of Electrical Engineering, Information Technology and Cybernetics Wireless Data Acquisition in HANS-PETTER HALVORSEN, LabVIEW Faculty of Technology, Postboks 203, Kjølnes ring 56, N-3901 Porsgrunn, Norway. Tel: Fax:

2 Preface It's not just phones and computers that can communicate wirelessly with the outside world. Wireless sensors appear both in medicine, in buildings and especially in industrial applications. It is developed more standardized radio network for wireless sensors. Zigbee is probably the most famous, where more than 300 large and small companies working to develop solutions. For industrial use requires special safety requirements. Radio network must have sufficient coverage to obtain an acceptable error rate. The network should have redundancy so that the random outcome can be repaired automatically. It is achieved in that messages can go several ways from the sensors to the centers. Also, the network for error handling and error correction so that random errors are corrected. Because of these requirements it has been shown that ZigBee is not always suitable for use in the industrial context. This particularly applies it in process control, where resistance to electromagnetic noise and encryption of the signals is important. A wireless standard specifically designed to satisfy industrial requirements is Wireless HART. This is based on the same physical radio technology such as ZigBee, but specifies additional frequency hopping to mitigate interference, better encryption and that provides for lower power consumption. Currently, the wireless sensors have been used for monitoring, where a human operator must decide whether the process parameters should be changed or not. The objective is that the technology will prove to be robust enough to also be used to process control where the changes in the industrial processes should happen automatically without human intervention. This will be the next major challenge for systems based on wireless technology. Wireless technology has many potential benefits for remote monitoring applications; however, it has been slow to see adoption in industry because of the complexities of programming and deploying a reliable, secure, and high-performance wireless system. NI Wi-Fi data acquisition (DAQ) devices meet these challenges by combining IEEE wireless or Ethernet communication, direct sensor connectivity, and the flexibility of NI LabVIEW software. Some Application Areas for Wireless technology such as Wi-Fi monitoring: ii

3 Challenges with wireless data acquisition technology: Proprietary protocols and network hardware Incomplete I/O offerings High-speed waveform measurements Lack of interoperability between suppliers Integration with existing wired systems Non-standard vendor-defined solutions National Instruments (NI), the vendor of the LabVIEW programming environment delivers several solutions for wireless monitoring and data acquisition. NI Wi-Fi data acquisition (NI Wi-Fi DAQ) devices combine IEEE b/g wireless or Ethernet communication, direct sensor connectivity, and the flexibility of NI-DAQmx software for remote monitoring of electrical, physical, mechanical, and acoustic signals Faculty of Technology, Postboks 203, Kjølnes ring 56, N-3901 Porsgrunn, Norway. Tel: Fax:

4 This document introduces wireless data acquisition features and teaches you how you can simplify wireless remote measurements without compromising on the security or performance of a cabled data acquisition solution. Faculty of Technology, Postboks 203, Kjølnes ring 56, N-3901 Porsgrunn, Norway. Tel: Fax:

5 Table of Contents Preface...ii Table of Contents... v 1 Wireless Technology Bluetooth Wireless USB ZigBee (IEEE ) Wi-Fi (IEEE ) Wireless Sensor Network (WSN) Wireless Standards ZigBee (IEEE ) IEEE WirelessHART Wireless Mesh Network (WMN) Introduction to LabVIEW Dataflow programming Graphical programming Benefits Introduction to Data Acquisition (DAQ) Introduction to DAQ - Data Acquisition Physical input/output signals DAQ device/hardware Driver software Your software application (Application software) MAX Measurement and Automation Explorer v

6 vi Table of Contents 4.3 NI-DAQmx DAQ Assistant Introduction to Wireless Data Acquisition NI Wireless DAQ Devices NI WLS NI WAP NI UES PS-5 Power Supply NI WSN Devices Devices NI WSN WSN Ethernet Gateway NI WSN Thermocouple Input Node NI WSN Analog Input Node LabVIEW Drivers... 25

7 1 Wireless Technology Wireless technology and wireless networks are widely used today, but it s quite new in industrial automation systems. There are different technologies and wireless standards available: Bluetooth Wireless USB ZigBee (IEEE ) Wi-Fi (IEEE ) 1

8 2 Wireless Technology Different wireless technologies: The Figure below compare the different wireless technologies: Wi-Fi and ZigBee are the primary wireless technologies for measurement and control systems. 1.1 Bluetooth

9 3 Wireless Technology 1.2 Wireless USB

10 4 Wireless Technology 1.3 ZigBee (IEEE ) 1.4 Wi-Fi (IEEE )

11 5 Wireless Technology

12 2 Wireless Sensor Network (WSN) Source: A wireless sensor network (WSN) consists of spatially distributed autonomous sensors to cooperatively monitor physical or environmental conditions, such as temperature, sound, vibration, pressure, motion or pollutants. The development of wireless sensor networks was motivated by military applications such as battlefield surveillance. They are now used in many industrial and civilian application areas, including industrial process monitoring and control, machine health monitoring, environment and habitat monitoring, healthcare applications, home automation, and traffic control. In addition to one or more sensors, each node in a sensor network is typically equipped with a radio transceiver or other wireless communications device, a small microcontroller, and an energy source, usually a battery. The applications for WSNs are varied, typically involving some kind of monitoring, tracking, or controlling. Specific applications include habitat monitoring, object tracking, nuclear reactor control, fire detection, and traffic monitoring. In a typical application, a WSN is scattered in a region where it is meant to collect data through its sensor nodes. 2.1 Wireless Standards Several standards are currently either ratified or under development for wireless sensor networks. ZigBee is a proprietary mesh-networking specification intended for uses such as embedded sensing, medical data collection, consumer devices like television remote controls, and home automation. Zigbee is promoted by a large consortium of industry players. WirelessHART is an extension of the 1

13 2 Wireless Sensor Network (WSN) HART Protocol and is specifically designed for Industrial applications like Process Monitoring and Control ZigBee (IEEE ) ZigBee is a low-cost, low-power, wireless mesh networking proprietary standard. The low cost allows the technology to be widely deployed in wireless control and monitoring applications, the low power-usage allows longer life with smaller batteries, and the mesh networking provides high reliability and larger range.

14 3 Wireless Sensor Network (WSN) Read more about ZigBee: ZigBee Alliance: Wikipedia: IEEE Wireless DAQ Products form National Instruments use the Wi-Fi IEEE standard. NI WSN Measurement Systems use the ZigBee (IEEE ) standard. Read more about wireless technology and products from National Instruments: NI Wireless Data Acquisition: NI Wireless Remote Monitoring: NI Wireless Devices: NI Wireless Sensor Networks: WirelessHART WirelessHART is an open-standard wireless networking technology developed by HART Communication Foundation. Developed as a multi-vendor, interoperable wireless standard, WirelessHART was defined specifically for the requirements of Process field device networks Read more about WirelessHART: HART Communication Foundation: Wikipedia: Wireless Mesh Network (WMN) Mesh networking is a type of networking where each node in the network may act as an independent router, regardless of whether it is connected to another network or not. It allows for continuous connections and reconfiguration around broken or blocked paths by hopping from node to node until the destination is reached. A mesh network whose nodes are all connected to

15 4 Wireless Sensor Network (WSN) each other is a fully connected network. Mesh networks differ from other networks in that the component parts can all connect to each other via multiple hops. A wireless mesh network (WMN) is a communications network made up of radio nodes organized in a mesh topology. Wireless mesh networks often consist of mesh clients, mesh routers and gateways. The mesh clients are often laptops, cell phones and other wireless devices while the mesh routers forward traffic to and from the gateways which may but need not connect to the Internet. The coverage area of the radio nodes working as a single network is sometimes called a mesh cloud. Access to this mesh cloud is dependent on the radio nodes working in harmony with each other to create a radio network. A mesh network is reliable and offers redundancy. When one node can no longer operate, the rest of the nodes can still communicate with each other, directly or through one or more intermediate nodes. Wireless mesh architecture is a first step towards providing high-bandwidth network over a specific coverage area. Wireless mesh architecture s infrastructure is, in effect, a router network minus the cabling between nodes. It's built of peer radio devices that don't have to be cabled to a wired port like traditional WLAN access points (AP) do. Mesh architecture sustains signal strength by breaking long distances into a series of shorter hops Below we see an example of a Wireless Mesh Topology: Wireless Mess Networks (WMN) is widely used in Wireless Sensor Networks (WSN).

16 5 Wireless Sensor Network (WSN)

17 3 Introduction to LabVIEW Sources: LabVIEW (short for Laboratory Virtual Instrumentation Engineering Workbench) is a platform and development environment for a visual programming language from National Instruments. The graphical language is named "G". Originally released for the Apple Macintosh in 1986, LabVIEW is commonly used for data acquisition, instrument control, and industrial automation on a variety of platforms including Microsoft Windows, various flavors of UNIX, Linux, and Mac OS X. The latest version of LabVIEW is version LabVIEW 2009, released in August Visit National Instruments at The code files have the extension.vi, which is a abbreviation for Virtual Instrument. LabVIEW offers lots of additional Add-Ons and Toolkits. 3.1 Dataflow programming The programming language used in LabVIEW, also referred to as G, is a dataflow programming language. Execution is determined by the structure of a graphical block diagram (the LV-source code) on which the programmer connects different function-nodes by drawing wires. These wires propagate variables and any node can execute as soon as all its input data become available. Since this might be the case for multiple nodes simultaneously, G is inherently capable of parallel execution. Multi-processing and multi-threading hardware is automatically exploited by the built-in scheduler, which multiplexes multiple OS threads over the nodes ready for execution. 3.2 Graphical programming LabVIEW ties the creation of user interfaces (called front panels) into the development cycle. LabVIEW programs/subroutines are called virtual instruments (VIs). Each VI has three components: a block diagram, a front panel, and a connector panel. The last is used to represent the VI in the block diagrams of other, calling VIs. Controls and indicators on the front panel allow an operator to input data into or extract data from a running virtual instrument. However, the front panel can also serve as a programmatic interface. Thus a virtual instrument can either be run as a program, with the front panel serving as a user interface, or, when dropped as a node onto the block diagram, the front panel defines the inputs and outputs for the given node through the connector pane. This implies each VI can be easily tested before being embedded as a subroutine into a larger program. The graphical approach also allows non-programmers to build programs simply by dragging and dropping virtual representations of lab equipment with which they are already familiar. The LabVIEW programming environment, with the included examples and the documentation, makes it simple to 6

18 7 Introduction to LabVIEW create small applications. This is a benefit on one side, but there is also a certain danger of underestimating the expertise needed for good quality "G" programming. For complex algorithms or large-scale code, it is important that the programmer possess an extensive knowledge of the special LabVIEW syntax and the topology of its memory management. The most advanced LabVIEW development systems offer the possibility of building stand-alone applications. Furthermore, it is possible to create distributed applications, which communicate by a client/server scheme, and are therefore easier to implement due to the inherently parallel nature of G-code. 3.3 Benefits One benefit of LabVIEW over other development environments is the extensive support for accessing instrumentation hardware. Drivers and abstraction layers for many different types of instruments and buses are included or are available for inclusion. These present themselves as graphical nodes. The abstraction layers offer standard software interfaces to communicate with hardware devices. The provided driver interfaces save program development time. The sales pitch of National Instruments is, therefore, that even people with limited coding experience can write programs and deploy test solutions in a reduced time frame when compared to more conventional or competing systems. A new hardware driver topology (DAQmxBase), which consists mainly of G-coded components with only a few register calls through NI Measurement Hardware DDK (Driver Development Kit) functions, provides platform independent hardware access to numerous data acquisition and instrumentation devices. The DAQmxBase driver is available for LabVIEW on Windows, Mac OS X and Linux platforms.

19 4 Introduction to Data Acquisition (DAQ) This chapter explains the basic concepts of using DAQ in LabVIEW. Topics: Introduction to DAQ - Data Acquisition MAX Measurement and Automation Explorer NI-DAQmx Driver software LabVIEW is very powerful when it comes to creating DAQ applications. LabVIEW includes a set of VIs that let you configure, acquire data from, and send data to DAQ devices. Often, one device can perform a variety of functions, such as analog-to-digital (A/D) conversion, digital-to-analog (D/A) conversion, digital I/O, and counter/timer operations. Each device supports different DAQ and signal generation speeds. Also, each DAQ device is designed for specific hardware, platforms and operating systems. National Instruments, the inventor of LabVIEW, also make DAQ devices, so the integration with the DAQ devices from NI and the LabVIEW software is seamless and makes it easy to do I/O operations from the LabVIEW environment. 4.1 Introduction to DAQ - Data Acquisition The purpose of data acquisition is to measure an electrical or physical phenomenon such as voltage, current, temperature, pressure, or sound. PC-based data acquisition uses a combination of modular hardware, application software, and a computer to take measurements. While each data acquisition system is defined by its application requirements, every system shares a common goal of acquiring, analyzing, and presenting information. Data acquisition systems incorporate signals, sensors, actuators, signal conditioning, data acquisition devices, and application software. So summing up, Data Acquisition is the process of: Acquiring signals from real-world phenomena Digitizing the signals Analyzing, presenting and saving the data The DAQ system has the following parts involved, see Figure: 8

20 9 Introduction to Data Acquisition (DAQ) The parts are: Physical input/output signals DAQ device/hardware Driver software Your software application (Application software) For an Introduction to Data Acquisition, see this webcast: Physical input/output signals A physical input/output signal is typically a voltage or current signal DAQ device/hardware DAQ hardware acts as the interface between the computer and the outside world. It primarily functions as a device that digitizes incoming analog signals so that the computer can interpret them A DAQ device (Data Acquisition Hardware) usually has these functions: Analog input Analog output Digital I/O Counter/timers We have different DAQ devices, such as: Desktop DAQ devices where you need to plug a PCI DAQ board into your computer. The software is running on a computer. Portable DAQ devices for connection to the USB port, Wi-Fi connections, etc. The software is running on a computer Distributed DAQ devices where the software is developed on your computer and then later downloaded to the distributed DAQ device.

21 10 Introduction to Data Acquisition (DAQ) Wi-Fi DAQ Devices Wireless: Driver software Driver software is the layer of software for easily communicating with the hardware. It forms the middle layer between the application software and the hardware. Driver software also prevents a programmer from having to do register-level programming or complicated commands in order to access the hardware functions. Driver software from National Instruments: NI-DAQmx NI-DAQmx Base

22 11 Introduction to Data Acquisition (DAQ) The DAQ Assistant, included with NI-DAQmx, is a graphical, interactive guide for configuring, testing, and acquiring measurement data. With a single click, you can even generate code based on your configuration, making it easier and faster to develop complex operations. Because DAQ Assistant is completely menu-driven, you will make fewer programming errors and drastically decrease the time from setting up your DAQ system to taking your first measurement. NI-DAQmx Base offers a subset of NI-DAQmx functionality on Windows and Linux, Mac OS X, Windows Mobile and Windows CE Your software application (Application software) Application software adds analysis and presentation capabilities to the driver software. Your software application normally does such tasks as: Real-time monitoring Data analysis Data logging Control algorithms Human machine interface (HMI) In order to create your DAQ application you need a programming development tool, such as LabVIEW. 4.2 MAX Measurement and Automation Explorer Measurement & Automation Explorer (MAX) provides access to your National Instruments devices and systems. With MAX, you can: Configure your National Instruments hardware and software Create and edit channels, tasks, interfaces, scales, and virtual instruments Execute system diagnostics View devices and instruments connected to your system Update your National Instruments software In addition to the standard tools, MAX can expose item-specific tools you can use to configure, diagnose, or test your system, depending on which NI products you install. As you navigate through MAX, the contents of the application menu and toolbar change to reflect these new tools.

23 12 Introduction to Data Acquisition (DAQ) 4.3 NI-DAQmx The NI-DAQmx Driver software is the layer of software for easily communicating with the hardware. It forms the middle layer between the application software and the hardware. Driver software also prevents a programmer from having to do register-level programming or complicated commands in order to access the hardware functions.

24 13 Introduction to Data Acquisition (DAQ) The DAQmx palette in LabVIEW: DAQ Assistant The DAQ Assistant, included with NI-DAQmx, is a graphical, interactive guide for configuring, testing, and acquiring measurement data. With a single click, you can even generate code based on your configuration, making it easier and faster to develop complex operations. Because DAQ Assistant is completely menu-driven, you will make fewer programming errors and drastically decrease the time from setting up your DAQ system to taking your first measurement.

25 5 Introduction to Wireless Data Acquisition Source: Wi-Fi DAQ is: Simple Direct sensors connectivity and graphical programming Secure Highest commercially available data encryption and authentication Wireless g Wi-Fi data acquisition is an extension of PC-based data acquisition to measurement applications where cables are inconvenient or uneconomical. NI Wi-Fi data acquisition (DAQ) devices combine IEEE g wireless or Ethernet communication; direct sensor connectivity; and the flexibility of NI-DAQmx driver software for remote monitoring of electrical, physical, mechanical, and acoustical signals. NI Wi-Fi DAQ devices can stream data on each channel at up to 250 ks/s. In addition, built-in NIST-approved 128-bit AES encryption and advanced network authentication methods offer the highest commercially available network security. With the flexibility of NI LabVIEW graphical programming and the ubiquity of network infrastructure, NI Wi-Fi DAQ makes it easy to incorporate wireless connectivity into new or existing PC-based measurement or control systems. 14

26 15 Introduction to Wireless Data Acquisition The Data Flow in Wi-Fi DAQ is as follows: Unlike most wireless sensors or wireless sensor networks, wireless data acquisition devices are meant to stream data continuously back to a host PC or laptop. A wireless sensor node is typically a low-power, autonomous battery-operated device intended for long-term deployment in applications where measurements are needed only every few minutes, hours, or even days. Wi-Fi data acquisition devices, on the other hand, behave in much the same way as a USB data acquisition device a host PC collects data continuously (in real time) as the device acquires it. The data acquisition device may be battery-operated, but the focus is on the measurement versus the battery life. Also, Wi-Fi data acquisition devices use the near-ubiquitous wireless networking standard, IEEE because of its higher bandwidth and broader applicability. Finally, because NI

27 16 Introduction to Wireless Data Acquisition Wi-Fi data acquisition uses the same NI-DAQmx driver software as other NI data acquisition devices, you can develop your applications using NI LabVIEW, LabWindows /CVI; ANSI C/C++; or Microsoft C#, Visual Basic, or Visual Basic.NET. More Information about Wi-Fi DAQ: Watch the Wi-Fi DAQ Tour: Wi-Fi DAQ Webcast:

28 6 NI Wireless DAQ Devices Common components in Wi-Fi DAQ are as follows: DAQ Devices Wireless Access Points (WAP) or a Wireless Router Network Switches How do I connect to an NI Wi-Fi DAQ device? When setting up your NI Wi-Fi DAQ device, you may choose to connect to an existing enterprise network through a wireless access point or set up your own network with a wireless router. For existing IT infrastructure, NI Wi-Fi DAQ devices support WPA Enterprise and WPA2 Enterprise (IEEE i). If you set up your own network, you may use WEP, WPA Personal (WPA-PSK), or WPA2 Personal (WPA2-PSK) security. NI Wi-Fi DAQ devices also support ad hoc or peer-to-peer networks, which do not require any routers or access points. However, ad hoc support is inconsistent across wireless network interface cards and is not secure. Communication through a wireless access point or wireless router is the preferred mode of operation. How do I program NI Wi-Fi DAQ devices? All NI Wi-Fi and Ethernet DAQ devices use the same NI-DAQmx measurement services and driver software as other National Instruments PCI, PXI, and USB DAQ devices. NI-DAQmx measurement services software controls every aspect of your data acquisition system from configuration to programming. With NI-DAQmx software, you can quickly configure and acquire measurements using the DAQ Assistant and automatically generate code to get your application started quickly. NI-DAQmx also features virtual channels that automatically scale raw data into engineering units. Because you can use the same driver API to program new NI Wi-Fi DAQ devices, incorporating wireless connectivity into your existing applications is easy. Wi-Fi DAQ Devices from National Instruments: 17

29 18 NI Wireless DAQ Devices TUC have the following wireless DAQ devices availible: NI WLS Wireless 4-Channel Accelerometer and Microphone Input NI WAP Wireless access points (WAPs) add wireless connectivity to all Ethernet-based NI programmable automation NI UES An eight-port unmanaged entry-level switch for networking between NI Ethernet-based controllers and devices using standard Ethernet protocols PS-5 Power Supply 6.1 NI WLS-9234 The NI WLS-9234 is a four-channel IEEE wireless or Ethernet C Series dynamic signal acquisition module for making high-accuracy audio frequency measurements from integrated electronic piezoelectric (IEPE) and non-iepe sensors. 4-Channel, 51.2 ks/s/ch, 24-Bit, ±5 V IEPE Input IEEE b/g (Wi-Fi) wireless and Ethernet communications interfaces 51.2 ks/s per-channel maximum sampling rate; ±5 V input 24-bit resolution; 102 db dynamic range; antialiasing filters

30 19 NI Wireless DAQ Devices Software-selectable AC/DC coupling; AC-coupled (0.5 Hz) Software-selectable IEPE signal conditioning (0 or 2 ma) The NI WLS-9234 is a four-channel IEEE wireless or Ethernet C Series dynamic signal acquisition module for making high-accuracy audio frequency measurements from integrated electronic piezoelectric (IEPE) and non-iepe sensors. The WLS-9234 delivers 102 db of dynamic range and incorporates software-selectable AC/DC coupling and IEPE signal conditioning for accelerometers and microphones. The four input channels simultaneously digitize signals at rates up to 51.2 khz per channel with built-in antialiasing filters that automatically adjust to your sampling rate. The WLS-9234 is well-suited for noise and vibration analysis applications. The NI Sound and Vibration Measurement Suite, which specifically addresses these applications, has two components: the NI Sound and Vibration Assistant and LabVIEW Analysis VIs (functions) for power spectra, frequency response (FRF), fractional octave analysis, sound-level measurements, order spectra, order maps, order extraction, sensor calibration, human vibration filters, and torsional vibration. WLS-9234 has 4 BNC connectors. The BNC connector is used for RF signal connections. The BNC connector is one of several radio frequency (RF) connectors on the market today. 6.2 NI WAP-3701 WAP Wireless Access Point The NI WAP-3701 wireless access points (WAPs) add wireless connectivity to all Ethernet-based NI programmable automation controllers (PACs). A WAP-37x1 can connect wireless devices to a wired

31 20 NI Wireless DAQ Devices network and has an IP address so other wireless clients can access the device. A WAP-37x1 can also serve as a Dynamic Host Configuration Protocol (DHCP) server and configure other WAP-37x1 devices as wireless clients. A single WAP-37x1 typically supports up to 30 client devices, with the range depending on the wireless antennae selection. It also serves as a wireless bridge and allows two devices to talk to each other. EEE g/b wireless access point, client, and bridge Web-based management software included 64- and 128-bit wired equivalent privacy (WEP) security Redundant dual 24 VDC power inputs Metal enclosure, IP30 rated; Class I, Division 2 hazardous locations DIN-rail mounting support 6.3 NI UES-3880 UES Unmanaged Ethernet Switch The NI UES-3880 is an eight-port unmanaged entry-level switch for networking between NI Ethernet-based controllers and devices using standard Ethernet protocols. To network with NI programmable automation controllers (PACs), the UES-3880 provides industrial features including -40 to 70 C operating temperature; Class I, Division 2 and ATEX Class 1, Zone 2 certifications for hazardous locations; and redundant dual 24 VDC power inputs.

32 21 NI Wireless DAQ Devices 6.4 PS-5 Power Supply PS Power Supply The PS-5 is a DIN-rail-mountable 24 VDC power supply that provides 5 A of current and is rated for operation from -25C to 60C. Two PS-5 supplies can be wired in parallel to provide up to 10 A. The PS-5 is recommended for industrial installations. The PS-4 is a DIN-rail-mountable 24 V power supply in FieldPoint packaging. The PS-3 and PS-2 are power supply "bricks" with a universal IEC power input. The PS-3 can also operate as a float charger for 12 VDC batteries. The PS-1 is a wall-mount power supply.

33 7 NI WSN Devices A wireless sensor network (WSN) is a wireless network consisting of spatially distributed autonomous devices that use sensors to monitor physical or environmental conditions. These autonomous devices, or nodes, combine with routers and a gateway to create a typical WSN system. The distributed measurement nodes communicate wirelessly to a central gateway, which provides a connection to the wired world where you can collect, process, analyze, and present your measurement data. To extend distance and reliability in a WSN, you can use routers to gain an additional communication link between end nodes and the gateway. The proprietary NI WSN protocol is based on IEEE and ZigBee technology. The IEEE communication standard defines the Physical and Medium Access Control layers in the networking model, providing communication in three frequency bands including the 2.4 GHz ISM band. ZigBee builds on the standard with the network and application layers, offering features such as device coordination, reliability through mesh networking topologies, and the functionality to create user-defined profiles that allow for customization and flexibility within the protocol. What is the difference between NI Wi-Fi data acquisition (DAQ) and NI WSN devices? NI Wi-Fi DAQ devices combine IEEE b/g (Wi-Fi) wireless or Ethernet communication, direct sensor connectivity, and the flexibility of NI-DAQmx software for a breadth of remote measurement and control options. Externally powered, NI Wi-Fi DAQ devices can stream continuous waveform data on each channel at more than 50 ks/s and offer the highest commercially available network security (WPA2 Enterprise). NI WSN devices deliver low-power measurement nodes that operate for up to three years on 4 AA batteries and can be deployed for long-term, remote operation. The wireless measurement nodes communicate with a central gateway using a protocol based on IEEE (ZigBee) to offer mesh routing capabilities that extend network distance and reliability. NI WSN systems support lower data rates to preserve power, are easily programmed using I/O variables, and currently accommodate thermocouple and ±10 V measurements. 22

34 23 NI WSN Devices Many of the WSN systems today are based on ZigBee or IEEE protocols due to their low-power consumption. ZigBee builds on the layers to provide security, reliability through mesh networking topologies, and interoperability with other devices and standards.

35 24 NI WSN Devices 7.1 Devices NI WSN WSN Ethernet Gateway The NI WSN-9791 Ethernet gateway coordinates communication between distributed measurement nodes and the host controller in your NI wireless sensor network (WSN). The gateway has a 2.4 GHz, IEEE radio based on ZigBee technology to collect measurement data from the sensor network and a 10/100 Mbits/s Ethernet port to provide flexible connectivity to a Windows or LabVIEW Real-Time OS host controller NI WSN Thermocouple Input Node

36 25 NI WSN Devices The NI WSN-3212 measurement node is a wireless device that provides four 24-bit thermocouple input channels and four bidirectional digital channels that you can configure on a per-channel basis for input, sinking output, or sourcing output NI WSN Analog Input Node The NI WSN-3202 measurement node is a wireless device that provides four ±10 V analog input channels and four bidirectional digital channels that you can configure on a per-channel basis for input, sinking output, or sourcing output. 7.2 LabVIEW Drivers National Instruments offer the NI-WSN software.

37 26 NI WSN Devices With NI-WSN software you can easily configure your network in the Measurement & Automation Explorer (MAX) utility. MAX provides an intuitive user interface to add and remove measurement nodes and configure wireless settings. NI-WSN software provides seamless LabVIEW integration so that you can quickly and easily extract measurement data from your WSN. After adding the NI WSN Ethernet 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.

38 27 NI WSN Devices National Instruments also offer WSN drivers for WSN equipments from other vendors:

39 Telemark University College Faculty of Technology Kjølnes Ring 56 N-3914 Porsgrunn, Norway Hans-Petter Halvorsen, M.Sc. Telemark University College Department of Electrical Engineering, Information Technology and Cybernetics Phone: Blog: Room: B-237a