Telemark University College
Department of Electrical Engineering, Information Technology and Cybernetics
Wireless Data Acquisition in
LabVIEW
HANS-PETTER HALVORSEN, 2011.02.03
Faculty of Technology,
Postboks 203, Kjølnes ring 56, N-3901 Porsgrunn, Norway.
Tel: +47 35 57 50 00
Fax: +47 35 57 54 01
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 802.11 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
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 802.11b/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: +47 35 57 50 00
Fax: +47 35 57 54 01
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: +47 35 57 50 00
Fax: +47 35 57 54 01
Table of Contents
Preface......................................................................................................................................................ii
Table of Contents .....................................................................................................................................v
1
2
Wireless Technology ....................................................................................................................... 1
1.1
Bluetooth ................................................................................................................................. 2
1.2
Wireless USB............................................................................................................................ 3
1.3
ZigBee (IEEE 802.15.4) ............................................................................................................. 4
1.4
Wi-Fi (IEEE 802.11) .................................................................................................................. 4
Wireless Sensor Network (WSN) .................................................................................................... 1
2.1
2.1.1
ZigBee (IEEE 802.15.4) ..................................................................................................... 2
2.1.2
IEEE 802.11 ...................................................................................................................... 3
2.1.3
WirelessHART .................................................................................................................. 3
2.2
3
4
Wireless Standards .................................................................................................................. 1
Wireless Mesh Network (WMN) ............................................................................................. 3
Introduction to LabVIEW ................................................................................................................ 6
3.1
Dataflow programming ........................................................................................................... 6
3.2
Graphical programming........................................................................................................... 6
3.3
Benefits.................................................................................................................................... 7
Introduction to Data Acquisition (DAQ) ......................................................................................... 8
4.1
Introduction to DAQ - Data Acquisition .................................................................................. 8
4.1.1
Physical input/output signals .......................................................................................... 9
4.1.2
DAQ device/hardware ..................................................................................................... 9
4.1.3
Driver software .............................................................................................................. 10
4.1.4
Your software application (Application software) ........................................................ 11
4.2
MAX – Measurement and Automation Explorer ................................................................... 11
v
vi
Table of Contents
4.3
NI-DAQmx .............................................................................................................................. 12
4.3.1
DAQ Assistant ................................................................................................................ 13
5
Introduction to Wireless Data Acquisition ................................................................................... 14
6
NI Wireless DAQ Devices .............................................................................................................. 17
7
6.1
NI WLS-9234 .......................................................................................................................... 18
6.2
NI WAP-3701 ......................................................................................................................... 19
6.3
NI UES-3880 ........................................................................................................................... 20
6.4
PS-5 Power Supply ................................................................................................................. 21
NI WSN Devices ............................................................................................................................ 22
7.1
Devices................................................................................................................................... 24
7.1.1
NI WSN-9791 - WSN Ethernet Gateway ........................................................................ 24
7.1.2
NI WSN-3212 - Thermocouple Input Node ................................................................... 24
7.1.3
NI WSN-3202 - Analog Input Node ................................................................................ 25
7.2
LabVIEW Drivers .................................................................................................................... 25
Tutorial: Wireless Data Acquisition in LabVIEW
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 802.15.4)
Wi-Fi (IEEE 802.11)
1
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
Tutorial: Wireless Data Acquisition in LabVIEW
3
Wireless Technology
1.2 Wireless USB
Tutorial: Wireless Data Acquisition in LabVIEW
4
Wireless Technology
1.3 ZigBee (IEEE 802.15.4)
1.4 Wi-Fi (IEEE 802.11)
Tutorial: Wireless Data Acquisition in LabVIEW
5
Wireless Technology
Tutorial: Wireless Data Acquisition in LabVIEW
2 Wireless Sensor Network (WSN)
Source: www.wikipedia.org
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
2
Wireless Sensor Network (WSN)
HART Protocol and is specifically designed for Industrial applications like Process Monitoring and
Control.
2.1.1 ZigBee (IEEE 802.15.4)
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.
Tutorial: Wireless Data Acquisition in LabVIEW
3
Wireless Sensor Network (WSN)
Read more about ZigBee:
ZigBee Alliance: http://www.zigbee.org/
Wikipedia: http://en.wikipedia.org/wiki/ZigBee
2.1.2 IEEE 802.11
Wireless DAQ Products form National Instruments use the Wi-Fi IEEE 802.11 standard.
NI WSN Measurement Systems use the ZigBee (IEEE 802.15.4) standard.
Read more about wireless technology and products from National Instruments:
NI Wireless Data Acquisition:
http://sine.ni.com/np/app/main/p/ap/daq/lang/en/pg/1/sn/n17:daq,n24:Wireless
NI Wireless Remote Monitoring: http://www.ni.com/wireless/remote_monitoring.htm
NI Wireless Devices: http://www.ni.com/wireless/
NI Wireless Sensor Networks: http://www.ni.com/wsn/
2.1.3 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: http://www.hartcomm.org/
Wikipedia: http://en.wikipedia.org/wiki/WirelessHART
2.2 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
Tutorial: Wireless Data Acquisition in LabVIEW
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).
Tutorial: Wireless Data Acquisition in LabVIEW
5
Wireless Sensor Network (WSN)
Tutorial: Wireless Data Acquisition in LabVIEW
3 Introduction to LabVIEW
Sources: www.Wikipedia.org, www.ni.com
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 2009. Visit National Instruments at
www.ni.com.
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
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.
Tutorial: Wireless Data Acquisition in LabVIEW
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
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:
http://zone.ni.com/wv/app/doc/p/id/wv-169
4.1.1 Physical input/output signals
A physical input/output signal is typically a voltage or current signal.
4.1.2 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.
Tutorial: Wireless Data Acquisition in LabVIEW
10
Introduction to Data Acquisition (DAQ)
•
Wi-Fi DAQ Devices
Wireless:
4.1.3 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
Tutorial: Wireless Data Acquisition in LabVIEW
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.
4.1.4 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.
Tutorial: Wireless Data Acquisition in LabVIEW
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.
Tutorial: Wireless Data Acquisition in LabVIEW
13
Introduction to Data Acquisition (DAQ)
The DAQmx palette in LabVIEW:
4.3.1 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.
Tutorial: Wireless Data Acquisition in LabVIEW
5 Introduction to Wireless Data
Acquisition
Source: www.ni.com
Wi-Fi DAQ is:
•
•
•
Simple – Direct sensors connectivity and graphical programming
Secure – Highest commercially available data encryption and authentication
Wireless – 802.11g
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 802.11g 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 802.11 network
infrastructure, NI Wi-Fi DAQ makes it easy to incorporate wireless connectivity into new or existing
PC-based measurement or control systems.
14
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 802.11 because of its higher bandwidth and broader applicability. Finally, because NI
Tutorial: Wireless Data Acquisition in LabVIEW
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:
http://sine.ni.com/np/app/culdesac/p/ap/daq/lang/en/pg/1/sn/n17:daq,n21:10423/docid/wv-795
Wi-Fi DAQ Webcast:
http://zone.ni.com/wv/app/doc/p/id/wv-794
Tutorial: Wireless Data Acquisition in LabVIEW
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
802.11i). 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
18
NI Wireless DAQ Devices
TUC have the following wireless DAQ devices availible:
•
•
•
•
NI WLS-9234 - Wireless 4-Channel Accelerometer and Microphone Input
NI WAP-3701 - Wireless access points (WAPs) add wireless connectivity to all Ethernet-based
NI programmable automation
NI UES-3880 - 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 802.11 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 802.11b/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
Tutorial: Wireless Data Acquisition in LabVIEW
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 802.11 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
Tutorial: Wireless Data Acquisition in LabVIEW
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 802.11g/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.
Tutorial: Wireless Data Acquisition in LabVIEW
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.
Tutorial: Wireless Data Acquisition in LabVIEW
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 802.15.4 and ZigBee technology. The IEEE 802.15.4
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 802.15.4 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 802.11b/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 802.15.4 (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
23
NI WSN Devices
Many of the WSN systems today are based on ZigBee or IEEE 802.15.4 protocols due to their
low-power consumption. ZigBee builds on the 802.15.4 layers to provide security, reliability
through mesh networking topologies, and interoperability with other devices and standards.
Tutorial: Wireless Data Acquisition in LabVIEW
24
NI WSN Devices
7.1 Devices
7.1.1 NI WSN-9791 - 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 802.15.4 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.
7.1.2 NI WSN-3212 - Thermocouple Input Node
Tutorial: Wireless Data Acquisition in LabVIEW
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.
7.1.3 NI WSN-3202 - 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.
Tutorial: Wireless Data Acquisition in LabVIEW
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.
Tutorial: Wireless Data Acquisition in LabVIEW
27
NI WSN Devices
National Instruments also offer WSN drivers for WSN equipments from other vendors:
http://zone.ni.com/devzone/cda/tut/p/id/5435
Tutorial: Wireless Data Acquisition in LabVIEW
Telemark University College
Faculty of Technology
Kjølnes Ring 56
N-3914 Porsgrunn, Norway
www.hit.no
Hans-Petter Halvorsen, M.Sc.
Telemark University College
Department of Electrical Engineering, Information Technology and Cybernetics
Phone: +47 3557 5158
E-mail: hans.p.halvorsen@hit.no
Blog: http://home.hit.no/~hansha/
Room: B-237a