National Instruments WSN-9791 User manual

USER GUIDE AND SPECIFICATIONS
NI WSN-9791 Ethernet Gateway
This user guide describes how to use the NI Wireless Sensor Network WSN-9791 Ethernet gateway and
lists specifications. The NI WSN-9791 provides an Ethernet data acquisition interface. The
NI WSN-9791 combines with NI WSN-32xx nodes to form a wireless sensor network. Figure 1 shows
the components of the NI WSN system.
Figure 1. NI WSN System Components
1 PC or NI Real-Time Hardware Running
Application Software
2 NI WSN-9791 Ethernet Gateway
3 NI WSN-32xx Nodes
4 Ethernet Cable/Connection
5 9–30 VDC Power Supply Connection
45
2
1
3
3

NI WSN-9791 User Guide and Specifications 2 ni.com
Figure 2 shows a close up of the NI WSN-9791.
Figure 2. NI WSN-9791 Ethernet Gateway
Dimensions
Figure 3 shows the NI WSN-9791 device dimensions.
Figure 3. NI WSN-9791 Device Dimensions
NI WSN-9791
117.54 mm
(4.628 in.)
146.88 mm
(5.783in.)
165.94 mm
(6.533 in.)
60.18 mm
(2.369 in.)
112.97 mm
(4.448 in.)
88.33 mm
(3.478 in.)
3.088 in.
(78.44 mm)
51.29 mm
(2.019 in.)
44.32 mm
(1.745 in.)
87.50 mm
(3.445 in.)

©National Instruments Corporation 3 NI WSN-9791 User Guide and Specifications
Safety Guidelines
Operate the NI WSN-9791 only as described in this user guide.
Hot Surface This icon denotes that the component may be hot. Touching this component may result
in bodily injury.
NI WSN Safety Information
The following section contains important safety information that you must follow when installing and
using NI WSN products.
Caution Do not substitute parts or modify the NI WSN product. Use the product only with the
devices, accessories, and cables specified in the installation instructions.
Caution Do not operate a NI WSN products in an explosive atmosphere or where there may be
flammable gases or fumes. If you need to operate NI WSN products in such an environment, the
NI WSN products must be in a suitably rated enclosure.
Caution If you need to clean a NI WSN product, use a dry towel. The product must be completely
dry and free from contaminants before you return it to service.
Caution Operate the product only at or below Pollution Degree 2. Pollution is foreign matter in a
solid, liquid, or gaseous state that can reduce dielectric strength or surface resistivity. The following
is a description of pollution degrees:
• Pollution Degree 1 means no pollution or only dry, nonconductive pollution occurs. The pollution
has no influence.
• Pollution Degree 2 means that only nonconductive pollution occurs in most cases. Occasionally,
however, a temporary conductivity caused by condensation must be expected.
• Pollution Degree 3 means that conductive pollution occurs, or dry, nonconductive pollution occurs
which becomes conductive due to condensation.
Caution You must insulate signal connections for the maximum voltage for which the NI WSN
product is rated. Do not exceed the maximum ratings for the product. Do not install wiring while
the product is live with electrical signals. Do not remove or add connector blocks when power is
connected to the NI WSN system. Avoid contact between your body and the connector block signal
wiring when hot-swapping devices.
Operate NI WSN products at or below the installation category1marked on the hardware label.
Measurement circuits are subjected to working voltages2and transient stresses (overvoltage) from
the circuit to which they are connected during measurement or test. Installation categories establish
standard impulse withstand voltage levels that commonly occur in electrical distribution systems.
The following is a description of installation categories:
• Installation Category I is for measurements performed on circuits not directly connected to the
electrical distribution system referred to as MAINS3voltage. This category is for measurements of
voltages from specially protected secondary circuits. Such voltage measurements include signal
1 Installation categories, also referred to as measurement categories, are defined in electrical safety standard IEC 61010-1.
2 Working voltage is the highest rms value of an AC or DC voltage that can occur across any particular insulation.
3 MAINS is defined as a hazardous live electrical supply system that powers equipment. Suitably rated measuring circuits may
be connected to the MAINS for measuring purposes.

NI WSN-9791 User Guide and Specifications 4 ni.com
levels, special equipment, limited-energy parts of equipment, circuits powered by regulated
low-voltage sources, and electronics.
• Installation Category II is for measurements performed on circuits directly connected to the
electrical distribution system. This category refers to local-level electrical distribution, such as that
provided by a standard wall outlet (for example, 115 V for U.S. or 230 V for Europe). Examples
of Installation Category II are measurements performed on household appliances, portable tools,
and similar products.
• Installation Category III is for measurements performed in the building installation at the
distribution level. This category refers to measurements on hard-wired equipment such as
equipment in fixed installations, distribution boards, and circuit breakers. Other examples are
wiring, including cables, bus-bars, junction boxes, switches, socket-outlets in the fixed installation,
and stationary motors with permanent connections to fixed installations.
• Installation Category IV is for measurements performed at the primary electrical supply
installation (<1,000 V). Examples include electricity meters and measurements on primary
overcurrent protection devices and on ripple control units.
Safety Guidelines for Hazardous Locations
The NI WSN-9791 is suitable for use in Class I, Division 2, Groups A, B, C, D, T4 hazardous locations;
Class I, Zone 2, AEx nC IIC T4 and Ex nL IIC T4 hazardous locations; and nonhazardous locations
only. Follow these guidelines if you are installing the NI WSN-9791 in a potentially explosive
environment. Not following these guidelines may result in serious injury or death.
Caution Do not disconnect the power supply wires and connectors from the gateway unless power
has been switched off.
Caution Do not install or remove the gateway unless power has been switched off.
Caution Substitution of components may impair suitability for Class I, Division 2.
Caution For Zone 2 applications, install the WSN system in an enclosure rated to at least IP 54 as
defined by IEC 60529 and EN 60529.
Special Conditions for Hazardous Locations Use in Europe
The NI WSN-9791 has been evaluated as Ex nA nL IIC T4 equipment under DEMKO Certificate No. 07
ATEX 0626664X. Each gateway is marked II 3G and is suitable for use in Zone 2 hazardous locations,
in ambient temperatures of –40 °C ≤Ta ≤70 °C.

©National Instruments Corporation 5 NI WSN-9791 User Guide and Specifications
Electromagnetic Compatibility Guidelines
This product was tested and complies with the regulatory requirements and limits for electromagnetic
compatibility (EMC) as stated in the product specifications. These requirements and limits are designed
to provide reasonable protection against harmful interference when the product is operated in its
intended operational electromagnetic environment.
This product is intended for use in industrial locations. There is no guarantee that harmful interference
will not occur in a particular installation, when the product is connected to a test object, or if the product
is used in residential areas. To minimize the potential for the product to cause interference to radio and
television reception or to experience unacceptable performance degradation, install and use this product
in strict accordance with the instructions in the product documentation.
Furthermore, any changes or modifications to the product not expressly approved by National
Instruments could void your authority to operate it under your local regulatory rules.
The following statements contain important EMC information needed before installing and using this
product:
Caution This product is intended for use in industrial locations. As a result, this product may cause
interference if used in residential areas. Such use must be avoided unless the user takes special
measures to reduce electromagnetic emissions to prevent interference to the reception of radio and
television broadcasts.
Caution Changes or modifications not expressly approved by National Instruments could void the
your authority to operate the hardware under the local regulatory rules.
Caution Operate this product only with shielded cables and accessories.
Related Documentation
Check ni.com/manuals for the most recent hardware documentation. For a complete list of
documentation related to the NI WSN system, refer to ni.com/info and enter rdwsnrd.
In addition to this guide, the following documents may be useful when configuring your NI WSN
system:
• NI Wireless Sensor Network Getting Started Guide
• NI WSN-32xx User Guide and Specifications
•Configuring WSN in MAX, available from Start»All Programs»National Instruments»NI-WSN
• The NI-WSN book on the Contents tab of the LabVIEW Help available by selecting Help»Search
the LabVIEW Help in LabVIEW
•NI-WSN Readme, available on the software installation disc included with your device.
Training Courses
If you need more help getting started developing an application with NI products, NI offers training
courses. To enroll in a course or obtain a detailed course outline, refer to ni.com/training.
Technical Support on the Web
For additional support, refer to ni.com/support or zone.ni.com.

NI WSN-9791 User Guide and Specifications 6 ni.com
Software Overview
Note Refer to the NI WSN Readme, available on the software installation disc included with your
device, for NI software application version support.
The NI-WSN software includes NI Measurement and Automation Explorer (MAX) as well as server and
driver software for easy integration into application software packages. These software components
manage the low-level communications and hardware details, simplifying programmatic access to
I/O channels. The NI-WSN software is on the software installation disc included with your
NI WSN-9791 gateway device. The NI-WSN software is supported by Windows 7/Vista/XP and
contains the following components:
•NIMAX
• NI-WSN software
You can download a current version of the NI-WSN software from ni.com/support. Using your web
browser, go to ni.com/support and select Drivers and Updates»Distributed I/O»Wireless Sensor
Networks, then select the latest version of NI-WSN software. If you are using other software, refer to
the installation instructions that accompany your software.
What You Need to Get Started
To set up and use NI LabVIEW for WSN with the NI WSN-9791, you need the following:
• NI WSN-9791 Ethernet Gateway device(s), with 9–30 V power supply
•NIWSN-32xx node devices with a 9–30 V power supply or four 1.5 V AA alkaline for each node
• Mounting hardware (DIN rail, panel-mount, or rack mount accessory)
• Ethernet cable/connection
• Screwdrivers: a 1/8 in. flathead and a number 1 Phillips
• NI-WSN software version 1.1 or later
• Host PC running Windows 7/Vista/XP
• NI LabVIEW version 8.6.1 (32-bit) or later
• NI LabVIEW Real-Time Module (32-bit)
• Related hardware and software documentation
• Optional accessories
• DIN rail terminal blocks
• I/O cables and sensors
• Mounting accessory

©National Instruments Corporation 7 NI WSN-9791 User Guide and Specifications
Unpack the Devices and Install the Antenna
Remove the devices from the package and inspect the device. Contact NI if the device appears damaged.
Do not install a damaged device.
Caution The device is static sensitive. Always properly ground yourself and the equipment when
handling or connecting to the device.
To attach the antenna, align the antenna with the mount and screw it on as shown in Figure 4.
Caution The antenna must be attached to the NI WSN device in order for the NI WSN device to
function correctly.
Figure 4. Attach Antenna to Device
Mounting the NI WSN-9791 Device
You can mount the NI WSN-9791 device on a panel or on a 35 mm DIN rail. For kit accessory ordering
information, refer to the accessory section of the NI WSN product page at ni.com.
Caution Your installation must meet the following requirements:
• Allows 25.4 mm (1 in.) of clearance above and below the NI WSN-9791 device for air
circulation.
•Allows 50.8 mm (2 in.) of clearance in front of modules for common connector cabling, such as
the 2-position detachable screw terminal connector.

NI WSN-9791 User Guide and Specifications 8 ni.com
Note Figure 5 is an actual size template. You can print it out and use it to determine screw hole
placement for panel mounting.
Figure 5. NI WSN-9791 Panel Mount Dimensions Template
NI WSN-9791
3.18 mm
(0.125 in.)
3.18 mm
(0.125 in.)
114.30 mm
(4.500 in.)
45.72 mm
(1.800 in.)
55.88 mm
(2.200 in.)
101.60 mm
(4.000 in.)

©National Instruments Corporation 9 NI WSN-9791 User Guide and Specifications
Using the Integrated Panel Mount Feature
The NI WSN-9791 integrated panel mount feature accepts number 8 or M4 pan head screws to secure
the device onto a flat surface. To install the NI WSN-9791 on a flat surface, complete the following
steps:
1. Prepare two holes in your panel 4.448 in. (112.97 mm) on center to accept the number 8 or M4 pan
head screws or bolts.
2. Install the front screw first in the mounting panel leaving .08 in. space under the head of the screw.
3. Slide the NI WSN-9791 front mount under this screw.
4. Fasten the rear screw into place through the rear enclosure mount of the NI WSN-9791.
Figure 6. Using the Integrated Mount Feature
4.500 in.
(114.30 mm)

NI WSN-9791 User Guide and Specifications 10 ni.com
Attaching to the NI WSN-3282 DIN Rail
Caution Power off the device before mounting it to the DIN rail.
The NI WSN-3282 DIN rail kit, NI part number 781074-01, contains one clip for mounting the device
on a standard 35 mm DIN rail. To mount the device on a DIN rail, complete the following steps:
1. Fasten the DIN rail clip to the device using a number 1 Phillips screwdriver and four 4-20,
5/16 inch length thread-forming screws. The screws are included in the DIN rail kit.
2. Make sure the DIN rail kit is installed as shown in Figure 7, with the larger lip of the DIN rail
positioned up.
Note Use thread-forming screws to permanently affix the DIN rail clip to the device. Unscrewing
and reinstalling the thread-forming screws will produce a compromised connection between the
DIN rail clip and the device.
Figure 7. NI WSN-9791 Device DIN Rail Installation
Figure 8. DIN Rail Installation Pictured Without the NI WSN-9791

©National Instruments Corporation 11 NI WSN-9791 User Guide and Specifications
Attaching to the NI WSN-3283 Panel Mount Plate
The NI WSN-3283 panel mount kit, NI part number 781075-01, contains a plate for mounting the device
to a panel. To mount the device, complete the following steps:
1. Fasten the plate to the device using a number 1 Phillips screwdriver and four 4-20, 5/16 inch length
thread-forming screws, as shown in Figure 9. The screws are included in the NI WSN-3283 panel
mount kit.
Figure 9. Mounting the NI WSN-9791 to the Panel Mount Plate
2. Attach the device and attached plate to a wall or other surface using four to six number 8 or M4
screws. Refer to Figure 5 for the mounting hole template.

NI WSN-9791 User Guide and Specifications 12 ni.com
Setting Up the NI WSN-9791 Device
Complete the following steps to prepare the NI WSN-9791 device for use:
1. Before connecting the hardware, install NI LabVIEW and the NI-WSN driver software. You must
be an Administrator to install NI software and devices on your computer. The NI-WSN driver
software is on the software installation disc included with your device and is available for download
at ni.com/support. You must have NI LabVIEW version 8.6.1 or later installed to use NI WSN
devices. Refer to the instructions included with your NI LabVIEW software to install
NI LabVIEW. Once NI LabVIEW is installed, complete the following steps:
2. Close all other applications.
3. Insert the NI-WSN software installation disc into the drive on your computer.
4. Follow the onscreen instructions to install the NI-WSN software and NI MAX.
Note The NI Wireless Sensor Network Getting Started Guide is available after installation
from Start»All Programs»National Instruments»NI-WSN.
5. Make sure the NI WSN-9791 device power is disconnected.
Powering the NI WSN-9791 Device
Caution You must use a UL Listed ITE power supply marked LPS with the NI 9791. The power
supply must also meet any safety and compliance requirements for the country of use.
To connect an external power supply to the NI WSN-9791, complete the following steps:
1. Remove the 2-position mini-combicon plug from the device, loosening the retaining screws
if necessary.
Figure 10. 2 Mini-Combicon Connector
2. Connect the positive lead of the external power supply to the V terminal.
3. Connect the negative (common) lead to the C terminal.
4. Reinstall the 2-position mini-combicon plug in the device and tighten the retaining screws.
10/100BaseT(X) Ethernet Port Connection
Use a standard Category 5 (CAT-5) Ethernet cable (a shielded cable is recommended) to connect the
NI WSN-9791 device to an Ethernet hub or to a computer.

©National Instruments Corporation 13 NI WSN-9791 User Guide and Specifications
Device Interface
Figure 11 shows the NI WSN-9791 device interface.
Figure 11. NI WSN-9791 Device Interface
Reset Button
The NI WSN-9791 is equipped with a reset button as shown in Figure 11.
Pressing the reset button results in the following device responses:
• When pressed for fewer than 5 seconds, the device reboots with the current configuration.
• When pressed for 5 seconds or more, the STATUS LED turns on. When released, the device reboots
into Factory Default Mode, which returns the device user configuration to the factory-set defaults.
Signal Strength/Status LED Indicators
The signal strength/status LED indicators for the NI WSN-9791 device are listed in Table 1.
1 Antenna RP-SMA Connector
2 RESET Button
3 RJ45 Ethernet Port, 10/100 LED, LINK/ACT LED
4 9–30 VDC Power Connector
5 LEDs: ACTIVITY, STATUS, and POWER
Table 1. LED State/Device Status
LED Description Color LED State Device Status
10/100 Green On Connected at 100 Mbps
Off No Ethernet connection or
10 Mbps connection
LINK/ACT Yellow On Ethernet link
Off No Ethernet connection
Blinking Ethernet activity
POWER Green On Power on
Off Power off
NI WSN-9791
1
2
3
4
5

NI WSN-9791 User Guide and Specifications 14 ni.com
Using the NI WSN-9791
Firmware
The firmware is updated in NI MAX. To update the NI WSN-9791 Ethernet Gateway firmware,
complete the following steps:
1. Open NI MAX.
2. Select the NI WSN-9791 Ethernet Gateway for which you want to update firmware.
3. Click the Gateway Firmware tab.
4. Click Browse and select the firmware file.
5. Click Update Firmware.
6. Follow the prompt to reboot and apply changes.
For more information, refer to Start»All Programs»National Instruments»NI-WSN»Configuring
WSN in MAX.
Adding, Removing, and Replacing NI WSN-32xx Devices
Use NI MAX to add and remove nodes to and from your NI Wireless Sensor Network.You can remove
and insert NI WSN-32xx devices while the system is operating and without powering down the
NI WSN system. NI WSN-32xx devices already working in the system remain operational and
accessible on the network. Commands sent to a missing NI WSN-32xx device return an error response,
but the NI WSN-9791 stores the commands and applies the effects of the commands if a suitable
replacement is installed
When you remove a NI WSN-32xx device and add a new one, the NI WSN-9791 first verifies that the
replacement device is compatible with the one that was removed. If it is compatible, the NI WSN-9791
device configures the replacement NI WSN-32xx device with the previous device settings.
For more information, refer to Start»All Programs»National Instruments»NI-WSN»Configuring
WSN in MAX.
STATUS Ye llow On Device firmware booting or resetting to
factory default
Off Normal operation
1 Blink Radio error
2 Blinks Firmware/FPGA image corrupted,
update firmware through NI MAX
3 Blinks Firmware error, reboot
ACTIVITY Green On Radio is active and sending or
receiving data
Off No radio activity
Table 1. LED State/Device Status (Continued)
LED Description Color LED State Device Status

©National Instruments Corporation 15 NI WSN-9791 User Guide and Specifications
NI Wireless Sensor Networks
The NI WSN system is built on an IEEE 802.15.4 wireless mesh network. The 802.15.4 radio in each
NI WSN device provides for low-power communication of measurement data across a large network of
devices. The NI-WSN software builds on top of that to provide network configuration and reliable
communication from the host PC or PAC to the NI WSN-32xx node devices.
Mesh Networking
The NI WSN system consists of two types of devices: gateways and nodes. Gateways act as the network
coordinator, in charge of node authentication, message buffering, and bridging from the 802.15.4
wireless network to the wired Ethernet network. Nodes primarily function as end nodes in the network
to collect data and control DIO channels, but can also be programmed as routers to relay data from other
nodes back to the gateway and Host PC or PAC. Use NI MAX to configure nodes as end nodes or routers.
Figure 1 shows a typical NI Wireless Sensor Network.
The gateways and nodes work together to form a mesh network. The gateway maintains a list of nodes
(by serial number) that have been authorized for network access. When a node powers up, it scans for
available networks, locates either a gateway or router, and attempts to join it. If the gateway has the node
in its list, the node joins the network, downloads the latest configuration from the gateway, and begins
its normal operation of acquiring measurement data and controlling DIO.

NI WSN-9791 User Guide and Specifications 16 ni.com
Since each node joins a network instead of a particular router or gateway, it can find a new path back
to the gateway in the event that the signal is lost or blocked to its existing network route. In this way,
the mesh network is inherently self-forming and self-healing. However, this may also cause network
throughput to decrease, as there is no way to force a router or end node to join to a particular device in
the network. Each time a node joins through a router, the overall throughput of that node is halved, due
to the fact that the node must hop to get its messages back to the gateway. Figure 12 shows an example
of one possible mesh configuration.
Figure 12. Mesh Configuration Example
R1
G
R2

©National Instruments Corporation 17 NI WSN-9791 User Guide and Specifications
In this configuration, R1(a router) and R2(a router) both communicate directly with the gateway.
Measurements taken by both devices can directly reach the gateway without having to hop through
another node. However, the configuration above does not always mesh in the same way. Figure 13 shows
another possible configuration for the same network.
Figure 13. Same Network Configuration Example
R1
G
R2

NI WSN-9791 User Guide and Specifications 18 ni.com
In this configuration, R1can still communicate with the gateway, but R2 is now connected through R1.
This means that all measurements taken by R2must hop through R1before making it back to the
gateway. In addition, R1is now not only responsible for sending its own measurement data, but also
the R2 data. This configuration is considered a worst case 1-hop system, as R2and R1both have the
possibility of meshing through a router that is connected to the gateway. National Instruments
recommends configuring your system for no more than three hops. Configuring multiple nodes as
routers and placing them within close proximity introduces the possibility that your system could mesh
inefficiently. Figure 14 shows how a system could mesh efficiently, yet also have the possibility of
meshing inefficiently.
Figure 14. Inefficient Versus Efficient Meshing
The network can be improved with two separate techniques:
1. Convert some routers to end nodes.
2. Set up the network to prevent the routers from being in range of each other (spatially separated by
distance, or introducing objects that increase radio interference such as buildings).
G
G
R
1
R
2
R
3
R
4
R
5
R
6
R
1
R
2
R
3
R
4
R
5
R
6

©National Instruments Corporation 19 NI WSN-9791 User Guide and Specifications
Another advantage of the mesh network is the ability to extend the distance of the end measurement
from the wired Ethernet gateway. By placing mesh routers throughout the space where you wish to
acquire signals, you can expand the area and distance across which measurement data can be acquired
and sent. Refer to the Specifications section for typical line of sight ranges for the NI WSN devices.
Figure 15 shows how a network can be set up to cover greater distances.
Figure 15. Network Containing Distance Example
End Node Versus Router
Each NI WSN-32xx node can be configured as either an end node or a router. NI WSN-32xx nodes are
configured by default at the factory in end node mode. You can change the mode of the node using
the NI-WSN software and NI MAX. One trade-off to consider when configuring nodes is power
consumption. NI WSN-32xx nodes configured as end node are designed to be run from battery power
while routers are designed to use external power at all times to send, receive, and buffer messages to and
from end nodes.
Data Transfer in the NI WSN Network
The NI WSN system is built on a low-power, reliable IEEE 802.15.4 network. In order to save power
and increase reliability, this network delivers a maximum theoretical throughput of 250 kbps. This
correlates to a typical maximum rate of 1 sample per second per node.
Measurements taken with NI WSN-32xx nodes are single point acquisition. NI WSN-32xx devices have
no onboard buffer, therefore the data is considered to be lost, meaning there is no way to retrieve past
data from the device.
G
R1 R2 R3

NI WSN-9791 User Guide and Specifications 20 ni.com
Configuring Your NI WSN System
As discussed in the Mesh Networking section, creating a reliable and efficient wireless sensor network
requires an understanding of the physical environment the network will reside in, as well as an
understanding of the expected meshing configuration. Additionally, the following consideration needs
to be taken into account: parent devices (routers and gateways) can only have a maximum of eight end
nodes connected to them at a given time.
This introduces the stranded node problem. The stranded node problem exists when a node configured
as an end node has the possibility of not being able to join a device node. Figure 16 shows a network
consisting of one gateway, two routers, and nine end nodes.
Figure 16. Network Containing Distance, Example 1
G
R2
R1
N
Nx 1
x 8