6402-0120 [ETC]
Wireless 8 Channel Analog Input Sensor Node;
| 型号： | 6402-0120 |
| 厂家： | 
ETC |
| 描述： | Wireless 8 Channel Analog Input Sensor Node 无线 |
| 文件： | 总97页 (文件大小：13310K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
LORD USER MANUAL
V-Link®-200
Wireless 8 Channel Analog Input Sensor Node
LORD Sensing Systems
459 Hurricane Lane
Suite 102
Williston, VT 05495
United States of America
Phone: 802-862-6629
Fax: 802-863-4093
9:00 AM to 5:00 PM (Eastern Time US & Canada)
http://www.microstrain.com
sensing_support@LORD.com
sensing_sales@LORD.com
Document 8500-0063 Revision I
Subject to change without notice.
V-Link®-200 User Manual
Table of Contents
1. Wireless Sensor Network Overview
2. Node Overview
6
7
2.1 Components List
8
2.2 Interface and Indicators
2.3 Node Diagnostics
9
10
13
14
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15
16
17
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21
23
26
26
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27
27
28
29
32
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2.4 Node Operational Modes
3. System Operation
3.1 Software Installation
3.2 System Connections
3.3 Gateway Communication
3.4 Connect to Nodes
3.4.1 Automatic Node Discovery on Same Frequency
3.4.2 Automatic Node Discovery on Different Frequency
3.4.3 Manually Add Node
3.5 Configure Node
3.6 Configure and Start Sampling
4. Viewing Data
4.1 SensorConnect
4.1.1 Using Dashboards and Widgets
4.1.2 Navigating Graphs
4.1.3 Widgets Options
4.1.4 Time Series Widget Menu
4.1.5 Exporting Data Files
4.1.6 Navigating Menus
5. Installation
5.1 Mounting Recommendations
V-Link®-200 User Manual
5.2 Optimizing the Radio Link
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35
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5.2.1 Range Test
6. Connecting Sensors
6.1 Sensor Requirements
6.2 Wiring Recommendations
6.3 Sensor Power
6.4 Node Channels Designations
6.5 Terminal Block Connections
6.6 Pin Descriptions
6.7 Differential Input Channels
6.7.1 Differential Sensors
6.7.2 Differential Channel Raw Voltage
6.7.3 Measuring Small Voltages
6.8 Single-Ended Input Channels
6.8.1 Measuring Small Currents (4 to 20mA Sensors)
6.9 Using the Excitation Output as a Switch
6.10 Connecting Accelerometers
6.11 On-board Temperature Sensor
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60
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67
7. Sensor Settings
7.1 Sensor Calibration
7.1.1 EXAMPLE: Internal Shunt Calibration
7.1.2 Calibration Lab or Field
7.1.3 Manufacturer Calibration
7.2 Sensor Conversion Values
7.2.1 Calculating a Linear Slope
7.2.2 Differential Input Gain and Offset
V-Link®-200 User Manual
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8.1 Powering the Node
8.2 Using the Internal Node Battery
8.3 Connecting an External Power Supply
9. Troubleshooting
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9.1 Troubleshooting Guide
9.2 Using the Node Tester Board
9.3 Updating Node Firmware
9.4 Repair and Calibration
9.5 Maintenance
10. Wireless Equipment
10.1 Standard Nodes
10.2 Node Accessories
10.3 Recommended Sensors
10.4 Wireless System Equipment
11. Specifications
11.1 Physical Specifications
11.2 Operating Specifications
11.3 Radio Specifications
11.4 Frequency Setting
12. Safety Information
12.1 Replacing Batteries
12.2 Battery Hazards
12.3 Power Supply
12.4 Disposal and Recycling
13. References
13.1 Related Documents
14. Glossary
V-Link®-200 User Manual
1. Wireless Sensor Network Overview
The LORD Sensing Wireless Sensor Network is a high-speed, scalable, sensor data acquisition and
sensor networking system. Each system consists of wireless sensor interface nodes, a data collection
gateway, and full-featured user software platforms based on the LORD Sensing Lossless Extended
Range Synchronized (LXRS) and data communications protocols. Bi-directional wireless communication
between the node and gateway enables sensor data collection and configuration. Gateways can be
connected locally to a host computer or remotely via local and mobile networks. Some gateways also
feature analog outputs for porting sensor data directly to stand-alone data acquisition equipment.
The selection of available nodes allows interface with many types of sensors, including accelerometers,
strain gauges, pressure transducers, load cells, torque and vibration sensors, magnetometers, 4 to 20 mA
sensors, thermocouples, RTD sensors, soil moisture and humidity sensors, inclinometers, and orientation
and displacement sensors. Some nodes come with integrated sensing devices such as accelerometers.
System sampling capabilities include lossless synchronized sampling, continuous and periodic burst
sampling, and data logging. A single gateway can coordinate many nodes of any type, and multiple
gateways can be managed from one computer with the SensorConnect™ and SensorCloud™ software
platforms. Integration to customer systems can be accomplished using OEM versions of the sensor nodes
and leveraging the LORD Sensing data communications protocol.
Common wireless applications of LORD Sensing Sensing Systems are strain sensor measurement,
accelerometer platforms, vibration monitoring, energy monitoring, environmental monitoring, and
temperature monitoring.
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2. Node Overview
The V-Link-200 wireless sensor node features eight analog input channels designed to accommodate a
wide range of Wheatstone bridge and analog sensors, including strain, load cell, torque, pressure,
acceleration, vibration, magnetic field, displacement, and geophones. There are four channels for single-
ended sensor measurement, four channels for differential sensor measurement, and an on-board internal
temperature sensor.
V-Link-200 inputs are 18-bit resolution with ± 0.1% full scale measurement accuracy. The node can log
data to internal memory, transmit real-time synchronized data, and it supports event driven triggers with
both pre- and post- event buffers.
To acquire sensor data, the V-Link-200 is used with a LORD Sensing WSDA gateway, and comes with
the following configuration options.
Figure 1 - V-Link-200
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2.1 Components List
V-Link-200 sensor node comes with the following configuration options. For a complete list of
available configurations, accessories, additional system products and ordering information, see
Wireless Equipment on page 83.
Item
A
Description
V-Link-200
Quantity
1
1
1
Antenna with right angle adapter
Node tester board
B
C
AA Lithium batteries (3.6 V dc, 2.4
Ah)
4
1
3
1
D
DIN rail clip
E
--
#6-32 x 3/8" Thread forming
screws
Calibration Certificate
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2.2 Interface and Indicators
The V-Link-200 LEDs indicate operational modes showing when the node is booting up, idle and
waiting for a command, sampling, resynchronizing, or if there is an error.
Figure 2 - Interface and Indicators
Indicator
Behavior
Node Status
Node is OFF
OFF
Rapid green flashing
on start-up
Node is booting up
1 (slow) green pulse
per second
Node is idle and waiting
for a command
Device
status
indicator
1 green blink every 2
seconds
Node is sampling
Blue LED during
sampling
Node is resynchronizing
Built-in test error
Red LED
Table 1 - Indicator Behaviors
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2.3 Node Diagnostics
In the Wireless Node Configuration menu under the Sampling tab, there are four user-set data points
to provide information about the status of the Node.
Figure 3 - Node Diagnostic Menu
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Lost Beacon Timeout: The time a node will search for a beacon before determining there
is no base station connectivity. User-set between 2 minutes and 600 minutes
Diagnostic Info Interval: The report rate of the diagnostic packet. User-set between 30
seconds and 65536 seconds. The following data channels are available.
o
Current State: The current state of the device when the Diagnostic
Packet is sent.
o
0 = Idle
o
1 = Deep Sleep
o
2 = Active Run
o
3 = Inactive Run
o
Run Time: The number of seconds the Node has been in each state.
o
Reset Counter: The number of times the Node has reset.
o
Low Battery Indicator: If 1, a low battery event has been detected
since the last Diagnostic Packet.
o
Sample Info:
o
Sweep Index: The total number of sweeps (good
and bad).
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o
Bad Sweep Count: The total number of failed
sweeps.
o
Transmit Info:
o
Total Transmissions: Number of unique packets
transmitted (not including retransmissions.)
o
Total Retransmissions: Number of retransmitted
packets. Packets are retransmitted when a node
does not receive acknowledgment from the base
station.
o
Total Dropped Packets: Number of packets the
Node has discarded due to buffer overflow, or
exceeding
retransmissions per packet.
Built in Test Result: The result of the Built in Test function.
the
maximum
number
of
o
o
Event Trigger Index: The index of the most recent Event Trigger
logged to the Node. When this number changes, a new event has
occurred.
o
o
External Power: Flag indicating if external power is connected or not.
o
0 = Not Connected
o
1 = External Power Connected
Internal Temperature: The internal temperature of the Node in
degrees Celsius.
l
l
Storage Limit Mode: Determines the behavior of the storage as either first in, first out
(FIFO), or stops when the storage is full. Set at Stop by default with an Overwrite option in
the drop down menu
Sensor Warm Up Delay: The delay time before sampling after excitation is enabled.
Sensor Always On is set by default and indicated by a check mark. To manually set this
feature, uncheck the box and set between 1 µsecond and 66000 µseconds.
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Figure 4 - Viewing Node Diagnostic Data
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2.4 Node Operational Modes
Sensor nodes have three operational modes: active, sleep, and idle. When the node is sampling, it is in
active mode. When sampling stops, the node is switched into idle mode, which is used for configuring
node settings, and allows toggling between sampling and sleeping modes. The node will automatically
go into the ultra low-power sleep mode after a user-determined period of inactivity. The node will not
go into sleep mode while sampling.
Figure 5 - Node Operational Modes
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3. System Operation
LORD Sensing has two software programs available for data acquisition from the wireless sensor
network: SensorCloud and SensorConnect. SensorCloud is an optional web-based data collection,
visualization, analysis, and remote management platform based on cloud computing technology.
SensorConnect is PC-based software used for configuring gateways and nodes, selecting sampling
modes and parameters, initializing data acquisition, and viewing and saving data.
3.1 Software Installation
Install the SensorConnect software on the host computer before connecting any hardware. Access the
free software download on the LORD Sensing website at:
http://www.microstrain.com/software
SensorCloud is an optional data collection, visualization, analysis, and remote management tool. It is
based on cloud computing technology and is accessed directly from a web connection. For more
information go to: http://www.sensorcloud.com/.
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3.2 System Connections
To acquire sensor data the following components are needed: a LORD Sensing wireless sensor node,
a LORD Sensing data gateway, and a host computer with access to the data acquisition software.
The sensor, node, gateway, and software selection are application-dependent, but the basic interfaces
are the same. The V-Link-200 gateway utilizes Ethernet communications and can be used with
SensorConnect and SensorCloud™, although system configuration is completed using
SensorConnect.
Figure 6 - System Connections
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3.3 Gateway Communication
Drivers for the USB gateways are included the SensorConnect software installation. With the
software installed, the USB gateway will be detected automatically whenever the gateway is plugged
in.
1. Power is applied to the gateway through the USB connection. Verify the gateway status
indicator is illuminated, showing the gateway is connected and powered on.
2. Open the SensorConnect™ software.
3. The gateway should appear in the Controller window automatically with a communication
port assignment. If the gateway is not automatically discovered, verify the port is active on the
host computer, and then remove and re-insert the USB connector.
Figure 7 - USB Gateway Communication
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3.4 Connect to Nodes
Several methods can be used in SensorConnect to establish communication with the nodes: the
automatic node discovery on the same frequency, automatic node discovery on a different frequency,
and add node manually.
3.4.1 Automatic Node Discovery on Same Frequency
If the base and node are on the same operating frequency, the node will populate below the
Base Station listing when powering on the V-Link-200.
Figure 8 - Node Discovered On Same Frequency
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3.4.2 Automatic Node Discovery on Different Frequency
If a red circle with a number appears next to the Base Station, the node is operating on a
separate radio channel. Select the Base Station and then select the Nodes on Other
Frequencies tile.
Figure 9 - Node On Other Frequency
Highlight the new node being added and select Move Node to Frequency (#).
Figure 10 - Move Node
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3.4.3 Manually Add Node
Adding a node manually requires entering the node address and its current frequency setting.
From the Base Station, select the Manual Add Node tile, enter the Node Address, last known
Frequency (factory default is 15), and select Add Node.
Figure 11 - Add Node By Address
If the node was successfully added, two confirmation messages will appear and it will be
listed under the Base Station.
Figure 12 - Add Node Confirmation
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V-Link®-200 User Manual
If the node failed to be added, a failure message will appear. This means the node did not
respond to the base station which could indicate the node is not in idle mode or it may be on
another frequency. If "Add Node Anyway" is selected, it will associate that node with the
channel entered but it is likely there will be a communication error. If the node was not in idle,
move the base station to the frequency of the node and issue a "Set to Idle" command.
Figure 13 - Failure to Add Node
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3.5 Configure Node
Node settings are stored to non-volatile memory and may be configured using SensorConnect. To
access the node configuration menu, under Devices select the node and then the Configure tile.
The configuration menus show the channels and configuration options available for the type of node
being used.
For this example the V-Link-200 tester board is on channel 1.
1. Select Hardware > Input Range for channel 1, select +/-2 mV from the drop down menu.
2. Under Hardware Offset, select Balance Target for channel 1, select Mid (50%) from the drop
down menu.
3. Select Auto- Balance. When auto- balance is complete, a blue information window will
indicate the balance result.
Figure 14 - Auto-Balance
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4. Select Calibration.
5. Select Microstrain from the Unit drop down menu, and select the Shunt Cal button enabled
on the right.
Figure 15 - Node Configuration Menu
6. Use the following settings:
a. Calibration Mode: Internal
b. Number of Active Gauges: 4
c. Gauge Factor: 2
d. Gauge Resistance: 1000
e. Shunt Resistance: 499000
7. Select Start Shunt Cal for Slope and Offset calibrations.
8. Select Accept Calibration.
Figure 16 - Channel Settings
9. When the calibration is complete, the Wireless Node Configuration window will appear.
10. Select Apply Configuration to write to node memory.
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3.6 Configure and Start Sampling
To start a sampling session, nodes can be selected individually by selecting the Node name and then
the Sample tile.
To sample multiple nodes as a group, select the Base Station and then the Sampling Network tile.
As a group, they will all be set to the same sampling mode. When the Base Station is selected, all the
nodes will appear in a list with a check mark to the left, all of the nodes checked off will be included in
the sampling. Uncheck the nodes to be excluded from the sampling.
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Figure 17 - Network and Node Configuration Menu
l
Synchronized - By selecting Synchronized, all nodes in the network will periodically synchronize
their time clocks to a beacon that is broadcasted by the WSDA gateway. Each beacon contains
a UTC timestamp, allowing nodes to timestamp their collected data within an accuracy of +/- 50
us.
Each node will also buffer data and transmit this data in time-slots allocated prior to sampling.
Using time-slots assures the transmissions will not “collide”, or corrupt each other. It also
provides a means for efficiently scaling the size of the network to allow as much data throughput
as possible.
If Synchronized is deselected, the node will not require a beacon time source and will transmit a
data transmission for each measurement sweep. The user should deselect Synchronized if,
either low latency, or the lowest possible power at slow sample rates, is required.
l
Lossless - The user can achieve near lossless data collection in most environments through the
use of data buffering, radio acknowledgments, and retransmissions. Each node buffers collected
data and timestamps to an internal 2 Mbit FIFO buffer. For each transmission, data is pulled from
this buffer. Upon receiving the data packet, an acknowledgment is sent from the WSDA
gateway providing the beacon. The node will retransmit data until this acknowledgment is
received. Inherent overhead in the transmission scheduling protocol assures the node time to
recover from periods of poor radio communication.
This feature allows lossless performance in environments where the node achieves as low as
50% packet error rate. It also allows for operation in situations where the gateway and node
move in and out of range of each other.
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V-Link®-200 User Manual
NOTE: The Lossless feature is only available when Synchronized is enabled. Disable Lossless if
the application requires consistent latency or can tolerate lost data.
l
Node: Indicates the node address beside a box with a check mark. This box is checked by
default to include the node in the sampling. Uncheck the box to exclude the node from the
sampling.
l
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Channels: Provides a drop-down menu to select the desired sensor channels for the node.
Sampling: Displays a drop-down menu to select the sample rate. "Continuously" samples
indefinitely, "For" specifies a fixed sampling time-frame, and "Bursting" allows short sampling
durations performed at periodic intervals.
l
l
Data Type: Select the resolution of the data reported by the node. Selecting lower resolution
data will require fewer transmissions and lower power. Selecting "Float" will request the node
send data in the configured calibration unit type.
Log/Transmit: Select "Log Only" to have the node store all collected data to flash memory for
later download. Select "Transmit Only" to have the node transmit all data while it is collected. Or
select "Log and Transmit" to have the node perform both operations.
l
l
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% Total: Indicates the percentage of total over-the-air bandwidth reserved for each node.
Status: Displays network errors.
Apply and Start Network: Applies all of the settings, starts the entire network, and starts the
Base Station's beacon.
l
Apply and Arm Nodes: This setting allows the user to Arm all of the
nodes without starting the beacon. If the gateway has already enabled
the beacon, this setting will keep the gateway's beacon.
l
Apply Only: Saves the settings to memory and not start the network.
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4. Viewing Data
4.1 SensorConnect
4.1.1 Using Dashboards and Widgets
Collected data is viewed on the Data page through the creation of dashboards and widgets. Think
of dashboards as individual pages and widgets as an illustration on the page. Create multiple data
widgets on each dashboard to display sampled data as a time-series graph, text chart, or a simple
gauge that only displays the most current reading. This format provides an easy way to organize
many sensors and networks, and it allows the information to be displayed in the most appropriate
layout.
Figure 18 - Viewing Data
4.1.2 Navigating Graphs
Use the mouse along with the shift and control keys inside the graph window to adjust the data view.
Control
Action
Zoom in/out on x-axis
Zoom in/out on y-axis
Zoom to extends
Mouse wheel
Shift + mouse wheel
Mouse double-click
Zoom window left/right
Zoom window up/down
Zoom box
Shift + mouse left-click, drag left/right
Shift + mouse left-click, drag up/down
Ctrl + mouse left-click, drag
Table 2 - Graph View Controls
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4.1.3 Widgets Options
The widget configuration menu is different for each type of widget but typically includes sensor or
channel selections and widget settings such as titles and legends.
After adding a widget, left click to select and configure it in the Channels and Settings left sidebar
menu. Under Channels, the channel(s) for the widget can be enabled and disabled.
Figure 19 - Widget Settings Menu
4.1.4 Time Series Widget Menu
The Time Series Widget menu has two features to help optimize sensor data collection for export to
a .csv file. Snap to Latest captures the most recent data and Zoom isolates specific events from a
larger data sample (see Exporting Data Files on page 28).
Figure 20 - Time Series Widget Menu
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4.1.5 Exporting Data Files
To export data to a .csv file, select the Export Data button on the Time Series widget > Export >
name the document > save to the preferred location on the host computer.
Figure 21 - Exporting Data
Data acquired through SensorConnect is automatically saved on the host computer. Saved data can
be uploaded to SensorCloud. Ethernet gateways provide the option to automatically port the data to
SensorCloud during data acquisition for near real-time display and aggregation. Ethernet gateways
can also be configured to save data locally to internal memory for future upload to the host computer or
SensorCloud.
SensorCloud is based on cloud computing technology and is designed for long term collecting and
preservation of data. Features include time series and visualization graphing, automated alerts, and
data interpretation tools such as data filtering, statistical analysis, and advanced algorithm
®
development with the integrated MathEngine
interface. Leveraging the open source API,
SensorCloud can also be used to collect data from other LORD Sensing sensor products or third-party
systems. Basic SensorCloud services are available to all users free of charge at:
http://www.sensorcloud.com/.
Figure 22 - SensorCloud Log-in or Register
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4.1.6 Navigating Menus
The SensorCloud interface has six main views. When logging in as a registered user, the Device
view is the default. Navigate to other views by clicking the view name at the top of the page (Figure
23 - SensorCloud Menu Views). The Data and Settings views are only available once a device is
selected from the device list.
Figure 23 - SensorCloud Menu Views
Device - The device list shows every Ethernet gateway and API device associated with the
SensorCloud account, including owned, shared, and demo devices. This view provides links to each
device’s SensorCloud subscription plan, configuration options, and a summary of last communications
and data transactions.
Account - The account view is for logistic management of the SensorCloud account, such as changing
the log-in password, accessing user email, and reviewing billing information.
CSV Uploader - The data upload feature enables data from any source (such as non-Ethernet LORD
Sensing gateways, or third-party sensor) to be uploaded to the SensorCloud platform. The data must
be in the LORD Sensing CSV format.
Data - This view is only available after a device is selected. It displays data that is collected from sensor
nodes or uploaded from files. Data selections are listed by node channel or a user-defined label and
can be enabled for display in the graph window. The interactive graph has navigational features such
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as panning, zooming, and an overview graph for single-click access to data points or ranges. There are
also use and management features such as viewing the meta-data and downloading, embedding, and
tagging data graphs.
Figure 24 - SensorCloud Data View
Settings - The settings view provides options for adding meta-data, configuring the data displays for
each channel, creating alerts based on data thresholds, setting the data timezone, and more.
®
MathEngine - is used to analyze sensor data. Functions include the ability to filter out frequencies,
smooth out noisy data, perform math operations such as Fast Fourier Transforms (FFTs), and more
®
(Figure 25 - MathEngine® View). MathEngine interfaces with the SensorCloud graphing view for
faster processing. Users can write their own algorithms for custom applications. Refer to the
®
MathEngine website for more information.
http://sensorcloud.com/mathengine
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®
Figure 25 - MathEngine View
Figure 26 - FFT Graph in SensorCloud
For more information about SensorCloud features and navigation, refer to the SensorCloud
website:http://www.sensorcloud.com/, or contact LORD Sensing Technical Support.
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5. Installation
5.1 Mounting Recommendations
The V-Link-200 is rated for indoor use only, unless housed in a ruggedized outdoor enclosure.
Enclosures for the V-Link-200 are available from LORD Sensing.
There are two mounting tabs on the node, with holes for fastening. A DIN rail clip and three screws are
included with the V-Link-200 for optional DIN rail mounting (Figure 29 - DIN Rail Mount Option).
The node can be mounted in any orientation, but it is recommended that it is mounted in a way that
optimizes wireless communications, typically with the antenna pointing upward. For more information,
see Optimizing the Radio Link on page 34.
Figure 27 - Mounting the Node
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Figure 29 - DIN Rail Mount Option
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5.2 Optimizing the Radio Link
NOTE
In the event of communication difficulties, it may be necessary to disable WIFI on the host
computer, or use a USB extender when collecting data.
The best method for ensuring optimal radio communication is to conduct an RF survey of the
installation site. This is easily accomplished in SensorConnect by using the range test feature to
quantify the radio signal strength (RSSI) in various scenarios. See Range Test on page 35 for
instructions on using SensorConnect for measuring RSSI. The following are general guidelines for
maximizing communication range:
l
Line of Sight (LOS) between the node and gateway. Try to avoid obstructions such as
buildings, terrain, vegetation, or other physical barriers.
l
Increase the Mounting Height of the node to allow a clearer LOS path to the
gateway. Height above the ground is also important because reflections off of the ground
can interfere at the receiver. Generally, the higher above the ground the better.
l
Minimize Radio Frequency Interference (RFI) from other wireless devices, especially
those operating in the same frequency range. This includes other nodes and 2.4 GHz
WIFI routers. If other wireless devices are required nearby, mount them at different
heights to minimize interference. Additionally, a different radio frequency may be selected
using SensorConnect software.
l
Minimize Electromagnetic Interference (EMI) such as that which is generated by power
transmission equipment, microwaves, power supplies, and other electromagnetic
sources.
l
Metal Objects in close proximity to either antenna, particularly ferrous metals such as
steel and iron, can be problematic for wireless communications. The larger the object, the
greater the influence.
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5.2.1 Range Test
After establishing communication between node and gateway, use the range test feature in
SensorConnect to monitor the signal strength and to optimally position the nodes, gateway, and
antennae for installation. Maximum achievable range is determined by the gateway and node
power settings (found in the device Configure menu) and is highly dependent on the physical
environment surrounding the devices.
1. Select the node name > Range Test
Figure 30 - Range Test Menu
2. RSSI is a measure of signal strength between the node and the base station. A higher
RSSI value (closer to zero), will result in better node to base station communication.
Reliable communication can be achieved with a signal strength greater than -75 dBm, in
the absence of radio frequency interference. Position the node and gateway antennas
where the best RSSI value is observed.
Figure 31 - Range Test Statistics
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6. Connecting Sensors
The V-Link-200 wireless sensor node features eightanalog input channels that interface with a wide range
of available sensor technologies, essentially converting them into wireless sensors. The node
accommodates Wheatstone Bridge and analog sensors for applications in wireless strain gauge
monitoring, such as torque, force, and pressure measurement, as well as sensors for other applications
like wireless accelerometers, vibration sensors, magnetic field and displacement sensors. Environmental
sensing can be achieved with wireless RTD and wireless thermocouple monitoring.
The V-Link-200 includes four single ended and four differential channels for sensor measurement.
Differential channels may need to be factory-set to work for specific types of sensors. For information
about channel configurations see Differential Input Channels on page 41. For ordering information
see Wireless Equipment on page 83.
6.1 Sensor Requirements
Below are guidelines for selecting sensors for use with the V-Link-200. For interfacing with sensors
outside of these parameters, or not included in the examples in the following sections,
contact Technical Support (see Technical Support on page 81).
Sensor Impedance:
l
Differential sensor inputs using a Wheatstone Bridge must have an impedance that is ≥
120 Ω. For half-bridge and quarter-bridge configurations, the node impedance value is
set to match the sensor when the node is manufactured and must be specified at the
time of order. For more information see Wireless Equipment on page 83. Custom
bridge completion impedance values are available on request.
Sensor Signal Voltage:
Differential sensor inputs include a hardware gain and offset stage before the sensor
l
input signal is processed by the analog to digital voltage converter within the
node. The combination of the gain, offset, and sensor signal voltage cannot exceed the
5 V dc input range of the analog to digital converter. For more information see
Differential Input Gain and Offset on page 67.
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Single-ended sensor signal voltages are measured with respect to the system ground
and must be between -10.24 to +10.24 V dc.
Sensor Power:
The total current available for all connected sensors must be less than 150mA. The
voltage is 4.096 V dc.
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6.2 Wiring Recommendations
It is good practice that all sensor wiring be done with shielded cable. The shield is connected to the
system ground only at one end to avoid ground loops. For sensitive small voltage signals (such as
strain gauges) sensor wire leads should be of matched lengths so the lead resistance for each
connection is as close to the other as possible. For long lengths of wire, a system calibration
is recommended over a sensor calibration. See Sensor Calibration on page 51.
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6.3 Sensor Power
Sensors can be powered by the node or with an external power supply. The node sensor excitation
voltage is 4.096 V dc and can provide up to 150mA total on all channels. If a higher voltage or more
current is required for the sensor, an appropriately sized external power supply can be used. For
example, using the node battery for current intensive devices such as 4 to 20mA sensors will drain the
battery quickly. For these applications, an external source is recommended for the sensor or the node.
Drain on the battery can also be limited by selecting low resource sampling modes and low duty
sampling rates, which automatically switch the node excitation voltage off after sampling. This feature
can also be utilized to turn switches on and off to further control resource use.See Using the Excitation
Output as a Switch on page 48.
External battery holders and ruggedized outdoor housings that accommodate larger batteries are
available for the V-Link-200 and can be used to extend battery operating capacity and duration.
See Node Accessories on page 83.
6.4 Node Channels Designations
Channel
Description
Pin Nomenclature
differential channel 1
differential channel 2
differential channel 3
differential channel 4
single ended channel 1
single ended channel 2
single ended channel 3
single ended channel 4
S1
S2
1
2
3
4
5
6
7
8
S3
S4
Ain5
Ain6
Ain7
Ain8
Table 1 - Channel Designations
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6.5 Terminal Block Connections
When inserting the sensor leads into the terminal block ensure the lead wire is being clamped under
the terminal screw and not the lead insulation. If the sensor wires are a very fine gauge, folding and
tinning them may be useful to provide more area for the terminal screw to make contact. Failure to
provide adequate connection may result in erroneous data.
Node Pin
Number
Node Pin
Number
Signal
Signal
SP+
S1+
S1-
SP+
S4+
1
2
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
S4-
3
GND
S1 S
SP+
S2+
S2-
GND
S4 S
Ain5
GND
Ain6
GND
Ain7
GND
Ain8
GND
Vin
4
5
6
7
8
GND
S2 S
SP+
S3+
S3-
9
10
11
12
13
14
15
GND
S3 S
GND
Table 3 - Terminal Block Connections
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6.6 Pin Descriptions
Pin
Type
Signal
Vin
Description
Node external power supply
Range
7.5 to 36 V dc
power
input
sufficient current capacity
for sensors
An alternate to the node power jack. See Powering
the Node on page 69.
Return
power
return
return
GND
S+
For node power and sensor excitation
Sensor excitation
4.096 V dc
maximum combined load
on all excitation pins is 150
mA.
Power to external sensors. At sampling rates under
32Hz, it is only active when the node is sampling the
sensors.
output
Differential sensor input +
0 to 5 V dc including
gain and offset
Sx+
Sx-
Positive input to the node programmable gain amp-
lifier (PGA). Used with S-.
Wheatstone Bridge com-
patible sensor with 120 Ω
input impedance recom-
mended
input
Differential sensor input +
Negative input to the node programmable gain
amplifier (PGA). Used with S+.
4.096 V dc including
gain and offset
Three wire input
Wheatstone Bridge com-
patible sensor with 120 Ω
input impedance recom-
mended
Used only for three wire configuration of quarter
bridge strain gauge bridges. Leave unconnected for
non quarter strain gauge bridge applications.
input
input
Sx S
Ainx
Single ended sensor input
-10.24 to +10.24 V dc
Routed directly to the node analog to digital (A/D)
converter. Return is node GND.
Table 4 - Node Pin Descriptions
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6.7 Differential Input Channels
The differential measurement channels provide a 5 V dc excitation voltage to the sensor and measure
the resulting sensor signal output. The sensor signal goes through a programmable gain amplifier
(PGA) and is then processed in the node by a18-bit analog-to-digital (A/D) converter over the 5 V dc
range. The resolution of the sensor measurement is dependent on the operating range of the sensor.
If the application is such that only a small portion of the 5 V dc range is being utilized, better resolution
can be achieved by increasing signal amplification and by zeroing the sensor baseline in the
appropriate offset biasing range. Sensor gain and offset values are configurable in SensorConnect.
See Configure Node on page 21.
Figure 32 - Differential Channel Signal Processing
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6.7.1 Differential Sensors
Sensors that are classified as differential sensors often utilize a Wheatstone Bridge configuration.
These sensors are essentially a resistive load that use the bridge configuration to detect very small
resistive changes and produce a precise voltage output as a result. Some examples include strain
gauge elements or strain gauge-based sensors, such as some load cells and pressure transducers,
as well as some soil moisture, temperature, and other sensors. For use with the V-Link-200,
sensors with an impedance of ≥ 120 Ω are recommended.
Calibration in the SensorConnect software for these devices varies depending on the type of sensor
and includes using the shunt calibration for strain gauges. The following diagrams show how to
connect these types of sensors. Note: Full- Bridge is the standard LORD Sensing offering.
Calibration for Half-Bridge, Two Wire Quarter-Bridge, and Three Wire Quarter-Bridge requires the
optional on-board bridge completion. See Sensor Calibration on page 51 for more information.
Figure 33 - Full Bridge Wiring
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Figure 34 - Half and Quarter-Bridge Wiring
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6.7.2 Differential Channel Raw Voltage
To set the V-Link-200 to show the raw voltage that is being applied (in mV) to channels 1 -4
(differential channels), enter the slope and offset for the input range being used. (See Table 5 -
below )
Input Range
[Gain]
Slope
Offset
[16]
[32]
0.0012207031
0.0006103516
0.0003051758
0.0001525879
0.0000762939
0.0000381470
0.0000190735
0.0000095367
-156.25
-78.13
-39.06
-19.53
-9.77
±156 mV
±78.1 mV
±39.0 mV
±19.5 mV
±9.76 mV
±4.88 mV
±2.44 mV
±1.22 mV
[64]
[128]
[256]
[512]
[1024]
[2048]
-4.88
-2.44
-1.22
Table 5 - Raw Voltage Output
The formula to derive the above raw voltage output:
Slope = 5120mv ÷ (262144 * gain)
Offset = -(5000mV ÷ (2 * gain)) (Assuming balance to mid-scale is perfect)
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6.7.3 Measuring Small Voltages
Some sensor types that have small signal voltages (around 20 mV or less) may be better measured
by biasing the sensor signal to the mid range of the node input range with a voltage divider, as
shown in Figure 35 - Small Voltage Measurement.
Channel configuration will include adjusting the gain setting accordingly in the SensorConnect
software.
Figure 35 - Small Voltage Measurement
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6.8 Single-Ended Input Channels
Single-ended channels are designed to measure voltages with reference to the system ground and can
accommodate many analog sensors types including accelerometers, pressure transducers,
geophones, temperature sensors, inclinometers, and more. These channels can also be used to
measure reference voltages.
Sensors that operate on 4.096 V dc can be powered with the node excitation voltage. Alternately,
sensors can be powered with an external source.
The sensor output signal is processed in the node by an 18 -bit analog to digital (A/D) converter, over
the -10.24 to +10.24 V dc range. The resolution of the sensor measurement is dependent on the full
scale output range of the sensor. More resolution can be achieved by changing the single-ended
channel input range, see below.
Voltage Range
Slope
Offset
0.0000781250
0.0000390625
0.0000195313
0.0000390625
0.0000195313
-10.24
-5.12
-2.56
0
±10.24 V
±5.12 V
±2.56 V
+10.24 V
+5.12 V
0
Table 6 - Single-ended Raw Voltage Ranges
The following sections provide examples of how various sensors can be connected to the node.
For other applications, see Technical Support on page 81.
Figure 36 - Single Ended Signal Processing
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6.8.1 Measuring Small Currents (4 to 20mA Sensors)
LORD Sensing nodes with analog inputs, such as theV-Link-200 and , support a wide range analog
sensors including acceleration, vibration, strain, load cells, torque, pressure, magnetic fields,
displacement, geophones, and more. To support these sensors, the nodes measure small voltage.
Additionally, sensors with small current outputs, such as 4 to 20mA sensors, can be used with the
nodes by adding a precision sampling resistor across a single-ended input channel to the node. An
example circuit is shown in Figure 37 - Small Current Measurements .
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Node Channel and Sensor Output Range: Either the single- channel or
differential analog input channel can be used to measure current. The external
circuit and node settings are different for each. The single-ended option is simpler
allows less adjustment. For applications in which very small currents will be
measured, the differential inputs offer better noise immunity and programmable
gain settings. Available gain settings vary between node models. Differential inputs
can be factory configured for various bridge completion and impedance values. For
this application, the standard full- bridge configuration is assumed. For other
configurations contact LORD Sensing Technical Support.
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Power Source: If the sensor will be operating continuously in the 20mA range, or if
multiple analogs inputs are in use, it is recommended that an external source be
used to power the sensor or the node. Typically nodes can only supply 50mA (to all
sensors), so 20mA would be a significant portion of the node capacity and would
drain the internal battery quickly. However for applications with lower current
requirements and measurement ranges, the internal battery may be a better option
to mitigate potential noise sources, especially when using differential channels.
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For battery life and current draw information see Using the Internal Node Battery on page 69.
The current limitations can be mitigated by using an external power source for the sensor or the
node. If using node excitation power is the best for the application, drain on the battery life can be
limited by only switching the node excitation voltage on just before sampling and then turning it
off afterward. This happens automatically at low duty sampling rates (32Hz or lower) and can be
set up for other sample rates with external circuitry. For more information see Using the
Excitation Output as a Switch on page 48.
Figure 37 - Small Current Measurements
6.9 Using the Excitation Output as a Switch
At low sampling rates (under 32Hz) the node automatically switches the excitation voltage output off
when the sensor is not being sampled, in order to conserve battery life. This feature can also be used
in applications where a switch is desired, such as for turning sensor power on and off when the sensor
is powered by the node but has a large current draw. It can also be used as a general purpose switch,
such as for controlling a relay or transistor. The same limitations apply as to a sensor; the device must
operate on 4.096 V dc and not require more than 150mA when combined with all other sensor current
draw. To use the excitation output in this way, connect the control line of the device (example: relay coil
or NPN transistor base) to the excitation pin on the node terminal block (SP+) and reference (example:
other side of the relay coil or the NPN transistor emitter) to the node ground pin (GND).
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6.10 Connecting Accelerometers
LORD Sensing bridge type accelerometers, such as the Triaxial Accelerometer Cubes, can be used
with V-Link-200 to create wireless acceleration sensor platforms. Connect each accelerometer axis
output to a node differential input channel. Power is provided to the accelerometer from the node
excitation supply.
For additional information on LORD Sensing accelerometers compatible for use with the V-
Link-200, see Recommended Sensors on page 84 . For information on integrating other types of
sensors not described in this manual, contact Technical Support (seeTechnicalSupportonpage81).
6.11 On-board Temperature Sensor
l
The V-Link-200 has an on-board, solid state temperature sensor mounted on the surface
of the circuit board.
l
l
Available as a channel in the Diagnostic Packet.
The temperature sensor has a measurement range of -40˚C to +85˚C range with an
accuracy of ± 0.5˚C @25˚C.
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7. Sensor Settings
LORD Sensing sensor nodes are designed to accept many sensor types. The node configuration interface
includes settings for measurement units and conversion values. There are preset measurement units, as
well as a user-defined field. Because the wireless sensor system is digital, the analog voltage readings
from the sensors are converted into a digital equivalent value based on the volt-to-bit scale of the internal
analog-to-digital voltage converter (A/D converter). Sensor readings can be displayed and recorded in
A/D value (bits) directly or further converted to engineering units by applying conversion values and
a conversion formula. For more information, See Sensor Conversion Values on page 61.
Some sensors require calibration to determine more accurate conversion values. Calibration incorporates
coefficients that normalize the sensor output to a known reference device and guarantee accuracy of
conversions.
External sensors can be attached to any channel that is suitable for sensor type.Table 7 - Example
External Sensor Types , describes example sensors, units, and calibration options.
example
external sensors
calibration
options
channel type
units
shunt calibration
strain
volts
strain gauges in full, half,
user entry from
manufacturer
data, lab or field
calibration
quarter/custom
Wheatstone
A/D value
custom
Bridge configurations
other Wheatstone Bridge sensors
such as:
g-force
analog
differential input
A/D value
some pressure sensors
some force sensors
volts
user entry from
manufacturer data,
lab or field
custom
some mass sensors
English and metric
some displacement sensors
some accelerometers
some temperature sensors
4-20mA sensors
calibration
measurements
for;
mass, pressure, force,
distance,
and
temperature.
user entry from
manufacturer data,
lab or field
volts
analog
single ended
input
sensors with voltage outputs
referenced to the system ground.
A/D value
custom
calibration
user entry from
manufacturer data,
lab or field
temperature
A/D value
custom
thermocouples
thermocouple
calibration
Table 7 - Example External Sensor Types
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7.1 Sensor Calibration
Many sensors require calibration coefficients to accurately report measurements. Methods for
determining the calibration coefficients depend on the type of sensor measurement and application.
The SensorConnect software facilitates multiple calibration methods. Calibration calculators for some
applications are also available by contacting LORD Sensing Technical Support. See
Technical Support on page 81.
l
Sensor manufacturer’s specifications or calibration: The slope and offset values, or the
data to derive them, are provided with the sensor by the manufacturer to prove its accuracy
and describe expected voltage output. Some sensors are calibrated individually, while
others are manufactured to a standard sensitivity value (plus or minus some tolerance),
which is provided in the device specifications.
l
Sensor lab calibration: If the manufacturer's calibration is not available or outdated,
calibration of the sensor can be performed with calibrated equipment in a controlled
environment. The calibration equipment and process will typically be traceable to an industry
standard, such as NIST or ASTM in the United States. Fixed loads are applied to the sensor
while the sensor output is recorded. The load is applied or measured by a calibrated
reference device. The known load value from the calibrated device is then plotted against the
measured output of the sensor to determine the calibration slope and offset. In
SensorConnect this can be accomplished by taking sensor readings while applying the
known loads.
Sensor wiring, tolerances in system electronics, and differences in mounting techniques are examples
of systemic variables that can influence the sensor readings. Sensors that are making small
measurements or are otherwise sensitive to these slight differences may benefit from a system
calibration. The following techniques are system calibrations:
l
System shunt calibration (internal and external): This option is only available for
Wheatstone bridge-type sensors (such as strain gauges) in SensorConnect. In the shunt
calibration process, an internal or external precision resistor is used to load part of the sensor
bridge while the sensor remains unloaded. The bridge output is measured and used as a
loaded calibration point for the sensor. In addition to the no-load value it can be used to
derive the calibration slope and offset. The internal shunt resistor is suitable for most
applications, however an external shunt may be beneficial in high gain scenarios.
l
System field calibration: The field calibration is a similar methodology to the sensor lab
calibration. Known loads are applied to the sensor while the sensor output is recorded. The
load is applied or measured by a reference device. In this scenario, the sensor may be
installed in final field configuration, and the load may be applied with the actual stimulus that
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V-Link®-200 User Manual
the sensor will be monitoring. The known load value from the reference device is then plotted
against the measured output of the sensor to determine the calibration slope and offset. In
SensorConnect this can be accomplished by taking sensors readings while applying the
known loads.
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7.1.1 EXAMPLE: Internal Shunt Calibration
NODE: V-Link-200, 18 bit (262144 A/D values)
CHANNEL TYPE: differential analog input, 0 to 5 V dc input range
SENSOR TYPE: strain gauge, Wheatstone Bridge, full bridge configuration
SENSOR PARAMETERS: application voltage range: +/-2 mV
This is the expected output voltage of the strain gauge based on the range of strain being measured
in the application and the sensitivity of the gauge (volts/strain).
DESIRED OUTPUT: engineering units, microstrain
PROCEDURE:
1. Open SensorConnect and establish communication with the gateway and node. (See
System Operation on page 14).
2. Select Hardware > Input Range for channel 1, select +/-2 mV from the drop down menu.
3. Under Hardware Offset, select Balance Target for channel 1, select Mid (50%) from the drop
down menu.
4. Select Auto- Balance. When auto- balance is complete, a blue information window will
indicate the balance result.
Figure 38 - Auto-Balance
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5. Select Calibration.
6. Select Microstrain from the Unit drop down menu, select the Shunt Cal button enabled on the
right.
Figure 39 - Node Configuration Menu
7. Use the following settings:
a. Calibration Mode: Is either Internal (using the shunt resistor on the V-Link-200)
or External (using an external shunt resistor).
For this example, Calibration Mode is set to: Internal
b. Number of Active Gauges: Typically full-bridge is 4, half-bridge is 2, and quarter-
bridge is 1.
For this example, Number of Active Gauges is: 4
c. Gauge Factor: Is a specification from the gauge.
For this example, Gauge Factor is: 2
d. Gauge Resistance: Is a specification from the gauge.
For this example, Gauge Resistance is: 1000
e. Shunt Resistance: 499000
8. Select Start Shunt Cal for Slope and Offset calibrations.
9. Select Accept Calibration.
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Figure 40 - Channel Settings
10. When the calibration is complete, the Wireless Node Configuration window will appear.
11. Select Apply Configuration to write to node memory.
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7.1.2 Calibration Lab or Field
The lab and field calibrations use similar methodology. See Sensor Calibration on page 51.
The primary difference is the traceability and calibration environment. Lab calibrations are
performed in controlled environments with traceable equipment and procedures. Field
calibrations are more improvised, although calibrated equipment can still be used to improve
accuracy.
NODE: V-Link-200, 18 bit (262144 A/D values)
CHANNEL TYPE: differential analog input, 0 to 5 V dc input range
SENSOR TYPE: load cell
SENSOR PARAMETERS: application voltage range: +/-2 mV
This is the expected output voltage of the sensor based on the range of force being measured in
the application and the sensitivity of the sensor (V/engineering units)
DESIRED OUTPUT: engineering units (EU), force (lbs)
PROCEDURE:
1. Open SensorConnect and establish communication with the gateway and node (See System
Operation on page 14).
2. Select Hardware > Input Range for channel one, select +/-2 mV from the drop down menu.
3. Under Hardware Offset, select Balance Target for channel one, select Mid (50%) from the
drop down menu.
4. Select Auto- Balance. When auto- balance is complete, a blue information window will
indicate the balance result.
Figure 41 - Auto-Balance
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5. Select Calibration.
6. Use the following settings:
a. Slope: 1
b. Offset: 0
c. Units: Bits
7. Select Apply Configuration. When the settings have been applied, a green pop up window
will confirm the process is complete.
Figure 42 - Node Configuration Menu
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8. To start sampling, click on the node name and select Sampling
9. The node is included in the sampling by default and is indicated by a white check mark in the
blue box to the left of the Node number. Uncheck any nodes to be excluded in the sampling.
10. Use the following settings:
a. Channel: 1
b. Hertz: 128
c. Float: 4
d. Log/Transmit: Transmit Only
Figure 43 - Channel Settings
11. Select Apply and Start Network.
12. Select the Quick View Dashboard pop up window to view sampling.
13. After making all measurements, calculate a slope from the data using the formula y=mx+b
in a data analysis program, such as Microsoft Excel. See Calculating a Linear Slope on
page 65.
14. Return to the Wireless Node Configuration screen for the sensor channel, select
Calibration, and enter the Slope and Offset values derived in the data analysis program.
Figure 44 - Enter Calibration Values
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15. Select Apply Configuration to save the values selected.
16. Collect data again with no load on the sensor.
17. Observe the value in the stream graph. If the value is not at zero, return to the Wireless Node
Configuration menu, and adjust the offset by increasing or decreasing the value.
18. Once the offset has been zeroed, verify the calibration by applying known loads on the sensor
throughout the load range, observing and verifying the measurement in engineering units.
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7.1.3 Manufacturer Calibration
NODE: V-Link-200 ,18 bit (262144 A/D values)
CHANNEL TYPE: differential analog input, 0 to 5 V dc input range
SENSOR TYPE: pressure transducer, voltage output, positive going
SENSOR PARAMETERS:
From the manufacturer calibration sheet included with the sensor;
sensor range: 0-250 psi
sensor zero load output: 0.0032 V dc
sensor full scale output (FSO) with 10V excitation: 86.07 mV
From the application parameters;
sensor excitation in application: scaled to 4.096 V
DESIRED OUTPUT: engineering units (EU), psi
CALCULATIONS:
Because the sensor will be powered from the node with 4.096 V, and the sensor manufacturer
calibrated it a 10 V, the manufacturer full scale output (FSO) value needs to be scaled to 3V.
(4.096 V/10 V) * 86.07 mV = 35.25 mV
Select a gain and offset scale value appropriate for the sensor. (See Differential Input Gain
and Offset on page 67).
The closest gain setting that accommodates 35.25 mV is +/- 39.0 mV. Using a lesser value would
exceed the input voltage capacity of the node when the sensor is at higher pressures. For more
information about gain values and associated input ranges, See This table lists the gain settings
available on the V-Link-200 differential input channels. The scaled input range is the approximate
signal range of a sensor that would work with that gain, without considering the offset setting.
on page 68
Multiply the sensor FSO by the gain setting to get the sensor voltage after amplification. For this
example, the range is 39.0 mV for a gain of 64.
64 * 35.25 mV = 2.256 V
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V-Link®-200 User Manual
Scale the (gained) sensor input voltage/EU ratio to the node input voltage/EU ratio to determine the
equivalent node FSO value (x).
2.256 V/250 psi = 4.096 V/x
(250 psi * 4.096 V)/2.256 V = x = 453.9 psi
The node converts voltage inputs to A/D values. For an 18-bit node, there are 262144 A/D values
over the 4.096 V input range. Divide the node EU FSO by the A/D value to get the ratio, or slope, of
EU to A/D value.
453.9 psi/262144 bits = 0.00173 = slope
Once the slope is entered, the sensor offset value can be measured in a data sampling session,
such as streaming. Sample the sensor channel with no load applied, and read the EU value. Enter
this as a negative value for the offset in order to have it subtracted from readings.
7.2 Sensor Conversion Values
NOTE
In order to report accurate readings, many sensors require calibration. Calibration
coefficients normalize the sensor output to a known reference device and are often expressed
in the measurement unit conversion values; the only difference being the use of a traceable
reference. Calibration can be used to account for the variations between individual sensors,
wiring, system electronics, sensor mounting and environmental conditions.
The conversion values include the slope, offset, gain, scale, and formula for converting the sensor
A/D value (bits) to engineering units. The bits are the digital representation of the sensor voltage
output. The type of sensor, channel, and desired engineering units determine what conversion
values are available. The conversion values are entered through SensorConnect and saved in the
node memory for the applicable channel.
Conversion values for the V-Link-200 are determined mathematically from the sensor sensitivity
specifications, from the sensor manufacturer calibration data, or through a calibration process.
Calibration incorporates coefficients that normalize the sensor output to a known reference device
in order to guarantee accuracy of the sensor readings, especially when making small or
precise measurements. See Sensor Calibration on page 51 for more information. Not all
sensors require calibration.
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Conversion Formula: The conversion formula assumes a linear relationship between the original
units (such as volts or A/D bits) and new engineering units (such as strain), and it is expressed
mathematically as y=mx+b, where y is the engineering units at a given point (measurement), m is
the slope of the line that represents the linear ratio, x is the original unit value at a given point, and b
is a unit conversion offset (in the case of unit conversions) or the fixed zero load offset of the sensor
(in the case of measurement calibration coefficients). Negative values may be entered for any
coefficient.
Slope: is the linear scaling slope coefficient. The slope is the ratio of original units to new
engineering units (EU), and it is used to convert the sensor measurements. The slope conversion
value will vary depending on the engineering units desired. For example if the original unit is A/D
values (bits), and the desired engineering units are acceleration in g-force, the slope conversion
would describe how many bits equal one unit of g-force (bits/g). Mathematically, the slope is m in the
formula y = mx +b.
Figure 45 - Conversion Values Menu
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Input Range (Gain): This sets the amplification of the signal within the node and is only available for
channels with differential inputs and gain amplifiers.
Hardware Offset: is the linear scaling offset coefficient, and it is typically the starting output value of
the sensor with no load applied (in the original units). Mathematically, the offset is b in y = mx +b.
Anti-Aliasing Filter: A filter applied before the digitization of the analog signal.
Figure 46 - Advanced Conversion Values Menu
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Offset Scale (with Auto Balance):This feature is only available for channels with differential inputs,
and assigns the position and value of the no load measurement of the sensor. The offset scale level
adjusts the operating window of the sensor measurements in reference to the entire range. For
example, in mid scale the sensor no load measurement will be placed in the middle of the range,
providing 50% of the range for positive readings and 50% of the range for negative readings. Once
the scale level is selected, the Auto Balance procedure is used to assign the actual sensor no-load
measurement to the designated scale.
l
l
l
Low is for positive-going signals (zero at 25% of total range).
High is for negative-going signals (zero at 75% of total range).
Midscale is for positive and negative-going signals (zero at 50% of range).
Figure 47 - Offset Scale Setting
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7.2.1 Calculating a Linear Slope
A data analysis tool such as Microsoft Excel can be used determine the slope of a linear relationship
between sensor output A/D value (bits) and engineering units. This is not a calibration unless a
calibrated reference device is used to measure the applied loads. For information and examples
for determining calibrations coefficientssee Sensor Calibration on page 51.
Here is an example, using Excel:
1. Open a blank spreadsheet.
2. Enter the A/D value (bits) measurements and applied load in the desired engineering units in
two columns. Enter A/D value in the left column (x-axis value) and the applied load in the right
(y-axis value).
3. From the Insert menu, select Chart > Scatter. Select the preferred format.
Figure 48 - Generate a Scatter Chart
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4. Right-click on the graphed line, and select Add Trendline .
5. Designate the line as Linear, and check the option to Display the Equation on the chart.
Figure 49 - Plot Trendline
6. The formula of the line is y=mx+b, where y is the engineering units at a given point
(measurement), m is the slope of the line that represents the linear ratio, x is the A/D value at
a given point, and b is the fixed zero load offset of the sensor. Enter the slope and offset as
the conversion values for the sensor channel under the applicable engineering units. In this
example, enter 0.1338 for the slope and -282.36 for the offset for the units conversion values
on the measured channel.
Figure 50 - Slope and Offset Values
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7.2.2 Differential Input Gain and Offset
The combination of the gain, offset, and sensor signal cannot exceed the 0 to 5 V dc input of the
analog to digital converter within the node.
Resolution: Applying gain to the sensor signal can be used to maximize the measurement
resolution. The more of the range that is used, the more digital counts are available to measure
the signal, which typically means higher resolution measurements. Limitations to the gain
adjustment are the sensor's measurement capabilities and the 0 to 5 V input range of the node.
The signal produced after gain is applied to the sensor at full scale must not exceed the input
range of the node.
Offset Scale: The scale setting positions the no-load measurement of the connected sensor
within the 0 to 5 V range of the node input. The range of A/D counts that corresponds with the 0
to 5 V node input depends on the resolution of the node. An 18-bit node will have a full scale bit
range of 262144. A mid-range setting positions the baseline offset in the middle of the range (2.5
V or full scale bits*1/2) and is used for sensors with negative and positive going signals. The low-
range setting positions the baseline offset in the bottom quarter range (1.25 V or full scale
bits*1/4) and is used for sensors with mostly positive going signals. The high-range setting
positions the baseline offset in the top quarter of the range (3.75 V or full scale bits *3/4) and is
used for mostly negative going signals.
Figure 51 - Differential Input Resolution and Offset (18-bit Node)
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This table lists the gain settings available on the V-Link-200 differential input channels. The scaled
input range is the approximate signal range of a sensor that would work with that gain, without
considering the offset setting.
Gain
Scaled input range
+/- 156 mV
+/- 78.1 mV
+/- 39.0 mV
+/- 19.5 mV
+/- 9.76 mV
+/- 4.88 mV
+/- 2.44 mV
+/- 1.22 mV
16
32
64
128
256
512
1024
2048
Table 8 - Differential Gain Values
Coefficients for Conversion to Volts:
Slope = 5.12 / (2 ^ 18 * gain)
Offset = -(5.0 / (2 * gain)) (assuming balance to mid-scale is perfect)
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8.1 Powering the Node
The node can be powered with either the internal battery or an external source within the 7.5 to 36 V dc
range.
8.2 Using the Internal Node Battery
The node is powered by four non-rechargeable, replaceable 3.6 V dc, 2.4 Ah, AA lithium batteries. If
the node will not power, the batteries may need to be replaced. For more information on replacing
the batteriesSee Replacing Batteries on page 91.
Node battery life is highly dependent on the type of sensor connected, as well as operational
parameters such as sample mode and rate. More active channels and higher sample rates equate to
decreased battery life.
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8.3 Connecting an External Power Supply
The node may be directly powered by a regulated AC to DC power supply with the appropriate
output parameters, see Operating Specifications on page 88). It can also be powered by an external
battery or other regulated DC supply. The supply must deliver a stable voltage between 7.5 to 36 V
dc and be capable of sourcing at least 100 mA.
External power is applied through the terminal block connector. Observe connection polarities, or the
node may be damaged.
Figure 52 - External Power Connection
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9. Troubleshooting
9.1 Troubleshooting Guide
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Possible cause and recommended solution
1.1 node or gateway power is off
The status indicator LED on the device may be off. Turn the
device on, and the status indicator LED should illuminate.
1. POWER
gateway or node does
1.2 wrong power supply or voltage
not turn on
Using a power supply other than the one specified for the
device (or an external supply that is outside of the device
operating range) could result in permanent damage to the
device or cause it to not work properly.
1.3 node battery is dead
If the node will not power on, the node battery may need to be
replaced.
1.4 sensors are drawing too much current
The node battery can only supply a limited amount of power to
the connected sensors. If an over-current condition occurs, the
node will shut down. This may occur if the sensors are wired
wrong.
1.5 node or gateway is damaged
If all power settings and connections have been verified, and
the node is still unresponsive, contact LORD Sensing
Technical Support (See Technical Support on page 81).
2.1 node or gateway has no power
Verify the node and gateway have power applied and that
applicable power switches are on. Power is indicated on both
devices by a status indicator LED.
2. COMMUNICATION
no communication to the
gateway or node
2.2 gateway has no communication with the computer
Verify gateway communication in the software. Check, remove,
and reconnect communications and power cables as
applicable.
2.3 node cannot be configured
Observe the node status indicator LED to determine the
device's state: boot, idle, sample, or sleep. If the node is
sampling or sleeping, it cannot be configured. In
SensorConnect, execute the Set to Idle command to put the
node in idle state, allowing configuration to occur.
If the user inactivity timeout is set very low, the configuration
menu will have to be entered quickly, before the timeout occurs,
putting the node back in a sample or sleep state.
2.4 node is out of range
Perform a bench test with the node in close proximity to the
gateway to verify they are operational. For range test and
installation recommendations See Range Test on page 35.
The system has been tested to operate with the node and
gateway up to 2 km apart with clear line of sight.
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Possible cause and recommended solution
2.5 node is not in normal boot mode
If the node status indicator shows the node booting in a mode
other than the normal boot mode, it can be bypassed by cycling
the node power rapidly three times, then leaving it on for normal
power up. In normal boot mode the communication can be
established with automatic node discovery (or manually) once
the boot process is complete and the node is in idle state. Start-
up mode can then be changed in the software.
2.6 node is sampling
Observe the node status indicator LED to determine the
device's state: boot, idle, active, or sleep. If the node is
sampling, it cannot be configured. In SensorConnect, execute
the Set to Idle command to put the node in idle state, allowing
configuration to occur.
2.7 node is sleeping
Observe the node status indicator LED to determine what state
it is: boot, idle, active, or sleep. If the node is sleeping, it cannot
be configured. In SensorConnect, execute the Set to Idle
command to put the node in idle state, allowing configuration to
occur.
2.8 gateway or node is damaged
Verify all connections, power, and settings. If available, try
installing alternate nodes and gateways one at a time to see if
the faulty device can be identified. If no conclusion can be
determined or to send a device in for repair, contact LORD
Sensing Technical Support (See Technical Support on page
81).
3.1 no communication to node or gateway
Verify connections and power to the node and gateway. Verify
they are powered on and communicating with the software.
Enter a configuration menu to verify that the node can be
accessed.
3. DATA ACQUISITION
sensor data is missing
or incorrect
3.2 sampling settings are incorrect
If the sampling mode, rate, or duration are not performing as
expected, enter the node configuration menu, and verify the
sampling settings.
3.3 sampling has not started
If sampling is occurring, the sampling mode will be displayed
next to the node name in SensorConnect. The node device
status indicator will also be flashing the sampling mode code. If
the node is not sampling, activate it in the software or with a
sample on start up boot sequence.
3.4 sensor is not connected correctly
Verify sensors connections and wiring. For non- standard
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Possible cause and recommended solution
connections contact LORD Sensing Technical Support
(See Technical Support on page 81).
3.5 sensor channel not configured correctly
Verify that the sensor is configured on the correct channel and
has been enabled for data acquisition.
3.6 sensor calibration is invalid
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9.2 Using the Node Tester Board
The node tester board is used to verify node and network functions before sensors are connected, or
for diagnostic purposes. The node tester board is used only on differential input channels, and
provides a fixed load so system functions can be verified including basic operations not related to the
sensor, such as communication and sampling. A fixed load is applied to the differential input by
pressing the load button.
There are various impedance value node tester boards available, depending on the node it is
being used with. See Wireless Equipment on page 83 for configuration options and part numbers.
Each is configurable to emulate full, half and quarter bridge strain gauges. Table 9 -
Tester Board Configuration describes the strain gauge load settings available. This setting must
match the type of node channel that is being tested. For example if the node is a quarter-bridge
node, the setting on the tester board must be the same. The configuration chart is also printed on the
underside of the board.
NOTE
The switches may come with a protective film covering them. Simply peel the film off to
access the switches.
SW 1
SW 2
SW 3
SW 4
Configuration
position position position position
ON
ON
ON
ON
OFF
OFF
ON
Full Bridge
OFF
OFF
OFF
OFF
Half Bridge
OFF
Quarter Bridge
Table 9 - Tester Board Configuration
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The following steps describe an example of how to use the tester board to sequence through the
primary functions of the node and the wireless system. If the results indicated in the final steps are
achieved, the system is fully operational for measuring a full bridge strain gauge. Other scenarios can
be tested as needed.
1. Set the jumpers for Full Bridge operation, using a small flat head screw driver to fully push the
switch into the desired position.
2. Verify the node is powered off and unplugged.
3. Plug the node tester board into the node Channel 1 position.
Figure 53 - Node Tester Board Installation
4. If not already completed, set up the Wireless Sensor Network equipment and install the
SensorConnect software. See System Operation on page 14.
5. Launch the SensorConnect software, and establish communications with the gateway and
node.
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6. Select Hardware > Input Range for channel 1, select +/-2 mV from the drop down menu.
7. Under Hardware Offset, select Balance Target for channel 1, select Mid (50%) from the drop
down menu.
8. Select Auto- Balance. When auto- balance is complete, a blue information window will
indicate the balance result.
Figure 54 - Auto-Balance
9. Select Calibration.
10. Select Microstrain from the Unit drop down menu, select the Shunt Cal button enabled on the
right.
Figure 55 - Node Configuration Menu
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11. Use the following settings:
a. Calibration Mode: Internal
b. Number of Active Gauges: 4
c. Gauge Factor: 2
d. Gauge Resistance: 1000
e. Shunt Resistance: 499000
12. Select Start Shunt Cal for Slope and Offset calibrations.
13. Select Accept Calibration.
Figure 56 - Channel Settings
14. When the calibration is complete, the Wireless Node Configuration window will appear.
15. Select Apply Configuration to write to node memory.
16. In the Wireless Node Configuration window, select the Node heading and then select
Sampling.
17. From the Wireless Network menu, select the drop down menu for channel 1 under Sampling
> uncheck Continuous streaming, and check For to select a duration of +/- 10 seconds using
the arrows to the right of the box, or by typing the number 10 in the box. (the system will auto
set to 10.15625).
18. Select Apply and Start Network.
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Figure 57 - Node Sampling Menu
19. As soon as Apply and Start Network is selected, the node will start collecting data for a
duration of +/-10 seconds. During that time, press and release the load button on the node
tester board to shunt the resistive load on and off. Verify the result is as shown in the figure
below. The pulse value should equal tester board ohm value. Testing is complete.
Figure 58 - Node Tester Output Stream
9.3 Updating Node Firmware
Under the recommendation of LORD Sensing Technical Support Engineers, nodes can be upgraded
to the latest available firmware to take advantage of new features or correct operating issues.
SensorConnect version 5.0.0 or greater can be used to update any mXRS or LXRS node or gateway
firmware to the most current version. Updates are found on the LORD Sensing website.
See Technical Support on page 81 for contact and website information.
1. Download the Firmware Upgrade file from the LORD Sensing website.
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2. Once downloaded, extract the contents of the .zip file into a folder on the computer. Verify
there is a file with a .zhex extension.
3. Launch SensorConnect, and establish communication between the node and gateway as
normal.
4. Select the Node address > Upgrade Firmware > select Browse > select the Firmware
Upgrade file > Start Upgrade
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9.4 Repair and Calibration
General Instructions
In order to return any LORD Sensing product, you must contact LORD
Sensing Sales or Technical Support to obtain a Return Merchandise
Authorization number (RMA). All returned merchandise must be in the original
packaging including manuals, accessories, cables, etc. with the RMA number
clearly printed on the outside of the package. Removable batteries should be
removed and packaged in separate protective wrapping. Please provide the
LORD Sensing model number and serial number as well as your name,
organization, shipping address, telephone number, and email. Normal turn-
around for RMA items is seven days from receipt of item by LORD Sensing.
Warranty Repairs
LORD Sensing warrants its products to be free from defective material and
workmanship for a period of one (1) year from the original date of purchase.
LORD Sensing will repair or replace, at its discretion, a defective product if
returned to LORD Sensing within the warranty period. This warranty does not
extend to any LORD Sensing products which have been subject to misuse,
alteration, neglect, accident, incorrect wiring, mis- programming, or use in
violation of operating instructions furnished by us. It also does not extend to any
units altered or repaired for warranty defect by anyone other than LORD
Sensing.
Non-Warranty Repairs
All non- warranty repairs/replacements include a minimum charge. If the
repair/replacement charge exceeds the minimum, LORD Sensing will contact
the customer for approval to proceed beyond the minimum with the
repair/replacement.
Technical Support
There are many resources for product support found on the LORD Sensing website, including
technical notes, FAQs, and product manuals.
http://www.microstrain.com/support/documentation
For further assistance our technical support engineers are available to help with technical and
applications questions.
Technical Support
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sensing_support@LORD.com
Phone: 802-862-6629
Fax: 802-863-4093
9:00 AM to 5:00 PM (Eastern Time US & Canada)
SKYPE: microstrain.wireless.support
Live Chat is available from the website during business hours:
9:00 AM to 5:00 PM (Eastern Time US & Canada)
9.5 Maintenance
The replaceable batteries are the only user serviceable parts in the V-Link-200. For instructions on how
to change the batteries, See Replacing Batteries on page 91.
For other service or repair needs contact LORD Sensing Technical Support (see Technical Support
on page 81).
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10. Wireless Equipment
10.1 Standard Nodes
For the most current product information, custom, and OEM options not listed below, refer to the LORD
Sensing website or contact the LORD Sensing Sales Department.
LORD Sensing
Part Number
Model Number
Description
l
l
l
Four differential channels
Four single ended channels
Internal temperature sensor
V-Link-200
6312-2000
Configuration Options (Required for use. Specify at time of order)
l
l
l
l
Full-bridge configuration on one or more differential channels.
120Ω, 350Ω or 1000Ω half-bridge completion on one or more differential channels.
120Ω, 350Ω or 1000Ω quarter-bridge completion on one or more differential channels.
High g-force option. Node operates in gravitational forces in excess of 550 g.
10.2 Node Accessories
The following parts are available for use with the V-Link-200. For the most current product information,
custom, and OEM options not listed below, refer to the LORD Sensing website or contact the
LORD Sensing Sales DepartmentSee Product Ordering on page 85
LORD Sensing Part
Description
Number
120Ω node tester board
350Ω Node tester board
3042-0062
3042-0061
3042-0060
9021-0034
9010-0048
1KΩ Node tester board
Lithium AA cell battery 2.4 Ah capacity
Standard whip antenna (FCC compliant)
Table 10 - Node Accessories
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10.3 Recommended Sensors
Many sensors can be used with the V-Link-200. The following sensors are supported for use with the
V-Link-200 and are available from LORD. For help with other sensor applications, see Technical
Support on page 81.
LORD Sensing
Model
Description
Part Number
6402-0320
6402-0120
6402-0220
6402-0420
ACCEL TRIAX-50
ACCEL-TRIAX-100
ACCEL-TRIAX-200
ACCEL-TRIAX-500
Triaxial Accelerometer, +/-50g
Triaxial Accelerometer, +/-100g
Triaxial Accelerometer, +/-200g
Triaxial Accelerometer, +/-500g
Table 11 - LORD Sensing Sensors
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10.4 Wireless System Equipment
The following system parts are available for use with the V-Link-200. For the most current standard,
custom, and OEM product options, refer to the LORD Sensing website or contact the LORD Sensing
Sales Department.
LORD Sensing
Model
Description
Part Number
8220-0023
6314-2000
6307-2040
6307-1010
6307-1020
6307-1021
6307-1011
9022-0029
6307-0900
4005-0005
various models
various models
--
WSDA-2000
WSDA-200-USB
WSDA-BASE-101
WSDA-BASE-102
WSDA-BASE-102-SK
WSDA-BASE-101-SK
--
SensorConnect Software
USB & Ethernet-based Gateway
USB Gateway
Analog Output Gateway
RS232 Serial Output Gateway
RS232 Gateway Starter Kit.
Analog Gateway Starter Kit
Replacement USB cable
USB Gateway cable extender
Replacement serial cable
Wireless Accelerometer Node
Wireless Accelerometer Node
--
--
G-Link-200
G-Link-LXRS
Wireless 2-Channel Analog Input Sensor
Node
SG-Link-LXRS
SG-Link-OEM
V-Link-200
various models
various models
various models
various models
Wireless 2-Channel Analog Input Sensor
Node
Wireless 8 Channel Analog Input Sensor
Node
Wireless 7-Channel Analog Input Sensor
Node
V-Link-LXRS
TC-Link-LXRS
DVRT-Link-LXRS
IEPE-Link -LXRS
Wireless Thermocouple Node
Wireless Displacement Sensor Node
Wireless IEPE Accelerometer Node
various models
various models
various models
Table 12 - Wireless System Equipment
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Product Ordering
Products can be ordered directly from the LORD Sensing website by navigating to the product page
and using the Buy feature.
http://www.microstrain.com/wireless
For further assistance, our sales team is available to help with product selection, ordering options, and
questions.
Sales Support
sensing_sales@LORD.com
Phone: 802-862-6629
Fax: 802-863-4093
9:00 AM to 5:00 PM (Eastern Time US & Canada)
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11. Specifications
11.1 Physical Specifications
Dimensions: 128.8 mm x 82.5 mm x 31.0 mm
283 grams (with batteries), 217 (without
batteries)
Weight:
Enclosure Environmental Rating: General purpose indoor
IP67/NEMA4X Enclosure Dimensions: 177.8 mm x 127 mm x 152.4 mm
Mounting: 4 x #8-32 UNC-2B
Weight: 1347.5 grams (with 3 D-cell batteries)
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11.2 Operating Specifications
Parameter
Specifications
General
Differential analog, 4 channels
Single-ended analog, 4 channels
Sensor input channels
Integrated sensors
Internal temperature, 1 channel
Data storage capacity
16 M Bytes ( 5+ million data points)
Differential: ± 1.22 mV dc to 156 mV dc
Single-ended: ±2.56 V dc, ±5.12 V dc, ±10.24 V dc, 0 to
5.12 V dc, 0 to 10.24 V dc
Selectable measurement ranges
Single-ended input impedance
1 Mohm
Input bandwidth
DC-4000 Hz (-3 dB cutoff)
ADC Resolution
18 bit
Accuracy
Noise
± 0.02 % full scale
Temperature stability
< 0.1 % full scale over temperature range
Differential Inputs :128 Hz to 4 kHz, 2nd order
Butterworth Single-ended Inputs: -3 dB at 15 kHz
Anti-aliasing filter
Integrated Temperature Channel
Measurement range
Accuracy
-40 °C to 85 °C
±1 °C (at 25 °C) typical
0.1 °C
Resolution
Sampling
Synchronized, low duty cycle, datalogging, event-
triggered
Sampling modes
Continuous sampling: 1 sample/hour to 4 KHz *
Periodic burst sampling: 32 Hz to 8 KHz *
Sampling rates
Sample rate stability
±5 ppm
Up to 127 nodes per RF channel depending on settings.
See:
Network capacity
http://www.microstrain.com/configure-your-system
Synchronization between nodes
± 50 μsec
Operating Parameters
Outdoor/line-of-sight: 1.5 km( ideal), 800 m (typical)**
Indoor/obstructions: 250 m (typical)**
Wireless communication range
Radio frequency (RF) transceiver
carrier
License-free 2.405 to 2.480 GHz with 16 channels
IEEE 802.15.4, FSK/GMSK
RF communication protocol
User-adjustable from 0 dBm to 20 dBm. Power output
restricted regionally to operate within legal requirements
RF transmit power
RF receive sensitivity
RF transmission rate
-99.4 dBm
250 kbps
Internal: +6.0 to +18.9 V dc - (4) 3.6 V dc, 2.4 Ah Lithium
batteries
Power source
External: +7.5 to 36.0 V dc
Operating temperature
Acceleration limit
-40 °C to + 85 °C
100 g
Physical Specifications
Dimensions
Weight
129 mm x 82.5 mm x 31 mm
283 grams (with batteries), 217 grams (without batteries)
Environmental rating
Enclosure material
Indoor use
Molded polycarbonate
Integration
Mounting
Bolt down or DIN-rail mount
All WSDA base stations and gateways
SensorCloud, SensorConnect™, Windows 7 (or newer)
Compatible gateways
Software
Open-source MicroStrain Communications Library
(MSCL) with sample code available in C++, Python, and
.NET formats
Software development kit (SDK)
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Parameter
Specifications
FCC (U.S.), IC (Canada), MIC (Japan), CE (European
Union), ROHS
Regulatory compliance
* Divide maximum rate by number of active channels ** Line of sight with antenna at 3 meters
11.3 Radio Specifications
The V- Link- 200 employs a 2.4GHz IEEE 802.15.4- compliant radio transceiver for wireless
communication. The radio is a direct-sequence spread spectrum radio and can be configured to
operate on 16 separate frequencies ranging from 2.405 GHz to 2.480 GHz. Following the 802.15.4
standard, these frequencies are aliased as channels 11 through 26. For all newly manufactured
nodes, the default setting is 2.425 GHz (channel 15).
For standard models, radiated transmit power is programmable from 4 dBm ( 2.5 mW) to 16 dBm (40
mW). A low-transmit power option is available (for use in Europe and elsewhere) and is limited to 10
dBm (10 mW).
FCC ID: XJQMSLINK0004
V-Link-200
This device complies with Part 15 of the United States FCC Rules, and Industry Canada’s
license-exempt RSSs. Operation is subject to the following two conditions: 1) This device may
not cause interference, and 2) This device must accept any interference, including
interference that may cause undesired operation of the device. Changes or modifications,
including antenna changes not expressly approved by LORD Corporation could void the
user’s authority to operate the equipment.
Cet appareil est conforme à la Partie 15 des Règles de la FCC des États-Unis et aux RSSS
exempts de licence d'Industrie Canada. Le fonctionnement est soumis aux deux conditions
suivantes: 1) Cet appareil ne doit pas causer d'interférences et 2) Cet appareil doit accepter
toute interférence, y compris les interférences pouvant entraîner un fonctionnement
indésirable de l'appareil. Les changements ou modifications, y compris les changements
d'antenne non expressément approuvés par LORD Corporation, pourraient annuler
l'autorisation de l'utilisateur d'utiliser l'équipement.
11.4 Frequency Setting
NOTE
l
The gateway can automatically manage nodes operating on different frequencies by using the Node
Discovery feature in SensorConnect. In this routine, the gateway listens for node broadcasts on the
frequency channel to which it is set. If the node is in normal boot-up mode, it will provide the
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broadcast when it is initially powered-on, and it will broadcast on all channels. As long as the node is
powered-on after activating the Node Discovery feature, the gateway will link to it and remember the
channel setting for future node queries.
l
Manually matching the node and gateway frequency channels is required in some applications. For
example, when sending broadcast messages from the gateway to multiple nodes (including the
synchronized sampling beacon) all nodes must be on the same channel as the gateway in order to
receive the broadcast. Assigning channels is also a good idea when multiple gateways are attached
to one host computer or when other wireless equipment is nearby and frequency or transmission
interference may occur.
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12. Safety Information
This section provides a summary of general safety precautions that must be understood and applied
during operation and maintenance of components in the LORD Sensing Wireless Sensor Network.
Throughout the manual, ANSI Z535 standard safety symbols are used to indicate a process or
component that requires cautionary measures.
12.1 Replacing Batteries
1. Remove the screws on both sides of the face plate to open the V-Link-200.
2. It is important to replace all four of the batteries at the same time, observing the correct polarity
orientation. The positive polarities are indicated on the batteries and the node by a "+" symbol.
3. Reassemble.
Figure 59 - Replace Batteries
12.2 Battery Hazards
The V- Link- 200 contains internal, non- rechargeable lithium batteries.
Lithium batteries are a fire and explosion hazard. Do not store or operate
the node at temperatures above 212°F (100°C). Do not disassemble, short
circuit, crush, puncture, or otherwise misuse the battery.
Lithium batteries contain toxic chemicals that are harmful to humans and
the environment. Disposal is subject to federal and local laws. Do not
discard the battery or the node in the trash. Follow proper battery disposal
protocol, or contact LORD Sensing Technical Support for information on
extracting the battery or returning the product for proper recycling and
disposal.
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12.3 Power Supply
Apply only the input voltage range specified for the V-Link-200 . Connect to
a power source that is near the device, is accessible, and adheres to all
national wiring standards. Compliance with wiring standards is assumed in
the installation of the power source and includes protection against
excessive currents, short circuits, and ground faults. Failure to do so could
result in personal injury and permanent damage to the device.
12.4 Disposal and Recycling
®
The V- Link - 200 contains internal batteries, printed circuit
boards, and electronic components. These items are known to
contain toxic chemicals and heavy metals that are harmful to
humans health and the environment. Disposal is subject to
federal and local laws. Do not discard the device or batteries in
the trash. Follow proper electronic and battery waste disposal
protocol, as dictated by federal and local authorities. Some
states have programs for extracting reusable parts for recycling.
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13. References
13.1 Related Documents
Many references are available on the LORD Sensing website including product user manuals,
technical notes, and quick start guides. These documents are continuously updated, and new
applications are added. They may provide more accurate information than printed or file copies.
Document
Where to find it
http://sensorcloud.com/?onlyCalc=true
http://www.sensorcloud.com/
Online Wireless Network Calculator
SensorCloud Overview
SensorCloud Pricing
http://sensorcloud.com/pricing
®
http://www.sensorcloud.com/mathengine
http://www.microstrain.com/software/sensorconnect
MathEngine Overview
SensorConnect Overview & Download
LORD Sensing Wireless Sensors Network
Software Development Kit
https://github.com/LORD-MicroStrain/SensorCloud
http://www.microstrain.com/wireless/sensors
http://www.microstrain.com/support/documentation
http://www.microstrain.com/applications
http://www.nist.gov/calibrations/
Product Datasheets
Product Manuals and Technical Notes
Product Application Notes
NIST Calibration Procedures
http://www.astm.org/Standard/standards-and-
publications.html
ASTM Testing Procedures
Table 13 - Related Documents
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14. Glossary
These terms are in common use throughout the manual:
A/D Value: the digital representation of the analog voltages in an analog-to-digital (A/D) conversion.
The accuracy of the conversion is dependent on the resolution of the system electronics; higher
resolution produces a more accurate conversion. Also referred to as "bits".
Base Station: The base station is the transceiver that attaches to the host computer and provides
communication between the software and the node(s). It is also referred to as a gateway.
Burst Sampling: a mode of operation in which the node is sampled for a fixed window of time (burst)
and then repeats that window at set intervals. The burst duration and time between bursts is
configurable. Also referred to as periodic burst sampling.
Calibration: to standardize a measurement by determining the deviation standard and applying a
correction (or calibration) factor
Configuration: a general term applied to the node indicating how it is set up for data acquisition. It
includes settings such as sampling mode/rate, number of active channels, channel measurement
settings, offsets, hardware gain, and calibration values.
Continuous Sampling: a mode of operation in which the node is sampled continuously until stopped or
sampled continuously for a fixed amount of time
Coordinated Universal Time (UTC): the primary time standard for world clocks and time. It is similar
to Greenwich Mean Time (GMT).
Cycle Power: a command transmitted to the node to reboot it either through a hardware or software
switch
Data Acquisition: the process of collecting data from sensors and other devices
Data Logging: the process of saving acquired data to the system memory, either locally on the node or
remotely on the host computer
DHCP (network): Dynamic Host Configuration Protocol is the standardized networking protocol used
on Internet Protocol (IP) networks, which automatically configures devices that are attached to it by
assigning and configuring the device IP address.
EMI: Electromagnetic Interference is an inductive or radiated disturbance that can create signal
degradation on electrical signals, including loss of data.
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ESD: Electrostatic Discharge is the sudden flow of electricity that can occur between two charged
objects of different potential that come in contact or in close proximity of each other. Static electricity is a
common source of ESD.
Event-Based Sampling: a mode of operation in which the node sampling is started when a sensor
measurement value (threshold) is achieved
Firmware: the code that is programmed onto a microcontroller or similar device in an embedded
system. It includes device operation commands, conditions, memory allocation, and many other tasks.
Gateway: The gateway is a transceiver that attaches to the host computer and provides
communication between the software and the node(s). It is also known as a base station.
Host (computer): The host computer is the computer that orchestrates command and control of the
attached devices or networks.
LED: Light Emitting Diode is an indicator light that is used in electronic equipment.
LOS (Line of Sight): is used in radio communications to describe the ideal condition between
transmitting and receiving antennas in a radio network. As stated it means the antennae are in view of
each other with no obstructions.
LXRS: Lossless Extended Range Synchronized is the proprietary LORD Sensing data
communications protocol used in the wireless sensor network.
Node: The node is the wireless transceiver to which the sensor (s) is connected, providing
®
®
®
®
®
®
communication with the gateway. The G-Link -LXRS , V-Link -LXRS , and SG-Link -LXRS are
®
examples of nodes manufactured by LORD MicroStrain .
®
Node Tester Board: The node tester board is a device designed by LORD MicroStrain that can be
plugged into nodes to test their functionality.
Offset: When describing a mathematically-linear relationship, the offset is the value where the line that
represents the relationship in a graph crosses the y-axis. The equation of a straight line is: y = mx+b,
where x is the x-axis coordinate, y is the y-axis coordinate, m is the slope and b is the offset.
Oversampling: In signal processing, oversampling is a technique used to achieve increased signal
resolution and better noise immunity by recording readings at a higher frequency than the output of the
device being measured. In analog-to-digital conversion, the higher the oversampling rate, the better
the recreated analog signal.
Packet: unit of sampled data
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Periodic Burst Sampling: a mode of operation in which the node is sampled for a fixed window of
time (burst) and then repeats that window at set intervals. The burst duration and time between bursts
is configurable. Also referred to as burst sampling.
Ping: a byte transmitted by the gateway to the node. The node responds by echoing the byte,
indicating communication exists between the node and gateway.
Range Test: a continuous string of pings used to validate communication between the gateway and
the node over distance and obstruction
Real Time Clock (RTC): a computer clock that keeps track of the current time
RFI: Radio Frequency Interference is a disturbance in an electrical circuit due to electromagnetic
induction or radiation.
RSSI: Received Signal Strength Indication is a measurement of the transmission power in a radio
signal. It is measured in decibels with reference to 1 milliWatt (dBm).
RS232: a serial data communications protocol
Sensor: a device that physically or chemically reacts to environmental forces and conditions, producing
a predictable electrical signal
Sleep: a command transmitted to the node to put it into sleep configuration
Sampling: the process of taking measurements from a sensor or device
Sampling Mode: the type of sampling that is being utilized, such as event-triggered, continuous, or
periodic. The nodes have several sampling modes that employ these types of sampling.
Sampling Rate: the frequency of sampling
Slope: When describing a mathematically linear relationship, the slope is the steepness of the line that
represents that relationship on a graph. The equation of a straight line is: y = mx+b, where x is the x-
axis coordinate, y is the y-axis coordinate, m is the slope, and b is the offset.
Streaming: Streaming is a sampling mode in which all active channels (and the sensors attached to
them) are measured, and the acquired data is transmitted to the gateway and software. The data is not
written to non-volatile memory during streaming. Streaming can either be finite (have a user defined
start and end time) or continuous (continued until the power is cycled on the node).
Synchronized Sampling: a sampling mode that automatically coordinates all incoming node data to a
particular gateway. This mode is designed to ensure data arrival and sequence.
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Transmission rate: the number of data packets per transmission window, measured in seconds.
Depending on the sampling mode and settings it will be between 1 and 64 packets/second.
Transmission window: the time allowed for one data transmission at the automatically determined
transmission rate
USB: Universal Serial Bus is a serial data communications protocol
WSN: Wireless Sensor Network describes a distribution of sensors and data acquisition equipment
that autonomously monitors environmental characteristics, such as temperature, pressure, and strain.
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