The EH-Link™ is a versatile multi-sensor node that runs on ambient energy sources such as vibration, light, and inductance.
Product Highlights
- Sophisticated self-powered node can harvest energy from ambient energy sources for indefinite remote deployment.
- On-board high-speed triaxial accelerometer, internal temperature sensor, internal relative humidity sensor, and an analog input channel provide many sensing options.
- Supports auxiliary energy storage options such as super-capacitors and rechargeable thin film batteries
LORD MicroStrain® LXRS® Wireless Sensor Networks enable simultaneous, high- speed sensing and data aggregation from scalable sensor networks. Our wireless sensing systems are ideal for sensor monitoring, data acquisition, performance analysis, and sensing response applications.
The gateways are the heart of the LORD MicroStrain wireless sensing system. They coordinate and maintain wireless transmissions across a network of distributed wireless sensor nodes . The LORD MicroStrain LXRS wireless communication protocol between LXRS nodes and gateways enable high- speed sampling, ±32 microseconds node- to- node synchronization, transmission range up to 2 kilometers, and lossless data throughput under most operating conditions.
Users can easily program nodes for data logging, continuous, event- triggered, and periodic burst sampling with the Node Commander ® software. The web- based SensorCloud™ interface optimizes data aggregation, analysis, presentation, and alerts for gigabytes of sensor data from remote networks.
Datasheet Manual
Wireless Simplicity, Hardwired Reliability™
High Performance
- Potential power sources include: solar energy (photovoltaic); electromagnetic fields (electrodynamic); thermal energy from temperature changes (thermoelectric); strain and vibration (piezoelectric); high impact energy, and capacitive discharge.
- Solar energy harvesting input operates in low light levels.
- Thermal energy harvesting input operates in thermal gradients below 8 ˚C when used with Peltier Thermoelectric Generators (TEGs).
- User-programmable sample rates up to 512 Hz
Ease of Use
- Scalable, wireless sensor networks up to 70 m
- Easy out-of-the-box wireless sensing for most analog sensors
General |
|
---|---|
Sensor input channels |
Energy harvesting, 3 source types and channels Differential analog, 1 channel |
Integrated sensors |
Triaxial MEMS accelerometer, 3 channels Internal temperature, 1 channel Relative humidity, 1 channel |
Energy Harvesting Inputs |
|
Wide range voltage (WRV) input |
5 to 20 V ac/dc peak, (piezoelectric, electrodynamic, photovoltaic, electromagnetic) |
Capacitive discharge voltage (CDV) input |
20 to 130 V ac (pulsed piezoelectric) |
Ultra-low voltage (ULV) input |
20 to 600 mV dc (thermoelectric, Peltier, thermopile) |
Analog Input Channel |
|
Measurement range |
Differential: full-bridge, ≥ 350 Ω (factory configurable), user programmable gain and offset |
Accuracy and resolution |
± 0.1% full scale typical, 12 bit resolution |
Bridge excitation voltage |
+2.7 V dc, 50 mA (pulsed @ sample rates ≤ 16 Hz to conserve power) |
Integrated Accelerometer Channels |
|
Measurement range |
± 16 g |
Accuracy and resolution |
± 4 mg, 12 bit resolution |
Integrated Temperature Channel |
|
Measurement range |
-40 °C to 85 °C |
Accuracy and resolution |
± 2 °C (at 25 °C) typical , 12 bit resolution |
Integrated Relative Humidity (RH) Channel |
|
Measurement range |
0 to 100 % |
Accuracy |
± 2 % (10 to 90 % RH), ± 4 % ( 0 to 10% RH and 90 to 100% RH) |
Repeatability |
± 0.1 % |
Sampling |
|
Sampling modes |
Low duty cycle |
Sampling rates |
Continuous sampling: 1 Hz to 512 Hz |
Sample rate stability |
± 3 ppm |
Network capacity |
Up to 2000 nodes per RF channel (and per gateway) depending on the number of active channels and sampling settings. |
Operating Parameters |
|
Radio frequency (RF) transceiver carrier |
2.405 to 2.470 GHz direct sequence spread spectrum over 14 channels, license-free worldwide, radiated power 0 dBm |
RF communication protocol |
IEEE 802.15.4 |
Range for bi-directional RF link |
70 m line of sight |
Energy use |
Startup: 12 μJ; sampling: accelerometer or RH sensor only, 105 μJ/sample; sampling: differential input only, 168 μJ/sample; data transmission: 92.4 μJ/packet |
Operating temperature |
-20 ˚C to + 60 ˚C |
Operating humidity |
0 to 95 %, non-condensing |
Acceleration limit |
500 g standard |
Physical Specifications |
|
Dimensions |
88 mm x 39 mm x 16 mm |
Weight |
26 grams |
Integration |
|
Compatible gateways |
All WSDA® base stations and gateways |
Compatible sensors |
Bridge type analog sensors (for analog inputs) |
Connectors |
Screw terminal blocks |
Software |
SensorCloud™, Node Commander®, WSDA® Data Downloader, Live Connect™, Windows XP/Vista/7 compatible |
Software development kit (SDK) |
Data communications protocol available with EEPROM maps and sample code (OS and computing platform independent) http://www.microstrain.com/software-development-kits-sdks |
Regulatory compliance |
ROHS |
General Documentation
- EH-Link® Data Sheet
- EH-Link™ Quick Start Guide
- Node Commander Wireless Sensing Software User Manual
- Wireless Products Comparison
Technical Notes
- EH-Link™ Powered by Thermoelectric Generator
- EH-Link™ Powered by Indoor Solar Cell
- EH-Link™ Powered by Piezoelectric Source
Mechanical Drawings
FAQs
What is Multipath?
Multipath is the phenomenon whereby a radio signal arrives at a receiver’s antenna by more than one path. This occurs by the reflection, diffraction, or scattering of radio waves from atmospheric ducting, reflection from water bodies or terrestrial objects (like mountains), etc.
Does Multipath impact signal strength?
Yes, multipath propagation of radio signals causes fading of the transmitted signal, which can be indicated by fluctuations in signal strength when received by the signal receiver.
How do I mitigate Multipath?
Pe-position base station or node to mitigate possible multipath interference.
Ensure a clear path to the antenna for the strongest signal, enhancing the strength of the strongest signal AND reducing the strength of the weaker signals.
Learn More: Mutipath Propagation
The WSDA-RGD (with internal GX3 inertial sensor) is configured to produce the following messages on startup.
GPS Data (1 Hz):
- UTC Time
- LLH Position
- NED Velocity
AHRS Data (100 Hz):
- Euler Angles
From this output the WSDA logs:
GPS (1 Hz):
- latitude
- longitude
- height above ellipsoid
- height above MSL
- horizontal accuracy
- vertical accuracy
- speed
AHRS (100 Hz):
- roll
- pitch
- yaw
The WSDA-RGD does not log any data until it gets a valid time, if it is set to get time from GPS only it will not log any output from the GX3 until the UTC timestamp from the GX3 is valid, even though the GX3 is producing valid AHRS data.
This data is not user configurable and is not available as a live stream through LiveConnect.
All LORD MicroStrain wireless sensor nodes, wireless base stations, and wireless sensor data aggregators are shipped from the factory with their radio frequency set to channel 15 (2.425 GHz).
This channel setting was established during 2012.
Previously all wireless products were set to channel 25 (2.475 GHz).
If you are mixing new nodes and base stations with older nodes and base stations, please be cognizant of these different channel settings.
The Node Discovery function of Node Commander will help you sort out which nodes are on what channels; Node Discovery is channel independent and allows the base station to communicate with any node, no matter what channel it is on
Sampling methods such as synchronized sampling, low duty cycle, network broadcast, etc. require that all nodes are on the same frequency so you will want to insure that you have adjusted the channels settings of the nodes to suit.
The wireless nodes all have 2 Mbytes of datalogging memory. This 2 Mbytes is organized into 8,191 ‘pages’ of memory, each page holds 132 data points. The maximum number of data points that can be held in memory can be calculated as follows: 8,191 pages x 132 data points/page = 1,081,212 total data points.
Now the question arises, ‘how long can a node datalog before its memory is full?’. The answer is that it varies depending on how many channels are being sampled and what sampling rate has been set. Here are two examples:
Let’s set a V-Link-LXRS so that channel 1 is active with a datalogging sampling rate of 2048 samples per second and we launch continuous datalogging. Our calculation would be:
- 1 channel x 2,048 samples per second = 2,048 data points per second
- 1,081,212 data points / 2,048 data points per second = 527 seconds
- 527 seconds / 60 seconds per minute = ~9 minutes to fill the memory
Let’s set a G-Link-LXRS so that channels 1, 2 and 3 are active with a datalogging sampling rate of 32 samples per second and we launch continuous datalogging. Our calculation would be:
- 3 channels x 32 samples per second = 96 data points per second
- 1,081,212 data points / 96 data points per second = 11,262 seconds
- 11,262 seconds / 60 seconds per minute = ~187 minutes to fill the memory
In FINITE sampling, the user sets a total number of samples to be taken which equates to a time period. Because the sampling rate per second is known, the user can adjust the number of samples to be taken to determine how long the sampling period will be.
In CONTINUOUS sampling, the user does not set the total number of samples and therefore does not set the time of the sampling period. By selecting CONTINUOUS sampling, the user is instructing the system to sample data until the user manually stops the sampling (via software), the power is cycled, the on-board datalogging memory is full, the battery dies, the power fails, etc.
LORD MicroStrain® Wireless Sensor Networks provide several data acquisition modes including:
- Synchronized Sampling
- Armed Datalogging
- Streaming
- Duty Cycle
See the particular wireless node for specifics.