1. Batteryless Operation
1.1 What does “batteryless” mean?
All Everactive Eversensors are battery-free, operating entirely and continuously from low levels of harvested energy.
1.2 What is meant by “low levels of harvested energy”?
Because the power requirements of Everactive’s custom integrated circuits is so low (up to 1 / 1,000th of that of competitors), our Eversensors can operate off trace amounts of existing energy sources within most environment. Currently, the two most utilized sources are heat and light.
To harvest from heat, we use a thermoelectric generator (TEG), which generates current from a temperature differential between two sides of the bimetallic device. With Everactive’s circuits under the hood, we only need a 15ºF (8ºC) difference between either side of a Scrabble tile-sized TEG. With MHM, that TEG is placed on the warmest part of the machine to provide maximum power.
To harvest from light, we use a photovoltaic (PV) harvester and only need ~200 Lux to power an Eversensor—roughly the light in a dimly lit facility. Outdoors, where sunlight is exponentially brighter, we are exposed to more than enough energy to power an Eversensor.
1.3 What happens if the energy harvesting source goes away?
Our Eversensors contain supercapacitors to store the energy that we harvest. If the harvesting source were to go away—the lights or machine turns off—the Eversensor will stay alive for several hours at a 60-second measurement and transmission interval. With a longer measurement and transmission interval, the device will stay remain powered for a longer period of time. Once the harvesting source returns, the Eversensor will power-on in a matter of minutes.
2. System Architecture
2.1 What components are required?
MHM is an end-to-end service provided by Everactive focused on delivering the data insights that help you run your operations more efficiently. Accordingly, we provide all of the components to get that system up and running—and keep it running.
Eversensors – Each Eversensor is accompanied by the appropriate energy harvester (TEG, PV, or combination of the two) and the required mounting accessories for our magnetic, stud, or epoxy attachment.
Evergateway – Everactive also provides its custom IoT gateway to facilitate communication between the Eversensors and the Evercloud. Each gateway can connect to upwards of 1,000 Eversensors at a range of 800+ ft. through heavy industrial interference.
Evercloud – as part of the end-to-end service, Everactive provides a cloud-based software platform to view, manage, and report on data.
2.2 How is data communicated?
2.2.1 Eversensors to the Evergateway – we utilize our proprietary protocol called Evernet. As the world’s lowest power radio protocol, Evernet allows us to wirelessly transmit data while keeping the battery out of the equation. Evernet operates in at sub-GHz frequency (915 MHz in North America), which allows it to penetrate physical obstructions more easily than protocols like Wi-Fi or Bluetooth that operate in the 2.4 GHz band. Evernet is an FCC-certified, standards-compliant protocol built on the 802.15.4g layer.
2.2.2 Evergateway to the Evercloud – data can be communicated via LTE, Wi-Fi, or wired Ethernet.
2.3 What is the wireless range?
Non-line-of-sight, through physical interference, Evernet’s range is ~820 ft. (250m). Line-of-sight, Evernet can communicate up to ½ mile (>1km).
2.4 How often is data measured?
The default setting is every 60-seconds.
2.5 How often is data transmitted?
The default setting is every 60-seconds.
2.6 Do the devices have IP and hazardous location certifications?
Our devices are IP66-rated and are Class I, Division 2 certified.
3. MHM Sense Node Data
3.1 How is vibration measured?
Each Eversensor measures vibration using a MEMS triaxial accelerometer, then converts the measured time domain waveform into the frequency domain via a Fast Fourier Transform (FFT). The 9 highest frequency domain peaks (measured in inches per second – peak) from each result is sent to the Evercloud.
3.2 What is the vibration frequency range?
We sample at 3.2 kHz and provide results from 6Hz – 1kHz.
3.2.1 In what units is vibration data displayed?
Overall Vibration Level is presented as velocity (inches per second – peak).
3.3 What does the Overall Vibration Level (Velocity) Chart tell me?
This chart provides a snapshot of the overall health of the machine, indicating whether or not a machine is operating within acceptable parameters, while also showing changes in machine behavior over time. With this chart, users can readily see if the monitored machine’s vibration signature has changed over time.
3.4 What does the FFT View tell me?
This view tells you the details of the machine’s vibration signature relative to the running speed of the machine (measured on this chart in CPM). This will provide the first step in diagnosing specific machine faults. The frequency and magnitude of peaks beyond the running speed (typically, the first high peak on the chart) gives a vibration analyst insight into the nature of the machine fault.
3.5 What does the VFD Output Chart tell me?
This chart displays the running speed of the motor as measured by the frequency of the current being applied to the machine (also known as the stator excitation frequency).
3.6 What does the Temperatures Chart tell me?
The Ambient Temperature displays the ambient temperature measured at the Eversensor. The Surface Temperature displays the skin temperature of the surface to which the TEG harvester is attached.
Note: the delta between Ambient and Surface temperature is not an indication of TEG harvesting strength because the Ambient temperature as measured at the Eversensor is not necessarily the same as the ambient temperature flowing over the heat sink of the TEG.
3.7 What does the Humidity Chart tell me?
This chart displays the relative humidity measured at the Eversensor.
3.8 What does the RSSI Chart tell me?
RSSI stands for Received Signal Strength Indication and is used here to measure the strength of the wireless link from each Eversensor to the Evergateway to which it reports. A signal of greater than -40dB is strong, whereas a signal of below -60dB would indicate a weaker link.
3.9 What does the VCAP / SCAP Chart tell me?
VCAP is a measure of the voltage that the part runs off. SCAP is a measure of the energy storage of the device. Taken together, these measurements are used to understand and diagnose the strength of the harvesting source and power of the device. The Eversensor will self-regulate data transmission based on the available energy in the system.
3.10 How many Eversensors do I need per machine?
Ideally, you should mount an Eversensor on each of the bearings. For a standard piece of driven equipment, you will want 4 Eversensors—two on the motor bearings and two on the driven equipment bearings.
Everactive Contact Information
Everactive is always available to support our customers. If additional assistance is required, please contact success@Everactive.com.