TE CONNECTIVITY 89X1N Series Wireless Vibration Sensor User Manual
- June 13, 2024
- TE connectivity
Table of Contents
TE CONNECTIVITY 89X1N Series Wireless Vibration Sensor
Product Information
The 89X1N Series Wireless Vibration Sensor is a versatile device that offers two BLE (Bluetooth Low Energy) modes and one LoRaWAN mode. It is designed to measure and transmit vibration data wirelessly.
The device operates in the following modes:
- BLE advertising mode: This mode starts automatically when the battery is inserted. The device advertises its presence once per second.
- LoRaWAN mode: After the initial BLE advertisement, the device transmits a Join Request on the LoRa frequency. If successful, it sends sensor data via uplink messages at intervals determined by the default settings. BLE features are disabled during LoRa communications.
The device supports configurable data collection intervals ranging from 1 minute to 24 hours. Upon wake-up, it powers the sensing element and waits for approximately 3 seconds to allow the accelerometer to boot and stabilize its output. Each measurement includes readings of the battery level, temperature, and a set of 4096 acceleration values at a configurable rate. The collected data is processed to transform the raw acceleration data into frequency peaks. The processing signal chain calculates parameters such as peak frequency and peak RMS magnitude ratio.
Product Usage Instructions
To use the 89X1N Wireless Vibration Sensor, follow these steps:
- Insert the battery into the sensor.
- The sensor will automatically start BLE advertising at a rate of once per second.
- After the first advertisement, the sensor will transmit a Join Request on the LoRa frequency. If successful, it will start sending sensor data via uplink messages at intervals determined by the default settings.
- During LoRa communications, BLE features are disabled.
- The device will perform measurements and transmit data at the configured interval.
- Upon wake-up, the device will power the sensing element and wait for approximately 3 seconds for the accelerometer to boot and stabilize its output.
- The measurement includes readings of the battery level, temperature, and a set of 4096 acceleration values at a configurable rate.
- The collected data is processed to calculate peak frequency and peak RMS magnitude ratio.
Note: Only the peak values are accessible to the user. Raw data and raw FFT spectrum are stored internally for computation and are not available outside the sensor.
Introduction
TE Connectivity’s 89X1N Series Wireless Vibration Sensor is composed of the
8931N and 8911N Family of models. Models in series are either 1-axis (8911N)
or 3-axis (8931N) accelerometer, and combine a data collector, and a radio
into one compact, battery-operated device that measures both vibration and
temperature data. These sensors were designed for hash environment and comes
with the ATEX certification.
Model 8911N and 8931 wireless vibration sensors use the LoRaWAN™ communication
protocol, offering a simple, reliable, and secure means of expanding
condition-based maintenance into plant areas where the cost to install wired
systems is prohibitive, making data available to existing process control and
information systems. In addition to that, they offers a Bluetooth Low Energy
interface to ease the embedded settings configuration at the sensor
installation.
These sensors incorporate a piezo-electric accelerometer which offers a wide
bandwidth to >15kHz, outstanding measrement resolution and superior long-term
stability compared to design using MEMS solutions.
All models contain digital signal processing capability that provides an FFT
analysis of the sensed vibration. The output data describes the center
frequency, peak value, bandwidth, and percent of the total spectral content
for the eight most significant acceleration peaks in the vibration signal.
Because of this feature, the 89X1N series directly provides the data most
needed to plot trends and monitor changes in the performance and condition of
factory machinery.
General Description
The 89X1N Series Wireless Vibration Sensor has two BLE modes and one LoRaWAN™ mode:
- BLE advertising mode – Starts automatically when the battery is inserted. Advertising occurs at a rate of once per second.
- BLE connected (pairing) mode – After each advertisement, the user can initiate a change to connected mode. When connected, the user can configure the device and use other special features.
- LoRaWAN™ mode – After being configured in the BLE connected mode, LoRa is used to communicate with an external network.
DEVICE START-UP
- Insert battery (refer to Installation Manual – Doc #20023687-24). On-board LED will flash once upon proper installation.
- The sensor will begin BLE advertising at the rate of once per second.
- After the first advertisement, the sensor will transmit a “Join Request” on the LoRa frequency. If successful, sensor data will be transmitted via uplink messages at intervals determined by the sensor default settings. BLE features are disabled during the LoRa communications.
- Once LoRa communications are complete, the sensor will revert back to BLE advertising.
- During advertising, the user can respond and establish the BLE “Connected” (or pairing) mode. While in Connected mode, the user can configure all sensor variables such as LoRa transmit interval and FFT features.
- At sixty minutes after start-up, all BLE features are disabled, and data communications will proceed via the LoRa connection. The communication parameters will follow the settings established during the BLE Connected mode time. The sensor configuration can be adjusted via LoRa communications just as it was during the initial sixty-minute BLE time.
- At any time after the initial sixty-minute BLE mode operation, a new sixty-minute period can be initiated by placing a magnet close to the magnet symbol on the sensor housing. Depending on the how the magnet is applied, either the new BLE mode can be initiated, or the sensor can be reset. See section 4 regarding the Magnetic Switch.
MODES OF OPERATION
The device operation can be summarized by the following state machine diagram.
DATA COLLECTION
Sensor measurements are performed and transmitted at a configurable interval
from 1 min up to 24 hours. This is driven by the Measurement interval
parameter.
Upon wake-up, the device powers the sensing element and waits for about 3
seconds to let the accelerometer boot and stabilize its output.
A measurement consists of reading the battery level, temperature, and a set of
4096 acceleration values at a configurable rate.
| Data | Unit | Accessibility |
|---|---|---|
| Battery level | % | LoRaWAN™, BLE |
| Temperature | °C | LoRaWAN™, BLE |
| Acceleration | mg | None |
DATA PROCESSING
The data processing signal chain transforms the acceleration raw data into
frequency peaks.
Acceleration data is collected at a chosen sampling frequency. Raw data passes
through an anti-aliasing filter. Once a set of acceleration readings is
measured (4096 points), the embedded algorithm removes the DC signal (to
remove the bias voltage of the sensing element) and multiplies the results by
the sensor element calibration sensitivity (mV/g). The algorithm then applies
a Hann window to the signal and converts it into a normalized FFT spectrum.
Finally, a peak search algorithm extracts the most significant peaks from the
spectrum.
Certain data is saved for each of the peaks:
| Parameter | Description |
|---|---|
| Peak Frequency | Frequency of the peak (Hz) |
| Peak RMS magnitude | Single frequency peak PMS magnitude (g) |
| Ratio | Ratio of energy. Maximum peak magnitude plus associated bins divided by |
total spectrum energy.
Note that only “Peak values” are accessible by the user. Raw data and raw FFT
spectrum are stored for internal computation and are not available outside the
sensor.
From this point, several customer defined options are available to further
process the data into useful output information.
The customer can establish and configure up to eight windows across the FFT
spectrum. For each window, the user can configure the following parameters:
| Parameter | Description |
|---|---|
| Peak number | Number of peaks to be found (0 to 24) |
Number of bins
| Number of bins around the main beam to be integrated into the ratio output.
This parameter can be used to filter side lobes and avoid multiple peaks found
around the same frequency
Minimum frequency| Minimum frequency of the search window| These define the
bandwidth of each window
Maximum frequency| Maximum frequency of the search window
By default, no windows have been established or configured. The peak search covers the full spectrum.
It is possible to program up to 8 custom windows to define several regions of interest. Any peak ouside the windows will be ignored.
The device includes a LoRaWAN™ MAC 1.0.3 rev A compliant interface (see LoRaWAN® 1.0.3 Specification). It operates as a Class A end-device. The LoRaWAN™ communication protocol operates in an unlicensed radio spectrum. The part number must be selected to match with the region of operation and be in line with the local regulation.
| Region | Frequency | Channel Plan | Common name |
|---|---|---|---|
| Europe (EU) | 868 MHz | EU862-870 | EU868 |
| United State (US) | 915 MHz | US902-928 | US915 |
The LoRaWAN™ upload interval can be configured by the customer for any time between one minute and 24 hours (in one-minute steps).
Data upload consists of this information:
- Battery status
- Sensor internal temperature
- All FFT data as configured by the user
- Raw sensor data (time domain accelerometer signal) is not available for upload
All customer configurable parameters can be adjusted via LoRaWAN™ using a data download:
- Reading/upload interval
- Number of peaks
- Number of bins around the peaks
- Number of windows
- Window minimum frequency
- Window maximum frequency
Many of the LoRaWAN™ communication features are adaptive and depend on the
network quality. The parameters are negotiated and optimized with the
connected gateway.
LoRaWAN™ communications are subject to various regulatory bodies around the
world and features in the device firmware help maintain compliance.
BLUETOOTH© LOW ENERGY
The device includes a Bluetooth 5.0 Low Energy compliant interface. This is a
low power communication technology which should be used at short distances. It
makes the 89X1N a connectable beacon which acts as a peripheral by default and
switches to a server role (pairing mode) once a remote device (central) is
connected. The BLE interface should be used for device configuration only. BLE
is activated automatically upon battery insertion. After one hour, the BLE is
de-activated to conserve battery energy. BLE can be re-activated by using the
magnet switch. After one hour, BLE is de-activated again.
Magnetic Switch
The 89X1N has an internal reed switch. This switch is activated when a strong
magnet is close to the magnetic sensor location. The magnetic switch location
is indicated by the magnet icon on the plastic housing. The magnet must be of
sufficient strength and proximity to create a magnetic field of 25 mT at the
switch location.
Two different functions are available depending on the user action:
| User action | Function | LED |
|---|
Short tap
| Activates BLE for another one hour plus trigs a new measurement and a
LoRaWAN™ transmission (uplink if joined, else join request).| One short blink.
If user holds the magnet close to the switch for a longer duration, the LED
will blink faster. Remove the magnet to only initiate a transmission.
Else it going to initiate a sensor reset.
Hold magnet for 10+ seconds|
Resets the sensor.
| Wait for at least 10 seconds, to see the very fast blink. Release the magnet once a very long orange led appears
LED Indicator
The orange LED indicates the state of the 89X1N.
| Category | Mode | Description | Pattern |
|---|---|---|---|
| Power-on/Reset | Led turned on at start up to confirm the battery | ||
| insertion. | A 2 sec long on | ||
| LoRaWAN™join request | Join request message sent | 3 very short blinks | |
| Uplink | Sending uplink message | very short blink | |
| Status | Success | Operation successful | very short blink |
| Fail | Operation failed | 1sec long on |
The time plots below show the different flash sequences that occur for various actions the sensor is taking.
LoRaWAN™ Join request examples
A normal join request gives 3 fast blinks (few milliseconds on), a 6 second
delay then another short blink. In case of error, the LED is turned on for
about 1 second.
Scenario #4: A LoRaWAN™ join request is shown with 3 short blinks (few
milliseconds on) and about a 6 second later, another short blink (join accept
from the gateway).
Scenario #5: For EU-868 region, if an error pattern (1 sec on) is shown
just after the 3 blinks, it means the device hasn’t sent the message due to
duty cycle restrictions.
Scenario #6: In case no response from the gateway, and after about 6 sec
after the 3 short blinks, the LED is turned on for about 1 second.
LoRaWAN™ Uplink transmission Examples
Scenario #1: A normal uplink transmission gives 1 short blink (few
milliseconds on) and few seconds later, another short blink (ack from the
gateway).
Scenario #2: For EU-868 region, if an error pattern (1 sec on) is shown
just after a short blink, it means the device hasn’t sent the message due to
duty cycle restrictions.
Scenario #3: In case no response from the gateway (Confirmed message up
needs a downlink with an acknowledge), delay is about 2 sec after the short
blink, the LED is turned on for about 1 second (nack).
Presets
The 89X1N has several adjustable functions that tailor the output data to meet
user needs. To easily manage these functions, the 89X1N has a feature called
“Preset”. This feature allows the user to combine functions into commonly used
or unique preset configurations.
The presets are divided in three different categories:
- User: editable area which allows the user to create his own configurations.
- Factory predefined: read only preset which are callable for an easy and fast configuration
- Factory customer predefined: same as above, read-only and hidden area reserved for identified customers including their own private settings
By default, the 89X1N uses the “User preset 0”. Any change to the sensor settings such as Bandwidth, Measurement interval, Windows count… will affect the “user preset 0” only. The table below shows the various preset configurations. There are 16 user adjustable configurations (ID 0 – 15) and 15 factory predefined configurations (ID 64 – 78).
Category
| Preset Name|
ID
| BW (Fs/2.56
)
| Meas interva l| Window s
Count
| Windows
---|---|---|---|---|---|---
FreqMi n| FreqMa x| Integ bin| Peak s
User
| User preset 0| 0| 14.4k| 1 hour| 0| bandwidth|
20| 8
User preset 1| 1| 14.4k| 1 hour| 0| bandwidth| 20| 8
…| ..| ..| ..| ..| ..| ..| ..| ..
User preset 15| 15| 14.4k| 1 hour| 0| bandwidth| 20| 8
Factory Predefine d
| 89X1_Legac y| 64| 14.4k| 1 hour| 0| bandwidth| 20| 8
BW1K6_ULP| 65| 1.6k| 1 day| 1| 0| 1.6k| 4| 8
BW4K8_ULP| 66| 4.8k| 1 day| 1| 0| 4.8k| 4| 8
BW9K6_ULP| 67| 9.6k| 1 day| 1| 0| 9.6k| 4| 8
BW1K6_LP| 68| 1.6k| 0.5
day
| 1| 0| 1.6k| 4| 8
BW4K8_LP| 69| 4.8k| 0.5
day
| 1| 0| 4.8k| 4| 8
BW9K6_LP| 70| 9.6k| 0.5
day
| 1| 0| 9.6k| 4| 8
BW1K6_STD| 71| 1.6k| 1 hour| 1| 0| 1.6k| 4| 8
BW4K8_STD| 72| 4.8k| 1 hour| 1| 0| 4.8k| 4| 8
BW9K6_STD| 73| 9.6k| 1 hour| 1| 0| 9.6k| 4| 8
BW1K6_HR| 74| 1.6k| 10 min| 1| 0| 1.6k| 4| 8
BW4K8_HR| 75| 4.8k| 10 min| 1| 0| 4.8k| 4| 8
BW9K6_HR| 76| 9.6k| 10 min| 1| 0| 9.6k| 4| 8
BW9K6_RTH| 77| 9.6k| 5 min| 1| 1.6k| 9.6k| 4| 8
BW1K6_RTL| 78| 1.6k| 55 min| 1| 0| 1.6k| 4| 8
MANAGING PRESETS
By default, the sensor uses the “User Preset 0”. It is possible to switch
between 2 presets by writing the preset identifier to be loaded in a specific
register. It can be done anytime.
Once the preset loaded, the paraAmeters shown in the previous table are
applied and are instantaneously effective.
If the selected preset is a user preset, the parameters of the active preset can be modified (and saved) in the usual way (over BLE or LoRaWAN™) using the default commands.
ROTATING PRESET MODE
In addition to the presets, the 89X1N implements a feature called “Rotating
mode”. This provides the user a way to alternate between two presets
continuously. After the execution of a preset, the second preset queued in the
mode will be loaded, then once executed it comes back to the first.
The example below shows how to take advantage of the rotating mode. Here 2
presets are configured with 2 different bandwidth and measurement interval.
The self-Rotating mode automatically switches between #0 and #1 without any
external user action required.
With the example, every 1 hour will result of having 2 measurements: one with a high frequency band and another (5min later) with a low bandwidth but with a higher resolution.
battery
BATTERY TYPE
To meet various certification requirements, the following battery must be
used:
| Parameters | Typical value |
|---|---|
| Manufacturer | SAFT |
| Reference | LS 17330 |
| Technology | Primary lithium-thionyl chloride (Li-SOCl2) |
| Nominal voltage | 3.6 V |
| Capacity at 20°C | 2100 mA |
| Operating temperature range | – 60°C/+ 85°C |
BATTERY LIFE
Depending on customer settings (measurement interval) and on LoRaWAN™ network
quality, the 89X1N battery life could go up to 10 years. The number of
measurements per day will affect the battery life. More measurements will
reduce the battery life.
BATTERY REPLACEMENT
The 89X1N’s battery must be replaced if depleted. Unscrew the plastic housing
and remove it from the base. Carefully use a small tool (such as a flat
screwdriver) to remove the battery. Note that it MUST be replaced by the same
battery type as shown above. Substitute batteries may damage and/or bring
uncontrolled behavior to the sensor. Double check the polarity and then insert
the new battery inside the holder. Re-attach the plastic cover on the sensor.
Refer to the Installation Manual (Doc# 20023687-24} for specific details
regarding battery installation and replacement.
When complete, the battery life estimator in the firmware must be reset to a
“full” battery status.
BATTERY ESTIMATION ALGORITHM
CURRENT CONSUMPTION PROFILES
Dimensions
Mounting Considerations & Accessories
A solid mounting method is required to get optimum performance from the accelerometer. Any loose parts or unsecured mounting features will introduce noise and corrupt the signals of interest. Shown below are six different mounting options available for the 89X1N accelerometer.
For the adhesive mounting stud, secure with a rigid adhesive such as epoxy or
cyanoacrylate. Do not use pressure sensitive adhesives or foam tapes. For the
magnetic mounting stud, remove the keeper prior to attachment. The magnetic
mounting will have a 30 lb pull strength when attached to a ferrous surface.
Note – Some mounting accessories may be supplied with sample orders. For
production deliveries, desired mounting accessories must be ordered as a
separate item.
Certifications & Compliances
CERTIFICATIONS
8911N and 8931N Wireless Sensors with characteristic (EX) in model name are
certified for Intrinsic Safety to the following classification:
IS Class I, Div1, Groups A, B, C, and D;
Class I Zone 0, AEx ia IIC T4 Ga;
Ex ia IIC T4 Ga;
ll 1 G Ex ia IIC T4 Ga
Please see section 12 for details on how to order.
REGLUATORY STATEMENTS
FCC and IC
This Radio Equipment is Certified for FCC (US) and ISED (Canada).
This equipment does not support simultaneous transmissions.
Changes or modifications not expressly approved or authorized by TE
Connectivity for compliance could void the user’s authority to operate the
equipment.
FCC Warning:
THIS DEVICE COMPLIES WITH PART 15 OF THE FCC RULES.OPERATION IS SUBJECT TO THE
FOLLOWING TWO CONDITIONS:
- THIS DEVICE MAY NOT CAUSE HARMFUL INTERFERENCE, AND
- THIS DEVICE MUST ACCEPT ANY INTERFERENCE RECEIVED, INCLUDING INTERFERENCE THAT MAY CAUSE UNDESIRED OPERATION.
Note: This equipment has been tested and found to comply with the limits for a Class B digital device, pursuant to Part 15 of the FCC Rules. These limits are designed to provide reasonable protection against harmful interference in a residential installation. This equipment generates, uses, and can radiate radio frequency energy and, if not installed and used in accordance with the instructions, may cause harmful interference to radio communications. However, there is no guarantee that interference will not occur in a particular installation. If this equipment does not cause harmful interference to radio or television reception, which can be determined by turning the equipment off and on, the user is encouraged to correct the interference by one or more of the following measures:
- Re-orient or relocate the receiving antenna
- increase the separation between the equipment and the receiver
- Connect the equipment to an outlet on a circuit that is different from that to which the receiver is connected.
- Consult the dealer or an experienced radio/TV technician for help.
Industry Canada (IC) Warning:
This device complies with ISED Canada licence-exempt RSS standard(s).
Operation is subject to the following two conditions:
- This device may not cause interference, and
- This device must accept any interference, including interference that may cause undesired operation of the device.
IMPORTANT NOTE:
Radiation Exposure Statement:
This equipment should be installed and operated with minimum distance 20cm
between the radiator & your body.
EU Conformity
Hereby, Measurement Specialties (China), Ltd. a TE Connectivity Company,
declares that this Wireless Vibration Sensor is in compliance with essential
requirements and other relevant provisions of the following directives:
- Directive 2014/53/EU
- Directive 2014/30/EU
- Directive 2014/35/EU
- Model Families: 8911N & 8931N
- Product Description: Wireless Vibration Sensor
- Operating Bands: BLE 2.4GHz, Lora 868MHz
- Max Output Power for E.U. Unit Configuration, BLE: +1.654dBm (-2.476 dBm EIRP)
- Data Communication, Lora: +5.252dBm (+7.402 dBm EIRP)
- Manufacturer/Brand: TE Connectivity Ltd
Manufacturer:
Measurement Specialties (China) LTD
No 26 Langshan Road
518057 Shenzhen-Nanshan District, China
European Contact:
TE Connectivity Sensors France
4 Rue Gaye Marie
31027 Toulouse – France
Ordering Information
Documents / Resources
| TE
CONNECTIVITY 89X1N Series Wireless Vibration
Sensor
[pdf] User Manual
8931N, 8911N, 89X1N Series Wireless Vibration Sensor, Series Wireless
Vibration Sensor, Wireless Vibration Sensor, Vibration Sensor, Sensor
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