SENTINEL
SENTINEL is a premium-quality accelerograph that was conceived for strong motion and structural monitoring with budget-sensitive constraints.
Description
HIGHLY PERFORMANT AND COST-EFFECTIVE
The onboard MEMS triaxial accelerometer is synchronously sampled up to 1000 sps at a resolution of 20 bit (or 24 bit SENTINEL-X) and exhibits a dynamic range > 85dB (or > 110 db SENTINEL-X) and a self-noise < 18µg/√Hz.
The integrated memory bank (32 – 256 GB) allows you to manage a ring-buffer for long continuous recordings as well as event data.
The data format is MiniSEED.
The system implements sophisticated trigger criteria (STA/LTA and threshold) that distinguishes false events (i.e. environment vibrations) from true seismic events.
The internal GNSS receiver allows you to create a network where all the instruments are synchronized with the absolute time.
EASY TO USE
You can control SENTINEL locally via network connection (LAN or WiFi), and remotely using the integrated 4G modem (optional). The instrument can be used as a “stand-alone” unit to record seismic events in the field or it can be used in a MASTER-SLAVE based monitoring network where multiple instruments are connected to each other; SENTINEL is compatible with both the Triton and Atlas and this can be useful when a superior dynamics are needed, for example, as a near field unit.
Thanks to SeedLink protocol SENTINEL is compatible with most popular seismic analysis software (Seiscomp3, Antelope, Earthworm).
INTEGRATED UPS
SENTINEL is powered by an external DC source (5 – 16 Volt DC) and it is equipped with its own internal battery (LiPo) which can guarantee an autonomy of 5 hours in case of a blackout. The battery is a standard 18650 and can easily be replaced. The internal HSPA modem (optional) is backed up by the internal battery.
ROBUST AND USABLE AS A SEISMIC SWITCH
SENTINEL can be equipped (optional) with 3 relays output and used as a seismic switch, to shut down sensitive equipment such as elevators, pumps, gas valve or to drive alarm systems like sirens or lights.
The instrument comes in an anodized aluminum case which is rugged and shock-resistant and thus suitable for field applications. SENTINEL is designed with an adjustable mounting plate in order to simplify the instrument leveling.
Application
Structural health monitoring is one of the main applications of SENTINEL, with tall buildings, where heavy oscillations excite the structure and the amplitude of physical signals is considerable, SENTINEL performs well even if its dynamic range cannot compete with that of TRITON’s.
In a scenario like this, the only high dynamic (and thus more expensive) accelerograph is placed on the ground floor, where the oscillations of the structure are negligible.
SENTINEL and TRITON can be interfaced and controlled using QUAKELOGIC’s Structural Health Monitoring software.
A real-time report of the building and a post-earthquake evaluation of the structural damage can be locally displayed or trasmitted remotely.
The good performance/price ratio makes SENTINEL the ideal choice when building a distributed system aimed at creating an array of seismic data.
Earthquake early warning (EEW) concept is the rapid detection of earthquakes and the alerting of people to shaking.
SENTINEL can detect the non-damaging P-waves and transmit the information about tremors to an alarm center or directly to predefined users before the most damaging S-waves arrive.
SENTINEL is currently used for an ongoing project with the INGV (National Institute of Geophysics and Volcanology) which is experimenting with AI algorithms to detect the earthquake autonomously and quickly.
SENTINEL would be an excelent solution for deactivating sensitive electronic devices when a seismic event is detected, closing gas valves or warning people.
Models
Sentinel models available
- SENTINEL: Accelerograph with integrated triaxial MEMS accelerometer, 85dB dynamic range.
- SENTINEL-GEO: Accelerograph with integrated triaxial MEMS accelerometer, 85dB dynamic range + triax 4.5Hz geophones.
- SENTINEL-M90H : Accelerograph with integrated high quality monoaxial horizontal MEMS accelerometer, 90dB dynamic range, 24bit.
- SENTINEL-M90V : Accelerograph with integrated high quality monoaxial vertical MEMS accelerometer, 90dB dynamic range, 24 bit.
- SENTINEL-M90HH : Accelerograph with integratedt high quality biaxial horizontal/horizontal MEMS accelerometer, 90dB dynamic range, 24 bit.
- SENTINEL-M90HV : Accelerograph with integratedt high quality biaxial horizontal/vertical MEMS accelerometer, 90dB dynamic range, 24 bit.
- SENTINEL-M90HHV : Accelerograph with integratedt high quality triaxial MEMS accelerometer, 90dB dynamic range, 24 bit.
- SENTINEL-M110H : Accelerograph with integratedt TOP quality monoaxial horizontal MEMS accelerometer, 110dB dynamic range, 24 bit.
- SENTINEL-M110V : Accelerograph with integratedt TOP quality monoaxial vertical MEMS accelerometer, 110dB dynamic range, 24 bit.
- SENTINEL-M110HH : Accelerograph with integratedt TOP quality biaxial horizontal/horizontal MEMS accelerometer, 110dB dynamic range, 24 bit.
- SENTINEL-M110HV : Accelerograph with integratedt TOP quality biaxial horizontal/vertical MEMS accelerometer, 110dB dynamic range, 24 bit.
- SENTINEL-M110HHV : Accelerograph with integratedt TOP quality triaxial MEMS accelerometer, 110dB dynamic range, 24 bit.
- SENTINEL-X : 4 channels, 24 bit digitizer / recorder.
- SENTINEL-R : Accelerograph with integrated triaxial MEMS accelerometer, 85dB dynamic range, removable batteries and data storage, 1.6 GHz processor, 4 GB RAM.
OPTIONS AND ACCESSORIES
- SENTINEL-4G : Internal 4G router.
- SENTINEL-SUIT : Suitcase for SENTINEL, SENTINEL-X and SENTINEL-M and all accessories.
- SENTINEL-GEO-SUIT : Suitcase for SENTINEL-GEO and all accessories.
- SENTINEL-EXT-PWR : External DC cable 2 mt.
- SENTINEL-PWR-EU : External Power supply. European power cord.
- SENTINEL-PWR-US : External Power supply. US power cord.
- SENTINEL-GEO-SPK : Set of 3 short adjustable spikes SS AISI316.
- SENTINEL-GEO-SPK-80 : Set of 3 spikes 80 mm lenght Al6061 Hard Coated.
- SENTINEL-GEO-SPK-80-316 : Set of 3 spikes 80 mm lenght SS AISI316.
- SENTINEL-GEO-SPK-150-316 : Set of 3 spikes 150 mm lenght SS AISI316.
- SENTINEL-GEO-MP : Mounting plate with for permanent installation.
FAQS
FREQUENTLY ASKED QUESTIONS
IS SENTINEL CAPABLE OF PERFORMING BOTH REAL-TIME STREAMING AND EVENT-TRIGGERING SIMULTANEOUSLY?
Answer: Yes, SENTINEL may do both tasks in parallel. For event-triggering, threshold exceedance instead of STA/LTA is recommended for accelerometers.
WHAT HAPPENS WHEN THE TELEMETRY IS DOWN? CAN THE DATA BE RETRIEVED EASILY?
Answer: The telemetry works through SeedLINK protocol, which holds data in its ring buffer whose size is by default 1GB (expandable): it corresponds to some days of continuous recording. When the telemetry goes down, the client may request data from the last packet received before the break and then recovered all the missing data. This is automatically handled by the SeedLINK client. Whether the telemetry is up or down, the device always stores data in a separate folder and the telemetry (SeedLINK) server detects it, and copies data in its ring buffer, ready to be sent on request.
CAN MULTIPLE SENTINEL DIGITIZERS AT DIFFERENT LOCATIONS BE TRIGGERED SIMULTANEOUSLY?
Answer: This could be done in two ways. For example, if the 2 or more SENTINEL digitizers are in the same LAN segment, either SENTINEL could reach the trigger status and trigger all the other units with a broadcast message. If they are installed in different LAN segments (for example there is a gateway in the middle), this won’t work and we should install an additional module on a Linux machine that catches the alarms from the devices and implements a trigger voting algorithm.
WHAT FORMAT DOES THE SENTINEL DIGITIZER USE TO SAVE EVENT FILES?
Answer: MiniSEED, just like the continuous recording. But if we install the QUAKELOGIC Event Watchdog software to the remote server, the trigger files may be sent automatically to a remote server and exported in ASCII format, or the server may extract the event data from the continuous recording and perform the export. For example, this would be the best way to interact with a LABVIEW application.
HOW DOES SENTINEL DIGITIZER SEND AN EVENT FILE TO A REMOTE SERVER?
Answer: The SENTINEL digitizer can communicate with the remote server (Linux Machine) through MQTT and SeedLINK. The Linux Machine takes care of storing all the continuous recordings from the SENTINEL devices and receives the trigger data through MQTT or just extracts it from the continuous buffer. At this point, data is still available in MiniSEED. Once we have a time window for an event, we may export it in ASCII.
HOW CAN SENTINEL DIGITIZER BE POWERED BY A SOLAR POWER?
Answer: The SENTINEL digitizer can be powered by a 12 V solar panel (>100 W). The system requires a solar panel, 12V backup battery and controller unit. QuakeLogic can provide all these auxiliary hardware including on-site installation.