GeoSIG Digital Sensor System has been developed to accommodate the requirements for a cost effective and practical installation in circumstances where several measuring points need to be deployed over long distances.
The system consists of GMSplusD recorder and AC-7xD or AC-4xD digital accelerometers, with the option of adding analogue sensors. Each digital accelerometer transfers its data digitally, accurately and effectively to the GMSplusD through a single cost effective Cat5E cable.
It is possible to connect up to 4 digital accelerometers (AC-7xD / AC-4xD) to a GMSplusD with a total length of 1’000 meters.
Additionally internal or external analogue sensors can be connected to the same GMSplusD to increase the number of monitored channels to 15.
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Sensor
- Various types of GeoSIG analogue sensors can be housed internally or connected externally, and up to four digital sensors can be connected externally to the GMSplusD. In case of internal sensor, the levelling is done on the base plate of the GMSplusD via its three levelling screws. The base plate is mounted using a single bolt during installation. All external sensors have built-in single bolt mounting with levelling screws.
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Digitizer
- Channels:
- Up to 15:
- 12 Ch (max. 4 sensors) for AC-7xD / AC-4xD digital sensors
- 3 Ch for analogue sensor
- A/D conversion:
- 24 bit D-S converters individual for each channel
- DSP:
- 32 bit output word length
- Dynamic range:
- 146 dB (per bin @ 1 Hz rel. full scale rms)
137 dB @ 50 sps
- Sampling rate:
- Analogue:
1000, 500, 250, 200, 100, 50 sps per channel
Digital:
Up to 1000 with 1 digital sensor
Up to 500 with 2 digital sensor
Up to 200 with 3 or 4 digital sensor
- Max Bandwidth:
- DC to 250 Hz, optionally DC to 500 Hz
3 or 4 digital sensors per chain: 120 Hz
2 digital sensors per chain: 250 Hz
1 digital sensor per chain: 500 Hz (optional)
- Anti Aliasing Filter:
- Analog and digital FIR (finite impulse response)
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Recorder
- Operating System:
- GNU/Linux
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Triggering
- Several Trigger Sets can be defined in the instrument. Each set can be flexibly configured regarding the source of trigger, main and advanced trigger parameters, trigger processing and selected channels for storage. A voting logic based on the monitored channels can be defined.
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Trigger Filter
- Fully independent high-, low- or band pass trigger filters can be configured.
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Level Triggering
- User adjustable threshold.
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STA/LTA Triggering
- User adjustable STA / LTA values and STA/LTA trigger and de-trigger ratio.
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Event Recording
- Pre-event memory:
- 1 to 720 seconds, typical
- Post-event duration
- 1 to 7200 seconds, typical
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Event Summary and Parameters
- Content:
- PGA, PGV, PGD, SA (at 0.3, 1, 3 Hz)
- Transmission delay:
- User defined from trigger time
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Ring Buffer
- Usage:
- User can request an event from any period of the ring buffer by specifying the start time/date and the duration from the console or remotely from a server.
- Method:
- Ringbuffer files with configurable duration, which can be uploaded automatically to data server.
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Data Stream
- Protocol/Compatibility:
- GSBU, SeedLink, compatible to Earthworm
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Storage Memory
- Size and Type:
- 8 GByte Removable SD Card or higher* FAT32 or EXT4 formatted
- Management:
- Intelligent management of memory card capacity using policies as per file type and ring buffer capacity specification
- Recording format:
- miniSEED, or extended miniSEED with extended information encapsulated into blockette 2000
- Estimated Capacity:
- Sampling rate [sps] x 0.4[MB / day / 3 channel] (example: 40 MByte / day / 3 channel @ 100 sps) typical, since the data is compressed, capacity depends on the context of the data.
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Housing
- Type:
- Cast aluminium housing
- Dimensions:
- Recorder: 296 x 225 x 156 mm
Accelerometer: 195 x 112 x 95 mm
- Weight:
- Recorder: 4.5 kg
Accelerometer: 2.5 kg
- Protection:
- IP65 (NEMA 4) or better*
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Environment / Reliability
- Operational temperature
- -20 to +70 °C**
- Storage temperature:
- -40 to +85 °C**
- Humidity:
- 0 to 100 % RH (non condensing)
- MTBF:
- > 500’000 hours
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Timing System
- Internal:
- Intelligent Adaptive Real Time Clock (IARTC)
- External:
- NTP, GPS*, Wired Interconnection*
- Free running drift of TXCO:
- ±0.5 ppm (15 s/year) @ +25 °C
±2.5 ppm (75 s/year) @ -10 to +50 °C
- Accuracy to UTC with NTP:
- < ±4 ms typical
- Accuracy to UTC with GPS:
- < ±10 us typical
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Power
- Input voltage:
- 15 VDC (12.5 - 18 VDC) or wider*
- Average Consumption:
- GMSplusD: 200 mA @ 12 VDC
AC-7xD: 200 mA @ 12 VDC per sensor
Cable loss: 35 mA @ 12 VDC per 100 m
Consumption of analogue sensor (if used) should be considered.
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Indicators
- Green
- Active Charge LED
- Green
- Run/Stop LED
- Yellow
- Event/Memory LED
- Blue
- Network link/Traffic LED
- Red
- Warning/Error LED
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Communication
- Configuration, Data Retrieval:
- Via Ethernet, Wi-Fi*, Serial line, Console, or directly via removable memory card.
- Network requirements:
- Fixed or Dynamic IP on Ethernet LAN and/or Internet connection with Ethernet interface Open VPN*
Wi-Fi(b/g/n) network with WEP, WPA, WPA2 security and Enterprise Mode*
- Security:
- GeoDAS proprietary protocol over SSL Checksum and software handshaking
- Serial ports:
- 2 ports standard, + 3 ports*
- Baud rates:
- Console: 115200 baud
Serial Stream: 38400, 57600, 115200 baud
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Storage Memory
- Size:
- up to 128 GByte
- Type:
- Compact Flash Card
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Timing System
- Interconnection:
- Wired common time and trigger interconnection network, distributing GPS-grade time precision among several units.
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Alarm / Seismic Switch / Warning / Notification
- Alarms:
- 3 independent or 4 common relay contacts for trigger alarm and/or error SMS notification
- Alarm levels:
- Configurable based on event triggers (NO or NC selectable during order)
- Relay Hold-On:
- 1 to 60 seconds (User programmable)
- Capacity:
- The contacts are suitable for a low voltage control. In case a large load must be switched then external relays should be implemented.
- Max voltage:
- 125 V / 250 mA
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Early Warning
- Please contact GeoSIG for the optional Earthquake Early Warning functionality.
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Communication
- Modem:
- External modems of different types, including cellular 3G/4G modems, are optionally available.
- Serial ports:
- Up to 3 additional serial ports can be enabled, please contact GeoSIG for details.
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Power
- Input voltage:
- 9 - 36 or 18 - 75 VDC
- Power source:
- External power block:
90 - 260 VAC / 50 - 60 Hz to 15 VDC, 40 W switched, UL
External GeoSIG Power Pack including power block:
90 - 260 VAC / 50 - 60 Hz to 15 VDC, 60 W switched UL
- Battery:
- Internal 7 or 9 Ah lead acid battery
External from 15 to 100 Ah lead acid battery, which can be supplied inside a separate Battery Pack
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Housing
- Protection:
- IP67 (NEMA 6)
- Transport:
- Portability accessories are available to facilitate short term measurements.
GMSplus & AC series are produced in different types to suit particular specifications or regulations. Specifications mentioned in this datasheet may be different among different types.
* Option. May require third party devices, software and/or services which may not typically be provided by GeoSIG. Not all options can be used together.
** Use of an internal battery may degrade this specification.
***Specifications subject to change without notice
