TECHNOLOGY

Topology:
Feedback:
Mass Centering:

Symmetric triaxial
Force balance with capacitive transducer
Not required

PERFORMANCE

Self-noise:
Sensitivity:
Off-axis Sensitivity:
  Bandwidth:
Transfer Function:


Clip Level:
Parasitic Resonances:
Operational Tilt Range:

 See graph
750 V·s/m nominal ±0.5% precision
±0.5 %
-3dB points at 120 s and 100 Hz
Lower corner poles within ±0.5% of nominal provided
High-frequency response within 1dB of nominal
No peak in response at high frequency
26 mm/s from 0.1 Hz to 10 Hz
None below 100 Hz
±2.5° without re-leveling

LEVELING AND ORIENTATION

Technology:


Clamping:
Range:
Accuracy:
Leveling Initiation:



 

Dual degree-of-freedom motorized gimbals
Jam-free mechanism
Kinematic design preserves full seismometer performance
Active, sequenced by gimbals processor
>±180° relative to upright case
Levels to within ±0.5° of true vertical
Some or all of:
> Configurable delay after power on
> Configurable periodic
> Automatic as-required, based on mass positions
> External Command 

DIGITAL INTERFACE

Type:

Leveling:
 

RS-232 compatible Serial Line Internet Protocol (SLIP)
On board Web Server, standard HTTP
Initiate immediate leveling via user interface
Automatic leveling mode (post power-on, periodic, as-needed)

DATA OUTPUTS

On Request:












Leveling Log:

State-of-Health Log:

Independent mass position values
Instrument temperature
SOH
Magnetometer readings
Case orientation (with respect to vertical)
Seismometer orientation (with respect to vertical)
Download state-of-health (SOH) log
Erase SOH log
Download custom information
Factory sensitivity and sensor response data
User calibration data (poles and zeros)
Instrument serial number and firmware revision
Every leveling event is logged in non-volatile memory
Full before-and-after state-of-health is logged
Scheduled interval logging of SOH, including:
> Time from power-on
> Seismometer mass positions
> Vessel and seismometer orientations
> Magnetometer readings
> Temperature
Internal relative humidity
Capacity for more >2 years of twice daily level checks and SOH logging

PHYSICAL

 Enclosure:


Diameter:
Height:
Weight:

Stainless Steel cylinder
Connector on top end cap

151 mm
258 mm, not including connectors
14.5 kg on land

CONNECTORS

Main Connector:

12-pin female, VSK-12-BCL rubber-molded glass epoxy
40V peak-to-peak differential seismic signal plus ground (3 channels)
Serial RS-232 port (Rx, Tx, GND)
Calibration voltage input
Power input and return

POWER

Supply Voltage:
Power Consumption:
Protection:

9 to 29 VDC isolated
<180 mW typical (leveled, quiescent)
Reverse-voltage and over-voltage protected
Self-resetting over-current protection
Unit can be powered on during installation and retrieval

ENVIRONMENTAL

Operating Temperature:
Storage Temperature
Shock:
Transportation:

Magnetic:

-20ºC to +60ºC
-40ºC to +70ºC
100g half sine, 5 ms without damage, 6 axes
No seismometer mass lock required prior to deployment and through full experiment cycle
Insensitive to natural variations of the Earth’s magnetic field