Broadband Seismometer of Seismic Systems:
Model: BBVS-360, BBVS-120,BBVS-60,BBVS-30,
Application
Local and Regional
Broadband Surface or Posthole Installation
GSN Installation
Features
High Performance Broadband Seismometer
Low Self-Noise Over a Wide Bandwidth
Portable Design
Low Power Consumption
Force-Balance Electronic Feedback
Robust Mass Locking Mechanism
Easy Installation
This Broadband Seismometer, is a force-balance feedback sensor available with frequency bandwidth 0.0083 Hz (120 sec) - 50 Hz, and 0.016 Hz (60 sec) - 50 Hz flat to velocity. The seismometer contains three independent sensors (one vertical and two horizontal) with built-in electronic feedback circuit, control and power conversion circuits, featuring low noise, large dynamic range and easy installation and use.
The seismometer has built-in leveling and mass lock/unlock facilities. The leveling mechanism includes two bubble levels, three adjustable feet and three locknuts which are located on the seismometer’s chassis.
The seismometer has a built-in mass zero-position adjusting mechanism to perform automatic mass adjustment. As soon as the seismometer is powered it checks the zero position of each component’s mass and automatically adjusts the zero position if needed.
The seismometer is a low noise seismometer (see next tab for Power Spectral Density plot). The low self noise performance makes the BBVS-120 an ideal seismometer for local, regional, and global seismicity studies in different installation configurations, including observatory and portable, surface and posthole applications.
Sensor Type | Triaxial, orthogonal |
Feedback | Force balance with capacitive displacement transducer |
Frequency Response | 0.0083 Hz (120 sec) - 50 Hz, Model BBVS-120 |
Sensitivity | 2000 V/m/s |
Full Scale Output | +/- 20 V peak-to-peak differential |
Dynamic Range | >140 dB @ 5Hz |
Output Impedance | <100 Ohms |
Calibration | Coil resistance 1,000 Ohms, sensitivity: 10 m/s2/A |
Leveling | Two Integrated bubble levels. Three adjustable leveling feet with locknuts |
Mass Position | Remote monitoring and adjusting zero-point using 3 independent voltage outputs |
Mass Locking | Mechanical lock-unlock mechanism accessible on outside of the case |
Distortion | Total distortion less than -80 dB |
Cross Axis Coupling | < 1% |
Mechanical Zero | No need for adjustment within ambient temperature fluctuation +/- 20o C |
Power-Fail Protection | Built-in |
Signal Overload Protection | Built-in |
Auto-recovery Time | Full operation recovery within 10 minutes after either power fail or signal overload |
Power Input | +12 VDC (9V to 18 VDC) |
Operating Temperature | -20o C to +60o C |
Power Consumption | ~ 1.1 W |
Water Tight Integrity | IP67 for outdoor use and immersion resistance |
Case | Aluminum, Powder Coated |
Dimensions | Diameter: 9.45 " (24 cm); Height: 10.6 " (27 cm) |
Weight | 26.4 lbs (12 kg) |
Alignment | Removable orientation N/S pins screw into the base (brass for N, silver for S) |
Lightning Protection | Built-in |
Low Spurious Resonance | Higher than 100 Hz |
Damping | 0.7 of Critical |
Linearity | Better than 1% of full scale |
Type | Free-running Oscillator |
Accessories (optional) | Rugged transportable hardigg case. Flexible insulation bag |
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