Force Balanced Medium Period Seismometer
Model SP-400
sp400 seismometer

The SP400 Medium period sensor is designed as a versatile, rugged, extended band short period active seismic sensor. They consume very low power and are packaged in compact, lightweight heavy-duty PVC cases.

Unlike traditional short period seismometers, they are based on proprietary electrochemical transducer technology MET. These transducers have many advantages over conventional electromechanical sensors. All three sensors in the SP400 are equipped with a force-balancing feedback and its noise is reduced by an additional 10dB.

The SP400 sensors are offered in two application-dependent versions: a higher clip level SP400SM, and a reduced noise SP400RN. Both have the same dynamic range, which is shifted by approximately 10db up toward stronger ground motions in the SM version.

The SP400 has an exceptionally rugged design, does not require mass lock or special installation equipment or procedures and stays operational in a wide range of installation tilts. These seismometers provide a low cost of ownership, requiring no maintenance over the life of the instrument. Borehole configurations including inclinometers are optional. Three and five-year extended warranties are available.

  • Passband 0.06 Hz to 50 Hz,
  • Low Power
  • No Mass Centering or Mass Locks
  • High Sensitivity
  • 142dB Dynamic Range
  • Rugged
  • Maintenance Free
  • Waterproof
  • Operates over a wide tilt
  • Flat Frequency Response
  • Force Balanced
  • OBS and Borehole Configurations
Operating principle: Electrochemical motion transducer with force-balancing feedback
Output signals: 2 horizontal, 1 vertical; very broad passband, velocity flat response
Output signal swing: 10 V single-ended; (20 V p-p)
Dynamic Range: 142 dB
Bandwidth: 0.06 Hz - 50 Hz;
Self-noise: RN -160dB; SM -150dB on the USGS NLNM
Generator constant: Standard: 2000 V/m/s; Opt.: 350 - 20,000 V/m/s
Mass Centering: NONE REQUIRED
Maximum installation tilt 15
Mechanical resonance >150 Hz
Waterproof: Submersible (1m)
Temperature range: Standard: -12 to + 55 C
Others optional
BasicSP-400 Configuration The standard configuration includes mating connector and calibration sheets
Sensitivity Option option -Sxxxxx
(x specifies sensitivity)
Low Power Option option -LP
Recorder Options DR-4000,
Supplies and Accessories Sensor Cable
General Spares None

S Printer Friendly Format For Specifications

Case diameter 200mm
Case height: 210mm
Weight 4.5kg (PVC housing), 8kg aluminum
Connector 10-pin circular
Power - Standard 10 - 15 Vdc; 12 Vdc nominal
Supply current Standard: 28 mA @ 12V; LP version: 4.5mA


sp400 noise

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