Trillium Compact Posthole


Nanometrics industry-leading portfolio of Trillium seismometers now includes a Trillium Compact Posthole for quick and easy deployment. Available in both 120s and 20s variants, the Trillium Compact Posthole features a stainless steel enclosure and waterproof connector ideally suited for downhole deployments.


Specifications are subject to change without notice.

Topology Symmetric triaxial
Feedback Force balance with capacitive transducer
Mass centering Not required
Sensitivity - 120s 750V-s/m nominal ±0.5% precision
Bandwidth - 120s -3 dB points at 120 s and 100 Hz
Sensitivity - 20s 750V-s/m nominal ±0.5% precision
Bandwidth - 20s -3 dB points at 20 s and 100 Hz
Off-axis sensitivity ±0.5%
Transfer function Lower corner pole frequency within ±0.5% of nominal provided
High-frequency poles within 1 dB of nominal up to 45 Hz
No peak in response at high frequency
Clip level 26 mm/s from 0.1 Hz to 10 Hz
Operational tilt range - 120s ±2.5°
Operational tilt range - 20s ±10°
Parasitic resonance None below 200 Hz
Dynamic range >152 dB @ 1 Hz
Connector - downhole 16-pin, underwater SubConn MCBH16MSS, top mounted
Velocity output ±20V peak (40V peak-to-peak differential)
Selectable XYZ or UVW mode
Mass position output Single voltage output representing maximum mass position
3-channel mass positions available through serial port
Calibration input Single voltage input and one active high-control signal to enable all 3 channels
Remote calibration in XYZ or UVW mode
Independent channel selection by serial port
Digital interface RS-232 compatible serial IP (SLIP)
Onboard web server standard HTTP
Digital commands XYZ, UVW mode switching

Calibration channel selection (off, enable all, U, V or W)
Short/long period mode
Firmware updates
State-of-health request
Digital data outputs
Independent mass position values
Instrument temperature
Factory sensitivity
User calibration data (poles and zeroes)
Instrument serial number and firmware revision
Diameter 97 mm 
Height 160 mm  (body and connector)
167 mm (on fixed studs)
230 mm (on optional 70 mm spikes)
Weight 3.3 kg
Housing Stainless steel surface, resistant to corrosion, scratches and chips
Alignment Vertical scribe marks for N/S
Case-top north/south guide for straight-edge, line, or laser level
Immersion rating Rated to IP68 for full submersion
Supply voltage 9 to 36 V DC isolated inputs
Power consumption <180mW typical (model TC120-PH2)
<195mW typical (model TC20-PH2)
Protection Reverse-voltage and over-voltage protected
Self-resetting over-current protection revision
Operating temperature -20°C to +60°C (ultra-low temperature option available, contact Nanometrics)
Storage temperature -40°C to +70°C
Shock 100 g half sine, 5 ms without damage, 6 axes
No mass lock required for transport
Magnetic Insensitive to natural variations of the earth's magnetic field
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