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LE-xD 1Hz Seismometer
Sensors
The LE-xD 1 Hz Models
These are the workhorses of the
scientific product line. Originally available in a blue
rectangular housing (known for a long time as the "LE-3D
classic", now out of production), hundreds of these
sensors are in daily duty all over the world. The
current model (shown below) comes in a cylindrical
stainless steel housing and is called LE-3Dlite.
Additionally, single component versions for vertical or
horizontal use are available, aptly named LE-1D/V and
LE-1D/H.
Users are attracted by these unique
features that set these sensors miles apart from their
mechanical predecessors:
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Extremely compact and
lightweight
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Rugged
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Sheer simplicity; true plug-and
play operation
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All sensors calibrated to
identical output voltages; no need to keep records
of which sensor has been connected to which
datalogger
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Low noise, low power (typically
3 mA per component @ 12 V DC)
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Dynamic range > 120 dB
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Comparatively insensitive to
improper leveling
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No mass lock, mass center,
control box, or other contraption required; can be
transported in any orientation
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Proven long-term stability;
well over ten years of field experience
Technical Details
The following table shows the
relevant technical parameters for both the single and
the three component versions of the 1 Hz seismometers:
| |
LE-1D/H and LE-1D/V |
LE-3Dlite |
| Power
Supply |
10...16V DC, unstabilised |
10...16V DC, unstabilised |
| Output
Voltage |
400 V/m/s, precisely adjusted |
400 V/m/s, precisely adjusted on all components |
|
Damping |
0.707 critical (internal damping; independent of
datalogger input resistance) |
0.707 critical (internal damping; independent of
datalogger input resistance) |
|
Dimensions |
85 mm diameter
55 mm height |
95 mm diameter
65 mm height |
|
Weight, including 1.5 m cable and Cannon KPT
connector) |
1.1 kg |
1.8 kg |
|
Temperature range |
-15...+35°C |
-15...+35°C |
|
Optional temperature range (specify when
ordering) |
0...+50°C |
0...+50°C |
|
Housing |
Stainless steel, matted surface, splash proof,
with level adjustment feet and water bubble
level control |
Stainless steel, matted surface, splash proof,
with level adjustment feet and water bubble
level control |
|
Eigenfrequency |
1 Hz |
1 Hz |
| Upper
corner frequency |
> 80 Hz |
> 80 Hz |
| RMS
noise at 1 Hz |
< 3 nm/s |
< 3nm/s |
The single component seismometer
must be ordered for vertical (/V) or horizontal (/H)
operation; the two versions are not convertible or
retrofittable.
The "upper corner frequency" row
denotes the frequency up to which the sensors have been
tested on a shake table. Users should be aware that
there is an inherent low pass filter in the sensor's
circuitry which will gradually damp away frequencies
higher than the upper corner frequency.
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