General Description; Description - Reftek 151D User Manual

Rev A

1 General Description

1.1 Description

The 151D is a force-balance feedback broadband seismometer. This
integrated seismometer incorporates 3 independent sensors mounted
symmetrically and combined to provide orthogonal Z-N-E outputs. The
151D incorporates the following functions: control, power-conversion and
feedback. The 151D offers low self-noise, large dynamic range, good
stability and quick installation as well as easy to use features.
The main characteristics of the 151D are as follows:
• Stable force-balance electronic feedback system.
• Frequency range: 120sec~80Hz (See Section 10)
• Self-noise below the NLNM in the range 145 seconds to ~10Hz.
• Automatic and electronic unlocking of the masses.
• Built in functionality for remote centering of the mass position.
• Leveling mechanism includes a bubble level and adjustable feet with
three locknuts.
• Powered by a single +12V DC with low power consumption.
Three separate mechanical sensors are combined together to provide a
vertical (Z; U-D), and two horizontal (X; E-W and Y; N-S) outputs. They are
mounted symmetrically on the circular base. The internal circuit boards are
fixed above the masses. A wire harness and sockets are used to connect the
mechanical and electronic parts.
Reftek Systems Inc.
REF TEK 151D Broadband Seismometer Users Guide
151D-UG
12/4/2023
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