Guralp Systems CMG-5T - Manual (Page 17)

Operator's Guide
4 Inside the 5T
The 5T unit is constructed of hard-anodised aluminium with “O” rings
throughout, ensuring a completely waterproof housing.
Inside, the mass of the vertical and horizontal components is attached
to the rigid frame with parallel leaf springs. The geometry of the spring
spacing, together with the symmetrical design, ensures large cross-axis
rejection. The sensor mass is centred between two capacitor plates,
and moves in a true straight line, with no swinging motion. Feedback
coils are attached either side of the sensor mass, forming a constant-
flux force feedback transducer.
The vertical and horizontal sensors are identical in mechanical
construction; the vertical sensor's mass spring system is adjusted to
compensate for gravity. They are mounted directly onto the base, with
the sensor electronics fixed onto the rigid sensor frame. A single-row,
12-way surface mount R/A Molex connector joins each sensor to the
main power supply circuit board.
The signal and feedback circuits inside the 5T accelerometer are
arranged according to the following diagram:
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