3B17 Datasheet, PDF (2/8 Pages) Analog Devices – Wide Bandwidth LVDT/RVDT Input

GENERAL DESCRIPTION
The 3B17 is a wide-bandwidth single-channel signal-
conditioning module which isolates, amplifies, and filters
signals from 4-, 5-, or 6-wire Linear Variable Displacement
Transformers (LVDTs) or Rotary Variable Displacement
Transformers (RVDT). The 3B17 input module provides an AC
excitation voltage of 1V rms to 5V rms at frequencies between 1
kHz and 10 kHz. All gain and zero suppression can be user-
calibrated by screwdriver adjustments through the sliding door
on the top of the module. Gain can vary over an extensive 256:1
range by adjusting a combination of a rotary switch and trim
potentiometer. Zero suppression can vary over +5V from the
center setting. The current output can be independently
adjusted over a +5% range for zero and span. In addition, the
3B17 is mix-and-match and hot-swappable with all 3B Series
modules, so it can be inserted or removed from any socket in
the same backplane without disrupting system power.
3B Series Custom-Ranging Program – Externally-
programmable Model 3B17-00, and 3B17-D-00, enable the user
to configure a special input range, excitation voltage and
excitation frequency by using the optional plug-on AC1310
ranging card, which houses user-supplied resistors to determine
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3B17
excitation voltage amplitude and frequency. To facilitate
selecting resistors, a Windows program, 3B-CUSTOM,
calculates resistor values based on the user-desired input/output
ranges and AC excitation.
The 3B17 input and AC excitation output terminals are
protected for up to 130V rms, protecting the computer side
from damage due to field-side over-voltage faults. The LVDT
input signal is amplified to give the high level output voltage.
The 3B17 automatically compensates for phase errors between
the primary and secondary of the LVDT or RVDT, eliminating
the need for a phase adjustment and automatically rejects any
residual quadrature voltages via a unique approach to error
compensation which uses the sum of the two secondary
winding to directly drive the demodulator. The amplitude and
frequency of the AC excitation can be factory configured to
meet custom needs (Model 3B17-Custom) or externally
configured (Models 3B17-00 and 3B17-D-00) with the optional
AC1310 plug-on custom ranging card.
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