3B17

Rev. 0 | Page 2 of 8

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

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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Figure 2