3B40 / 3B41
GENERAL DESCRIPTION
assures long-term stability. At the amplifier input, a stable, zero-
scale input voltage is subtracted from the input signal to set the
zero-scale value. Zero suppression can exceed 100% of the input
range. This is ideal for expanded-scale applications requiring
high-resolution measurement of a selected portion of an input
signal. For user convenience, the zero and span can be factory
configured to meet custom range needs (Models 3B40-
CUSTOM and 3B41-CUSTOM) or can be externally
programmed (Models 3B40-00 and 3B41-00) via user supplied
resistors inserted in the optional AC1310 plug-on ranging card.
Internal low-pass filtering with a 10 kHz cutoff (-3dB) is
determined by a two-pole Butterworth filter.
The 3B40 and 3B41 are wide-bandwidth (10kHz) single-
channel signal conditioning modules which amplify, isolate,
filter and protect analog input voltages and provide
simultaneous precision voltage and current outputs. Each
module performs complete signal conditioning, including
isolating (+1500 V peak input-to-output and power) and
protecting their computer side outputs from damage and loss of
signal integrity, and shielding their inputs from damage from
field-side over-voltage faults up to 220 V rms. The current
output withstands 130V rms without damage and interfaces
user equipment through screw terminals located on the 3B
Series backplane. Each plug-in, mix-and-match, hot-swappable
module is easily field calibrated via front-panel zero and span
adjustments for both voltage and current outputs.
Signal isolation is accomplished by transformer coupling with a
proprietary modulation technique for linear, stable and reliable
performance. The differential input circuit on the field side is
fully floating, eliminating the need for any input grounding. A
demodulator on the computer side of the signal transformer
recovers the original signal, which is then filtered and buffered
to provide a low-noise, low-impedance output voltage: this
output also drives a voltage-to-current (V/I) converter to
provide a simultaneous current output for interfacing versatility.
3B Series Custom-Ranging Program – Externally-
programmable versions, Models 3B40-00 and 3B41-00, enable
the user to configure a special input range by using the optional
plug-on AC1310 ranging card, which houses user-supplied
resistors to determine zero and span. To facilitate selecting
resistors, a Windows program, 3B-CUSTOM, calculates resistor
values based on the user-desired input/output ranges.
A chopper-stabilized low-drift (+1uV/oC) input amplifier
.
.
Figure 2
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