3B40 / 3B41

Rev. 0 | Page 2 of 8

GENERAL DESCRIPTION

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.

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.

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.

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.

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Figure 2