AD 3B41-02

Isolated Wideband Voltage Input
3B40 / 3B41
Interfaces, amplifies, protects& filters wide-bandwidth (h0
kHz) single-channel analog voltage inputs.
Module provides simultaneous precision voltage and
current outputs.
Module circuitry can withstand 130v rms at the current
output screw-terminals.
All 3B40 & 3B41 series modules are mix-and-match and Hot
Industrial signal conditioning
Industrial signal isolation
Industrial signal filtering
The 3B Series of Signal Conditioning I/o Subsystems provide a
low-cost, versatile method of transferring analog transducer
signals to a data acquisition, monitoring or control system
without the inherent noise, non-linearity, drift and extraneous
voltages. The modules are designed to directly accept analog
signals from Thermocouples, RTD’s, AC and DC Strain Gages,
Torque Transducers, Frequency Transducers, LVDTs, millivolt
or process current signals. The modules amplify, isolate,
linearize and convert the transducer output signals to
standardized analog inputs for high-level analog I/O
subsystems. The 3B Series Subsystem consists of a 10” relay
rack with universal mounting backplane and a family of plug-in
(up to 16 per rack) input and output signal conditioning
Eight and four channel backplanes are also available. Each
backplane incorporates screw terminals for sensor inputs and
current outputs and a 26-pin connector for high-level singleended voltage outputs to the user’s equipment.
The input modules feature complete signal conditioning
circuitry optimized for specific sensors or analog signals and
provide two simultaneous high-level analog outputs: 0 to +10V
(or +10V) and 4-20 mA (or 0-20 mA).
Figure 1. 3B40 & 3B41 Functional Block Diagram
Output modules accept 0 to +10V (or +10V) single-ended
signals and provide an isolated 4-20 mA (or 0-20 mA) process
signal. All modules feature a universal pin-out and may be
readily hot-swapped under full power and interchanged without
disrupting field wiring.
The Analog Devices 3B Series Signal Conditioning Subsystem is
designed to easily handle signal conditioning problems in
measurement and control applications. Some typical uses are in
microcomputer-based data acquisition systems, programmable
controllers, analog recorders, dedicated control systems, and any
other applications where monitoring of temperature, pressure,
flow and analog signals are required. Since each input module
features two simultaneous outputs, the voltage output can be
used to provide an input to a microprocessor-based data
acquisition or control system while the current output can be
used for analog transmission, operator interface, or an analog
backup system.
Each input module is a single-channel signal conditioner which
plugs into a socket on the backplane and accepts its signal from
the input screw terminals. All input modules provide input
protection, amplification and filtering of the input signal,
accuracy of +0.1%, low drift of +1 uV/ oC (low-level input
modules), and feature two high-level analog outputs that are
compatible with most process instrumentation. The isolated
input modules also provide +1500 V peak isolation.
The choice of a specific 3B module depends upon the type of
input signal. Input modules are available to accept millivolt, volt,
process current, thermocouple, RTD, AC and DC strain gage,
frequency and LVDT inputs. The voltage output of each module
is available from the system I/O connector while the current
output is available on the output screw terminals.
Rev. 0
Information furnished by Analog Devices is believed to be accurate and reliable.
However, no responsibility is assumed by Analog Devices for its use, nor for any
infringements of patents or other rights of third parties that may result from its use.
Specifications subject to change without notice. No license is granted by implication
or otherwise under any patent or patent rights of Analog Devices. Trademarks and
registered trademarks are the property of their respective companies.
One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
Tel: 781.329.4700
Fax: 781.326.8703
© 2004 Analog Devices, Inc. All rights reserved.
3B40 / 3B41
assures long-term stability. At the amplifier input, a stable, zeroscale 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 3B40CUSTOM 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) singlechannel 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 – Externallyprogrammable 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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3B40 / 3B41
3B40 and 3B41 Models Available
Input Range
Output Ranges1
Externally Programmable2
-10 V to +10 V & 0 mA to 20 mA
-10 mV to +10 mV
-10 V to +10 V & 0 mA to 20 mA
-50 mV to +50 mV
-10 V to +10 V & 0 mA to 20 mA
-100 mV to +100 mV
-10 V to +10 V & 0 mA to 20 mA
Input Range
Output Ranges1
Externally Programmable2
-10 V to +10 V & 0 mA to 20 mA
-1 V to +1 V
-10 V to +10 V & 0 mA to 20 mA
-5 V to +5 V
-10 V to +10 V & 0 mA to 20 mA
-10 V to +10 V
-10 V to +10 V & 0 mA to 20 mA
Output current range may be user programmed to 4 mA to 20 mA using jumper supplied.
Requires AC1310 ranging card.
* Custom Input/Output ranges are available. Refer to configuration guide.
3B40 and 3B41 Specifications
(typical @ +25°C and ±15 V dc, and +24 V dc Power)
Model 3B40
Model 3B41
Input Ranges
Standard Ranges
±10 mV to ±1 V
±1 mV to ±10 V
Custom Ranges
±5 mV to ±1 V
±0.5 V to ±20 V
Output Ranges
Voltage (RL > 2 kΩ)
-10 V to +10 V
Current (RL = 0 to 850 Ω)1
4 mA to 20 mA or 0 mA to 20 mA
Maximum Current Output Span
0 mA to 31 mA
Initial @ +25°C
±0.1% Span
±0.02% Span
Stability vs. Temperature
Voltage Output
Input Zero
±2 µV/°C (RTI)
±10 µV/°C (RTI)
Output Zero
±25 µV/°C (RTI)
±25 ppm of Reading/°C
Zero and Span Adjustment Range4
±5% of Span
Input Bias Current
=5 nA
Input Resistance
200 M Ω
250 kΩ
Input, 10 MHz Bandwidth
5 µV rms
Rev. 0 | Page 3 of 8
3B40 / 3B41
Output, Ripple and Noise
25 mV peak-to-peak
Bandwidth, -3 dB
10 kHz
Output Rise Time, 10% to 90% Span
55 µs
Common-Mode Voltage (CMV)
Input-to-Output, Continuous
±1500 V peak, maximum
ANSI/IEEE C37.90.1-1989
Common Mode Rejection (CMR)
1 kΩ Source Imbalance, 50/60 Hz
100 dB
85 dB
Input Protection
220 V rms, maximum
ANSI/IEEE C37.90.1-1989
Voltage Output Protection
Continuous Short to Ground
Current Output Protection
130 V rms, continuous
Power Supply Voltages
±15 V dc Supplies
Rated Operation
±(11.5 V dc to 16.5 V dc)
±10 mA
±0.01% span/V
Rated Operation
+12 V dc to +30 V dc
+27 mA @ lout = 20 mA
±0.0002% span/V
3.15" x 3.395" x 0.775"
(80.0 mm x 86.2 mm x 19.7 mm)
+24 V dc Loop Supply
Mechanical Dimensions
Temperature Range
Rated Performance
-25°C to +85°C
-55°C to +85°C
Relative Humidity, 24 hours
0 to 95% @ +60°C non-condensing
RFI Susceptibility
±0.5% Span error @ 400 MHz, 5 Watt, 3 ft
*Specifications same as model 3B40.
For a 0 to 20 mA range, a typical minimum output current is 10 µA.
Includes the combined effects of repeatability, hysteresis, and nonlinearity.
With respect to the voltage output.
A wide range of custom zero suppression and span is available with the 3B40-00 and 3B41-00 models, using the AC1310 ranging card.
+24 V dc loop power is required for driving the current output at loads up to 850Ω. If a current output load of 400Ω or less is applied, +15 V dc is sufficient for loop power. If only
voltage output is used, loop power is not required. Specifications subject to change without notice.
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3B40 / 3B41
Figure 3 3B40 & 3B41 Input Field Connections
Table 1. Pin Function Descriptions—
Pin No.
Figure 4 . Model 3B Series Module, with pin-out assignments.
ESD (electrostatic discharge) sensitive device. Electrostatic charges as high as 4000 V readily accumulate on the human
body and test equipment and can discharge without detection. Although this product features proprietary ESD
protection circuitry, permanent damage may occur on devices subjected to high energy electrostatic discharges.
Therefore, proper ESD precautions are recommended to avoid performance degradation or loss of functionality.
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3B40 / 3B41
Figure 5. Outline Dimensions
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3B40 / 3B41
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3B40 / 3B41
© 2004 Analog Devices, Inc. All rights reserved. Trademarks and
registered trademarks are the property of their respective companies.
Rev. 0 | Page 8 of 8