AD 3B31-03

Isolated Voltage Input
3B30 / 3B31
Interfaces, amplifies, & filtersanalog input voltages.
Narrow-bandwidth (3Hz) single-channel single
Module provides simultaneous precision voltage and
current outputs.
Module circuitry can withstand 220v rms at the input screwterminals
Current output withstands 130V rms without damage.
All 3B30 & 3B31 series modules are mix-and-match and Hot
Figure 1. 3B30 & 3B31 Functional Block Diagram
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).
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.
3B30 / 3B31
set the zero-scale value. Zero suppression can exceed 100% of
the input range. This is ideal fro expanded-scale applications
requiring high-resolution measurement of a selected portion of
an input signal. For users convenience, the zero and span can be
factory configured to meet custom range needs (Models 3B30CUSTOM and 3B31-CUSTOM) or can be externally
programmed (Models 3B30-00 and 3B31-00) via user supplied
resistors inserted in the optional AC1310 plug-on ranging card.
Internal low-pass filtering with a 4Hz cutoff (-3dB) two-pole
Butterworth filter enhances both 60dB normal-mode and 160
dB common-mode rejection at 50/60 Hz, enabling accurate
measurement of small signals in high electrical noise.
The 3B30 & 3B31 are narrow-bandwidth (3Hz) 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 (+1500V 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 220V 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-andmatch, hot-swappable module is easily field calibrated via frontpanel zero and span adjustments for both voltage and current
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 Models 3B30-00 and 3B31-00, 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
assures stable long-term stability. At the amplifier input, a stable,
zero-scale input voltage is subtracted from the input signal to
Figure 2
Rev. 0 | Page 2 of 8
3B30 / 3B31
3B30 and 3B31 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
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
-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.
3B30 and 3B31 Specifications
(typical @ +25°C and ±15 V dc, and +24 V dc Power)
Model 3B30
Model 3B31
Input Range
Standard Ranges
±10 mV to ±100 mV
±1 V to ±10 V
Custom Ranges
±5 mV to ±500 mV
±0.5 V to ±20 V
Output Range
Voltage (RL > 2 KΩ)
-10 V to +10 V
Current (RL = 0 to 850Ω)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
±0.01% Span
Stability vs. Temperature
Voltage Output
Current Output
±1 µV/°C (RTI)
±25 ppm of Span/°C
±25 ppm of Reading/°C
±25 ppm of Span/°C
±25 ppm of Reading/°C
±5% of Span
Zero and Span Adjustment Range
Rev. 0 | Page 3 of 8
3B30 / 3B31
Input Bias Current
+3 nA
Input Resistance
15 MΩ
650 kΩ
Input, 0.1 Hz to 10 Hz Bandwidth
0.2 µV rms
Output, 100 kHz Bandwidth
50 µV rms
Bandwidth, -3 dB
3 Hz
Output Rise Time, 10% to 90% Span
200 ms
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
160 dB
160 dB
150 dB (3B31-02); 145 dB (3B31-03)
Normal Mode Rejection, 50/60 Hz
60 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 3B30.
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 3B30-00 and 3B31-00 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.
Rev. 0 | Page 4 of 8
3B30 / 3B31
Figure 3 3B30 & 3B31Input 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.
Rev. 0 | Page 5 of 8
3B30 / 3B31
Figure 5. Outline Dimensions
Rev. 0 | Page 6 of 8
3B30 / 3B31
Rev. 0 | Page 7 of 8
3B30 / 3B31
© 2004 Analog Devices, Inc. All rights reserved. Trademarks and
registered trademarks are the property of their respective companies.
Rev. 0 | Page 8 of 8