ANALOG DEVICES 3B16 Service Manual
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Narrow Bandwidth Strain Gage Input
FEATURES
Interfaces, amplifies, & filters signals from 4-arm full-bridge
strain-gage bridges with a resistance from 300Ω to 1 kΩ.
Module provides a constant +10V bridge excitation voltage.
Module provides simultaneous precision voltage and
current outputs.
Module circuitry can withstand 130v rms at the input screw-
terminals
All 3B16 series modules are mix-and-match and Hot
Swappable
APPLICATIONS
Industrial signal conditioning
Industrial signal isolation
Industrial signal filtering
PRODUCT OVERVIEW
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
modules.
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).
3B16
FUNCTIONAL BLOCK DIAGRAM
Figure 1. 3B16 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 +
modules), and feature two high-level analog outputs that are
compatible with most process instrumentation. The isolated
input modules also provide +
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.
0.1%, low drift of +1 uV/ oC (low-level input
1500 V peak isolation.
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.
www.analog.com
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GENERAL DESCRIPTION
The 3B16 is a single-channel signal conditioning module which
interfaces, amplifies, and filters signals from 4-arm full-bridge
strain-gage bridges with a resistance from 300W to 1kW. The
module provides a constant +10V bridge excitation voltage and
provides simultaneous precision voltage and current outputs.
The user-configurable Model 3B16-00 can be applied in
applications involving large tare weights which must be
compensated with zero suppression. The 3B16 protects the
computer side from damage due to field-side over-voltage faults
up to 130V rms. In addition, the current output withstands
130V rms without damage and interfaces user equipment
through screw terminals located on the 3B Series backplane.
The 3B16 is a plug-in, mix-and-match, hot-swappable module
which is easily field calibrated via front-panel zero and span
adjustments for both voltage and current outputs.
3B Series Custom-Ranging Program – Externallyprogrammable Model 3B16-00, enables the user to configure a
special input range, including tare weight suppression, by using
the optional plug-on AC1310 ranging card, which houses usersupplied resistors to determine zero and span. To facilitate
.
3B16
selecting resistors, a Windows program, 3B-CUSTOM,
calculates resistor values based on the user-desired input/output
ranges.
A chopper-stabilized low-drift (+
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 (Model 3B16CUSTOM) or can be externally programmed (Model 3B16-00)
via user supplied resistors inserted in the optional AC1310 plugon ranging card. Internal low-pass filtering with a 3 Hz cutoff
(-3dB) two-pole Butterworth filter enhances a 60 dB normalmode rejection at 50/60 Hz, enabling accurate measurement of
small signals in high electrical noise.
1uV/oC) input amplifier
Figure 2
.
Rev. 0 | Page 2 of 8
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3B16 Models Available
Model Input
3B16-00
3B16-01
3B16-Custom
1
Output current range may be user programmed to 4 mA to 20 mA using jumper supplied.
2
Requires AC1310 ranging card.
* Custom Input/Output ranges are available. Refer to configuration guide.
Bridge
Full Bridge Externally
Full Bridge -30 mV to +30 mV +10 V 3 mV/V -10 V to +10 V &
Full Bridge * +10 V * *
3B16 Specifications
(typical @ +25°C and ±15 V dc, and +24 V dc Power)
Description Model 3B16
Standard Range ±30 mV (3 mV/V sensitivity @ V
Custom Ranges ±5 mV to ±500 mV
Voltage (RL > 2 KΩ)
Current (RL = 0 to 850Ω)1
Maximum Current Output Span 0 mA to 31 mA
Initial @ +25°C ±0.1% Span
2
Nonlinearity
Voltage Output
Zero ±3 µV/°C (RTI)
Span ±25 ppm of Reading/°C
Current Output
Zero ±25 ppm of Span/°C
Span ±25 ppm of Reading/°C
±0.01% Span
3
Input
Range
Programmable2
Excitation Sensitivity Output
+10 V Externally
Programmable2
Input Range
Output Range
-10 V to +10 V
4 mA to 20 mA or 0 mA to 20 mA
Accuracy2
Stability vs. Temperature
= +10V)
exc
3B16
Ranges1
-10 V to +10 V &
0 mA to 20 mA
0 mA to 20 mA
Bridge Excitation
Voltage +10 V
Voltage, tolerance ±2%
Voltage vs. Temperature ±0.0015%/°C
Bridge Resistance Range
Rev. 0 | Page 3 of 8
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