ANALOG DEVICES 3B42, 3B43, 3B44 Service Manual

Isolated AC Sine Wave Input

3B42 / 3B43 / 3B44

Rev. 0

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FEATURES

AC averaging technique used to rectify, amplify, and filter 50

Hz to 400 Hz sine-wave signals.

Accepts inputs of between 20 mV to 550 V rms to give an rms

output reading.

Module provides simultaneous precision voltage and

current outputs.

Module circuitry can withstand 130v rms at the input screw-

terminals.

All 3B42, 3B43, & 3B44 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 single-

ended 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).

FUNCTIONAL BLOCK DIAGRAM

Figure 1. 3B42, 3B43, & 3B44 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/

o

C (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.

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3B42 / 3B43 / 3B44

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GENERAL DESCRIPTION

The 3B42, 3B43, and 3B44 are single-channel AC sine wave

signal conditioning modules which use an AC averaging

technique to rectify, amplify, and filter 50 Hz to 400 Hz sine-

wave signals ranging from 20 mV to 550 V rms to give an rms

output reading. Simultaneous precision voltage and current

outputs are provided including isolation (+

1500 V peak input-

to-output and power). The 3B42 and 3B43 modules withstand

220 V rms, and Model 3B44 withstands 550 V rms at its input

terminals without damage, thereby shielding computer-side

circuitry from field-side over-voltage conditions. 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 3B42-00, 3B43-00, and 3B44-

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.

Signal isolation by transformer coupling uses 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 signal.

.

.

Figure 2

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3B42 / 3B43 / 3B44

Rev. 0 | Page 3 of 8

3B42, 3B43 and 3B44 Models Available

Model Input Range Output Ranges

1

3B42-00

Externally Programmable

2

0 V to +10 V & 0 mA to 20 mA

3B42-01

0 mV to +50 mV rms 0 V to +10 V & 0 mA to 20 mA

3B42-02

0 mV to +100 mV rms 0 V to +10 V & 0 mA to 20 mA

3B42-Custom

* *

Model Input Range Output Ranges

1

3B43-00

Externally Programmable

2

0 V to +10 V & 0 mA to 20 mA

3B43-01

0 V to +10 V rms 0 V to +10 V & 0 mA to 20 mA

3B43-Custom

* *

Model Input Range Output Ranges

1

3B44-00

Externally Programmable

2

0 V to +10 V & 0 mA to 20 mA

3B44-01

0 V to +150 V rms 0 V to +10 V & 0 mA to 20 mA

3B44-02

0 V to +250 V rms 0 V to +10 V & 0 mA to 20 mA

3B44-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.

3B42, 3B43 and 3B44 Specifications

(typical @ +25°C and ±15 V dc, and +24 V dc Power)

Description Model 3B42 Model 3B43 Model 3B44

Input Ranges

Standard Ranges, 50 Hz to 400 Hz Refer to Model Table Refer to Model Table Refer to Model Table

Custom Ranges, 50 Hz to 400 Hz 20 mV rms to 1 V rms 1 V rms to 50 V rms 50 V rms to 550 V rms

Output Ranges

Voltage (R

L

> 2 kΩ)

0 V to +10 V * *

Current (R

L

+ 0 to 850 Ω)

1

4 mA to 20 mA or 0 mA to 20 mA * *

Accuracy

2

Initial @ +25°C ±0.05% Span * *

Nonlinearity ±0.02% Span * *

Stability vs. Temperature

Voltage Output

Zero ±0.005% of Span/°C * *

Span ±0.005% of Reading/°C * *

Current Output

3

Zero ±25 ppm of Span/°C * *

Span ±25 ppm of Reading/°C * *

Zero and Span Adjustment Range

4

±5% of Span * *

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