ANALOG DEVICES 3B45, 3B46 Service Manual

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Isolated Frequency Input

FEATURES

Interfaces, isolates, & filters frequency inputs.
The 3B45 accepts full-scale inputs from 25 to 1100 Hz
The 3B46 accepts full-scale inputs from 520 Hz to 25 kHz.
Modules provide simultaneous precision voltage and

current outputs.
Modules circuitry can withstand 130v rms at the input screw-

terminals.
All 3B45 & 3B46 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).

3B45 / 3B46

FUNCTIONAL BLOCK DIAGRAM

Figure 1. 3B45 & 3B46 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: [phone]
Fax: [phone] © 2004 Analog Devices, Inc. All rights reserved.

www.analog.com

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GENERAL DESCRIPTION

The 3B45 and 3B46 are single-channel isolated frequency input
moduels which produce simultaneous precision voltage and
current outputs proportional to input frequency. Model 3B45
accepts full-scale inputs ranging from 25 Hz to 1100 Hz, while
Model 3B46 accepts full-scale input from 520 Hz to 25kHz.
Both models enable the user to set the threshold to either 0 V
(for zero crossing signals) or +1.6 V (for positive level signals),
and the hysteresis to either 0 or +
any value within this range using the supplied AC1310 ranging
card. The 3B45 and 3B46 shield their computer side outputs
from damage and loss of signal integrity from field-side over­voltage faults, withstanding up to 220 V rms at their input
terminals. The current output withstands 130 V rms without
damage and interfaces user equipment through screw terminal
connections. In addition, all 3B45 and 3B46 models are plug-in,
mix-and-match and hot-swappable, so each can be inserted or
removed from any socket in the same backplane without
disrupting system power.

3B Series Custom-Ranging Program – Externally­programmable Model 3B45-00 and 3B46-00 enable the user to
configure a special input range by using the supplied plug-on
AC1310 ranging card, which houses user-supplied resistors to
determine hysteresis, zero and span. To facilitate selecting
resistors, a Windows program, 3B-CUSTOM, calculates resistor
values based on the user-desired input/output ranges.

4 V. Hysteresis can be set for

3B45 / 3B46

selected threshold (V
any wave shape that exceed the combined threshold and
hysteresis levels (V
determined by the input frequency. The comparator output is
then transmitted across a proprietary transformer-coupled
isolation barrier. 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.

Setting the threshold value is a simple matter of externally
wiring to the 3B Series backplane screw terminals. The
threshold for measuring a zero-crossing voltage waveform (such
as sine waves) can be set to 0 volts by connecting terminal 3 to
terminal 4. The threshold for a positive level signal (such as a
TTL or pulse train waveform) can be set at +1.6 V by
connecting terminals 1 and 2. Hysteresis for both input signal
types is set at 0 V, but can be changed to +
jumper that is installed on the AC1310 ranging card shipped
with each unit.

) and hysteresis (Vh). Signals of virtually

t

+ Vh) will trigger a comparator at a rate

t

4V by removing the

The 3B45 and 3B46 compare the input signal to the user-

.

.

Figure 2

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3B45 / 3B46

3B45 and 3B46 Models Available

Model Input Range Output Ranges1 Step Response

3B45-00

3B45-01

3B45-02

3B45-Custom

Model Input Range Output Ranges1 Step Response

3B46-00

3B46-01

3B46-02

3B46-03

3B46-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.

Externally Programmable2 0 V to +10 V & 0 mA to 20 mA

0 Hz to 25 Hz 0 V to +10 V & 0 mA to 20 mA 1.6 sec

0 Hz to 300 Hz 0 V to +10 V & 0 mA to 20 mA 0.6 sec

* *

Externally Programmable2 0 V to +10 V & 0 mA to 20 mA

0 kHz to 1.5 kHz 0 V to +10 V & 0 mA to 20 mA 0.07 sec

0 kHz to 3 kHz 0 V to +10 V & 0 mA to 20 mA 0.03 sec

0 kHz to 25 kHz 0 V to +10 V & 0 mA to 20 mA 0.03 sec

* *

3B45 and 3B46 Specifications

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

Description Model 3B45 Model 3B46

Input Ranges

Standard Ranges Refer to Model Table Refer to Model Table

Custom Ranges 25 Hz span, min : 1100 Hz span, max. 520 Hz span, min : 25 kHz span, max.

Output Ranges

Voltage (RL > 2 kΩ)

Current (RL + 0 to 850 Ω)1

Maximum Current Output Span 0 mA to 31 mA *

Initial @ +25°C ±0.1% Span *

Nonlinearity ±0.02% Span *

Voltage Output

Output Zero ±500 µV/°C *

Span ±50 ppm of Reading/°C *

Current Output3

Zero ±25 ppm of Span/°C *

Span ±25 ppm of Reading/°C *

Zero and Span Adjustment Range4

Input Bias Current +3 nA *

Small Signal, V

< 4 V pk-pk

in

0 V to +10 V *

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

2

Accuracy

Stability vs. Temperature

Input Resistance

±5% of Span *

15 MΩ

*

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3B45 / 3B46

Large Signal, Vin > 4 V pk-pk

Output, 100 kHz Bandwidth 75 µV rms *

Output, Ripple 10 mV rms @ 10% F

Output Step Response Time

Common-Mode Voltage (CMV)

Input-to-Output, Continuous ±1500 V peak, maximum *

Transient ANSI/IEEE C37.90.1-1989 *

Common-Mode Rejection (CMR)

1 kΩ Source Imbalance, 50/60 Hz

Continuous 220 V rms maximum *

Transient ANSI/IEEE C37.90.1-1989 *

Voltage Output Protection

Current Output Protection

Power Supply Voltages5

±15 V dc Supplies

Rated Operation ±(11.5 V dc to 16.5 V dc) *

Current ±16 mA ±19 mA

Sensitivity ±0.01% span/V *

+24 V dc Loop Supply

Rated Operation +13.5 V dc to +30 V dc *

Current +27 mA @ l

Sensitivity ±0.0002% span/V *

Mechanical Dimensions

Temperature Range

Rated Performance -25°C to +85°C *

Storage -55°C to +85°C *

Relative Humidity 0 to 95% @ +60°C noncondensing *

RFI Susceptibility ±0.5% Span error @ 400 MHz, 5

* Specifications same as model 3B45.

1

For a 0 to 20 mA range, a typical minimum output current is 10 µA.

2

Includes the combined effects of repeatability, hysteresis, and nonlinearity.

3

With respect to the voltage output.

4

A wide range of custom zero suppression and span is available with the 3B45-00 and 3B46-00 models, using the AC1310 ranging card.

5

+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.

82 kΩ

Noise

, maximum *

span

Refer to Model Table *

100 dB *

Input Protection

Continuous Short to Ground *

130 V rms, continuous *

= 20 mA *

out

3.15" x 3.395" x 0.775"
(80.0 mm x 86.2 mm x 19.7 mm)

Environmental

Watt, 3 ft

*

*

*

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PIN CONFIGURATIONS AND FUNCTIONAL DESCRIPTIONS

Figure 3 3B45 & 3B46 Input Field Connections

Table 1. Pin Function Descriptions—

Pin No. Description

1 PROT PULL-UP
2 HI
3 LO
4 GND

Figure 4 . Model 3B Series Module, with pin-out assignments.

3B45 / 3B46

ESD CAUTION

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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OUTLINE DIMENSIONS

3B45 / 3B46

Figure 5. Outline Dimensions

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NOTES

3B45 / 3B46

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NOTES

3B45 / 3B46

© 2004 Analog Devices, Inc. All rights reserved. Trademarks and
registered trademarks are the property of their respective companies.

D05161-0-9/04(0)

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