Analog Devices B22 Datasheet

Isolated High Level Voltage Output

FEATURES

Unity gain single-channel signal conditioning output
module.

Interfaces and filters a +
isolated precision output of +

All 7B22 series modules are mix-and-match and Hot
Swappable.

APPLICATIONS

Industrial signal conditioning
Industrial signal isolation
Industrial signal filtering

PRODUCT OVERVIEW

The 7B Series of signal conditioners feature small size, low cost
and a wide output voltage range for a variety of applications
including process control and factory-floor environments. The
single-channel 7B modules accept inputs from a range of
transducers and are fully rated over the extended -40

o

C industrial temperature range.

+85

All 7B Series modules are rated for a nominal power supply
input of +24 VDC; and, for maximum flexibility, they will
accept supply voltages in the +14 VDC to +35 VDC range. The
input modules, with the exception of the 7B21, provide a high­level output voltage that is factory configured for either the +1
V to +5 V or 0 V to +10 V range. The 7B21 is a unity gain,
isolated input module with an input/output range of +10V.
Output modules are available that provide either isolated
process current or isolated bipolar voltage output. Model 7B39
converts either a +1 V to +5 V input to a 4 to 20 mA output or a
0 V to +10 V input to a 0-20 mA output. The input/output
ranges of the 7B39 are factory configured. The 7B22 is a unity
gain module that provides an isolated +10V output signal. All
modules have a universal pin-out and may be readily hot­swapped under full power without disrupting field wiring.

Each module accepts analog transducer signals and transfers
them to a process control or factory data collection system
without the inherent noise, non-linearity, drift and extraneous
voltages which frequently accompany the signals.

10 V input signal and provides an

10V.

o

C to

7B22

FUNCTIONAL BLOCK DIAGRAM

Figure 1. 7B22 Functional Block Diagram

The modules feature a maximum nonlinearity of +0.02% and
are factory calibrated to guarantee a maximum accuracy
specification of +

The 7B Series offers up to 1500 V rms continuous common
mode voltage isolation and 120 V rms of field wiring input
protection. The power supplies necessary to drive each of the
individual module’s input circuitry are internally isolated,
enabling the 7B Series modules to offer true channel-to-channel
isolation of the input signals.

The modules directly accept analog signals from
thermocouples, RTDs, current loop powered transmitters, and
other process control signals. The 7B Series modules amplify,
linearize, isolate, protect and convert the transducer output
signals to standardized analog inputs for high-level analog I/O
subsystems. The 7B Series Subsystem consists of 19-inch rack­compatible hardware (model AC 1363), with universal
mounting backplane and a family of plug-in (up to 16 per
backplane) input and output signal conditioning modules. Four­, eight-, and sixteen-channel backplanes are available. Each
backplane incorporates screw terminals for easy power
connections and field wiring, and includes a 25-pin D-type
connector for interfacing the high-level single-ended voltage
outputs to the user’s equipment. Gold-plated sockets are
provided on each channel of the backplane to ensure the
reliability of each module’s electrical connection.

0.1%.

Rev. 0

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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
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Tel: [phone]
Fax: [phone] © 2004 Analog Devices, Inc. All rights reserved.

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GENERAL DESCRIPTION

The 7B22 is a unity gain single-channel signal conditioning
output module that interfaces and filters a +
and provides an isolated precision output of +
voltage appears at the 7B Series backplane screw terminal block.
Model 7B22 features a nonlinearity of +
accuracy of +
V rms of galvanic transformer based isolation, output-to-input
and power, the 7B22 offers a common mode rejection (CMR) of
100 dB @ 50/60 Hz to preserve the integrity of low level signals
in noisy environments. The 7B22 is mix-and-match and hot­swappable with other 7B Series modules, so it can be inserted or
removed from any socket in the same backplane without
disturbing system power. Model 7B22 is rated to operate with a
nominal +24 VDC supply.

The input and floating isolated voltage output of Model 7B22
are protected up to +
system is buffered and then used to modulate the amplitude of a
square wave carrier. The modulated signal is transmitted across
the signal transformer and demodulated to retrieve the original
input voltage signal. This voltage is then filtered by a two-pole
low pass 400 Hz filter. The nominal +24 VDC module supply

0.1% maximum (+0.01% typical). Providing 1500

35 VDC. The input signal from the user’s

10 V input signal

10 V. The output

0.02% maximum and an

7B22

voltage powers the input side of the 7B22. The oscillator on the
input side provides the square wave carrier signal used by the
modulator and also drives the power transformer. The signal at
the secondary of the transformer is used in the demodulator
and is also converted to a DC voltage that powers the circuit on
the module’s output. The two-pole output filter and subsequent
buffer ensures that a low noise, low impedance (<1Ω) signal is
available at the isolated output to drive loads down to 5 kΩ.

Figure 2

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7B22 Models Available

Model Input Range Output Range

7B22

7B22 Specifications

(typical @ +23°C ±5°C and Vs = +24 V dc)

Description Model 7B22

Standard Ranges -10 V to +10 V (-14 V to +14 V, maximum)
Custom Ranges Not Available*
Input Range

Initial @ +25°C ±0.01% Span (±0.1% Span, maximum)
Nonlinearity2 ±0.02% Span, maximum
Span vs. Temperature ±35 ppm/°C
Output Offset vs. Temperature ±0.001% Span/°C
Input Bias Current

Power ON
Power OFF

5 MHz Bandwidth 7 mV peak
10 Hz to 100 kHz Bandwidth 3 mV rms

0.1 Hz to 10 Hz Bandwidth 6 µV peak

Bandwidth, -3 dB
Output Rise Time, 10% to 90% Span
Normal Mode Rejection @ 50/60 Hz

Output-to-Input and Power 1500 V rms continuous

Output-to-Input and Power @ 50/60 Hz 100 dB

Input Protection
Input Transient Protection

Output Resistance

Voltage Range, Operating +19 V dc to +29 V dc
Current +20 mA, maximum

-10 V to +10 V -10 V to +10 V

Output Range (RL > 5 kΩ)

-10 V to +10 V

Accuracy1

+3 nA

Input Resistance

2 MΩ
30 kΩ, minimum

Output Noise

400 Hz
1 ms
60 dB

Common-Mode Voltage (CMV)

Common Mode Rejection (CMR)

±35 V dc, continuous
ANSI/IEEE C376.90.1-1989

IEEE-STD 472
IEC 255-4, Class II

< 1 Ω

Power Supply

7B22

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