Analog Devices B33 Datasheet

Isolated, Voltage or Current Input

FEATURES

Interfaces, amplifies, and filters unipolar voltage inputs.
Module provides a precision output of either +1 V to +5 V or

0 V to +10 V, linear with temperature.
Module features a nonlinearity of +

accuracy of +
All 7B33 series modules are mix-and-match and Hot

Swappable.

0.1% maximum (+0.01% typical).

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. All 7B Series modules are

+85
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 high-level 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 pin­out and may be readily hot-swapped 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.

0.02% maximum and an

o

C to

7B33

FUNCTIONAL BLOCK DIAGRAM

Figure 1. 7B33 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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GENERAL DESCRIPTION

The 7B33 is a single-channel signal conditioning module that
interfaces, amplifies and filters unipolar voltage inputs and
provides a protected precision output of either +1 V to +5V or 0
V to +10 V. To measure a process current input, a plug-on 250Ω
current sensing resistor, Model AC1391, may be installed
directly on the 7B backplane, using available pin sockets. The
external current sense resistor allows the current loop to be
maintained even when the module is removed from the
backplane. Model 7B33 features a nonlinearity of +
maximum and an accuracy of +
typical). To accurately measure low level signals in electrically
noisy environments, 1500 V rms of galvanic transformer-based
isolation with a common mode rejection (CMR) of 105 dB @
50/60 Hz is provided. Rated to operate with a nominal +24
VDC supply, Model 7B33 is mix-and-match and hot-swappable
with other 7B Series input modules, so it can be inserted or
removed from any socket in the same backplane without
disturbing system power.

0.1% maximum (+0.01%

0.02%

7B33

Amplitude modulation is used to implement transformer
isolation (1500 V rms input-to-output and power). Isolated
front-end circuitry power is supplied by a DC/DC converter.
The output section contains a two-pole low pass filter (-3 dB @
100 Hz), a buffer amplifier and a power oscillator. The two-pole
output filter and subsequent buffer ensures that a low noise, low
impedance (<1Ω) signal is available at the output to drive loads
of 2 kΩ minimum.

The two input pins of Model 7B33 are fully protected up to 120
V rms line voltage. A one-pole 100 Hz filter preconditions the
input signal prior to amplification by a low drift input amplifier.

Figure 2

Rev. 0 | Page 2 of 8

7B33 Models Available

Model Input Range Output Range

7B33-01-1
7B33-01-2
7B33-01-1
7B33-01-2

7B33 Specifications

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

Description Model 7B33

Standard Ranges +1 V to +5 V; 0 V to +5 V (Refer to Model Table)
Custom Ranges Not Available*
Output Range Options (RL > 2 kΩ)

Initial @ +25°C ±0.01% Span (±0.1% Span, maximum)
Nonlinearity3 ±0.02% Span, maximum
Input Offset vs. Temperature N/A4
Span vs. Temperature ±15 ppm/°C
Output Offset vs. Temperature ±0.003% span/°C
Input Bias Current ±0.1 nA

Power ON
Power OFF

5 MHz Bandwidth 6 mV peak
10 Hz to 100 kHz Bandwidth 0.4 mV rms

0.1 Hz to 10 Hz Bandwidth 4 µV peak
Bandwidth, -3 dB 100 Hz
Output Rise Time, 10% to 90% Span 10 ms
Common-Mode Voltage (CMV)
Input-to-Output and Power 1500 V rms continuous

Input-to-Output and Power @ 50/60 Hz 105 dB
Input Protection 120 V rms, continuous

+1 V to +5 V +1 V to +5 V
0 V to +5 V 0 V to +10 V
+4 mA to +20 mA
0 mA to +20 mA1 0 V to +10 V

Common Mode Rejection (CMR)

1

+1 V to +5 V

Input Range1

+1 V to +5 V or 0 V to +10 V

Accuracy1

Input Resistance

2 MΩ
30 kΩ, minimum

Output Noise

7B33

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