Converts a High-level analog input voltage into a floating
proportional output current.
Output current of 4 to 20 mA or 0 to 20 mA across loads from
0Ω to 750Ω.
High Accuracy of +0.05%, Low nonlinearity of +0.02%.
Module circuitry can withstand 240v rms at the input screw-
All 5B39 series modules are mix-and-match and Hot
Industrial signal conditioning
Industrial signal isolation
Industrial signal filtering
The 5B Series represents an innovative generation of low cost,
high performance plug-in signal conditioners. Designed for
industrial applications, these modules incorporate highly
reliable transformer-based isolation and automated surface-
mount manufacturing technology. They are compact,
economical components whose performance exceeds that
available from more expensive devices. Combining 1500 V rms
continuous isolation, +0.05% calibrated accuracy, small size and
low cost, the 5B Series is an attractive alternative to expensive
signal conditioners and in-house designs
All modules are potted and identical in pin-out and size (2.27” x
2.32” x 0.595”). They can be mixed and matched, permitting
users to address their exact needs, and may be “hot swapped
without disturbing field wiring or power. The isolated input
modules provide 0 to +5V or +5V outputs and accept J, K, T, E,
R, S, N, or B type thermocouples.
These modules feature complete signal conditioning functions
including 240 V rms input protection, filtering, chopper
stabilized low drift +1 uV/oC amplification, 1500 V rms
isolation, and sensor excitation when required.
All modules feature excellent common mode rejection and
meet industrial transient surge withstand specifications.
FUNCTIONAL BLOCK DIAGRAM
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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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registered trademarks are the property of their respective companies.
Isolated Current Output
Figure 1. 5B39 Functional Block Diagram
There are also a number of backplanes and mounting sockets
which provide a complete signal conditioning solution for end
users. Each backplane incorporates screw terminals for field
wiring inputs and outputs and cold junction sensors for
These signal conditioners are designed to provide an easy and
convenient solution to signal conditioning problems of both
designers and end users in measurement and control
applications. Typical uses include microcomputer-based
measurement systems, standard data acquisition systems,
programmable controllers, analog recorders and dedicated
control systems. The 5 B series modules are ideally suited to
applications where monitoring and control of temperature,
pressure, flow, rotation and other analog signals are required.
The 5B Series modules and backplanes are approved by Factory
Mutual (FM) and the 5B Series modules are approved by the
Canadian Standards Association (CSA) for use in Class 1,
Division 2, Groups A, B, C, and D locations. These approvals
certify that the 5B Series is suitable for use in locations where a
hazardous concentration of flammable gas may exist only under
fault conditions of operation. Equipment of this category is
called “nonincendive” and they need no special enclosures or
other physical safeguards.
The 5B series modules and backplanes have been tested and
passed the stringent heavy industrial requirements of the
European Union’s electromagnetic compatibility (ENC)
directive – EN50082-1 and EN50081-2. When used according
to installation directions (refer to 5B series User Manual), any
errors caused by EMI/RFI interference will be less than 0.1% of
the full scale 5B measurement range for field strengths up to 10
V/M and frequencies up to 1 GHz.
One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
Fax: 781.326.8703 © 2004 Analog Devices, Inc. All rights reserved.
The 5B39 is a single-channel signal conditioning module that
converts a high-level analog input voltage into a floating,
isolated proportional output current of 4 to 20 mA or 0 to 20
mA across loads from 0Ω to 750Ω. The module provides high
accuracy of +0.05%, low nonlinearity of +0.02%, and the
protection of 1500V rms isolation between output-to-input and
output-to power supply. The input common must be held to
within +1V of power common.
Signal isolation by transformer coupling uses a proprietary
modulation technique for linear, stable and reliable
performance. A demodulator on the output side of the signal
transformer recovers the original signal, which is then filtered
and converted to an accurate current output by a current (V-to-
I) converter output stage. Output protection enables the 5B39 to
withstand accidental connection to 240V rms power lines
without damage, while isolating computer-side circuitry. In
addition, the 5B39 is mix-and-match and hot-swappable with
all 5B Series modules, so can be inserted or removed from any
socket in the same backplane without disrupting system power.
Track-and-Hold for DAC Applications – In applications where
a single system digital-to-analog converter (DAC) is used to
drive a number of current output channels, the 5B39 includes a
track-and-hold input circuit. Selected by a high Write Enable
input, the hold mode exhibits an output droop rate of 80 uA/s.
This corresponds to a refresh interval of 25 ms for 0.01% span
droop. On power-up, the module’s output remains at 0 mA for
about 100 ms to allow the user to initialize the track-and-hold
In applications using one DAC per channel, where the track-
and-hold feature of the 5B39 is not used, the Write Enable input
should be set to low by grounding it to power common, as on
the 5B01 and 5B08 backplanes. The module current output will
then track its input signal.
Generating A Voltage Output Signal – The 0 to 20 mA output
of the 5B39-04 and the 5B39-03, can produce a 0 to +10V
output by connecting a 500Ω conversion resistor across the
modules’ output terminals,. This approach should be used with
caution because the output lacks the low impedance of a true
voltage source. This means that the tolerance and size of the
load impedance relative to the conversion resistor can introduce
significant error. For example, a load impedance < 500kΩ would
contribute <0.1% error.
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