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~ ANALOG
-.. DEVICES
FEATURES
Low Cost
Compatible with Standard 4-20 mA Loops
Broad Family
Direct Sensor Interface to Thermocouples,
RTDs and AD590s
Loop-Powered Isolator
High Performance
RFllmmunity
APPLICATIONS
Monitoring and Control
Factory Automation
Energy Management
GENERAL DESCRIPTION
The 2B Series is a family ofIow cost, two-wire transmitters.
These high performance transmitters were designed for indus-
trial environments. They provide input protection, filtering and
amplification, as well as isolation and cold junction compensa-
tion for thermocouples, and excitation and linearization for
RTDs. They are true two-wire transmitters using the same
wiring for power and output. The load resistance is connected
in series with a dc power supply and the current drawn from the
supply is the 4-20 mA output signal.
2B24
2B52/2B53
2B57A- 1
2B58
2B59
The 2B Series Transmitters
Loop-Powered Isolator
Thermocouple Temperature Transmitters
AD590 Temperature Transmitter
Linearized RTD Temperature Transmitter
Low Cost RTD Temperature Transmitter
APPLICATIONS
The 2B Series two-wire transmitters provide low cost, accurate
and reliable measurement and transmission in a wide variety of
industrial applications. These transmitters are especially useful
in process control and monitoring applications where the pro-
cess sensor is located remotely from the receiver. They may then
be used to provide signal conditioning near the point of mea-
surement and transmit an accurate, noise immune, high level
current signal over conventional copper wires resulting in im-
proved performance and reduced cost.
REV. A
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
which may result from its use. No license is granted by implication or
otherwise under any patent or patent rights of Analog Devices.
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LowCost
Two-WireTransmitters
28Series I
USER BENEFITS
Two-wire transmitters process information in the form of a
4-20 mA current. In this form, the analog signal information is
unaffected by noise-induced voltages, by voltage drops or by
contact potentials, and it may be transmitted 2,000 feet
(610 meters) or more without degradation. Since the minimum
output current is 4 mA, there is a clear distinction between a
zero measurement and an open-circuit transmission line.
Low Cost: Two-wire transmitters minimize total system instal-
lation cost. Inexpensive, unshielded copper wire, usually in the
form of a twisted wire pair, may be used for signal transmission.
DC power is furnished to the transmitter over the same two-wire
line by a power supply at the receiving end. Since the transmit-
ter may be close to the sensor, long runs of expensive shielded
sensor wire are urmecessary. In addition, a number of wire pairs
may be bundled together in cables without cause for concern
about crosstalk between channels.
High Noise Rejection: Internal filtering circuitry in the trans-
mitter eliminates errors caused by RFI/EMI and line frequency
pickup.
High Isolation (2B24 and 2B52): Input to output isolation
eliminatesground loop errors in installations requiring grounded
sensors and permits direct transmission of signal to receiver
where high common-mode voltages may exist.
Environmental Protection: High quality electronic compo-
nents, protective coating and mechanical packaging combine to
provide a high degree of reliability and protection against tem-
perature, humidity and noise interference.
One TechnologyWay, P.O. Box9106, Norwood, MA02062-9106. U.S.A.
Tel: 617/329-4700 World Wide Web Site: http://www.analog.com
Fax: 617/326-8703 @Analog Devices. Inc., 1997
OBSOLETE
