Analog Devices B37 Datasheet

Isolated Thermocouple Input

FEATURES

Interfaces, amplifies and filters J, K, T, E, R, S, B, N, and C-type
Thermocouple.

Generates an isolated and protected precision output of 0 to
+5V.

Module circuitry can withstand 240v rms at the input screw­terminals.

All 5B37 series modules are mix-and-match and Hot
Swappable.

APPLICATIONS

Industrial signal conditioning
Industrial signal isolation
Industrial signal filtering

PRODUCT OVERVIEW

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 surface­mount 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

5B37

Figure 1. 5B37 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
thermocouple applications.

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, f low, 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.

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

GENERAL DESCRIPTION

The 5B37 is a single-channel signal conditioning module that
interfaces, amplifies and filters J, K, T, E, R, S, B, N, and C-type
thermocouple and provides an isolated and protected precision
output of 0 to +5V.

Accurate and System-Ready – Internal cold-junction
compensation largely corrects errors arising from parasitic
thermocouples formed by thermocouple connection to the
input screw terminals, providing an accuracy of +0.25oC @

25oC ambient temperature. The module generates a

+
predictable upscale signal to indicate an open thermocouple, for
a downscale response, connect a 47MΩ, 0.25 W resistor across
screw terminals 1 and 3.

The 5B37 protects the computer side from damage due to field­side over-voltage faults. All models withstand 240V rms at their
input terminals without damage, thereby shielding computer­side circuitry from field-side over-voltage conditions. Further,
the 5B37 is mix-and-match and hot-swappable with other 5B
Series modules, so can be inserted or removed from any socket
in the same backplane without disrupting system power.

A chopper-stabilized input amplifier provides low drift and
stable gain. At the amplifier input a stable, laser-trimmed zero­scale input voltage is subtracted from the input signal to set the
zero-scale value. For user convenience, the zero can be

.

5B37

optionally factory-set to meet custom needs. This allows
suppression of a zero-scale input value many times larger than
the total span for precise expanded-scale measurements.

Internal multi-pole low-pass filtering with a four Hz cutoff (-3
dB) provides 60 dB of normal-mode rejection (noise on signal)
and enhancement of common-mode rejection (noise on signal
return) at 60 Hz, enabling accurate measurement of small
signals in high electrical noise.

Signal isolation by transformer coupling uses a proprietary
modulation technique for linear, stable and reliable
performance. The differential input circuit on the field side is
fully floating, eliminating the need for any input grounding. 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 signal. The
output common must be kept within 3 V of power common.

A series output switch eliminates the need for external
multiplexing in many applications. The switch is turned on by
an active-low enable input. If the switch is to be on at all times,
the enable-input should be grounded to power common as it is
on the 5B01 and 5B08 backplanes..

.

Figure 2

Rev. 0 | Page 2 of 8

5B37 Models Available

Model Input Type Input Range Output Range

5B37-J-01
5B37-K-02
5B37-T-03
5B37-E-04
5B37-R-05
5B37-S-05
5B37-B-06
5B37-N-08

5B37-Custom

* Custom Input/Output ranges are available. Refer to conf ig ur ation guide.

5B37 Specifications
(typical @ +25°C and Vs = +5 V dc)

Type J -100°C to +760°C (-148°F to +1400°F) 0 V to +5 V
Type K -100°C to +1350°C (-148°F to +2462°F) 0 V to +5 V
Type T -100°C to +400°C (-148°F to +752°F) 0 V to +5 V

Type E 0°C to +900°C (+32°F to +1652°F) 0 V to +5 V
Type R 0°C to +1750°C (+32°F to +3182°F) 0 V to +5 V
Type S 0°C to +1750°C (+32°F to +3182°F) 0 V to +5 V
Type B 0°C to +1800°C (+32°F to +3272°F) 0 V to +5 V
Type N 0°C to +1300°C (+32°F to +2372°F) 0 V to +5 V

Type J, K, T, E, R,

S, B, N, C

5B37

* *

Description Model 5B37

Input Ranges

Standard Ranges Refer to Model Table
Custom Ranges ±5 mV to ±500 mV

Output Range (RL > 50 kΩ)4

Initial @ +25°C ±0.05% Span ±10 µV RTI ±0.05% of Vz1 +CJC Sensor Error
Nonlinearity ±0.02% Span
Input Offset vs. Temperature ±1 µV/°C
Output Offset vs. Temperature ±20 µV/°C
Gain vs. Temperature ±0.0025% of Reading/°C

3

Initial Accuracy @ +25°C
Accuracy, +5°C to +45°C ±0.5°C (±0.0125°C/°C)
Input Bias Current

Power On
Power Off
Overload

Input, 0.1 Hz to 10 Hz Bandwidth 0.2 µV rms
Output, 100 kHz Bandwidth 200 µV rms

±0.25°C (±0.75°C, maximum)

-5 V to +5 V or 0 to +5 V

Accuracy2

Cold Junction Compensation

-25 nA

Input Resistance

5 MΩ
40 kΩ
40 kΩ

Noise

Rev. 0 | Page 3 of 8