Impulse SCM5B38 User Manual

SCM5B38

Strain Gage Input Modules, Wide Bandwidth

Description

Each SCM5B38 Strain Gage input module provides a single channel of Strain

Gage input which is filtered, isolated, amplified, and converted to a high level

analog voltage output (Figure 1). This voltage output is logic switch controlled,

which allows these modules to share a common analog bus without the

requirement of external multiplexers.

The SCM5B modules are designed with a completely isolated computer side

circuit which can be floated to ±50V from Power Common, pin 16. This complete

isolation means that no connection is required between I/O Common and

Power Common for proper operation of the output switch. If desired, the output

switch can be turned on continuously by simply connecting pin 22, the Read-

Enable pin, to I/O Common, pin 19.

The SCM5B38 can interface to full-bridge or half-bridge transducers with a

nominal resistance of 100

resistors (to ±1mV at +10V excitation) allows use of low cost half-bridge or

quarter-bridge transducers (Figures 2, 3, 4). The 10kHz bandwidth allows

measurement of high speed processes such as vibration analysis.

Strain Gage excitation is provided from the module by a very stable 10V

or 3.333V source. The excitation supply is fully isolated, allowing the amplifier

inputs to operate over the full range of the excitation voltage. This feature

offers significant flexibility in real world applications. Full scale sensitivities of

2mV/V, 3mV/V or 10mV/V are offered as standard. With 10V excitation, this

results in ±20mV, ±30mV or ±100mV full scale input range producing ± 5V full

scale output.

The input signal is processed through a pre-amplifier on the field side of the

isolation barrier. This pre-amplifier has a gain-bandwidth product of 5MHz and

is bandwidth limited to 10kHz. After amplification, the input signal is chopped by

a proprietary chopper circuit. Isolation is provided by transformer coupling,

Ω to 10kΩ. A matched pair of bridge-completion

Isolated Analog Signal Conditioning Products

SCM5B

▲

Features

 Interfaces to 100Ω Thru 10kΩ, Full-Bridge,

Half-Bridge, or Quarter-Bridge Strain Gages

 High Level Voltage Output

 1500Vrms Transformer Isolation

 ANSI/IEEE C37.90.1 Transient Protection

 Input Protected to 240VAC Continuous

 Fully Isolated Excitation Supply

 100dB CMR

 10kHz Signal Bandwidth

 ±0.03% Accuracy

 ±0.01% Linearity

 ±1µV/°C Drift

 CSA Certified, FM Approved, CE and ATEX

Compliant

 Mix and Match SCM5B Types on Backpanel

again using a proprietary technique to suppress transmission of common mode

spikes or surges. The module is powered from +5VDC, ±5%.

Special input circuits on the SCM5B38 module provide protection of the signal

inputs and the isolated excitation supply up to 240VAC.

Figure 1: SCM5B38 Block Diagram

For information call 800-444-7644

Isolated Analog Signal Conditioning Products

SCM5B

Specifications

Typical at TA=+25°C and +5V power

Full Bridge Half Bridge

Module SCM5B38-01,-02,-05,-06,-07 SCM5B38-03,-04

Input Range ±10mV to ±100mV

Input Bias Current ±0.3nA *

Input Resistance

Normal 50MΩ * Power Off 40kΩ * Overload 40kΩ *

Signal Input Protection

Continuous 240Vrms max *

Transient ANSI/IEEE C37.90.1 *

Excitation Output

Load Resistance 300Ω to 10kΩ *

Excitation Output

Load Resistance 100Ω to 10kΩ *

Excitation Load Regulation ±5ppm/mA *

Excitation Stability ±15ppm/°C *

Half Bridge Voltage Level

Isolated Excitation Protection

Continuous 240Vrms max *

Transient ANSI/IEEE C37.90.1 *

CMV, Input to Output

Continuous 1500Vrms max *

Transient ANSI/IEEE C37.90.1 *

CMR (50 or 60Hz) 100dB *

NMR (3dB at 10kHz) 120dB per Decade above 10kHz *

Accuracy

Nonlinearity ±0.01% Span *

Stability

Input Offset ±1µV/°C *

Output Offset ±40µV/°C *

Gain ±25ppm of Reading/°C *

Noise

Input, 0.1 to 10Hz 0.4µVrms 2µVrms

Output, 100kHz 10mVp-p *

Bandwidth, 3dB 10kHz *

Rise Time, 10 to 90% Span 35µs *

Setting Time, to 0.1% 250µs *

Output Range See Ordering Information *

Output Resistance 50Ω *

Output Protection Continuous Short to Ground *

Output Selection Time 6µs at C

(to ±1mV of V

Output Current Limit ±8mA *

Output Enable Control

Max Logic 0 +0.8V *

Min Logic 1 +2.4V *

Max Logic 1 +36V *

Input Current 0,1 0.5µA *

Power Supply Voltage +5VDC ±5% *

Power Supply Current 170mA Full Exc. Load, *

Power Supply Sensitivity ±2µV/% RTI

Mechanical Dimensions 2.28" x 2.26" x 0.60" *

(h)(w)(d) (58mm x 57mm x 15mm)

Environmental

Operating Temperature Range 40°C to +85°C *

ATEX Group II, Category 3 20°C to +40°C *

Storage Temperature Range 40°C to +85°C *

Relative Humidity 0 to 95% Noncondensing *

Emissions EN61000-6-4 ISM, Group 1 *

Radiated, Conducted Class A *

Immunity EN61000-6-2 ISM, Group 1 *

R F Performance A ±0.5% Span Error *

ESD, EFT, Surge, Voltage Dips Performance B *

(-02, -04, -05, -07)

(-01, -03, -06)

(2)

)

OUT

(-04)

(-03)

+10V ±3mV *

+3.333V ±2mV *

NA +5V ±1mV

NA +1.667V ±1mV

±0.03% Span *

= 0 to 2000pF *

load

70mA No Exc. Load

(3)

Ordering Information

Model

(10kHz) Type

Bridge

Input Range

Excitation

Sens.

Output

Range

SCM5B38-01 Full -10mV to +10mV +3.333V 3mV/V 1, 2

Input

SCM5B38-02 Full

SCM5B38-03 Half

SCM5B38-04 Half

SCM5B38-05 Full

SCM5B38-06 Full

SCM5B38-07 Full

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Output Ranges Available

-30mV to +30mV +10.0V 3mV/V 1, 2

-10mV to +10mV +3.333V 3mV/V 1, 2

-30mV to +30mV +10.0V 3mV/V 1, 2

-20mV to +20mV +10.0V 2mV/V 1, 2

-33.3mV to +33.3mV +3.333V 10mV/V 1, 2

-100mV to +100mV +10.0V 10mV/V 1, 2

Output Range Part No. Suffix Example

1. -5V to +5V NONE SCM5B38-01

2. -10V to +10V D SCM5B38-01D

Figure 2: Full Bridge Connection

Figure 3: Half Bridge Connection

Figure 4: Quarter Bridge Connection

NOTES:

* Same as 01, 02, 05, 06, 07 modules.

(1) Strain element. (2) Includes nonlinearity, hysteresis and repeatability. (3) Referenced

to input.

SCM5B

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