Impulse SCM7B32, SCM7B33 User Manual

Isolated Process Control Signal Conditioning Products

SCM7B32/33

Isolated Process Current/Voltage Input Modules

Description

The SCM7B32 current input modules accept input signals in the 4-20mA or 0-

20mA ranges from the field and provide a high level output to the process control

system (Figure 1). Current to voltage conversion occurs internal to the module,

which is factory calibrated to ensure the highest accuracy.

SCM7B33 voltage input modules accept input signals in the +1V to +5V or 0 to

+5V ranges from the field and provide a high level output to the process

control system. As an alternative, the SCM7B33 can be used with an external

250Ω resistor (Dataforth SCM7BXR1 or equivalent), to accept input signals in

the 4-20mA or 0-20mA ranges. Using the external sense resistor allows the

module to be removed without disrupting the current loop. All SCM7B33s are

shipped with a SCM7BXR1 resistor.

These modules incorporate a five-pole filtering approach to maximize both time

and frequency response by taking advantage of both Thomson (Bessel) and

Butterworth characteristics. One pole of the filter is on the field side of the isolation

barrier; four are on the process control system side.

After the initial field-side filtering (conversion-SCM7B32 only), the input signal

is chopped by a proprietary chopper circuit and transferred across the

transformer isolation barrier, suppressing transmission of common mode spikes

and surges. The signal is then reconstructed and filtered for process control

system output.

Modules accept a wide 14 - 35VDC power supply range (+24VDC nominal).

Their compact packages (2.13"x1.705"x0.605" max) save space and are ideal

for high channel density applications. They are designed for easy DIN rail

mounting using any of the -DIN backpanels.

SCM7B

▲

Features

 Accepts Current or Voltage Input

 Provides High Level Voltage Outputs

 1500Vrms Transformer Isolation

 Accuracy, ±0.03% of Span Typical,

±0.1% Max

 ANSI/IEEE C37.90.1 Transient Protection

 Input Protected to 120Vrms Continuous

 Noise, 500µV Peak (5MHz), 300µV RMS

(100kHz)

 CMRR, up to 105dB

 80dB Per Decade of Attenuation

Above 100Hz

 Easy DIN Rail Mounting

 CSA Certified, FM Approved

 CE and ATEX Compliant

Figure 1: SCM7B32/33 Block Diagram

For information call 800-444-7644

Isolated Process Control Signal Conditioning Products

SCM7B

Specifications

Typical at 25°C and +24VDC

Module SCM7B32 SCM7B33

Input

Signal Range 4-20mA, 0-20mA +1 to +5V, 0 to +5V

Bias Current N/ A ±0.1nA

Resistance

Normal <100Ω 2MΩ Power Off <100Ω 2MΩ Overload 30kΩ 2MΩ

Protection

Continuous 120Vrms max *

Transient ANSI/IEEE C37.90.1 *

Output

Signal Range

Effective Available Power

Resistance <1Ω *

Protection Continuous Short-to-Ground *

Voltage/Current Limit ±12V, ±14mA *

CMV (Input-to-Output)

Continuous 1500Vrms *

Transient ANSI/IEEE C37.90.1 *

CMRR (50 or 60Hz) 105dB *

Accuracy

Nonlinearity

Stability (-40°C to +85°C)

Gain ±35ppm/°C *

Input Offset N/A

Output Offset ±0.003% Span/°C *

Noise

Peak at 5MHz B/W 500µV *

RMS at 10Hz to 100kHz B/W 300µV *

Peak at 0.1Hz to 10Hz B/W 1µV RTI *

Frequency and Time Response

Bandwidth, -3dB 100Hz *

NMR (-3dB at 100Hz) 80dB per decade above 100Hz *

Step Response, 90% Span 5ms *

Supply Voltage 14 to 35VDC *

Current

Sensitivity ±0.0001%/%V

Mechanical Dimensions 2.13" x 1.705" x 0.605" max *

(h)(w)(d) 54.1mm x 43.3mm x 15.4mm max *

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 *

NOTES:

*Specification same as preceding model

(1) Output Range and Supply Current specifications are based on minimum output load resistance. Minimum output load

resistance is calculated by V

accuracy, and linearity specifications.

(2) Accuracy includes the effects of repeatability, hysteresis, and linearity.

(3) Nonlinearity is calculated using the best-fit straight line method.

(4) Input offset term included in output offset specification.

(1) 

(2)

(3)

(1)

40mW *

±0.03% Span typical, *

±0.1% Span max

±0.01% Span typical, *

±0.02% Span max

(4)

(1)

/PE, where PE is the output Effective Available Power that guarantees output range,

OUT

12mA *

Ordering Information

Model Input Range

SCM7B32-01 4 to 20mA

SCM7B32-02 0 to 20mA

SCM7B33-01 +1 to +5V

SCM7B33-02 0 to +5V







Output Ranges Available

Output Range Part No. Suffix Example

+1 to +5V NONE SCM7B32-01

0 to +5V A SCM7B32-01A

0 to +10V D SCM7B32-01D

SCM7B

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