Impulse SCM7B39 - Manual

Isolated Process Control Signal Conditioning Products SCM7B
For information call 800-444-7644 80
SCM7B39
Isolated Process Current Output Modules
Description
SCM7B39 process current modules accept high level signals from the process
control system and provide either 0 to 20mA or 4 to 20mA current to the field
(Figure 1).
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 process control system
side of the isolation barrier, and the other four poles are on the field side.
After the initial process control system side filtering, the 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, filtered, and converted to a process current for
output to the field.
Modules accept a wide 18 - 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.
Figure 1: SCM7B39 Block Diagram
▲
Features
• Accepts High Level Voltage Input
• Provides 4-20mA or 0-20mA Current Output
• 1500Vrms Transformer Isolation
• Accuracy, ±0.03% of Span Typical, ±0.1%
Max
• ANSI/IEEE C37.90.1 Transient Protection
• Output Protected to 120Vrms Continuous
• Noise, 46µA Peak (5MHz), 4µA RMS
(100kHz)
• CMRR, 110dB
• 80dB Per Decade of Attenuation Above 100Hz
• Easy DIN Rail Mounting
• CSA Certified, FM Approved
• CE and ATEX Compliant