SCM7B32/33 Isolated Process Current/Voltage Input Modules
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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. 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, 500µVp-p (5MHz), 300µVrms (100kHz) • 105dB CMRR • Easy DIN Rail Mounting • CSA C/US Certified • CE and ATEX Compliant 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. Figure 1: SCM7B32/33 Block Diagram ©1995-2011 Dataforth Corporation, All Rights Reserved ISO9001:2008-Registered QMS

Isolated Process Control Signal Conditioning Products Ordering Information Module Input Signal Range Bias Current Resistance Normal Power Off Overload Protection Continuous Transient Output Signal Range(1) Effective Available Power(1) Resistance Protection Voltage/Current Limit Environmental Operating Temperature Range Storage Temperature Range Relative Humidity Emissions EN61000-6-4 Radiated, Conducted Immunity EN61000-6-2 RF ESD, EFT –40°C to +85°C –40°C to +85°C 0 to 95% Noncondensing ISM, Group 1 Class A ISM, Group 1 Performance A ±0.5% Span Error Performance B Output Range Part No....