Impulse SCM5B33 - Manual

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Isolated Analog Signal Conditioning Products SCM5B
SCM5B33
Isolated True RMS Input Modules
Description
Each SCM5B33 True RMS input module provides a single channel of AC input
which is converted to its True RMS DC value, filtered, isolated, amplified, and
converted to a standard process voltage or current output (Figure 1).
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 field voltage or current input signal is processed through a pre-amplifier and
RMS converter on the field side of the isolation barrier. The converted DC signal
is then chopped by a proprietary chopper circuit and transferred across the
transformer isolation barrier, suppressing transmission of common mode
spikes and surges. The computer side circuitry reconstructs, filters and converts
the signal to industry standard outputs. Modules are powered from
+5VDC, ±5%.
For current output models, an external loop supply of 4.2V to 26V is required.
The loop supply connection, with series load, is between Pin 20 (+) and
Pin 19 (-).
Figure 1: SCM5B33 Block Diagram
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Features
• Interfaces RMS Voltage (0 – 300V) or RMS
Current (0 – 5A)
• Designed for Standard Operation with
Frequencies of 45Hz to 1000Hz
(Extended Range to 20kHz)
• Compatible with Standard Current and
Potential Transformers
• Industry Standard Output of either 0-1mA,
0-20mA, 4-20mA, 0-5V or 0-10VDC
• ±0.25% Factory Calibrated Accuracy
(Accuracy Class 0.2)
• 1500Vrms Continuous Transformer Isolation
• Input Overload Protected to 480V Max
(Peak AC & DC) or 10A RMS Continuous
• ANSI/IEEE C37.90.1 Transient Protection
• CSA Certified, CE and ATEX Compliant