Impulse DSCT32 - Manual

DIN Rail Mount Two-WireTransmitters DSCT
For information call 800-444-7644 202
DSCT32
Analog Current Input Transmitters
Figure 1: DSCT32 Block Diagram
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Features
• Accepts Milliamp Level Signals
• Process Current Output
• 1500Vrms Transformer Isolation
• ANSI/IEEE C37.90.1 Transient Protection
• Input and Output Protected to 240VAC
Continuous
• Up to 60V Loop Voltage
• 160dB CMR
• NMR, 80dB Per Decade Above 100Hz
• ±0.03% Accuracy
• ±0.01% Linearity
• Easily Mounts on Standard DIN Rail
• CSA and FM Approvals Pending
• CE Compliant
Description
Each DSCT32 current input transmitter provides a single channel of analog
input which is filtered, isolated, amplified, and converted to a process current
output (Figure 1). Signal filtering is accomplished with a five-pole filter, which
provides 80dB per decade of normal-mode-rejection above 100Hz. An anti-
aliasing pole is located on the field side of the isolation barrier, and the other four
are on the process loop side. After the initial field-side filtering, the input signal
is chopped by a proprietary chopper circuit. Isolation is provided by transformer
coupling, again using a proprietary technique to suppress transmission of
common mode spikes or surges.
Special input and output circuits on the DSCT32 transmitters provide protection
against accidental connection of power-line voltages up to 240VAC and against
transient events as defined by ANSI/IEEE C37.90.1. Signal and loop power
lines are secured to the module using screw terminals, which are in pluggable
terminal blocks for ease of system assembly and reconfiguration.
The modules have excellent stability over time and do not require recalibration,
however, zero and span settings are adjustable up to ±10% to accommodate
situations where fine-tuning is desired. The adjustments are made using
potentiometers located under the front panel label and are non-interactive for
ease of use.