Impulse DSCA42 - Manual

High Performance Signal Conditioners DSCA
For information call 800-444-7644 148
DSCA42
2-Wire Transmitter Interface Signal Conditioners With Loop Power
Features
• Accepts Process Loop Signals
• Industry Standard Output of either
0-10V, 2-10V, 0-20mA, or 4-20mA
• Provides Isolated Loop Excitation
• 1500Vrms Transformer Isolation
• ANSI/IEEE C37.90.1 Transient Protection
• Input Protection to 240VAC Continuous
• True 3-Way Isolation
• Wide Range of Supply Voltage
• 105dB CMR
• 5 Poles of Filtering
• ±0.03% Accuracy
• ±0.01% Linearity
• Easily Mounts on Standard DIN Rail
• C-UL-US Listed
• CE and ATEX Compliant
Description
Each DSCA42 2-wire transmitter interface module provides a single channel
of 4 to 20mA process current input which is filtered, isolated, amplified, and
converted to a high level voltage output. An isolated 24V power supply is
provided to power the 2-wire transmitter. Signal filtering is accomplished with
a five-pole filter which is optimized for step response. An anti-aliasing pole is
located on the field side of the isolation barrier, and the other four poles are on
the system 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.
Module output is either voltage or current. For current output models a dedicated
loop supply is provided at terminal 3 (+OUT) with loop return located at terminal
4 (-OUT). The system-side load may be either floating or grounded.
Special input circuits provide protection against accidental connection of power-
line voltages up to 240VAC and against transient events as defined by ANSI/
IEEE C37.90.1. Protection circuits are also present on the signal output and
power input terminals to guard against transient events and power reversal.
Signal and 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 ±5% 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.
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Figure 1: DSCA42 Block Diagram