Impulse DSCT30_31 - Manual

DIN Rail Mount Two-WireTransmitters DSCT
For information call 800-444-7644 200
DSCT30/31
Analog Voltage Input Transmitters
Figure 1: DSCT30/31 Block Diagram
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Features
• Accepts Millivolt and Voltage 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
• 85dB NMR at 60Hz, 80dB at 50Hz
• ±0.03% Accuracy
• ±0.01% Linearity
• Easily Mounts on Standard DIN Rail
• CSA and FM Approvals Pending
• CE Compliant
Description
Each DSCT30 and DSCT31 voltage 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 85dB of normal-mode-rejection at 60Hz and 80dB at 50Hz. 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 trans-
mission of common mode spikes or surges.
Special input and output circuits on the DSCT30 and DSCT31 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.