Impulse DSCA38 - Manual

High Performance Signal Conditioners DSCA
For information call 800-444-7644 142
DSCA38
Strain Gage Input Signal Conditioners
Description
Each DSCA38 strain gage input module provides a single channel of strain gage
input which is filtered, isolated, amplified, and converted to a high level voltage
output. 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.
The DSCA38 can interface to transducers with a nominal resistance of 100
Ω
to 10k Ω . Strain gage excitation is provided from the module by a stable 10V or
3.333V source. This source is fully isolated, allowing the amplifier inputs to
operate over the full range of the excitation voltage. This feature enables the
module to be interfaced to other sensors requiring exctitation.
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 signal input and excitation 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
Figure 1: DSCA38 Block Diagram
Features
• Interfaces to 100 Ω through 10k Ω Strain Gages
• Industry Standard Output of either ±10V,
0-20mA, or 4-20mA
• 1500Vrms Transformer Isolation
• ANSI/IEEE C37.90.1 Transient Protection
• Input Protected to 240VAC Continuous
• True 3-Way Isolation
• Wide Range of Supply Voltage
• 100dB CMR
• Fully Isolated Excitation Supply
• ±0.03% Accuracy
• ±0.01% Linearity
• Easily Mounts on Standard DIN Rail
• C-UL-US Listed
• CE and ATEX Compliant
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situations where fine-tuning is desired. The zero adjustment can be used to offset
bridge imbalances. The adjustments are made using potentiometers located
under the front panel label and are non-interactive for ease of use.