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Impulse DSCA36 User Manual

Dsca36, Potentiometer input signal conditioners, Dsca

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High Performance Signal Conditioners

DSCA

For information call 800-444-7644

138

DSCA36

Potentiometer Input Signal Conditioners

Description

Each DSCA36 potentiometer input module provides a single channel of

potentiometer input which is filtered, isolated, amplified, and converted to a high

level voltage output. 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

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.
Potentiometer excitation is provided from the module using a precision current

source. Lead compensation is achieved by matching two current paths which

cancels the effects of lead resistance. The excitation current is small (approx.

0.25mA) which minimizes self-heating of the sensor.
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.

Figure 1: DSCA36 Block Diagram

Features

• Interfaces to Potentiometers up to 10k

• Industry Standard Output of Either 0-10V,

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
• 160dB CMR
• 85dB NMR at 60Hz, 80dB at 50Hz
• ±0.03% Accuracy
• ±0.01% Linearity
• Easily Mounts on Standard DIN Rail
• C-UL-US Listed
• CE and ATEX Compliant