Impulse DSCT36 User Manual

DSCT36

Potentiometer Input Transmitters

Description

Each DSCT36 potentiometer input transmitter provides a single channel of

potentiometer 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

transmission of common mode spikes or surges.

Potentiometer excitation is provided from the transmitter using a precision current

source. The excitation current is small (less than 0.26mA) which minimizes self-

heating of the potentiometer. Lead compensation is achieved by matching two

current paths which cancels the effects of lead resistance.

Special input and output circuits on the DSCT36 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.

DIN Rail Mount Two-WireTransmitters

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Features

 Interfaces to Potentiometers up to 10kΩ

 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

DSCT

Figure 1: DSCT36 Block Diagram

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For information call 800-444-7644

DIN Rail Mount Two-Wire Transmitters

DSCT

Specifications

Module

Input Range 0Ω to 10kΩ

Input Resistance

Normal 50MΩ
Power Off 66kΩ
Overload 66kΩ

Input Protection

Continuous 240Vrms max

Transient ANSI/IEEE C37.90.1

CMV, Input to Output

Continuous 1500Vrms max

Transient ANSI/IEEE C37.90.1

CMR (50Hz or 60Hz) 160dB

NMR 85dB at 60Hz, 80dB at 50Hz

Adjustability ±10% Zero and Span

(1)

Accuracy

Conformity ±0.01%

Stability

Offset ±50ppm/°C

Gain ±100ppm/°C

Sensor Excitation Current 0.26mA; 100Ω, 500Ω Sensor

Lead Resistance Effect ±0.01Ω/Ω; 100Ω, 500Ω, 1kΩ Sensor

Noise

Output, 100kHz 3µArms

Bandwidth, 3dB 3Hz

Response Time, 90% Span 165ms

Typical at TA=+25°C and +24V loop voltage

DSCT36

±0.03%

0.13mA; 1kΩ Sensor

0.065mA; 10kΩ Sensor

±0.02Ω/Ω; 10kΩ Sensor

Ordering Information

Model Input Range

DSCT36-01 0 to 100Ω
DSCT36-02 0 to 500Ω
DSCT36-03 0 to 1kΩ
DSCT36-04 0 to 10kΩ

Output Range 4mA to 20mA

Output Limits

Under-range 3mA

Over-range 29mA

Output Protection

Reverse Polarity Continuous

Over-voltage 240Vrms Continuous

Transient ANSI/IEEE C37.90.1

Loop Supply Voltage 10.8V to 60V

Loop Supply Sensitivity ±0.0005%/V

Turn-On Delay 400ms

Environmental

Operating Temp. Range 40°C to +80°C

Storage Temp. Range 40°C to +80°C

Relative Humidity 0 to 95% Noncondensing

Emissions EN50081-1, ISM Group 1,

Immunity EN50082-1, ISM Group 1,

Mechanical Dimensions 2.95" x 0.89" x 4.13

(h)(w)(d) (75mm x 22.5mm x 105mm)

Mounting DIN EN 50022 35x7.5 or 35x15 rail

NOTES:

(1) Includes nonlinearity, hysteresis and repeatability.

Class A (Radiated, Conducted)

Class A (ESD, RF, EFT)

DSCT

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