Impulse DSCA34 User Manual

High Performance Signal Conditioners

DSCA34

Linearized 2- or 3-Wire RTD Input Signal Conditioners

Description

Each DSCA34 RTD input module provides a single channel of RTD input which

is filtered, isolated, amplified, linearized, 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.

RTD 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 RTD.

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 ±3% 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.

DSCA

▲

Features

 Interfaces to 100Ω Platinum or 120Ω

Nickel RTDs

 Linearizes RTD Signal

 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

 ±0.08% Accuracy

 ±0.025% Conformity

 Easily Mounts on Standard DIN Rail

 C-UL-US Listed

 CE and ATEX Compliant

Figure 1: DSCA34 Block Diagram

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High Performance Signal Conditioners

DSCA

Specifications

Module

Input Range Limits -200°C to +850°C (100Ω Pt)

Input Protection

Continuous 240Vrms max

Transient ANSI/IEEE C37.90.1

Sensor Excitation Current ≈ 250µA Lead Resistance Effect +0.02°C/Ω

Output Range See Ordering Information

Load Resistance (I

Current Limit 8mA (V

Output Protection

Short to Ground Continuous

Transient ANSI/IEEE C37.90.1

CMV, Input to Output, Input to Power

Continuous 1500Vrms max

Transient ANSI/IEEE C37.90.1

CMV, Output to Power

Continuous 50VDC max

CMR (50Hz or 60Hz) 160dB

Accuracy See Ordering Information

Conformity ±0.025% (100Ω Pt)

Adjustability ±3% zero and span

Stability

Input Offset ±1µV/°C

Output Offset ±6ppm/°C (V

Gain ±60ppm/°C

Output Noise, 100kHz Bandwidth 250µVrms (V

Bandwidth, 3dB 3Hz

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

Response Time, 90% Span 250ms

Open Input Response

+ Lead Upscale

 Lead Non-deterministic

x Lead Downscale

Power Supply

Voltage 15 to 30VDC

Current 25mA (V

Sensitivity ±0.0001%/%

Protection

Reverse Polarity Continuous

Transient ANSI/IEEE C37.90.1

Environmental

Operating Temp. Range 40°C to +80°C

ATEX Group II, Category 3 20°C to +40°C

Storage Temp. Range 40°C to +80°C

Relative Humidity 0 to 95% Noncondensing

Emissions EN61000-6-4 ISM, Group 1

Radiated, Conducted Class A

Immunity EN61000-6-2 ISM, Group 1

R F Performance A ±0.05% Span Error

ESD, EFT, Surge, Voltage Dips Performance B

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 conformity, hysteresis and repeatability.

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

DSCA34

-80°C to +320°C (120Ω Ni)

) 600Ω max

OUT

±0.07% (120Ω Ni)

OUT

), 30mA (I

), ±20ppm/°C (I

OUT

), 1µArms (I

), 55mA (I

OUT

Ordering Information

Output

Model

ΩΩ

100

Ω Pt **

ΩΩ

Input Range

Range



Accuracy

DSCA34-01 -100°C to +100°C 2, 3, 4 ±0.08% ±0.16°C

(-148°F to +212°F)

DSCA34-02 0°C to +100°C 2, 3, 4 ±0.10% ±0.10°C

(+32°F to +212°F)

DSCA34-03 0°C to +200°C 2, 3, 4 ±0.08% ±0.16°C

)

(+32°F to +392°F)

DSCA34-04 0°C to +600°C 2, 3, 4 ±0.05% ±0.30°C

(+32°F to +1112°F)

DSCA34-05 -50°C to +350°C 2, 3, 4 ±0.05% ±0.20°C

(-58°F to +662°F)

ΩΩ

120

Ω Ni **

ΩΩ

DSCA34N-01 0°C to +300°C 2, 3, 4 ±0.15% ±0.45°C

(+32°F to +572°F)







Output Ranges Available

Output Range Part No. Suffix Example

1. -10V to +10V NONE NA

2. 0V to +10V NONE DSCA34-01

OUT

)

3. 4 to 20mA C DSCA34-01C

4. 0 to 20mA E DSCA34-01E

DSCA

**RTD Standards

Type Alpha Coefficient DIN JIS

)

100Ω Pt 0.00385 DIN 43760 JIS C 1604-1989 120Ω Ni 0.00672

Installation Notes:

1.) This Equipment is Suitable for Use in Class I, Division 2, Groups A, B, C, D, or Non-Hazardous Locations Only.

2.) Warning - Explosion Hazard - Substitution of Components May Impair Suitability for Class I, Division 2.

3.) Warning - Explosion Hazard - Do Not Disconnect Equipment Unless Power Has Been Switched Off or The

Area is Known to be Non-Hazardous.

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