Impulse DSCA37 User Manual

DSCA37

Thermocouple Input Signal Conditioners

Description

Each DSCA37 thermocouple input module provides a single channel of

thermocouple 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.

The DSCA37 can interface to eight industry standard thermocouple types: J, K,

T, E, R, S, B and N. Each module has cold junction compensation to correct for

parasitic thermocouples formed by the thermocouple wire and input screw

terminals on the module. Upscale open thermocouple detection is provided

by internal circuitry. Downscale indication can be implemented by installing a

47MΩ, ±20% resistor between screw terminals 6 and 8 on the input terminal block.

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.

Power lines are secured to the module using screw terminals which are in

pluggable terminal blocks for ease of system assembly and reconfiguration.

High Performance Signal Conditioners

▲

Features

 Interfaces to Types J, K, T, E, R, S, B, and N

Thermocouples

 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

 ±0.05% Accuracy

 ±0.01% Linearity

 Easily Mounts on Standard DIN Rail

 C-UL-US Listed

 CE and ATEX Compliant

DSCA

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 potentiom-

eters located under the front panel label and are non-interactive for ease of use.

Figure 1: DSCA37 Block Diagram

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For information call 800-444-7644

High Performance Signal Conditioners

DSCA

Specifications

Module

Input Range Standard Thermocouple

Input Bias Current -30nA

Input Resistance

Normal 50MΩ Power Off 65kΩ Overload 65kΩ

Input Protection

Continuous 240Vrms max

Transient ANSI/IEEE C37.90.1

Cold Junction Compensation

Accuracy, +5°C to +45°C ±0.5°C

Accuracy, -40°C to +85°C ±1.25°C

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

Nonlinearity ±0.01% Span

Adjustability ±5% Zero and Span

Stability

Input Offset ±0.5µV/°C

Output Offset ±6ppm/°C (V

Gain ±35ppm/°C

Output Noise, 100kHz Bandwidth 250µVrms (V

Bandwidth, 3dB 3Hz

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

Response Time, 90% Span 165ms

Open Input Response Upscale

Open Input Detection Time <5s

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, and CJC error.

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.

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

DSCA37

Temperature Limits as per

NIST Monograph 175, ITS-90

) 600Ω max

OUT

), 30mA (I

), ±20ppm/°C (I

), 1µArms (I

), 55mA (I

OUT

)

OUT

)

Ordering Information



Model Input Range

Type

DSCA37J-01 J -100°C to +760°C 2, 3, 4 ±0.05% ±0.43°C

(-148°F to +1400°F)

DSCA37K-02 K -100°C to +1350°C 2, 3, 4 ±0.05% ±0.73°C

(-148°F to +2462°F)

DSCA37T-03 T -100°C to +400°C 2, 3, 4 ±0.05% ±0.25°C

(-148°F to +752°F)

DSCA37E-04 E 0°C to +900°C 2, 3, 4 ±0.05% ±0.45°C

(+32°F to +1652°F)

DSCA37R-05 R 0°C to +1750°C 2, 3, 4 ±0.05% ±0.88°C

(+32°F to +3182°F)

DSCA37S-06 S 0°C to +1750°C 2, 3, 4 ±0.05% ±0.88°C

(+32°F to +3182°F)

DSCA37B-07 B 0°C to +1800°C 2, 3, 4 ±0.05% ±0.90°C

(+32°F to +3272°F)

DSCA37N-08 N 100°C to +1300°C 2, 3, 4 ±0.05% ±0.70°C

(-148°F to +2372°F)

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Output Ranges Available

Output Range Part No. Suffix Example

1. -10V to +10V NONE NA

2. 0V to +10V NONE DSCA37J-01

3. 4 to 20mA C DSCA37J-01C

4. 0 to 20mA E DSCA37J-01E



Thermocouple Alloy Combinations

Standards: DIN IEC 584, ANSI MC96-1-82, JIS C 1602-1981

Type Material

J Iron vs. Copper-Nickel K Nickel-Chromium vs. Nickel-Aluminum T Copper vs. Copper-Nickel E Nickel-Chromium vs. Copper-Nickel R Platinum-13% Rhodium vs. Platinum S Platinum-10% Rhodium vs. Platinum B Platinum-30% Rhodium vs. Platinum-6% Rhodium N Nickel-14.2% Chromium-1.4% Silicon vs. Nickel-4.4%

Silicon- 0.1% Magnesium

Output

Range



Accuracy

DSCA

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