DSCT34-02

Linearized 2- or 3-Wire RTD Input Transmitters

DSCT34-02
Linearized 2- or 3-Wire RTD Input Transmitters

Description

Each DSCT34 RTD input transmitter provides a single channel of RTD input which is filtered, isolated, amplified, linearized, and converted to a process current 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 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.

RTD excitation is provided from the transmitter using a precision current source. The excitation currents are very small (0.26mA max for 100 ohm Pt and 120 ohm Ni) which minimizes self-heating of the RTD. Linearization is achieved by creating a non-linear transfer function through the module itself. This non-linear transfer function is configured at the factory and is designed to be equal and opposite to the specific RTD non-linearity. Lead compensation is achieved by matching two current paths thus canceling the effects of lead resistance.

The specifications listed are for a 3-wire connection. A 2-wire connection of the RTD to the module is also possible and is achieved by adding a jumper between pin 5 (+EXC) and pin 6 (+IN) on the terminal block and connecting the RTD leads between pin 6 (+IN) and pin 7 (-IN). The 2-wire connection nullifies the lead resistance compensation feature of the module.

Special input and output circuits on the DSCT34 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 ±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.

Specifications

  • Input Configuration 2 & 3 Wire
  • RTD Type 100 Ohm Platinum
  • Input Range 0 to 100 (°C)
  • Output Range 4 to 20 mA
  • Mechanical Format DIN rail
  • Isolation Voltage 1500 Vrms
  • Isolation Type Transformer
  • Accuracy ±0.1% (0.1°C) max
  • Supply Voltage 10.8V to 60V
  • Input Voltage Withstand 240Vrms
  • Gain/Offset Adjust ±3% Zero and Span
  • Module Bandwidth 3 Hz
  • NMR (60 Hz) Rejection 85 dB at 60 Hz, 80 dB at 50 Hz
  • External I-to-V Resistor N/A
  • Output Control Always enabled
  • Output Resistance
  • Dimensions 2.95 x 0.89 x 4.13 inches
  • Interface 8 Pos terminal block
  • Customization YES
  • Weight 103 grams (3.63 ounces)

Features

  • Interfaces to 100 Ohm Platinum or 120 Ohm Nickel RTDs
  • Linearizes RTD Signal
  • 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
  • ±0.1% Accuracy
  • ±0.025% Conformity
  • Easily Mounts on Standard DIN Rail
  • CSA and FM Approvals Pending
  • CE Compliant

Block Diagram

DSCT34 block diagram

Accessories

DSCX-BLANK
Blank Empty DIN Rail Case for Holding Positiion. DSCA or DSCT View
SCMXRAIL1-1.0
DIN EN 50022-35 x 7.5 (slotted steel), 1 meter length View
SCMXRAIL1-2.0
DIN EN 50022-35 x 7.5 (slotted steel), 2 meter length View
SCMXRAIL2-01
DIN EN 50035-G32 (slotted steel), 1 meter length View
SCMXRAIL2-02
DIN EN 50035-G32 (slotted steel), 2 meter length View
SCMXRAIL3-01
DIN EN 50022-35 x 15 (slotted steel), 1 meter length View
SCMXRAIL3-02
DIN EN 50022-35 x 15 (slotted steel), 2 meter length View

Competitive Cross-Reference

  • No cross reference is available.
View Dataforth cross-reference data.
The information available through this competitive cross reference guide are based upon product catalog information obtained from a variety of sources. The competitive cross reference information is being provided to you free of charge for your use. While Dataforth Corp has used reasonable efforts to ensure data accuracy, Dataforth Corp does not guarantee that it is error-free, nor does Dataforth Corp make any other representation, warranty or guarantee that the information is accurate, correct, reliable or up-to-date. Dataforth Corp expressly disclaims all implied warranties regarding this information, including but not limited to any implied warranties of merchantability or fitness for a particular purpose.

This information is provided only as a convenience on an "as is" basis and Dataforth Corp. or its representatives or distributors are not responsible for any incorrect, inaccurate, or incomplete information. You are solely responsible for (1) selecting the appropriate Dataforth products for your application, (2) designing, validating and testing your application, and (3) ensuring your application meets applicable standards, and any other safety, security, or other requirements.

FAQ

Due to resource constraints on my computer, I'm unable to open the three dimensional CAD models provided on your website. Does Dataforth provide two demensional CAD models for download as well?
Two dimensional CAD models can be generated upon customer request. Please contact Customer Service for assistance.
How does the load resistance of a module affect the noise at the output?
Noise at the output of a module is independent of load resistance.
Can Dataforth provide calibration reports for modules I purchased?
Yes we can provide calibration reports for the modules that you purchased. You can either a) visit https://www.dataforth.com/TestDataReport.aspx to search for Test Report Datasheets by Serial Number or b) you can send us a list of model numbers and their serial numbers to support@dataforth.com

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