7Semi PT100 RTD 3-Wire Temperature Sensor Probe

7Semi PT100 RTD 3-Wire Temperature Sensor Probe Technical Information

Overview

The 7Semi PT100 RTD 3-wire temperature sensor probe is a high-accuracy resistance temperature detector (RTD) based on a platinum sensing element (Pt100).

• Measures:

  • Temperature

   

• Type:

  • 3-wire RTD configuration

   

• Output:

  • Resistance (analog, requires signal conditioning)

   

Designed for precision temperature measurement with improved accuracy over 2-wire RTDs.

Working Principle

RTD (Resistance Temperature Detection)

• Uses platinum (Pt100) element

• Resistance varies with temperature

oR0(1+T)

Where:

• R0=100R_0 = 100 \, \OmegaR0=100 at 0C

• 0.00385/C\alpha \approx 0.00385/C0.00385/C

• TTT = temperature

Operation

• Constant current flows through RTD

• Temperature change resistance change

• Measured resistance converted into temperature

Provides highly linear and stable measurement.

Measurement Characteristics

• Temperature range: typically 50C to +250C (probe dependent)

• Base resistance: 100 @ 0C

• Accuracy: high (often Class B or better)

• Linearity: excellent

Enstant current source

RTD interface circuit

3-Wire Configuration

Principle

• Uses three wires instead of two

• Compensates for lead wire resistance

How It Improves Accuracy

• Two wires measure resistance

• Third wire helps cancel:

  • Cable resistance error

   

More accurate than:

• 2-wire RTD Slightly less accurate than:

• 4-wire RTD

Internal Features

Platinum Sensing Element

• High stability

• Low drift over time

Lead Resistance Compensation

• Reduces measurement error in long cables

Wide Temperature Range

• Suitable for:

  • Industrial processes

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    Mechanical Characteristics

    • Probe material: Stainless steel

    • Cable type: 3-wire insulated cable

    • Designed for:

      • Harsh environments

      • Liquid and surface sensing

       

     

    Operating Behavior

    High Precision Measurement

    • Accurate and repeatable readings

    Stable Output

    • Low noise and drift

    Moderate Response Time

    • Depends on probe size and medium

    Environmental Characteristics

    • Suitable for:

      • Liquids

      • Air

      • Industrial surfaces

       

    Limitations

    • Requires:

      • External RTD interface (e.g., amplifier or ADC)

       

    • Slower than thermocouples

     

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    Typical Connection

    • Wire 1 & 2: measurement leads

    • Wire 3: compensation lead

     

    Functional Role

    The probe acts as a:

    • High-precision temperature sensor

    • Industrial thermal measurement device

    • Resistance-based sensing element

     

    Summary

    The 7Semi PT100 3-wire RTD probe is a precision temperature sensing solution that:

    • Uses platinum RTD technology (Pt100)

    • Provides high accuracy and stability

    • Reduces error via 3-wire compensation

    • Requires external signal conditioning

    • Is ideal for industrial and scientific temperature measurement systems