SRTD-1-SRTD-2

Supported Applications

The Omega SRTD-1 and SRTD-2 series are polyimide insulated surface mount RTD temperature sensors designed for measuring surface temperature. These small, flexible sensors feature low mass to minimize thermal effect on the material being measured. They are intended for applications where the sensor can be mounted directly to a surface using adhesives or mechanical mounting methods.

Operating Conditions & Performance

The series utilizes 100 ohm wire wound platinum sensing elements with an alpha coefficient of 0.00385 ohm/ohm/°C (DIN 43760). The continuous operating temperature range is -320°F (-200°C) to 500°F (260°C), with a short-term limit up to 550°F (288°C) for less than 1500 hours. Stability is rated at <0.2°C drift per year at the rated service temperature with proper mounting.

Performance characteristics include:

• SRTD-1 Accuracy: ±0.50 ohms, ±0.50% of temperature
• SRTD-2 Accuracy: ±0.22 ohms, ±0.25% of temperature reading
• Response Time: 70 ms to reach 63.2% of a step change in water flowing at 3 ft/sec transverse to the sensor (ASTM-E-644); <200 milliseconds lag on metal surfaces.
• Self-Heating Effect: The bare sensor will rise less than 1°C while dissipating an I2R power of 3 milliwatts in still air (ASTM-E-644).
• Insulation Resistance: Minimum 50 megohms with 50 volts dc applied to a dry sensor at room temperature; minimum 100G Ohm at 500 Vdc for round twisted cable in dry conditions.

Configuration Options

The series is configured as "Cement-On" sensors with polyimide insulation. Standard construction includes a sensor head measuring 1.00 inch (length) x 0.62 inch (height). The electrical connection uses a 3-wire configuration.

Lead Wire and Cabling

Sensors are available with standard lead lengths of 36 inches, or extended options including 48, 60, 72, and 120 inches. The standard cable is a #26 AWG stranded nickel-plated copper ribbon cable (PFA insulated). An alternative round twisted cable option provides higher insulation resistance ratings.

Mounting and Installation

The sensors are designed for installation using OMEGABOND® Epoxy Adhesives (#100, #101, or #200) or other mechanical methods. Minimum bend radius requirements are 3/8" transverse to the element winding and 1-1/2" longitudinal to the winding.

Optional Accessories

An MTP-U-M heavy-duty connector is available as a popular option for electrical termination.

Key Product Differences

The primary distinction between models lies in resistance tolerance and accuracy class:

• SRTD-1 Series: Offers 100 +/- 0.5Ω at 0°C, or +/- 0.5% of reading up to 232°C.
• SRTD-2 Series: Provides tighter tolerance with 100 +/- 0.22Ω at 0°C, or +/- 0.25% of reading up to 232°C.

Variants are further differentiated by lead length suffixes (e.g., SRTD-1-60 INCH). The SRTD-2-72 INCH model is noted for having a black/black/red cable configuration. Other sizes beyond the standard 36-inch leads are available upon request.