ON-400-PROBES

Supported Applications

The Omega Precision Thermistor Sensors & Probes series (ON-400) provides high-accuracy temperature measurement for laboratory and process environments. Documented applications include immersion temperature measurements, air temperature monitoring, surface temperature readings, water baths, soil readings, thermal titration studies, freezing point determination, heat loss analysis, compressor efficiency testing, and manifold or bearing temperature assessment.

Operating Conditions & Performance

Sensors in this series feature a standard resistance of 2252 Ω at 25°C (Thermistor Curve #44004) unless otherwise specified. Interchangeability is rated at ±0.1°C or ±0.2°C over the range of 0 to 70°C, depending on the specific model and thermistor element selected. Maximum operating temperatures are typically listed as 100°C (212°F), with certain optional high-stability elements limited to a maximum working temperature of 75°C (165°F). For best stability, storage and working conditions for these optional elements range from -80 to 75°C (-110 to 165°F).

Probe diameters vary by model style, including sizes such as 2.4 mm (³⁄₃₂) dia., 3.2 mm (¹⁄₈) dia., 3.6 mm (0.1406) Dia., 4.8 mm (³⁄₁₆) diameter, 6.3 mm (¼) diameter, and 10.3 mm (¹³⁄₃₂) dia.

Configuration Options

The series supports multiple probe configurations to accommodate diverse installation needs:

• Housing & Sheath Materials: Options include 300 Series Stainless Steel, Pyrex (Glass), Vinyl Coated, Soft Flexible Vinyl Tipped, Epoxy Coated, and PFA Insulated.
• Cable Termination: Standard configurations feature a phone plug connector. Some models are available with stripped wires instead of integral connectors.
• Cable Lengths: Standard lengths include 3 m (10') for many probe styles and 300 mm (12") or 1 m (40") for specific sensor types. Custom cable lengths can be ordered by adding the required length in inches to the model number.
• Thermistor Elements: While 2252 Ω is standard, optional thermistors are available with resistances of 3000 Ω, 5000 Ω, 10,000 Ω, and 30,000 Ω at 25°C.
• Accessories: Compatible handheld meters include the 450-ATH (thermistor input), HH41, and HH42 (with RS232 communications). Additional accessories include the 865F thermistor meter and DP25-TH-A controller with analog output. A compression fitting option is available as SSLK-14-18 (¼" tube OD, ⅛ NPT, 316 SS).

Key Product Differences

The series encompasses several distinct model families differentiated by probe style and termination:

• ON-400 Series (e.g., ON-401, ON-402): Precision probes with phone plug connectors.
• ON-403 & ON-404 Series: Tubular and air temperature sensors featuring 2252 Ω resistance at ±0.1°C interchangeability.
• ON-905, ON-906, & ON-909 Series: Surface and immersion probes available with stripped wire terminations or phone plugs (e.g., -PP suffix). These models offer a wider range of resistance values including 3000 Ω through 30,000 Ω.
• ON-408 & ON-409 Series: Includes 'banjo' style and surface temperature sensors with specific tip diameters (e.g., 0.44" for ON-409).