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TH-21
Thermistor Immersion Probes with a Standard M12 Connector
- Maximum Continuous Use, 200°C (392°F)
- [Short Term Use to 250°C (482°F)] for Sensing End,
- 85°C (185°F) Max at the Connector
- Vibration Tested to ASTM-E1137: 3Gs from 5 to 500 Hz
Product Overview
- Accuracy ± 0.2 °C (± 0.36 °F)
- Accuracy Detail ± 0.2°C (0 to 70ºC)
- Color Code Standard ANSI
- Connector Temperature, Max 85 °C
- Connector Temperature, Min 0 °C
- Electrical Connection M12 4 pin Male
- Enclosure Ratings IP67
- Insulation Resistance 100 MΩ
- Insulation Resistance Note 100 MΩ minimum at 100 Vdc at ambient temperature
- Nominal Resistance/Curve Note Resistance at 25°C
- Operating Current 12 µA
- Process Temperature, Max 200 °C
- Process Temperature, Min -50 °C
- Response Time 14 sec
- Response Time Note Approximately 7 seconds (50%), 8 seconds (63.2%), 14 seconds (90%) in water flowing at 0.91 m (3') per second
- Series ID TH-21
- Sheath Material 316L Stainless Steel
- Temperature Sensor Type Thermistor
- Thermocouple Type N/A
Supported Applications
The Omega TH-21 series consists of thermistor immersion probes featuring a standard M12 connector. These sensors utilize 55000 Series glass encapsulated thermistor elements to provide temperature measurement with excellent stability and accuracy.
Operating Conditions & Performance
The TH-21 series is designed for continuous operation from -80 to 200°C (-112 to 392°F) and supports intermittent use up to 250°C (482°F). The measurement range spans -50 to 200°C (-58 to 392°F), with an accuracy of ±0.2°C from 0 to 70°C (32 to 158°F).
Response time in water flowing at 0.91 m (3') per second is approximately:
- 7 seconds for 50% response
- 8 seconds for 63.2% response
- 14 seconds for 90% response
Configuration Options
The series offers configurable sensor elements, sheath dimensions, and mounting options to accommodate specific installation requirements.
Sensor Elements & Resistance
- Available resistances at 25°C: 2252 Ω, 3K (3000 Ω), 5K (5000 Ω), and 10K (10,000 Ω).
- Dual element versions are available by adding "-DUAL" to the model number; this option is not available in 1/4" or 3 mm diameter probes.
Sheath Dimensions & Materials
- Probe diameters: 1/8", 1/4" (6 mm), 3/8" (9.5 mm), and 1/2" (12.7 mm).
- Standard insertion lengths include 6" (150 mm); custom lengths are available.
- A minimum immersion depth of 1.5" is recommended to avoid stem conduction errors, particularly for short probes.
- Wetted materials consist of a 316L stainless steel sheath and housing, excluding the connector insert.
Mounting & Connections
- Process connections include: 1/2-14 NPT, 3/8-18 NPT, 1/4-18 NPT, M8x1 Thread, M10x1 Thread, G1/2 BSPP, and G1/4 BSPP.
- Electrical connection: M12 4-pin connector with an IP67 enclosure rating when the mating connector is installed.
Certifications & Options
- NIST certification (Optional).
- RoHS compliant.
- Optional extension cables sold separately: M12CM-T24SSPC-SF-2 and M12CM-T24SSPC-RF-2.
Key Product Differences
The TH-21 series model number structure follows the format TH-21<Design><Resistance><Length><Connector>. The design letter (A, B, C, D, E, F, G, H) indicates the specific mounting configuration or sheath style. For example:
- Model TH-21A denotes a straight sheath without integral NPT threading.
- Models TH-21B through TH-21D include 1/2", 3/8", and 1/4" NPT mounting threads, respectively.
- Metric models (TH-21E to TH-21H) feature M8x1, M10x1, G1/2, or G1/4 mounting threads with a 6 mm diameter sheath.
Resistance values are specified in the model number as "-2252", "-3K", "-5K", or "-10K". Probe lengths are indicated numerically (e.g., "-0600" for 6 inches), and custom lengths can be ordered by modifying this segment.
PDFs & Manuals
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