High Precision PT100 RTD Temperature Sensor 150mm Probe 2m Cable M8

Specifications

• Sensor Type: PT100 RTD.

• Temperature Range: -200°C to +450°C.

• Probe Material: Stainless Steel (Waterproof & Corrosion Resistant).

• Probe Dimensions: 5mm Diameter x 150mm Length.

• Cable Length: 2 Meters (Fibreglass braided with internal shielding).

• Wire Configuration: 3-Wire (Compensates for cable resistance).

• Accuracy: Class B (approx ±0.3°C at 0°C).

• Thread/Mounting: M8.

Key Applications & Projects

• Industrial Ovens & Kilns: Precise PID control for reflow ovens or ceramic firing up to 450°C.

• Cryogenics: Monitoring liquid nitrogen or dry ice storage at sub-zero temperatures.

• Food Processing: Sous-vide cooking or brewing setups where 0.5°C accuracy impacts the result.

• HVAC Systems: Duct temperature monitoring where long cable runs are necessary.

Project Evolution

• The Bottleneck: Using a thermistor or LM35 limits you to a narrow range (-55°C to 125°C). You cannot measure boiling oil or exhaust gases.

• The Upgrade: This PT100 unlocks the Industrial Spectrum. It enables your microcontroller to monitor processes that would destroy standard silicon sensors.

• Effort Level: Intermediate. You cannot plug this directly into an Arduino analogue pin. You need a dedicated amplifier module like the MAX31865.

Virtual Technician & Wiring Guide

• ⚠️ Amplifier Required: This is a resistance-based sensor. You MUST use an RTD amplifier module (e.g., MAX31865) to convert the resistance to a digital signal for your Arduino/ESP32.

• 3-Wire Connection: Connect the two wires of the same colour to the "Force" and "RTD" terminals on one side of your amplifier, and the single wire to the other. This configuration cancels out the resistance of the 2 m-long wire for higher accuracy.

• Shielding: Connect the external metal braid of the cable to Earth Ground to prevent electrical noise from scrambling your readings.

Accessories & Compatibility

• Included: 1x PT100 Probe with 2m Cable.

• Required (Sold Separately): MAX31865 PT100/PT1000 Amplifier Module.

• Related: Heat Shrink Tubing, High-Temp Kapton Tape.

Helpful Tutorials & Resources

• Using PT100 Sensors with Arduino and MAX31865

Frequently Asked Questions (Technical SEO)

• Is this a thermocouple or an RTD? It is an RTD (Resistance Temperature Detector). It uses a platinum element (PT100) instead of the Seebeck effect used by thermocouples.
• Can I connect this directly to an Arduino Analog Pin? No, the resistance change is too small (0.385Ω/°C) for direct reading. You need an amplifier board like the MAX31865.
• What is the advantage of 3-wire over 2-wire? The third wire allows the amplifier to measure and subtract the resistance of the cable itself, providing a much more accurate reading over long distances.
• Can I cut the cable to shorten it? Yes, you can shorten the cable, but remember that changing the length changes the resistance. Recalibration or using the 3-wire compensation is recommended.
• Is the probe waterproof? Yes, the stainless steel probe is sealed and waterproof, making it suitable for liquid immersion.
• What is the maximum temperature for the cable? The probe handles 450°C, but the fiberglass cable is typically rated for ~250-300°C. Keep the cable away from direct flame or heating elements.
• Does it work with the MAX6675 module? No, the MAX6675 is strictly for K-Type Thermocouples. It will not work with this PT100 RTD.
• What is the resistance at 0°C? As a PT100 sensor, it has a nominal resistance of exactly 100 Ohms at 0°C.
• Can I use this with a Raspberry Pi? Yes, but you will need a digital interface module (like a MAX31865 HAT or breakout) since the Pi has no analogue inputs.
• How fast is the response time? The thermal time constant is roughly 2-3 seconds in moving water due to the stainless steel sheath mass.
• Can I extend the cable beyond 2 meters? Yes, using the 3-wire configuration allows you to extend it significantly without losing accuracy, provided you use shielded wire.
• Is it suitable for food contact? The probe is stainless steel, generally safe for food contact, but it is not certified food-grade for commercial kitchens.
• What is the diameter of the probe? The probe diameter is 5mm, fitting into standard 1/4" compression fittings with appropriate ferrules.
• Will it work with 5V or 3.3V logic? The sensor itself is passive. Logic compatibility depends entirely on the amplifier module you use (MAX31865 works with both).
• Can I bend the probe? No, the stainless steel sheath is rigid and contains the delicate platinum element. Bending it will destroy the sensor.
• Why do I get a reading of -242°C? This usually indicates an open circuit (broken wire or bad connection). Check your wiring continuity.
• Is there a polarity for the wires? RTDs are resistors, so they are non-polarized. However, for 3-wire setups, color coding matters for the compensation loop.
• Can I use this to measure air temperature? Yes, but response time in air is slower than in liquid.
• What is the Alpha value? It follows the standard DIN/IEC 60751 curve with an alpha coefficient of 0.00385.
• Is this better than a DS18B20? For range, yes (DS18B20 stops at 125°C). For accuracy near room temp, they are comparable, but the PT100 is far more robust.