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Enabling better global research outcomes in soil, plant & environmental monitoring.

ST-100, ST-110 and ST-200

The ST series of thermistor temperature sensors are designed to measure temperature in a range of applications.
The ST-100 is suitable for measuring air and soil temperatures with a datalogger, the ST-110 is optimised for air temperature measurement in long-term outdoor installations in radiation shields, in all climates.
The ST-200 is a fine wire thermistor, ideally suited for taking measurements of surfaces or small samples where even a narrow field of view infrared radiometer may not be suitable.

Common Specifications

Measurement Range -50 to 70°C
Measurement Repeatability < 0.05°C
Non-Stability (long-term Drift) < 0.02°C per year (when used in non-condensing environments where the annual average temperature is less than 30°C, continuously high temperatures or continuously humid environments increase drift rate)
Self-Heating < 0.01°C (typical, assuming pulsed excitation of 2.5V DC), 0.08C at 5°C (maximum, assuming continuous input excitation of 2.5V DC)
Operating Environment -50 to 70°C, 0 to 100% relative humidity
Input Voltage Requirement 2.5V DC excitation
Output Voltage Range 0 to 2.5V DC (assuming input excitation of 2.5V DC)
Current Drain 0.1mA DC at 70°C (maximum, assuming continuous input excitation of 2.5V DC)
Dimensions 7cm length, 0.6cm diameter
Cable 5m of shielded, twisted-pair wire. Santoprene rubber jacket (high water resistance, high UV stability, flexibility in cold conditions), Pigtail lead wires.
Warranty 4 years

ST-100 Specific Specifications

Measurement Uncertainty 0.1°C (from 0 to 70°C), 0.2°C (from -25 to 0°C), 0.4°C (from -50 to -25°C)
Equilibration Time 30 s
Mass 60g

ST-110 Specific Specifications

Measurement Uncertainty 0.1°C (from 0 to 70°C), 0.2°C (from -25 to 0°C), 0.4°C (from -50 to -25°C)
Equilibration Time 4 s
Mass 70g

ST-200 Specific Specifications

Measurement Uncertainty 0.2°C (from 0 to 70°C), 0.4°C (from -50 to 0°C)
Equilibration Time 1 s
Mass 60g

The ST-100 thermistor temperature sensor is a small thermistor enclosed in a weatherproof housing. It is suitable for measuring air and soil temperatures with a datalogger.

The ST-110 precision thermistor temperature sensor is optimised for air temperature measurement. Reflective white heat-shrink reduces solar loading on the cable behind the thermistor.  A constantan wire transition is used to minimise thermal conduction to the sensor tip.  The sensor is designed for long-term outdoor installations in radiation shields in all climates.

The ST-200 fine-wire thermistor is ideally suited for taking measurements of surfaces or small samples where even a narrow field of view infrared radiometer may not be suitable due to the integration over its conical field of view. The small size also provides a more rapid response to changes in temperature than larger sensors.

In spite of the small size, the ST-200 sensor is remarkably rugged and can be repeatedly pushed into plant tissues with a tweezers.  The wires are flexible so it is less sensitive to breakage than similarly-sized fine wire thermocouples.