109 Temperature Probe for CR200X-Series Dataloggers
Rugged, Accurate, Versatile
Can be used in a variety of applications
weather aplicaciones soportadas water aplicaciones soportadas energy aplicaciones soportadas gas flux and turbulence aplicaciones soportadas infrastructure aplicaciones soportadas soil aplicaciones soportadas


The 109 is a rugged, accurate probe that measures air, soil, and water temperature for a variety of applications. It consists of a thermistor encapsulated in an epoxy-filled aluminum housing. The housing protects the thermistor, allowing the 109 to be buried or submerged. The 109 measures from -50° to +70°C.

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Benefits and Features

  • Versatile product—measures air, soil, or water temperature
  • Wide temperature measurement range
  • Compatible with most Campbell Scientific data loggers
  • Easy to install or remove
  • Durable


Detailed Description

The 109 consists of a thermistor encapsulated in an epoxy-filled aluminum housing. The housing protects the thermistor allowing it to be buried in soil or submerged in water.

This probe outputs a 0 to 2.2 V signal when using 2500 mV excitation.


Output Analog
Operating Temperature Range -50° to +70°C
Sensor Description Measurement Specialties™ 10K3A1iA Thermistor
Tolerance ±0.2°C (over 0° to 70°C range)
Temperature Measurement Range -50° to +70°C
Steinhart-Hart Equation Error ≤ 0.03°C (-50° to +70°C)
Interchangeability Error ±0.1°C (over 0° to 70°C range increasing to ±0.5°C at -50°C)
Time Constant in Air 30 to 60 s (in a wind speed of 5 m s-1)
Maximum Submergence 15 m (50 ft)
Maximum Cable Length 305 m (1000 ft)
Probe Length 10.4 cm (4.1 in.)
Probe Diameter 0.76 cm (0.3 in.)
Weight 136 g (5 oz) with 3.05-m (10-ft) cable


Please note: The following shows notable compatibility information. It is not a comprehensive list of all compatible products.


Product Compatible Note
21X (retired)
CR10 (retired)
CR1000 (retired)
CR1000 (retired)
CR10X (retired)
CR200X (retired)
CR206X (retired)
CR211X (retired)
CR216X (retired)
CR23X (retired)
CR3000 (retired)
CR500 (retired)
CR5000 (retired)
CR510 (retired)
CR9000 (retired)
CR9000X (retired)

Additional Compatibility Information

Datalogger Considerations

The 109 was designed specifically for our CR200(X)-series dataloggers. Other dataloggers may measure the 109 probe, but the 107 and 108 temperature probes are more often used for dataloggers that can measure them.


The instruction set for our CR200(X)-series, CR800-series, CR1000, and CR3000 dataloggers contains the Therm109 instruction for measuring the 109 probe. Programming is more complicated for other dataloggers because they must use generic measurement instructions.

Compatible Contemporary Dataloggers

CR200(X) Series CR800/CR850 CR1000 CR3000 CR9000X CR6

Compatible Retired Dataloggers

CR500 CR510 CR10 CR10X 21X CR23X CR5000 CR9000 CR7X

Installation Considerations

Air Temperature

When exposed to sunlight, the 109 must be housed in a radiation shield. It is typically housed in a 41303-5A 6-plate naturally aspirated shield. It may also be housed in a 41003-5 10-plate shield if a 41322 Adapter Plate is used. The radiation shield mounts to a mast, tower leg, or crossarm.

Soil Temperature

The 109 is suitable for shallow burial only. Placement of the cable inside a rugged conduit may be advisable for long cable runs—especially in locations subject to digging, mowing, traffic, use of power tools, or lightning strikes.

Water Temperature

The 109 can be submerged to 50 ft. Please note that the probe is not weighted. Therefore, the installer should either add a weighting system or secure the probe to a fixed, submerged object, such as a piling.


Listed Under

Common Accessory for the following products: