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 aluminium housing. The housing protects the thermistor, allowing the 109 to be buried or submerged. The 109 measures from -50° to +70°C.Read More
The 109 consists of a thermistor encapsulated in an epoxy-filled aluminium 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.
|Operating Temperature Range
|-50° to +70°C
|Measurement Specialties™ 10K3A1iA Thermistor
|±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)
|±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)
|15 m (50 ft)
|Maximum Cable Length
|305 m (1000 ft)
|10.4 cm (4.1 in.)
|0.76 cm (0.3 in.)
|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.
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 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.
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.
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.
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.
Number of FAQs related to 109: 8
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The thermistor is located approximately 3 mm (0.125 in.) back from the probe tip.
For both of these services, calibration can be made at different values if it is requested by the purchaser at the time of purchase. In addition, both of these calibration services can be requested after sensor purchase using a return material authorization (RMA) number. To request an RMA number, refer to the Repair and Calibration page.
The sensor/probe consists of a non-linear thermistor configured with a precision resistor in a half-bridge circuit, as shown in the product’s manual:
To measure the sensor/probe, the measurement device has to provide a precision excitation voltage (Campbell Scientific data loggers use 2000 mV), measure the voltage across the precision resistor, determine the thermistor resistance (Ohm's law), and convert the resistance to temperature using the Steinhart-Hart equation.
The Steinhart-Hart equation is 1/T = A + Bln(R) + C(ln(R))3 where:
For the 107-L, 107-LC, 108-L, and 108-LC, the following are the coefficients for the Steinhart-Hart equation:
For the 109-L, the following are the coefficients for the Steinhart-Hart equation:
Most Campbell Scientific sensors are available as an –L, which indicates a user-specified cable length. If a sensor is listed as an –LX model (where “X” is some other character), that sensor’s cable has a user-specified length, but it terminates with a specific connector for a unique system:
If a sensor does not have an –L or other –LX designation after the main model number, the sensor has a set cable length. The cable length is listed at the end of the Description field in the product’s Ordering information. For example, the 034B-ET model has a description of “Met One Wind Set for ET Station, 67 inch Cable.” Products with a set cable length terminate, as a default, with pigtails.
If a cable terminates with a special connector for a unique system, the end of the model number designates which system. For example, the 034B-ET model designates the sensor as a 034B for an ET107 system.
Not every sensor has different cable termination options. The options available for a particular sensor can be checked by looking in two places in the Ordering information area of the sensor product page:
If a sensor is offered in an –ET, –ETM, –LC, –LQ, or –QD version, that option’s availability is reflected in the sensor model number. For example, the 034B is offered as the 034B-ET, 034B-ETM, 034B-LC, 034B-LQ, and 034B-QD.
All of the other cable termination options, if available, are listed on the Ordering information area of the sensor product page under “Cable Termination Options.” For example, the 034B-L Wind Set is offered with the –CWS, –PT, and –PW options, as shown in the Ordering information area of the 034B-L product page.
Note: As newer products are added to our inventory, typically, we will list multiple cable termination options under a single sensor model rather than creating multiple model numbers. For example, the HC2S3-L has a –C cable termination option for connecting it to a CS110 instead of offering an HC2S3-LC model.
Note the difference between calibration and a field check. Calibration cannot be done in the field, as it requires an experienced technician and specialized equipment.
Field checks of measurements can be done to determine if the data make sense with the real-world conditions. Follow these steps to field check a sensor:
Many Campbell Scientific sensors are available with different cable termination options. These options include the following:
Note: The availability of cable termination options varies by sensor. For example, sensors may have none, two, or several options to choose from. If a desired option is not listed for a specific sensor, contact Campbell Scientific for assistance.
To incorporate a sensor that is compatible with wireless sensor interfaces into a wireless network, a CWS900-series wireless sensor interface is needed, as well as an A205 CWS-to-PC interface to configure it.