The 107 is a rugged, accurate probe that measures temperature of air, soil, or water from -35° to +50°C. It easily interfaces with most Campbell Scientific dataloggers and can be used in a variety of applications.
The 107 consists of a thermistor encapsulated in an epoxy-filled aluminum housing. The housing protects the thermistor allowing the probe to be buried in soil or submerged in water.
One single-ended channel per probe is required; an excitation channel can be shared by several probes.
When exposed to sunlight, the 107 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 107 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 107 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.
To measure large numbers of probes, the AM16/32B multiplexer is recommended.
Number of FAQs related to 107: 10
Expand AllCollapse All
For descriptions and illustrations (with part numbers) of the various instruments used in measuring fuel temperature and moisture, see the "Remote Measurements" brochure.
Both of these dowels can be easily replaced in the field with a Phillips screwdriver and an adjustable wrench.
The thermistor is located approximately 3 mm (0.125 in.) back from the probe tip.
Both the 26601 10-Hour Fuel Moisture Stick (used with the CS506-L) and the CS205 10-Hour Fuel Temperature Stick (used with the 107-L) can be easily replaced in the field with a Phillips screwdriver and an adjustable wrench.
The dowels should be replaced each spring; more frequent replacements may be required in some environments. The more wet/dry cycles the dowels experience, the more frequently they will need to be replaced.
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 returned 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 dataloggers 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:
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:
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.
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 an application engineer at Campbell Scientific for assistance.