Campbell Scientific 108-LC Temperature Probe for MetData1 - Manual (Page 5)

1
Model 108-LC Temperature Probe
for MetData1
1. General
The 108 Air/Soil/Water Temperature Probe uses thermistors to measure
temperature. Custom lead lengths are available up to 1000 ft.
For air temperature measurement, a 41303 radiation shield is needed to mount
the 108 Probe and limit solar radiation loading of the 108. The 108 probe is
designed to be buried or submerged in water up to 100 feet.
1.1 Specifications
Temperature Measurement Range: -5
° to +95°C
Thermistor Interchangeability Error: Typically <
±0.2°C over 0°C to 70°C ±0.3
@ 95
°C.
Polynomial Linearization Error: <
±0.5°C over -7°C to +90°C.
The black outer jacket of the cable is Santoprene ® rubber. This
compound was chosen for its resistance to temperature extremes,
moisture, and UV degradation. However, this jacket will support
combustion in air. It is rated as slow burning when tested
according to U.L. 94 H.B. and will pass FMVSS302. Local fire
codes may preclude its use inside buildings.
2. Accuracy
The overall probe accuracy is a combination of the thermistor's
interchangeability specification, the precision of the bridge resistors, and the
polynomial error. In a "worst case" all errors add to an accuracy of ±0.3
°C
over the range of -3
° to 90°C and ±0.7°C over the range of -7°C to 95°C. The
major error component is the interchangeability specification of the thermistor,
tabulated in Table 2-1. For the range of 0
° to 50°C the interchangeability error
is predominantly offset and can be determined with a single point calibration.
Compensation can then be done with an offset entered in the measurement
instruction. The bridge resistors are 0.1% tolerance with a 10 ppm temperature
coefficient. Polynomial errors are tabulated in Table 2-2 and plotted in Figure
2-1.
NOTE