Campbell Scientific 109SS Temperature Probe - Manual (Page 17)

Model 109SS Temperature Probe
where:
Tk = temperature in Kelvin
X = 0.001 • ln(Rs)
C0 = A = 0.001129
C1 = B • 1E3 = 0.234108
C2 = 0
C3 = C • 1E9 = 87.7547
C4 = 0
C5 = 0
See Appendix C, Thermistor Resistance Table.
1 CRBasic dataloggers are CR800, CR1000, CR3000, and CR5000.
2 Coefficients provided by the thermistor manufacturer.
3 Edlog dataloggers are CR10(X), CR510, CR500, CR23X, 21X, and CR7.
8.3 Electrically Noisy Environments
EMF noise emanating from the ac mains power grid can be a significant source
of measurement error. 60 Hz noise is common in the United States. 50 Hz
noise is common in Europe and other regions. Depending on the datalogger
model, this noise can usually be filtered out.
The following code examples filter 60 Hz noise. The key parameters are in
bold type.
CRBasic
Therm109 (T109_C,1,1,1,20000,_60Hz,1.0,0.0)
Filtering parameter options are not available for CR200(X) series
dataloggers.
Edlog
1: AC Half Bridge (P5)
1: 1
Reps
2: 25 2500 mV 60 Hz Rejection Range ;CR23X:5000 mV; 21X,CR7:5000 mV slow
3: 1 SE Channel
4: 1 Excite all reps w/Exchan 1
5: 2500 mV Excitation ;CR23X,21X,CR7: 5000 mV
6: 1 Loc [ V_Vx ]
7: 1.0 Mult
8: 0.0 Offset
8.4 Long Cable Lengths
Long cable lengths may require longer than normal analog measurement
settling times. Settling times are increased by adding a measurement delay to a
datalogger program.
CRBasic
For CRBasic loggers, the 60 Hz and 50 Hz integration options include a 3 ms
settling time; longer settling times also can be entered into the Settling Time
parameter. The following example uses a 20000 µs settling time:
NOTE
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