Campbell Manufacturing TEMPERATURE PROBE 109SS User Manual

The resistance of the thermistor is: 

⎟

⎠

⎞

⎜

⎝

⎛

−

=

1

900

,

24

 

The Steinhart and Hart equation is used to calculate temperature from 
Resistance: 

3

))

(ln(

)

ln(

1

+

+

=

 

Where T

K

 is the temperature in Kelvin.  The Steinhart and Hart coefficients 

used in the Therm109 instruction are: 

A = 1.129241x10

-3

 

B = 2.341077x10

-4

 

C = 8.775468x10

-8 

The 109SS Probe requires minimal maintenance.  Periodically check cabling 

for proper connections, signs of damage, and possible moisture intrusion.  For 

all factory repairs and recalibrations, customers must get a returned materials 

authorization (RMA).  Customers must also properly fill out a “Declaration of 

Hazardous Material and Decontamination” form, and comply with the 

requirements specified in it.  Refer to the “Warranty and Assistance” page for 

more information. 

Symptom:  Temperature is NAN, -INF, -9999, -273 

Verify the red wire is connected to the correct Single-Ended analog input 
channel as specified by the measurement instruction, the black wire is 
connected to the switched excitation channel as specified by the measurement 
instruction, and the purple wire is connected to datalogger ground.  

Symptom:  Incorrect Temperature 

Verify the multiplier and offset parameters are correct for the desired units 
(Section 5).  Check the cable for signs of damage and possible moisture 
intrusion. 

For all factory repairs, customers must get an RMA.  Customers 
must also properly fill out a “Declaration of Hazardous Material 
and Decontamination” form and comply with the requirements 
specified in it.  Refer to the “Warranty and Assistance” page for 
more information.