Model 109SS Temperature Probe
The resistance of the thermistor is:
⎟
⎠
⎞
⎜
⎝
⎛
−
=
1
900
,
24
V
V
R
EX
t
The Steinhart and Hart equation is used to calculate temperature from
Resistance:
3
))
(ln(
)
ln(
1
T
T
K
R
C
R
B
A
T
+
+
=
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
7. Maintenance and Calibration
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.
8. Troubleshooting
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.
NOTE
11
