Cs107 Temperature Sensor (Cs107Temp) - Sutron Xpert2 Operation And Maintenance Manual

CS107 Temperature Sensor (CS107Temp)

Inputs
<none>
Outputs
Temp
Wiring
Connect the Thermistor black wire to the selected signal channel of the analog module
CH1..CHxx
Connect a precision 100K 0.1% resistor between CHx above and the selected excitation channel
CH1..CH8.
NOTE: DO NOT USE CHANNELS ABOVE 8 FOR EXCITATION
Connect the Thermistor red to GND
Do not connect the purple AG to anything. Keep it insulated so it will not contact anything.
Connect the clear shield to GND.
Description
This block measures a CS 107 temperature probe. The CS 107 uses a thermistor to measure
temperature in air/soil or water over the range of –35 to +50C with an accuracy of about 0.5C.
The Xpert measures the CS107 using its special double voltage reading where it measures its
excitation voltage in addition to the signal voltage. The nominal excitation voltage is 5 volts.
After making the measurement, the temperature is computed as follows:
R = VM*100000./(VX-VM)
Where R is the resistance of the thermistor, VM is the measured excitation voltage and VX is the
measured signal voltage.
X = 800000/(R) (this converts the resistance to a format compatible with the published
conversion polynomial.
Temp = a + b*X + c*X
Where:
Temp = temperature in degrees Celsius
a = -53.4601;b = 90.807;c = -83.257;d = 52.283;e = -16.723;f = 2.211
159
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+ d*X +e*X + f*X
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