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1. worst-case probe and measurement errors, 2. steinhart-hart linearization error – Campbell Scientific 109SS Temperature Probe User Manual

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Model 109SS Temperature Probe

Maximum

Steinhart-Hart

Linearization Error:

0.02 °C at –40 °C

FIGURE 6-1. Worst-case probe and measurement errors

FIGURE 6-2. Steinhart-Hart linearization error

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The overall probe accuracy is a combination of the thermistor interchangeability specification and the

accuracy of the bridge resistor. The Steinhart-Hart equation used in CRBasic instruction

Therm109()

(CRBasic dataloggers) has negligible error. The major error component is the interchangeability

specification of the thermistor. The bridge resistor has a 0.1% tolerance with a 10 ppm temperature

coefficient.

-0.005

0

0.005

0.01

0.015

0.02

0.025

0.03

-50

-40

-30

-20

-10

0

10

20

30

40

50

60

70

Er

ror

D

egr

ees

C

Temperature Degrees C

Steinhart & Hart - Tabulated values

5