Campbell Scientific 107 107-L Temperature Probe - Page 17

Model 107 Temperature Probe TABLE 8-1. 107 Measurement Details Datalogger Model CR800 CR1000 CR3000 CR5000 Measurement Instruction CRBasic Therm107() Excite mV Result Scaling Equation Applied to Scaled Result Steinhart-Hart (automatically applied) CR10 CR10X CR500 CR510 CR23X Edlog Temp(107)(P11) 2000 Vs/Vx Multiply by 800‡ Fifth-order polynomial (automatically applied) 21X CR7(X) Edlog Temp(107)(P11) 4000 Vs/Vx Multiply by 800‡ Fifth-order polynomial (automatically applied) † Fixed series resistance is subtracted before applying Steinhart-Hart. ‡ Multiplier of 800 scales Vs/Vx for the polynomial fit. TABLE 8-2. Temperature Calculation CRBasic Dataloggers1 Therm107() instruction measures the ratio Vs/Vx, calculates the thermistor resistance Rs, and converts Rs to temperature using the Steinhart-Hart equation2: T = 1 / (A + (B • ln(Rs))) + (C • ((ln(Rs))) ^ 3) - 273.15 where: T = temperature in Celsius A = 8.271111E-4 B = 2.088020E-4 C = 8.059200E-8 Edlog Dataloggers3 Temp(107) (P11) instruction measures the ratio Vs/Vx and coverts it to temperature using a fifth-order polynomial: T = C0 + C1•X + C2•X^2 + C3•X^3 + C4•X^4 + C5•X^5 where: X = (Vs/Vx) • 800 C0 = -53.4601 C1 = 9.0807 C2 = -0.83257 C3 = 0.052283 C4 = -0.0016723 C5 = 0.00002211 See Appendix C, Thermistor Resistance Table. 1CRBasic dataloggers are CR800, CR1000, CR3000, and CR5000. 2Coefficients provided by the thermistor manufacturer. 3 Edlog dataloggers are CR10(X), CR500, CR510, CR23X, 21X, and CR7. 11