ILX Lightwave LDC-3900 User Manual

The Steinhart-Hart Equation
180 LDC-3900 Series
CHAPTER A

1 Resistance of a 10 k, Dale 1T1002-5 thermistor
2 Constants A' = 0.99 * 10
-3
, B' = 2.57 * 10
-4
(C1 = 0.99, C2 = 2.57).
Table A.1 Comparison of Curve Fitting Equations
For the LDC-3900, the Steinhart Hart equation has been simplified to a first order
polynomial:
1/T = A' + B' * ln R Equation 2
This equation is easier to solve and provides adequate results. Table A.1 also
shows that the use of Equation 2 introduces temperature errors of less than 0.3
o
C
over the range 20
o
C to 50
o
C, with accuracies of up to 0.06
o
C over smaller
temperature ranges near room temperature
2
.
Error T (
o
C) Error T (
o
C)
R
1
T Actual Third Order Fit Eq 1 First Order Fit Eq 2
32128 0.00 -0.0000 -0.23
19549 10.00 0.0005 -0.11
12262 20.00 -0.0001 -0.06
9814 25.00 -0.0002 -0.06
7908 30.00 0.0009 -0.07
5331 40.00 0.0003 -0.15
3542 50.00 -0.0030 -0.30

ILX Lightwave LDC-3900 Specifications

General

Brand	ILX Lightwave
Model	LDC-3900
Category	Controller
Language	English