National Instruments SCB-68 - Manual (Page 43)

© National Instruments Corporation 4-1 SCB-68 Shielded Connector Block User Manual
4
Using Thermocouples
This chapter describes how to take thermocouple measurements using the
SCB-68. A thermocouple is created when two dissimilar metals touch, and
the contact produces a small voltage that changes as a function of
temperature. By measuring the voltage of a thermocouple, you can
determine temperature using a nonlinear equation that is unique to each
thermocouple type. Thermocouple types are designated by capital letters
that indicate their composition according to the American National
Standards Institute (ANSI) conventions. To determine the type of
thermocouple that you are using, refer to Table 4-1. For more information
on the theory of operation of thermocouples, refer to the NI Developer
Zone tutorial, Measuring Temperature with Thermocouples, at
ni.com/zone .
Table 4-1. Thermocouple Coloring
Thermocouple
Type Positive Color Negative Color
Thermocouple
Cover Color
Extended
Grade Cover
Color
B Gray Red — Gray
C White/Red Trace Red — White/Red Trace
E Purple Red Brown Purple
J White Red Brown Black
K Yellow Red Brown Yellow
N Orange Red Brown Orange
R Black Red — Green
S Black Red — Green
U Black Red — Green
T Blue Red Brown Blue