272
Chapter 7 Tutorial
Measurement Fundamentals
In some measurement situations, however, it would be nice to remove
the need for an ice bath (or any other fixed external reference). To do
this, an
isothermal block
is used to make the connections. An isothermal
block is an electrical insulator, but a good heat conductor. The additional
thermocouples created at J1 and J2 are now held at the same
temperature by the isothermal block.
Once the temperature of the isothermal block is known, accurate
temperature measurements can be made. A temperature sensor is
mounted to the isothermal block to measure its temperature.
Thermocouples are available in a variety of types. The type is specified
by a single letter. The table on the following page shows the most
commonly used thermocouple types and some key characteristics of each.
Note
:
The thermocouple conversion routines used by the 34970A/34972A
are compatible with the International Temperature Scale of 1990 (ITS-
90).
Measurement
Thermocouple
Internal DMM
Reference
Temperature
Reference
Sensor
Isothermal Block
(Internal or External Reference)
34970A Refresh UG.book Page 272 Wednesday, February 17, 2010 12:34 PM
Summary of Contents for 34970A
Page 16: ...16 34970A Refresh UG book Page 16 Wednesday February 17 2010 12 34 PM ...
Page 20: ...34970A Refresh UG book Page 20 Wednesday February 17 2010 12 34 PM ...
Page 21: ...1 1 Quick Start 34970A Refresh UG book Page 21 Wednesday February 17 2010 12 34 PM ...
Page 39: ...2 2 Front Panel Overview 34970A Refresh UG book Page 39 Wednesday February 17 2010 12 34 PM ...
Page 59: ...3 3 System Overview 34970A Refresh UG book Page 59 Wednesday February 17 2010 12 34 PM ...
Page 87: ...4 4 Features and Functions 34970A Refresh UG book Page 87 Wednesday February 17 2010 12 34 PM ...
Page 217: ...5 5 Error Messages 34970A Refresh UG book Page 217 Wednesday February 17 2010 12 34 PM ...
Page 241: ...6 6 Application Programs 34970A Refresh UG book Page 241 Wednesday February 17 2010 12 34 PM ...
Page 254: ...254 34970A Refresh UG book Page 254 Wednesday February 17 2010 12 34 PM ...
Page 255: ...7 7 Tutorial 34970A Refresh UG book Page 255 Wednesday February 17 2010 12 34 PM ...
Page 324: ...324 34970A Refresh UG book Page 324 Wednesday February 17 2010 12 34 PM ...