Keithley 3730 User Manual

Section
5: Basic Digital Multimeter (DMM) Operation Series 3700 System Switch/Multimeter
User's Manual
5
-40 Document Number: 3700S-900-
01 Rev. A / August 2007
When using the Series 3700 analog backplane connector, use a simulated reference junction for
thermocouple temperature measurements. An ice bath, as shown below, serves as an excellent
cold junction since it is relatively easy to hold the temperature to 0°C. Notice that copper wires
are used to connect the thermocouple to the Series 3700 input.
Figure 5-23: Simulated reference junction
NOTE The positive lead of the type T thermocouple is made of copper. Therefore, that lead
can be connected directly to the input of the switching module (it does not have to be
maintained at the simulated reference temperature, in other words, immersed in an ice
bath).
For the thermocouple-capable switching modules, you can also use a simulated reference
junction as shown, or you can connect the thermocouple wires directly to the screw terminals
(internal reference junction). Using a simulated reference junction may be inconvenient, but it
will provide more accurate temperature measurements (assuming the user enters a precise
reference temperature).
Figure 5-24: Simulated reference junction switching module
Figure 5-25: Internal reference junction (40 channel switching module)

Keithley 3730 Specifications

General

Brand	Keithley
Model	3730
Category	Multimeter
Language	English