Figure 1-2 Shunt Bar Testing - Keithley 2790 User Manual

Model 2790 SourceMeter
Figure 1-2
Shunt bar testing
Keithley 2790 SourceMeter Switch System
NOTE
NOTE
®
Switch System User's Manual
Keithley
7751,7752,
or 7753
Module
I
SOURCE
(1mA max)
If required, a more accurate resistance measurement of the shunt bar can be
achieved by disabling the dry circuit and using a test current of 50mA. An even
more accurate resistance measurement can be achieved using the Ω4 function of
the Model 2790. Keep in mind that this is an additional test and does not replace
the test using the dry circuit.
Use this 2-step process to detect the presence of oxide build-up and more
accurately measure the resistance of the shunt bar:
1. Test the shunt bar using dry circuit ohms (channel 24 closed) and a test
current of 1mA. A resistance >100mΩ indicates the presence of oxide
build-up.
2. Accurately measure shunt bar resistance without dry circuit (channel 24
open) and a test current of 50mA or use the Ω4 function of the Model 2790.
Section 6 explains how to use the Ω4 function of the Model 2790 with the
7702 or 7751/7752/7753 module.
Shunt Bar
20mV
Under
Dry
Test
Ckt
(R )
SHUNT
v
V
2790
R =
SHUNT
DMM
I
1-7
MEAS
SOUR