Dual Multiplexer Application - Keithley 2700 User Manual

Model 2700 Multimeter/Switch System User's Manual

Dual multiplexer application

This application demonstrates how to use the Model 7700 as a dual multiplexer to bias and
measure 10 DUT. An external source powers DUT, while the DMM of the Model 2700
measures the output of the DUT. To prevent overloading of the external source, each DUT
is powered (and measured) separately.
Figure 2-9
the Sense terminals of the switching module, and DUT is connected to channels 1 through
10. Channels 11 through 20 are used to connect external power to each DUT.
For this application, the 2-pole/4-pole relay and backplane isolation relays of the switch-
ing module are to be controlled as follows:
•
•
•
In Figure
for DUT 1 is shown in
ferent source and measure channels are closed. Closed channels for each DUT test are
listed as follows:
Tested
device
DUT 1
DUT 2
DUT 3
DUT 4
DUT 5
NOTE
shows the connections for this application. The external source is connected to
Closing channel 23 isolates the input measurement channels (1 through 10) from
the external source channels (11 through 20). It also connects the DUT to the exter-
nal source. This channel must remain closed while testing DUT.
Opening channel 24 isolates the external source from the backplane of the Model
2700. This channel must remain open while testing DUT.
Closing channel 25 connects an input channel (1 through 10) to the DMM.
2-9, channels 1 and 11 are closed to test DUT 1. A more detailed view of the test
Figure
Closed channels
1, 11, 23 and 25
2, 12, 23 and 25
3, 13, 23 and 25
4, 14, 23 and 25
5, 15, 23 and 25
Do not use this application to measure the temperature of DUT using a
thermocouple with the INTernal or EXTernal reference junction selected. The
SIMulated reference junction will instead be used resulting in invalid readings.
The "ERR" annunciator will turn on to indicate that the integrity of the
temperature reading is questionable.
Close/Open Switching Module Channels
2-10. The test for the other DUTs is similar except that dif-
Tested
device
DUT 6
DUT 7
DUT 8
DUT 9
DUT 10
Closed channels
6, 16, 23 and 25
7, 17, 23 and 25
8, 18, 23 and 25
9, 19, 23 and 25
10, 20, 23 and 25
2-21