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Chapter 4 Features and Functions
34901A 20-Channel Multiplexer
4
34901A 20-Channel Multiplexer
This module is divided into two banks of 10 channels each. Two
additional fused channels are available for making direct, calibrated DC
or AC current measurements with the internal DMM (external shunts
are not required). All 22 channels switch both HI and LO inputs, thus
providing fully isolated inputs to the internal DMM or an external
instrument. When making 4-wire resistance measurements, the
instrument automatically pairs channel
n
with channel
n+10
to provide
the source and sense connections. The module has a built-in
thermocouple reference junction to minimize errors due to thermal
gradients when measuring thermocouples.
NOTES:
•
Only one of channels 21 and 22 can be connected to the internal DMM and/or Com at a
time; connecting one channel will close the other (thus shorting the input “I” to “LO”).
•
If any channels are configured to be part of the scan list, you cannot close multiple
channels; closing one channel will open the previously closed channel.
•
Connections to AC line are not recommended unless you provide external transient
suppression.
Backplane Switches
Channel Switches
Internal
DMM Input
Reference
Sensor
Internal
DMM Input
(4W Sense)
Internal
DMM Input
(Current)
01
10
Com
Com (4W Sense)
11
20
21
Current Channels
22
Com (Current)
98
99
97
96
Fuse
Fuse
94
93
Bank Switches
Shunt Switches
Junction
34970A Refresh UG.book Page 201 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 ...