34901A 20-Channel Multiplexer - Agilent Technologies 34972A User Manual

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.
Backplane Switches
Internal
DMM Input
98
Reference
99
Junction
Sensor
Internal
DMM Input
(4W Sense)
97
Internal
DMM Input
(Current)
96
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.
Chapter 4 Features and Functions

34901A 20-Channel Multiplexer

Channel Switches
Bank Switches
Shunt Switches
Fuse
93
Fuse
94
01
10
Com
Com (4W Sense)
11
20
21
Current Channels
22
Com (Current)
201
4