34908A 40-Channel Single-Ended Multiplexer - Agilent Technologies 34901A User Manual

Chapter 4 Features and Functions

34908A 40-Channel Single-Ended Multiplexer

34908A 40-Channel Single-Ended Multiplexer
The module is divided into two banks of 20 channels each. All of the
40 channels switch HI only, with a common LO for the module.
The module has a built-in thermocouple reference junction to minimize
errors due to thermal gradients when measuring thermocouples.
Internal
DMM Input
Reference
Junction
Sensor
NOTES:
•
Refer to the diagrams on page 20 to connect wiring to the module.
•
Only one channel can be closed at a time; closing one channel will open the previously
closed channel.
•
This module cannot be used to directly measure current or any 4-wire measurements.
•
When connecting thermocouples to the screw terminals on this module (not recommended
due to the common LO configuration), be sure to provide electrical isolation between
thermocouples to avoid current loops and subsequent measurement errors.
•
Connections to ac line are not recommended unless you provide external transient suppression.
Maximum Input Voltage: 300 V (CAT I)
Maximum Input Current: 1 A
Maximum Switching Power: 50 W
WARNING: To prevent electrical shock, use only wire that is rated for the highest voltage applied
to any channel. Before removing a module cover, turn off all power to external devices connected to
the module.
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Channel Switches
Backplane
Switch
Bank Switch
99
98
01
20
Com
Com
21
40
20 AWG Typical
6 mm