34908A 40-Channel Single-Ended Multiplexer - Agilent Technologies 34972A User Manual

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.
Backplane
Switch
Internal
DMM Input
98
Reference
Junction
Sensor
NOTES:
• Refer to the diagrams on page 27 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
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.
Chapter 4 Features and Functions

34908A 40-Channel Single-Ended Multiplexer

Channel Switches
Bank Switch
99
20 AWG Typical
6mm
01
20
Com
4
Com
21
40
213