Table of Contents
Advertisement
Chapter 4 Features and Functions
HP 34908A 40-Channel Single-Ended Multiplexer
HP 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 isothermal block 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 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, be sure to
provide electrical isolation between thermocouples.
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.
176
Channel Switches
Bank Switch
99
20 AWG Typical
6 mm
01
20
Com
Com
21
40
Advertisement
Table of Contents
