HP 34970A manual HP 34908A 40-Channel Single-Ended Multiplexer

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.

	Channel Switches
	01
	20
Backplane	Com
	Com
Switch
Internal	Bank Switch
DMM Input	99
98
	21

Reference	40
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)	20 AWG Typical
Maximum Input Current: 1 A
Maximum Switching Power: 50 W		6 mm

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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