Agilent / HP 44708A

The HP 44708A is an analog signal multiplexer used to switch (multiplex) signals from up to 20 inputs for measurement by HP 3852A voltmeter accessories or by external voltmeters. This accessory provides switching capability for up to 20 inputs at scanning speeds up to 450 channels/second using HP 3852A voltmeters. The accessory can switch signals up to 120 V dc or 120 V ac rms (170 V peak).

The HP 44708A consists of a component module and a 20-channel terminal module. The HP 44708A uses the same component module as the HP 44705A. A special isothermal connector block on the terminal module provides the reference junction for thermocouple measurements. A thermistor mounted on the isothermal connector block is used to measure the isothermal block reference temperature. The HP 3852A uses software compensation to automatically compensate for the reference temperature when making thermocouple measurements.

Field wiring from user sources (such as voltage sources) is connected to the terminal module and signals are sent to the switches on the component module. Each channel on the HP 44708A can be independently configured to allow multiple functions to be measured using the same accessory.