Chapter 3 System Overview

Signal Routing and SwitchingSignal Routing and Switching

The switching capabilities of the plug-in modules available with the HP 34970A provide test system flexibility and expandability. You can use the switching plug-in modules to route signals to and from your test system or multiplex signals to the internal DMM or external instruments.

Relays are electromechanical devices which are subject to wear-out failure modes. The life of a relay, or the number of actual operations

before failure, is dependent upon how it is used – applied load, switching 3 frequency, and environment. The HP 34970A Relay Maintenance System automatically counts the cycles of each relay in the instrument and

stores the total count in non-volatile memory on each switch module. Use this feature to track relay failures and to predict system maintenance requirements. For more information on using this feature, refer to “Relay Cycle Count” on page 147.

Switching Topologies

Several switching plug-in modules are available with different topologies for various applications. The following switching topologies are available:

∙Multiplexer (HP 34901A, 34902A, 34905A, 34906A, 34908A)

∙Matrix (HP 34904A)

∙Form C – Single Pole, Double Throw (HP 34903A)

The following sections describe each of these switching topologies.

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