Part 2

DESCRIPTIONEXAMPLE 64-WIRE RESISTANCEMEASUREMENTSExample 3497A Configurations 579The VOLTAGE MEASUREMENTS examples showed some ways that the 20 ChannelRelay Multiplexer assembly (Option 010) can be used to measure voltages in-put to the 3497A. The Option 010 assembly can also be combined with the currentsource in the 3497A internal DVM (Option 001) to make resistancemeasurements. In this example, we'll show a way to make 4-wire ohmsmeasurements. If your application does not require highly accurate measurements,see the 2-WIRE RESISTANCE MEASUREMENTS example (EXAMPLE 5).PROCEDUREFigure 191 illustrates the procedure for making 4-wire resistance measurements andshows a connection diagram for the Option 010 assembly. J-he current source outputfrom the 3497A is connected to the Decade B COMMON connector. Jumpers-- - _ _ _ . ----L_---J4, J5 and J6 must be opened since it is necessary to close two channels-- -simultaneously (by using the k- chan#,chan# command).& -When the current source is set for a specified output (10 PA, 100 pA or 1 mA) anda channel relay is closed, the voltage drop across the channel resistance can bemeasured and, since the current I is known, the resistance computed from R = Ell.CONFIGURATIONWith 4-wire ohms techniques, you can measure the resistance of up to 10 resistorswith a single Option 010 assembly or up to 50 resistances per 3497A. See Figure191 which shows connections for a resistor tied to channels A0 and BO.ejumperthat the current source from the 3497A rear panel CURRENT SOURCE terminalsLis connected to the B COM connector on the Option 010 terminal card by a shieldedtwisted pair (for better measurement accuracy).When the terminal card is configured, check the relay card to ensure that the TICis in the NO TIC COMP position before installing the assembly in the 3497A.To use the program shown, install the assembly in slot 3.Artisan Technology Group - Quality Instrumentation ... Guaranteed | (888) 88-SOURCE | www.artisantg.com