Part 2

434 Plug-In Assembly ConfigurationThe assemblies require an external power supply for bridge excitation and a DVM(such as the internal 3497A DVM, -hp- 3456A voltmeter or equivalent DVM). Initialvoltmeter readings for bridge excitation and bridge unbalance are used to solvethe bridge equation, eliminating the need for any span and offset adjustments. Tocompute strain, the assembly should be used with a controller. Data acquisition andstrain calculation can be done manually, however.The excitation voltage, Vs, is always applied, never switched, so there are no errorsdue to dynamic heating and cooling of the transducer. Since the excitationvoltage is measured on each assembly, measurement accuracy is independent of longterm power supply voltage changes and an inexpensive supply (such as the -hp-Model 6214A or 62005A) is adequate to achieve listed specifications. The Model6214A can provide power for 50 channels (5 assemblies) while the 62005A canpower up to 80 channels.RELAY CARDTERMINAL CARDDiagnostic TestsFigure 109. Options 0701071 - Strain GaugeIBridge AssembliesSeveral diagnostic tests are available on the 44427AiB assemblies to check circuitintegrity or enhance measurement accuracy. Each assembly consists of 20 channelswith the first 10 channels reserved for strain gauge inputs. The remaining 10 channels(60 through 69) can be used for measuring the excitation voltage and fordiagnostic tests.Artisan Technology Group - Quality Instrumentation ... Guaranteed | (888) 88-SOURCE | www.artisantg.com