Part 2

624 Interface ConceptsHP-IBBUS COMPATIBLEDEVICESmDEVICEAVAILABLECOMPUTERPERIPHERALSIPERIPHERAL- I 1DEVICEEl=DEVICEfPERIPHERALI I I0HEWLETT0 PACKAROINTERFACE0BUSFigure A-1. Typical HP-IB SystemHP-IBStructureAs shown in Figure A-2, the HP-IB is a parallel bus of 16 active signal lines, groupedinto 3 functional sets, to interconnect up to 15 instruments.Eight signal lines, called the DATA lines, are used to transmit data in the form ofcoded messages. These messages are used to program the instrument function,transfer measurement data, coordinate instrument operation and to manage thesystem. Input and output of messages, in bit parallel-byte serial format, are alsotransferred in the DATA lines. A 7-bit ASCII code normally represents each pieceof data.The three DATA BYTE TRANSFER CONTROL lines coordinate and control transferof data by means of an interlocking "handshake" technique which permits asynchronousdata transfer at the rate of the slowest active device used in that transfer.Artisan Technology Group - Quality Instrumentation ... Guaranteed | (888) 88-SOURCE | www.artisantg.com