National Instruments GPIB-120A Acceptable Identification Codes

Theory of Operation Chapter 3

GPIB-120A User Manual 3-4 © National Instruments Corporation

Acceptable Identification Codes

Bus A and Bus B of the GPIB-120A are each capable of appearing as a GPIB device having the

GPIB capabilities listed in Table 3-1. For a complete description of each code, consult the

ANSI/IEEE Standard 488.1-1987, IEEE Standard Digital Interface for Programmable

Instrumentation.

Table 3-1. IEEE 488 Capability Identification Codes

Capability Code Description

SH1 Source Handshake

AH1 Acceptor Handshake

T5, TE5 Talker, Extended Talker

L3, LE3 Listener, Extended Listener

SR1 Service Request

RL1 Remote/Local

PP1, PP2 Parallel Poll

DC1 Device Clear

DT1 Device Trigger

C1, C2, C3, C4, C5 Controller

E1, E2 Three-state bus drivers with automatic switch

to open collector during parallel poll

Contents

Main Page Limited Warranty Copyright Trademarks WARNING REGARDING MEDICAL AND CLINICAL USE OF NATIONAL INSTRUMENTS PRODUCTS FCC/DOC Radio Frequency Interference Compliance Federal Communications Commission Canadian Department of Communications Instructions to Users Danger Contents Page About This Manual Organization of This Manual Conventions Used in This Manual Page Chapter 1 Introduction Description of the GPIB-120A Page What You Need to Get Started Optional Equipment Unpacking Your GPIB-120A Chapter 2 Connection Isolation Considerations Placing Your Instruments Connecting the GPIB-120A Connecting to Hewlett-Packard Controllers Mounting the GPIB-120A Chapter 3 Theory of Operation Circuitry of the GPIB-120A The GPIB-120A Front Panel Power On System Controller Detection Active Controller Detection Source Handshake Detection Data Direction Control Parallel Poll Detection Acceptable Identification Codes Appendix A Operation of the GPIB History of the GPIB GPIB Operation Types of Messages Talkers, Listeners, and Controller The Controller-In-Charge and System Controller GPIB Signals and Lines Page Appendix A Operation of the GPIB National Instruments Corporation A-5 GPIB-120A User Manual Physical and Electrical Characteristics Figure A-1. GPIB Connector and the Signal Assignment Page Page Configuration Restrictions: The Role of Expanders and Extenders Related Document Appendix B Specifications Page Page Multiline Interface Messages Hex Oct Dec ASCII Msg Hex Oct Dec ASCII Msg Message Definitions Multiline Interface Messages Hex Oct Dec ASCII Msg Hex Oct Dec ASCII Msg Appendix D Customer Communication Technical Support Form ___________________________________________________ GPIB-120A Hardware and Software Configuration Form Documentation Comment Form Glossary ___________________________________________________