Black Box IC026AE-R2, IC026A-R2 manual Ieee 488 Primer, History, General Structure

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CHAPTER 6: IEEE 488 Primer

6. IEEE 488 Primer

6.1 History

The IEEE 488 bus is an instrumentation-communication bus adopted by the Institute of Electrical and Electronic Engineers in 1975 and revised in 1978. The interface converter conforms to this most recent revision, designated IEEE 488-1978.

Before this standard was adopted most instrumentation manufacturers offered their own versions of computer interfaces. This placed the burden of system hardware design on the end user. If your application required the products of several different manufacturers, then you might need to design several different hardware and software interfaces.

The popularity of the IEEE 488 interface (sometimes called the General Purpose Interface Bus or GPIB) is due to the total specification of the electrical and mechanical interface as well as the data transfer and control protocols. The use of the IEEE 488 standard has moved the responsibility of the user from design of the interface to design of the high-level software that is specific to the measurement application.

6.2 General Structure

The main purpose of the GPIB is to transfer information between two or more devices. A device can either be an instrument or a computer. Before any information transfer can take place, it is first necessary to specify which will do the talking (send data) and which devices will be allowed to listen (receive data). The decision of who will talk and who will listen usually falls on the System Controller, which is the Active Controller at power-on.

The System Controller is similar to a committee chairman. On a well-run committee, only one person may speak at a time and the chairman is responsible for recognizing members and allowing them to have their say. On the bus, the device that is recognized to speak is the Active Talker. There can only be one Talker at a time if the information transferred is to be clearly understood by all. The act of “giving the floor” to that device is called Addressing to Talk. If the committee chairman cannot attend the meeting, or if other matters require his attention, he can appoint an acting chairman to take control of the proceedings. For the GPIB, this device becomes the Active Controller.

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Contents RS-232↔IEEE Interface Converter RS-232↔IEEE 488 Interface Converter Trademarks Used in this Manual RS-232↔IEEE 488 Interface Converter NOM Statement RS-232↔IEEE 488 Interface Converter Contents RS-232↔IEEE 488 Interface Converter Contents Serial Interface SpecificationsIEEE-488 Interface General SpecificationsDescription IntroductionAbbreviations Getting Started ConfigurationInspection Serial PortSW3 Serial Port Settings Switch SW1 Selecting the Serial Baud Rate Switch SW1 Selecting the Serial Word Length Data Bits Switch SW2 Selecting the Serial Parity Switch SW1 Selecting the Serial Handshake Selecting Terminator Substitution Switch SW2 Selecting the Serial TerminatorSwitch SW3 Selecting the Ieee Bus Terminator Selecting the ModeSelecting the Ieee Address 10. Switch SW2 Selecting the ModeFeature Selections Serial Interface 15. Selecting RS-232 or RS-422 Signal Levels TxD Transmit Data-Output-Pin RxD Receive Data-Input-PinClear To Send-Input-Pin Request To Send-Output-PinGnd Ground-Pin Vtest Test Voltage-Output-Pin+RxD Receive Data Plus-Input-Pin +TxD Transmit Data Plus-Output-PinRTS CTS DSR RTS CTS GeneralGetting Started Controller-Mode Serial to Ieee Operation Controller OperationSerial and Ieee Terminator Substitution Ieee Address Selection Talk-Back FeaturesSwitch SW1 Enabling or Disabling Talk-Back on Terminator Switch SW2 Enabling or Disabling Talk-Back on Timeout SP1PA1000,1000PDPA1000,6000PUSP0 7470APlotter Applications A PC-Based Graphics System SW3 MacPlot Configuration Screen Setting the Internal DIP Shorting Jumper for RS-422 SW3 Printer Applications Serial and Ieee Input Buffers Peripheral OperationPeripheral-Mode Operation Ieee Data Transfers Controlled BUS Data Transfers DIO8 Ieee Input Buffer not Empty Serial-Poll Status-Byte RegisterNot Defined-Always RsvSerial Input Buffer not Empty Ieee Input Buffer FullIeee 488 Bus Implementation Use of Serial and Bus TerminatorsUntalk UNT SW3 View for Ieee Address Selection General Structure Ieee 488 PrimerHistory RS-232↔IEEE 488 Interface Converter DMM Send It to My AddressBus Management Lines Data Valid DAV Handshake LinesData Lines Multiline CommandsTalk Address Group TAG More on Service Requests Serial Poll Address Device Part Number Function Theory of OperationComponent Layout of the Interface Converter’s Motherboard Board LayoutRED BLK CLS Appendix A. Sample Dumb-Terminal ProgramSOH Multiline MessagesAscii Character How To Read the ChartDIO1 DIO2 DIO3 IndexIndex SW1 Copyright 1998. Black Box Corporation. All rights reserved
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