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Section 5 - Remote Operation
Introduction
The IEEE-488 interface sometimes called GPIB (General Purpose Interface Bus) or
HPIB (Hewlett Packard Interface Bus) allows remote control of the 9814 by a suitable
computer. Repetitive calibration work can be speedily and accurately carried out giving
printed results if required.
The IEEE-488 defines a complete interface system for the interconnecting of instru-
ments and computers using a bit parallel, byte serial bi-direction bus.
Protocols, connections and cables are also defined, enabling computer controlled sys-
tems to be quickly realised.
The main limitations of the IEEE are:-
1). A maximum of 15 devices on the bus.
2). The maximum bus length should not be greater than 20m or number of devices x2,
which ever is the shorter.
Data Transfer and Device Addressing
Before a controller can send data it has to identify the recipient. Each device on the
IEEE is given an address to which it will respond when called by the controller in this
way data can be transferred between selected devices in an orderly manner. The rate at
which it is transferred is controlled by hand shake signals, the speed being governed by
the slowest device active on the bus. Set baud rates are unnecessary with the system.
Further information on the IEEE-488 can be found in the condensed description of the
Hewlett Packard Interface Bus.
IEEE Cables/Connectors
The IEEE-488 cable contains 24 wires terminated at both ends with identical plug/
sockets which allow for daisy - chaining of additional cables to extend the bus. See Ta-
ble 5.1 for details of connections.
Cables used on IEEE systems are available in various lengths to suit different layouts.
Manufacturer/Supplier Part No. Length
Belden 9642 1m
Belden 9643 2m
Belden 9644 4m
Belden 9645 8m
Time Electronics 9596 1m
Time Electronics 9597 2m
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