Valhalla 2300, Operation Manual

Page: 45 / 115

SECTION VII REMOTE OPERATION
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7-1. General
This section describes the operation of the
2300 Series of Power Analyzers via the
optional IEEE-488 interface bus. It is
assumed throughout this section that the user
has read Sections 4 through 6 and is familiar
with the manual operation of the 2300.
7-2. Definitions
The following are definitions of the terms
used in describing the IEEE-488 interface and
its operation in the 2300.
Bus: A data link which is usually a set of
several parallel wires within a multi-wire
cable.
Bi-directional Bus: A "highway" used for
two-way communication between two
devices, with input and output data being
carried on the same wires.
Bit parallel: A data transmission method in
which all of the bits composing an item of
data are present simultaneously on a group of
wires in a bus.
Byte: A group of 8 data bits which are treated
as a single item of data.
Byte serial: A data transmission method in
which information, in bit parallel bytes, is
transferred sequentially between devices.
Device: A unit or controller connected to the
bus.
Device dependent message: A message
containing information or commands having
meaning only to the recipient device (usually
refers to commands which are not
defined in IEEE Standard 488 of
1978).
Handshake: An exchange of signals between
two devices which is usually used to control
the transfer of data between them.
Interface message: A message intended for
interface or bus management.
Local operation: Operation of a device by its
front panel controls or other form of manual
operation.
Remote operation: Operation of a device
under the control of another via the bus.
7-3. Basic Description of the Bus
This chapter gives a basic description of the
general principles of the IEEE-488 (1978) bus
(also known as GPIB, HP-IB, IEC DTC-66,
ANSI MCI-1 etc.) The user is recommended
to read the full IEEE-488 standard for more
details if required.
7-3-1. The Purpose of the IEEE-488
Standard
The purpose of the standard is to allow for
interconnection of programmable instruments
with a minimum of engineering. The intent is
to remove the need for adapters and numerous
types of patching cables often encountered
with other forms of interfaces. The IEEE-488
standard defines a system configuration for
programmable instruments: calculators,
voltmeters and other types of peripheral
devices produced by various manufacturers,
providing a set of rules for establishing a
defined communications link with a high
degree of compatibility yet maintaining