F.W. Bell 7030, Инструкция по эксплуатации

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F.W. BELL Model 7030 Gauss/Tesla Meter Instruction Manual
Section 7 – Remote Operation 7-1
Section 7 Remote Operation
INTRODUCTION In 1975 the IEEE-488 standard defined the electrical and mechanical
aspect for cables and connectors, as well as the handshaking,
addressing and general protocol for transmitting individual bytes of
information between instruments and computers. The standard was later
updated and is now called IEEE 488.1-1987.
Although the standard solved the problem of how to communicate it did
not specify the meaning of the bytes. Instrument manufacturers freely
invented new commands as they developed new instruments. For
instance a command to program a range on one manufacturer’s
voltmeter may not have worked with another’s. Eventually some
manufacturers began offering models that recognized other
manufacturer’s command sets so that customers could easily switch over
without making extensive changes to their programs.
The IEEE 488.2-1987 standard was a step toward creating a universal
way to communicate with any instrument, regardless of the manufacturer
or the type of instrument used. It defined a set of “common” commands
that all instruments should respond to in a predictable manner. Yet it did
not specify which features or commands should be implemented for a
particular instrument.
Later the SCPI-1991 standard (Software Commands for Programmable
Instruments) defined specific commands and responses that covered a
broad range of applications. For a given measurement function such as
frequency or voltage, SCPI defines a specific command set that is
available for that function. The command sets are easy to learn and
read. Manufacturers can still create new commands unique to their own
instruments while conforming to the structure and spirit set forth by SCPI.
The gauss/tesla meter supports most of the IEEE-488-1987.2 “common”
commands as well as a subset of the SCPI-1999.0 commands. Due to
the uniqueness of a gauss/tesla meter, there are some commands that
are not specified by SCPI but that conform to the rules indicated by the
standard.
Prior to using the IEEE-488 bus the instrument must be assigned a
unique address on the bus. Prior to using the RS-232 serial port
parameters such as baud rate and character length must be set to match
that of the computer. This is done with the COMMUNICATIONS menu,
discussed later in this section.