Table of Contents
Advertisement
Protocols
The message exchange protocols of IEEE 488.2 define the overall scheme used
by the computer and the oscilloscope to communicate. This includes defining
when it is appropriate for devices to talk or listen, and what happens when the
protocol is not followed.
Functional Elements
Before proceeding with the description of the protocol, you should understand
a few system components, as described here.
Input Buffer
memory area where commands and queries are
stored prior to being parsed and executed. It
allows a computer to send a string of commands,
which could take some time to execute, to the
oscilloscope, then proceed to talk to another
oscilloscope while the first oscilloscope is
parsing and executing commands.
Output Queue
memory area where all output data or response
messages are stored until read by the computer.
Parser
that interprets the commands sent to the
oscilloscope and decides what actions should be
taken. "Parsing" refers to the action taken by
the parser to achieve this goal. Parsing and
execution of commands begins when either the
oscilloscope recognizes a program message
terminator, or the input buffer becomes full. If
you want to send a long sequence of commands
to be executed, then talk to another oscilloscope
while they are executing, you should send all of
the commands before sending the program
message terminator.
Message Communication and System Functions
The input buffer of the oscilloscope is the
The output queue of the oscilloscope is the
The oscilloscope's parser is the component
Protocols
3-3
Advertisement
Table of Contents
