Manual

P ART O NE : ABOUT REMOTE CONTROL
16 ISSUED: February 2005 WM-RCM-E Rev D
• EOI (End Or Identify): This line has two purposes: The talker uses it to mark the end of a message
string. The controller uses it to tell devices to identify their response in a parallel poll (discussed later
in this section).
I/O BUFFERS
The oscilloscope has 256-byte input and output buffers. An incoming program message is not decoded before
a message terminator has been received. However, if the input buffer becomes full (because the program
message is longer than the buffer), the oscilloscope starts analyzing the message. In this case, data transmission
is temporarily halted, and the controller may generate a timeout if the limit was set too low.
USE IEEE 488.1 STANDARD MESSAGES
The IEEE 488.1 standard specifies not only the mechanical and electrical aspects of the GPIB, but also the
low-level transfer protocol. For instance, it defines how a controller addresses devices, turns them into talkers
or listeners, resets them, or puts them in the remote state. Such interface messages are executed with the
interface management lines of the GPIB, usually with ATN true.
All these messages except GET are executed immediately upon receipt.
The command list in Part Two of this manual does not contain a command for clearing the input or output
buffers or for setting the oscilloscope to the remote state.
NOTE: In addition to the IEEE 488.1 interface
message standards, the IEEE 488.2 standard
specifies certain standardized program messages,
i.e., command headers. They are identified with a
leading asterisk * and are listed in the System
Commands section.
This is because such commands are already specified as IEEE 488.1 standard messages. Refer to the GPIB
interface manual of the host controller as well as to its support programs, which should contain special calls for
the execution of these messages.
The following description covers those IEEE 488.1 standard messages that go beyond mere reconfiguration of
the bus and that have an effect on X-Stream DSO operation.