User manual

Part 5: IEEE 488.2 Programming Reference
IEEE 488.1 Standard Messages
The IEEE 488.1 standard (of which IEEE 488.2 can be considered an extension) 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 through the interface management lines of
the GPIB, usually with ATN true. All these messages except GET are executed immediately upon receipt.
The Command Reference in this manual does not contain a command for clearing the input or output
buffers or for setting the oscilloscope to the remote state because such commands are already specified
as IEEE 488.1 standard messages. Refer to the GPIB interface manual of the host controller as well
regarding its support programs, which should contain special calls for the execution of these messages.
Note: In addition to the IEEE 488.1 interface message standards, the IEEE 488.2 standard specifies
certain standardized program messages (or command headers). They are identified in the
Command Reference section with a leading asterisk * .
Remote Enable, RWLS
Teledyne LeCroy oscilloscopes do not lock out any local controls when placed in the remote state, or in
RWLS. They always accept remote and local control inputs (unless the remote control capability is turned
off).
Device Clear, DCL
In response to a universal Device CLear (DCL) or a Selected Device Clear message (SDC), the oscilloscope
clears the input or output buffers, cancels the interpretation of the current command (if any) and clears
pending commands. However, status registers and status-enable registers are not cleared. Although DCL
will have an immediate effect, it can take several seconds to execute if the oscilloscope is busy.
Group Execute Trigger
The Group Execute Trigger message (GET) causes the oscilloscope to arm the trigger system, and is
functionally identical to the *TRG command.
Interface Clear, IFC
The Interface Clear message (IFC) initializes the GPIB but has no effect on the operation of the
oscilloscope.
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