Keithley 2657A, Reference Manual, Page: 110 / 805

Section 2: General operation Model 2657A High Power System SourceMeter® Instrument Reference Manual
2-86 2657A-901-01 Rev. B/December 2012
IFC
The interface clear (IFC) command is sent by the controller to place the Model 2657A in the talker idle
state and the listener idle state. The instrument responds to the IFC command by canceling front-
panel TALK or LSTN lights, if the instrument was previously placed in one of these states.
Transfer of command messages to the instrument and transfer of response messages from the
instrument are not interrupted by IFC. If transfer of a response message from the instrument was
suspended by IFC, transfer of the message will resume when the instrument is addressed to talk. If
transfer of a command message to the instrument was suspended by IFC, the rest of the message
can be sent when the instrument is addressed to listen.
LLO
When the instrument is in remote operation, all front-panel controls are disabled, except the LOCAL
and OUTPUT OFF keys (and the POWER switch). The local lockout (LLO) command disables the
LOCAL key, but does not affect the OUTPUT OFF control, which cannot be disabled.
GTL
Use the go to local (GTL) command to put a remote-mode instrument into local mode. Leaving the
remote state also restores operation of all front-panel controls.
DCL
Use the device clear (DCL) command to clear the GPIB interface and return it to a known state. Note
that the DCL command is not an addressed command, so all instruments equipped to implement DCL
will do so simultaneously.
When the Model 2657A receives a DCL command, it:
•
Clears the input buffer, output queue, and command queue
•
Cancels deferred commands
•
Clears any command that prevents the processing of any other device command
A DCL does not affect instrument settings and stored data.
SDC
The selective device clear (SDC) command is an addressed command that performs essentially the
same function as the device clear (DCL) command. However, because each device must be
individually addressed, the SDC command provides a method to clear only selected instruments,
instead of clearing all instruments simultaneously with the DCL command.
When the Model 2657A receives an SDC command, it:
•
Clears the input buffer, output queue, and command queue
•
Cancels deferred commands
•
Clears any command that prevents the processing of any other device command
An SDC does not affect instrument settings and stored data.