Keithley 2000, User Manual, Page: 101 / 280

IFC (interface clear)
The IFC command is sent by the controller to place the Model 2000 multimeter in the local,
talker, listener idle states. The unit responds to the IFC command by canceling front panel TALK
or LSTN lights, if the instrument was previously placed in one of those states.
Note that this command does not affect the status of the instrument; settings, data, and event
registers are not changed.
To send the IFC command, the controller need only set the IFC line true for a minimum of
100µs.
Program fragment
PRINT #1, "output 16; *idn?" 'Send query command
PRINT #1, "enter 16" 'Read data; turn on TALK annunci-
ator
SLEEP 3 'Wait 3 seconds
PRINT #1, "abort" 'Talker idle state; turn off TALK
annunciator
LLO (local lockout)
Use the LLO command to prevent local operation of the instrument. After the unit receives
LLO, all its front panel controls except the POWER are inoperative. In this state, pressing the
LOCAL will not restore control to the front panel. The GTL command restores control to the
front panel.
Program fragment
PRINT #1, "remote 16" 'Place 2000 in remote
PRINT #1, "local lockout" 'Lock out front panel (including
LOCAL key)
SLEEP 6 'Wait 6 seconds
PRINT #1, "local 16" 'Restore front panel operation
GTL (go to local)
Use the GTL command to put a remote-mode instrument into local mode. The GTL com-
mand also restores front panel key operation.
Program fragment
PRINT #1, "remote 16" 'Place 2000 in remote
SLEEP 3 'Wait 3 seconds
PRINT #1, "local 16" 'Place 2000 in local mode
Remote Operation 4-15