Keithley 2520, User Manual, Page: 146 / 329

Model 2520 User’s Manual Remote Operations 10-7
REN (remote enable)
The remote enable command is sent to the Model 2520 by the controller to set up the
instrument for remote operation. Generally, the instrument should be placed in the remote
mode before you attempt to program it over the bus. Setting REN true does not place the
instrument in the remote state. You must address the instrument to listen after setting REN
true before it goes into remote.
The Model 2520 must be in remote in order to use the following commands to trigger and
acquire readings:
• :INITiate and then :FETCh?
• :READ?
• :MEASure?
IFC (interface clear)
The IFC command is sent by the controller to place the Model 2520 in the local, talker, lis-
tener idle states. The unit responds to the IFC command by cancelling front panel TALK
or LSTN lights if the instrument was previously placed in one of these 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.
LLO (local lockout)
Use the LLO command to prevent local operation of the instrument. After the unit receives
LLO, all of its front panel controls except OUTPUT OFF are inoperative. In this state,
pressing LOCAL will not restore control to the front panel. The GTL command restores
control to the front panel. Cycling power will also cancel local lockout.
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.
DCL (device clear)
Use the 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.