Keithley 2182, User Manual, Page: 184 / 339

11-10 Remote Operation
Transmit — A transmit routine is used to send General Bus Commands. It contains a series
of GPIB commands to be carried out. In addition to the commands listed in Table 11-1 , there are
other commands used in the transmit command string. Some of the more frequently used ones
are explained as follows (refer to the User’s Manual for the interface card for details on all the
commands):
UNL Unlisten — Disables any listeners that may exist.
UNT Untalk — Disables the current talker, if any
LISTEN 7 Listen — Assigns the device at address 7 (2182) to be a listener
MTA My Talk Address — Assigns the computer as the talker
The General Bus Commands are explained as follows:
REN (remote enable)
The remote enable command is sent to the Model 2182 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. Simply setting REN true does not actually place
the instrument in the remote state. You must address the instrument to listen after setting REN
true before it goes into remote.
Note that the instrument does not have to be in remote to be a talker.
Program Fragment
CALL TRANSMIT (“MTA LISTEN 7 REN”, status%) ‘ Place Model 2182 in remote;
' turn on REM annunciator.
Note that all front panel controls except for LOCAL and POWER are inoperative while the
instrument is in remote. You can restore normal front panel operation by pressing the LOCAL
key.
IFC (interface clear)
The IFC command is sent by the controller to place all instruments on the bus in the local,
talker, listener idle states. The initialize routine (CALL INITIALIZE) uses this command
internally.
The Model 2182 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 must set the IFC line true for a minimum of 100.
Program Fragment
CALL INITIALIZE (21, 0) ‘ Initialize GPIB system (sends IFC) and set
‘ interface card address to 21.
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
LOCAL will not restore control to the front panel. The GTL command restores control to the
front panel.