B&K Precision 4078 - Manual - Manual (Page 91)

SPE-Serial Poll Enable (24 with ATN)
The SPE message generates output serial poll status bytes when talk-addressed.
SPD-Serial Poll Disable (25 with ATN)
The SPD message switches back to generating output data from the Output Buffer.
MLA-My Listen Address (GPIB Address + 32)
MTA-My Talk Address (GPIB Address + 64)
The instrument GPIB primary address establishes the listen and talk addresses. To see the current GPIB primary
address, press SPECIAL and then F1:SYS on the front panel. When the waveform generator is talk-addressed or
listen-addressed, the front-panel ADRS indicator lights.
LLO-Local Lockout (17 with ATN)
When the waveform generator is listening addressed, the LLO message changes the waveform generator to the
front-panel lockout state.
REN-Remote Enable (GPIB pin 17)
REN is normally held true by the controller and allows the controller to then put the waveform generator into one of
the remote states. Pulsing REN false or holding it false forces the device into local state (LOCS).
NOTE
If you disconnect and reconnect the GPIB cable when the controller is holding REN true, the REN goes false and the
device got to local state (LOCS).
GTL-Go To Local (1 with ATN)
Listen-addressed instruments respond to GTL by changing to a local state. Remote-to-local transitions caused by
GTL do not affect the execution of the message being processed when GTL was received.
Remote-Local Operation
Most front-panel controls cause a transition from REMS to LOCS by asserting a message called return-to-local (rtl).
This transition can occur during message execution. However, in contrast to TGL and REN transitions, a transition
initiated by rtl affects message execution. In this case, the waveform generator generates an error if there are any
unexecuted setting or operational commands.
Front-panel controls that change only the display, do not affect the remote-local states. Only front-panel controls
that change settings assert rtl. The rtl message remains asserted when you enter multiple keystroke settings from the
front panel, and is unasserted after you execute the settings changes. Since rtl prevents transition to REMS, the
waveform generator unasserts rtl if you do not complete a multiple key sequence in a reasonable length of time
(about 5 to 10 seconds).
A record of the front-panel settings is in the Current Settings Buffer; however, new settings entered from the front
panel or the controller update these recorded settings. In addition, the front panel updates to reflect setting changes
from controller commands. Settings are unaffected by transitions among the 4 remote-local states. The REMOTE
indicator lights when the waveform generator is in REMS or RWLS.