Keithley 194 Instruction Manual page 100

IEEE-488 PROGRAMMING
Model 8573 Programming Example-Use the statements
below to demonstrate an IDDCO error:
Note that the IDDCO error message is displayed when the
second statement above is executed.
4.7.2 IEEE-488
Status Indicators
The REMOTE, TALK, and LISTEN indicators show the
present IEEE-488 status of the instrument. Each of these
indicators is briefly described below.
STATUS INDICATORS
TALK-This indicator will be on when the instrument is
in the talker active state. The unit is placed in this state
by addressing it to talk with the correct MTA (My Talk Ad-
dress) command. TALK will be off when the unit is in the
talker idle state. The instrument is placed in the talker idle
state by sending it an UNT (Untalk) command, address-
ing it to listen, or with the IFC (Interface Clear) command.
LISTEN-This indicator will be on when the Model 194 is
in the listener active state, which is activated by address-
ing the instrument to listen with the correct MLA (My
Listen Address) command. LISTEN will be off when the
unit is in the listener idle state. The unit can be placed in
the listener idle state by sending UNL (u&ten), address-
ing it to talk, or by sending IFC (Interface Clear) over the
bus.
REMmE-As the name implies, this indicator shows when
the instrument is in the remote mode. Note that REMOTE
does not necessarily indicate the state of the REN line, as
the instrument must be addressed to listen with REN true
before the REMOTE indicator will turn on. When the in-
strument is in remote, all front panel keys except for the
LOCAL key will be locked out. When REMOTE is turned
off, the instrument is in the local mode.
4.7.3 LOCAL Key
The local key cancels the remote mode and restores local
operation of the instrument.
LOCAL KEY
Since all front panel keys except LQCAL are locked out
when the instrument is in remote, this key provides a con-
venient method of restoring front panel operation. Press-
ing LOCAL will also turn off the REMOTE indicator and
return the display to the normal mode if user messages
were previously displayed with the D command.
Note that the LOCAL key will also be inoperative if the
LLO (Local Lockout) command is in effect.
4.8 GENERAL BUS COMMAND
PROGRAMMING
General bus commands are those commands such as DCL
that have the same general purpose regardless of the in-
strument. Commands supported by the Model 194 are
summarized in Table 4-6, which also lists HP-85 and Model
8573 statements necessary to send each command. Note
that commands requiring a primary address assume that
the Model 194 primary address is set to 9 (its factory default
address). If you are using Model 8573 programming ex-
amples, be sure to use the declaration file, as described
in paragraph 4.6.3.
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