User manual

Front panel GPIB operation
This section describes aspects of the front panel that are part of GPIB operation, including
messages, status indicators, and the LOCAL key.
Error and status messages
See Section 2 for a list of error and status messages associated with IEEE-488 program-
ming. The instrument can be programmed to generate an SRQ, and command queries can
be performed to check for specific error conditions.
GPIB status indicators
The REM (remote), TALK (talk), LSTN (listen), and SRQ (service request) annunciators
show the GPIB bus status. Each of these indicators is described below.
• REM — This indicator shows when the instrument is in the remote state. REM does
not necessarily indicate the state of the REM line, as the instrument must be ad-
dressed to listen with REM true before the REM indicator turns on. When the instru-
ment is in remote, all front panel keys, except for the LOCAL key, are locked out.
When REM is turned off, the instrument is in the local state, and front panel operation
is restored.
• TALK — This indicator is on when the instrument is in the talker active state. Place
the unit in the talk state by addressing it to talk with the correct MTA (My Talk Ad-
dress) command. TALK is off when the unit is in the talker idle state. Place the unit
in the talker idle state by sending an UNT (Untalk) command, addressing it to listen,
or sending the IFC (Interface Clear) command.
• LSTN — This indicator is on when the Model 2000 Multimeter is in the listener active
state, which is activated by addressing the instrument to listen with the correct MLA
(My Listen Address) command. LSTN is off when the unit is in the listener idle state.
Place the unit in the listener idle state by sending UNL (Unlisten), addressing it to
talk, or sending IFC (Interface Clear) command over the bus.
• SRQ — You can program the instrument to generate a service request (SRQ) when
one or more errors or conditions occur. When this indicator is on, a service request
has been generated. This indicator stays on until the serial poll byte is read or all the
conditions that caused SRQ have ceased to exist. See “status structure” for more in
-
formation.
LOCAL key
The LOCAL key cancels the remote state and restores local operation of the instrument.
Pressing the LOCAL key also turns off the REM indicator and returns the display to nor-
mal if a user-defined message was displayed.
If the LLO (Local Lockout) command is in effect, the LOCAL key is also inoperative.
2000-900 (J - Aug 2010) BOOK.fm Page 18 Wednesday, October 12, 2011 12:29 PM