Keithley 2600a series, Reference Manual, Page: 285 / 696

2600AS-901-01 Rev. B / September 2008 Return to Section Topics 15-7
Series 2600A System SourceMeter® Instruments Reference Manual Section 15: Communications Interfaces
SPE, SPD (serial polling)
Use the serial polling sequence to obtain the Series 2600A serial poll byte. The serial poll byte
contains important information about internal functions. (See
Appendix C .) Generally, the serial
polling sequence is used by the controller to determine which of several instruments has
requested service with the SRQ line. The serial polling sequence may be performed at any time to
obtain the status byte from the Series 2600A.
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 Appendix A for a list of status and error messages associated with IEEE-488 programming.
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) indicators show the
GPIB bus status. Each of these indicators is described below.
REM
This indicator shows when the instrument is in the remote state. When the instrument is in remote,
all front panel keys, except for the
LOCAL and OUTPUT OFF keys, 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 talk command. TALK is off when the unit is in the talker idle
state. Place the unit in the talker idle state by sending a UNT (Untalk) command, addressing it to
listen, or sending the IFC (Interface Clear) command.
LSTN
This indicator is on when the Series 2600A is in the listener active state, which is activated by
addressing the instrument to listen with the correct listen 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 been cleared.