Sdc (Selective Device Clear) - Keithley 2520 User Manual

10-8 Remote Operations
When the Model 2520 receives a DCL command, it clears the Input Buffer and Output
Queue, cancels deferred commands, and clears any command that prevents the processing
of any other device command. A DCL does not affect instrument settings and stored data.

SDC (selective device clear)

The SDC command is an addressed command that performs essentially the same function
as the DCL command. However, since each device must be individually addressed, the
SDC command provides a method to clear only selected instruments instead of clearing all
instruments simultaneously, as is the case with DCL.
GET (group execute trigger)
GET is a GPIB trigger that is used as a trigger event to control operation. The Model 2520
reacts to this trigger if it is the programmed trigger control source. The following com-
mand selects the GPIB trigger control source:
:TRIG:SOURce BUS
NOTE
SPE, SPD (serial polling)
Use the serial polling sequence to obtain the Model 2520 serial poll byte. The serial poll
byte contains important information about internal functions. See
the serial polling sequence is used by the controller to determine which of several instru-
ments has requested service with the SRQ line. However, the serial polling sequence may
be performed at any time to obtain the status byte from the Model 2520.
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 B
ming. The instrument can be programmed to generate an SRQ, and command queries can
be performed to check for specific error conditions.
With :TRIG:SOURce BUS selected and an :INITiate command sent, do not send
any commands (except GET, DCL, SDC, IFC, *TRG, and :ABORt) while per-
forming source and measure operations (ARM annunciator on). If you do,
erratic operation will occur.
for a list of status and error messages associated with IEEE-488 program-
Model 2520 User's Manual
Section 11. Generally,