1257 User Manual
SCPI Command Basics 5-16
EADS North America Defense
Test and Services, Inc.
©
2001
*SRE? Query
This query reads the value presently programmed for
the Service
Request Enable Register
. This reads the value as programmed by
the *SRE command. The reply to this command is a numeric value
in the range 0 to 255.
*STB? Query
This query reads the value of the
Status Byte Register
. Each bit of
this register indicates a true/false status condition. When the bit is
set, the corresponding condition is TRUE; when the bit is cleared,
the condition is FALSE. The bit assignments are defined by the
IEEE-488.2 specification. The bit assignments are described in the
Status Byte Register section of this chapter.
The value returned by the *STB? Query may also be read using
the GPIB serial poll command.
Note that bit 6 (MSS) of the
Status Byte Register
remains set until
all enabled conditions are cleared. This is in contrast to the GPIB
serial poll operation, where the SRQ bit is set until it is read once,
and cleared after.
*OPC Command
The *OPC command will cause the Operation Complete bit of the
Standard Event Status Register to be set when the command is
executed. This is bit 0 of the register.
This command could be used to cause an interrupt (if bit 0 of the
Standard Event Status Enable Register
is set, and bit 5 of the
Service Request Enable Register
is set). This provides a means of
synchronizing the application program with the 1257 and ensuring
that all commands have been parsed and executed before
continuing execution of the application program.
The *OPC command has no parameters. The only valid syntax for
this command is:
*OPC
*OPC? Query
The *OPC? query causes the 1257 to reply with the value of “1"
when the query is executed. This query may be used to ensure
that all previous commands have been executed so the application
program may be sure that relays have been programmed to their
desired states before continuing execution of the application
program.
