HP E4418B, Programming Manual

Page: 105 / 481

prog.book : chapter1.fm 81 Mon Feb 15 09:24:37 1999
Power Meter Remote Operation
Status Reporting
HP E4418B/E4419B Programming Guide 1-81
Particular bits in the status byte register are cleared when:
• The standard event, Questionable status, operation status and
device status are queried.
• The error/event queue becomes empty.
• The output queue becomes empty.
The status byte enable register (
SRE
, service request enable) is cleared
when you:
• cycle the instrument power.
• execute a
*SRE 0
command.
Using *STB? to Read the Status Byte
The
*STB?
(status byte query) command is similar to a serial poll except it
is processed like any other power meter command. The
*STB?
command
returns the same result as an IEEE-488 serial poll except that the request
service bit (bit 6)
is not cleared if a serial poll has occurred. The
*STB?
command is not handled automatically by the IEEE-488 bus interface
hardware and the command will be executed only after previous
commands have completed. Using the
*STB?
command does not clear the
status byte summary register.
The Standard Event Register
The standard event register reports the following types of instrument
events: power-on detected, command and syntax errors, command
execution errors, self-test or calibration errors, query errors, or when an
overlapped command completes following a
*OPC
command. Any or all of
these conditions can be reported in the standard event summary bit
through the enable register. You must write a decimal value using the
*ESE
(event status enable) command to set the enable register mask.