HP E4418B Programming Manual page 105

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.
HP E4418B/E4419B Programming Guide
Power Meter Remote Operation
Status Reporting
1-81